How Strathlon works out your numbers

Daily calories

How Strathlon sets your calories each day: resting burn, everyday activity, sport, your goal and the minimums underneath.

Where you see it

1. Tap the ⓘ next to Training day or Rest day on the Your targets card in Settings, next to your daily target on the Nutrition tab, or on the Tracker's Target tile, to see your own figures.

How your daily calories are worked out

Strathlon works out your calories from your profile and your latest weigh-in, in the steps below. They are estimates: real bodies vary, so watch your weight trend over a few weeks. A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Your resting burn (BMR). BMR (basal metabolic rate) is the calories your body burns at rest. Strathlon uses the Mifflin-St Jeor equation^[3], from your weight, height and age:

   • Men: BMR = 10 × weight in kg, plus 6.25 × height in cm, minus 5 × age in years, plus 5
   • Women: BMR = 10 × weight in kg, plus 6.25 × height in cm, minus 5 × age in years, minus 161

   New profiles choose Male or Female. An older profile with sex recorded as Other uses the men's equation, and the men's minimum in step 6, until you choose Male or Female in Body & stats. Using the men's figures for Other is Strathlon's own setting: the published equation gives figures for men and women only.

   If you have told Strathlon about a hormone therapy that changes body composition, the estimate is adjusted using a body-fat estimate worked out from your BMI, age and sex^[4]. Moving it half of the way is Strathlon's own setting, because hormone therapy changes body composition gradually and only partly.

   Where the Tracker's Calories burned figure has to estimate the part you burn at rest, it uses this same equation.

2. If you turn on Use body composition. When Use body composition is on and Strathlon knows your lean mass (everything in your body except fat), it uses the Katch-McArdle equation^[5][6] instead:

   • BMR = 370 + 21.6 × lean mass in kg
   • Lean mass comes from Apple Health when a smart scale or another app has recorded it. Otherwise it is worked out from the body fat you entered: lean mass = weight × (100 minus body fat percentage) ÷ 100

   With no lean mass and no body fat on record, the step 1 estimate is used.

3. Your everyday activity. Your BMR is multiplied by an activity factor for the kind of day:

   • Rest day: BMR × 1.40
   • Training day: BMR × 1.55 at Beginner or Intermediate level, or BMR × 1.65 at Advanced level

   All three sit inside the 1.40 to 1.69 range that FAO/WHO/UNU give for sedentary or lightly active lifestyles^[7]. Using a separate factor for rest days and training days is Strathlon's own setting. The result is your maintenance: the calories that would keep your weight steady.

4. Sport and activity sessions. On a day with a match, a practice or an activity you add, the session's energy cost goes on top. Each kind of session has a MET value (the energy the session takes, as a multiple of what you burn at rest) from the 2024 Adult Compendium of Physical Activities^[8]. For stop and start sports it is averaged over the whole session, breaks included. Only the part above rest is added, because step 3 already counts your resting burn:

   • Session bonus = about (MET minus 1) × weight in kg × hours
   • A run or walk with a logged distance uses the distance instead: 0.9 × weight in kg × km for a run, 0.5 × weight in kg × km for a walk. These per km figures are Strathlon's own settings, chosen to agree with its per hour figures for running and walking
   • A custom session uses the calories you type

   A day with only sport or activity starts from your rest day calories. A day with a gym session as well starts from your training day calories. If you set a sport's intensity higher or lower, its bonus moves with it.

   With more than one planned session on a day, the biggest counts in full, the second at 55% and each further one at 30%, and the planned total is capped at three quarters of your BMR. These weights and the cap are Strathlon's own settings, so that a busy day cannot overstate how much extra you need to eat: no published source sets them, and the Compendium^[8] is the nearest source. An activity you log yourself is added in full, outside that cap.

5. Your goal. Then your maintenance is adjusted for your goal:

   • Fat loss with a goal weight: weekly loss = (weight minus goal weight) ÷ weeks left in your plan, never more than 0.65% of your body weight a week. Daily cut = weekly loss × 7,700 ÷ 7, the same on every day of the week
   • Fat loss with no goal weight set: 200 kcal off rest days and 250 kcal off training days (Strathlon's own setting)
   • Muscle gain: plus 200 kcal on rest days and plus 300 kcal on training days
   • Performance: plus 100 kcal on rest days and plus 200 kcal on training days (Strathlon's own setting)
   • General fitness: no change on rest days and plus 100 kcal on training days (Strathlon's own setting)
   • Body recomposition (fat loss and muscle gain together): the same as general fitness, with higher protein (see Protein) (Strathlon's own setting)

   The fat loss pace. Research on people who train advises losing about 0.5 to 1% of your body weight a week to keep as much muscle as possible^[9]. In a trial with athletes, those losing about 0.7% a week gained lean mass and those losing about 1.4% a week did not^[10]. Strathlon's cap of 0.65% a week sits at the careful end of that range. A bigger deficit than your plan sets risks losing muscle^[9][10] and your body burning less^[9], so Strathlon never uses one to go faster.

   7,700 kcal is the usual rule of thumb for the energy in 1 kg of body fat^[11]. Early on, some of the change on the scale is water, so the trend matters more than any one week.

   The end of the cut. The cut stops when you are within 1 kg of your goal weight, and from there your calories are set to maintain it. Stopping at 1 kg is Strathlon's own setting. A goal weight below a BMI of 18.5 for your height is planned only down to that weight^[12].

   The muscle gain surplus. The small surplus (eating a little more than you burn) aims for a gain of about 0.25 to 0.5% of your body weight a week, the rate a review of muscle building advises for novice and intermediate lifters^[13]. A much larger surplus mostly adds fat, not extra muscle: in a trial with athletes, the group eating the bigger surplus gained more fat and no more lean mass^[14].

   The top-ups for performance and general fitness, and the recomposition setting, are small buffers so you have fuel to train. No published source sets a figure for them.

   In the maintenance phase after fat loss, your calories step back up to maintenance over 4 weeks, so your weight settles gradually. The 4 weeks are Strathlon's own setting.

   Safety rules. Under 18s stay at maintenance or above, with no cut. If your answers to the eating questions in Health & safety flag a concern, your plan also stays at maintenance. If your readiness answers suggested checking with a doctor and you have not yet confirmed clearance, a cut is limited to 100 kcal on rest days and 125 kcal on training days. All three are Strathlon's own safety settings: Health and safety checks below has the details. Pregnancy and breastfeeding: no target at all (see the box above the steps).

6. The minimums. Your daily calories never go below either of these, whichever is higher:

   • Your BMR
   • 1,200 kcal a day for women, or 1,500 kcal a day for men (and for an older profile with sex recorded as Other)^[15][16]

   A sport or activity bonus from step 4 is added on top of the day after this check.

7. If you turn on the period ease. When Ease my targets around my period is on, your daily target goes up by 100 kcal in the days before and during your period, because appetite commonly rises then:

   • Eased target = the day's target + 100 kcal
   • Eased carbs = the day's carbs + 25 g (100 kcal ÷ 4 kcal per gram)

   A review that pooled 15 sets of data found that people eat about 168 kcal a day more in the second half of the cycle than in the first^[17], and resting burn is slightly higher in that phase^[18]. The 100 kcal ease sits below that average. Giving the extra as carbs, which fuel training, is Strathlon's own setting: the sources give calories, not the split. The ease only ever adds food, so it never deepens a deficit. The Cycle and energy chart on Progress shows the phase, so a normal bump on the scale around your period is not mistaken for fat gain.

8. From calories to protein, carbs and fat. The day's calories are then shared out: protein first (see Protein), then fat (see Fat), and carbs take what is left (see Carbohydrates).

References for this section

1. National Institute for Health and Care Excellence. Maternal and child nutrition: nutrition and weight management in pregnancy, and nutrition after pregnancy (NG247). Section 1.2, recommendations marked [2025]. The box above the steps: intentional weight loss during pregnancy is not recommended because of potential adverse effects on the baby, so Strathlon sets no calorie target then. NICE NG247
2. NHS. Breastfeeding and diet. The box above the steps: you do not need a special diet while breastfeeding, so Strathlon sets no calorie target then. nhs.uk
3. Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241-247. The source of the step 1 equations: the abstract prints the men's (plus 5) and women's (minus 161) versions used here. PubMed 2305711
4. Deurenberg P, Weststrate JA, Seidell JC. Body mass index as a measure of body fatness: age- and sex-specific prediction formulas. British Journal of Nutrition. 1991;65(2):105-114. The body-fat estimate from BMI, age and sex behind the hormone therapy adjustment in step 1. doi:10.1079/bjn19910073
5. Cunningham JJ. Body composition as a determinant of energy expenditure: a synthetic review and a proposed general prediction equation. American Journal of Clinical Nutrition. 1991;54(6):963-969. The origin of the step 2 equation, 370 + 21.6 × lean mass (the abstract writes lean mass as FFM, fat free mass). It is known as the Katch-McArdle equation after the McArdle, Katch and Katch textbook Exercise Physiology. PubMed 1957828
6. Molina-Luque R, Carrasco-Marín F, Márquez-Urrizola C, Ulloa N, Romero-Saldaña M, Molina-Recio G. Accuracy of the resting energy expenditure estimation equations for healthy women. Nutrients. 2021;13(2):345. Names the Katch-McArdle equation as 370 + (21.6 × FFM) and tests it against measured resting burn in 620 women. PMC7912292
7. FAO/WHO/UNU. Human energy requirements: report of a Joint FAO/WHO/UNU Expert Consultation. FAO Food and Nutrition Technical Report Series 1. Rome: FAO; 2004. Chapter 5, Table 5.3. The step 3 activity factors: Table 5.3 puts sedentary or lightly active lifestyles at 1.40 to 1.69. FAO, Human energy requirements, chapter 5
8. Herrmann SD, Willis EA, Ainsworth BE, Barreira TV, Hastert M, Kracht CL, Schuna JM Jr, Cai Z, Quan M, Tudor-Locke C, Whitt-Glover MC, Jacobs DR Jr. 2024 Adult Compendium of Physical Activities: a third update of the energy costs of human activities. Journal of Sport and Health Science. 2024;13(1):6-12. The MET values behind the step 4 sport and activity bonus, and the nearest source for its busy-day weights and daily cap. PMC10818145
9. Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition. 2014;11:20. The fat loss pace in step 5: losses of about 0.5 to 1% of body weight a week to keep as much muscle as possible, slower loss being better for keeping lean mass, and energy expenditure falling during dieting, by far more on a large, long deficit. PMC4033492
10. Garthe I, Raastad T, Refsnes PE, Koivisto A, Sundgot-Borgen J. Effect of two different weight-loss rates on body composition and strength and power-related performance in elite athletes. International Journal of Sport Nutrition and Exercise Metabolism. 2011;21(2):97-104. Also the fat loss pace in step 5: athletes losing about 0.7% of body weight a week gained lean mass, and those losing about 1.4% a week did not. doi:10.1123/ijsnem.21.2.97
11. Hall KD. What is the required energy deficit per unit weight loss? International Journal of Obesity. 2008;32(3):573-576. The step 5 rule of thumb: 3,500 kcal per pound, or 32.2 MJ per kg, which is about 7,700 kcal per kg. It also explains why the rule overestimates for leaner people. PMC2376744
12. National Institute for Health and Care Excellence. Overweight and obesity management (NG246). 2025. Recommendations 1.9.10 and 1.9.11. The lowest goal weight in step 5: a BMI of 18.5 is the bottom of the healthy range. NICE NG246, identifying and assessing
13. Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154. The muscle gain rate in step 5: a surplus of about 10 to 20%, aiming for about 0.25 to 0.5% of body weight a week for novice and intermediate lifters. PMC6680710
14. Garthe I, Raastad T, Refsnes PE, Sundgot-Borgen J. Effect of nutritional intervention on body composition and performance in elite athletes. European Journal of Sport Science. 2013;13(3):295-303. Step 5: athletes eating a planned surplus gained more fat than those eating freely, with no difference in lean mass gained. doi:10.1080/17461391.2011.643923
15. Jensen MD, Ryan DH, et al. 2013 AHA/ACC/TOS guideline for the management of overweight and obesity in adults. Circulation. 2014;129(25 Suppl 2):S102-S138. The minimum daily calories in step 6, 1,200 kcal for women and 1,500 kcal for men, follow this US obesity guideline. doi:10.1161/01.cir.0000437739.71477.ee
16. National Institute for Health and Care Excellence. Overweight and obesity management (NG246). 2025, updated 8 January 2026. Recommendations 1.16.8 and 1.16.9. Also the minimums in step 6: NICE keeps very low calorie diets for specialist care. NICE NG246, physical activity and diet
17. Tucker JAL, McCarthy SF, Bornath DPD, Khoja JS, Hazell TJ. The effect of the menstrual cycle on energy intake: a systematic review and meta-analysis. Nutrition Reviews. 2025;83(3):e866-e876. Step 7: across 15 datasets, people ate about 168 kcal a day more in the luteal phase than in the first half of the cycle. doi:10.1093/nutrit/nuae093
18. Benton MJ, Hutchins AM, Dawes JJ. Effect of menstrual cycle on resting metabolism: a systematic review and meta-analysis. PLoS One. 2020;15(7):e0236025. Step 7: resting metabolism is slightly higher in the second half of the cycle (the luteal phase). doi:10.1371/journal.pone.0236025

Related: Your targets · Ease my targets around my period · Body composition

Protein

Your daily protein, set per kg of body weight by goal, with a lower limit it never drops below.

Where you see it

1. Tap the ⓘ next to Daily protein on the Your targets card in Settings, or next to Protein on the Nutrition tab, to see your own figure.

How your protein target is worked out

Strathlon sets protein before fat and carbs, because it matters most for keeping and building muscle. A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Grams per kg, by goal. Protein is set per kg of body weight:

   • Fat loss, muscle gain, body recomposition and performance: 2.2 g per kg, the top of the 1.6 to 2.2 g range in the research^[1]
   • General fitness: 1.8 g per kg, inside that range

   Research on people who strength train finds the benefit levels off at about 1.6 g per kg a day^[2]. Eating less than you burn makes protein more important for keeping muscle, so fat loss uses the top of the range^[3].

   The protein chart on Progress shows how much protein you ate per kg of body weight, on average, so you can compare it with that range.

2. With Use body composition on. When Use body composition is on and Strathlon knows your lean mass (see Daily calories, step 2), protein is counted on lean mass instead:

   • 2.6 g per kg of lean mass, or 2.2 g per kg of lean mass for general fitness

   A review of lifters preparing for competition used 2.3 to 3.1 g per kg of lean mass^[3]. Strathlon's 2.6 sits inside that range, and 2.2 for general fitness a little below it.

3. Which weight it is counted on. If your weight is above a BMI of 25 for your height, the top of the healthy range^[4], protein is counted on your goal weight or on the weight at a BMI of 25, whichever is higher (and never on more than your current weight).

   This is Strathlon's own method: protein per kg of current weight would overshoot when part of that weight is fat.

4. On a tight day. If a day's calories cannot fit everything (see Carbohydrates), protein may come down for that day, but never below 1.6 g per kg of the same weight. In a review of strength training studies, protein above about 1.6 g per kg a day added no further muscle gain^[2].

5. Protein after training. The Plan tab's post-workout and post-match cards suggest 20 to 40 g of protein in the hours after exercise, to help your muscles repair and grow^[5]. Your total for the day matters most. The whey suggestion on the supplement cards uses the same 20 to 40 g.

References for this section

1. Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154. 1.6 to 2.2 g of protein per kg a day for people building muscle, the range behind step 1. PMC6680710
2. Morton RW, Murphy KT, McKellar SR, Schoenfeld BJ, Henselmans M, Helms E, Aragon AA, Devries MC, Banfield L, Krieger JW, Phillips SM. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. British Journal of Sports Medicine. 2018;52(6):376-384. Steps 1 and 4: in this review, protein above about 1.6 g per kg a day added no further muscle gain, which is why protein never drops below 1.6 g per kg. PMC5867436
3. Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition. 2014;11:20. Steps 1 and 2: higher protein while dieting to keep muscle, and the 2.3 to 3.1 g per kg of lean mass this review used for lifters preparing for competition. PMC4033492
4. National Institute for Health and Care Excellence. Overweight and obesity management (NG246). 2025. Recommendations 1.9.10 and 1.9.11. Step 3: a BMI of 25 is the top of the healthy range. NICE NG246, identifying and assessing
5. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. Step 5: 20 to 40 g of protein after training. doi:10.1186/s12970-017-0177-8

Related: Your targets · Body composition

Carbohydrates

Your daily carbs: what is left of the day's calories after protein and fat, never below a daily minimum.

Where you see it

1. Tap the ⓘ next to Training carbs or Rest carbs on the Your targets card in Settings, or next to Carbohydrates on the Nutrition tab.

How your carbs are worked out

Carbs are set last, from the calories protein and fat leave. A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. What is left after protein and fat. Protein and carbs carry 4 kcal per gram, fat 9 kcal per gram:

   • Carbs = (day's calories minus protein × 4 minus fat × 9) ÷ 4

   Setting carbs from what is left is Strathlon's own method: it is a calculation, not a figure from a guideline.

   When the period ease is on, its extra 100 kcal is added as 25 g of carbs (see Daily calories, step 7).

2. The daily minimums. Carbs never go below a minimum for the kind of day:

   • Training, practice and other sport or activity days: 130 g, the recommended daily intake of carbohydrate for everyone aged 2 and over^[1]
   • Match day: 150 g, a little higher for the extra demand of a match (Strathlon's own setting)
   • Rest day: 80 g (Strathlon's own setting)

   The rest day minimum sits below the recommended 130 g on purpose: when your calories are low, a higher carb minimum would push your protein down, and protein matters more for keeping muscle. On most rest days your carbs are well above 80 g.

3. When the calories run short. If the carbs would fall below the day's minimum, carbs stay at the minimum and fat comes down first, to no less than 40 g (see Fat). If that is still not enough, protein comes down, to no less than 1.6 g per kg (see Protein). Only then can carbs go below the minimum.

4. Carbs and your weight on the scale. Carbs fuel hard effort through glycogen, the carbs your muscles and liver store. Each gram of stored glycogen holds about 3 g of water^[2], so eating more carbs raises your scale weight for a while, and that gain is water, not fat^[3]. Lower-carb rest days hold less of this water.

5. Carbs around sessions and matches. Some Plan tab cards give carb timing from sports nutrition guidance^[4]:

   • Two sessions less than 8 hours apart (the Fuel between sessions card): eat carbs as soon as you can after the first, 1 to 1.2 g per kg of body weight each hour for up to 4 hours, with 20 to 40 g of protein to help your muscles repair^[5]
   • Match day (the Carbs at breakfast card): starchy carbs 1 to 4 hours before exercise that lasts more than an hour, with little fat or fibre close to the start, which can upset your stomach
   • The pre-match snack card: a light snack about 1 hour before, inside that window

   These cards are guidance in words. Your day's carb target is still the figure from step 1.

6. A caution about low carbs. Less than 130 g of carbs a day is usually called a low-carbohydrate intake^[6], and it is not suited to everyone. If you have diabetes, take insulin or other diabetes medicine, or take an SGLT2 inhibitor (medicines whose names end in gliflozin), talk to your diabetes team before eating fewer carbs: low intakes can cause low blood sugar with diabetes medicine^[7], and restricted eating raises the risk of ketoacidosis (a dangerous build-up of acids in the blood) with SGLT2 inhibitors^[8]. There is no agreed definition of a low-carbohydrate diet, and the research does not cover children or type 1 diabetes^[7].

References for this section

1. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2020-2025. 9th edition. 2020. Appendix 1, Table A1-2, Daily Nutritional Goals, Ages 2 and Older. The 130 g minimum in step 2: the table lists an RDA (recommended dietary allowance) of 130 g of carbohydrate for every age group from 2 years up. Dietary Guidelines, Table A1-2 (PDF, 32 MB)
2. Fernández-Elías VE, Ortega JF, Nelson RK, Mora-Rodriguez R. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. European Journal of Applied Physiology. 2015;115(9):1919-1926. Step 4: each gram of stored glycogen holds about 3 g of water. doi:10.1007/s00421-015-3175-z
3. Kreitzman SN, Coxon AY, Szaz KF. Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition. American Journal of Clinical Nutrition. 1992;56(1 Suppl):292S-293S. Step 4: glycogen is stored with water, so eating more carbs raises scale weight for a while, and that gain is water, not fat. doi:10.1093/ajcn/56.1.292S
4. Burke LM, Hawley JA, Wong SHS, Jeukendrup AE. Carbohydrates for training and competition. Journal of Sports Sciences. 2011;29(Suppl 1):S17-S27. Table II. Step 5: carbs between two sessions less than 8 hours apart (1 to 1.2 g per kg each hour for up to 4 hours), and carbs 1 to 4 hours before exercise lasting more than an hour, with little fat or fibre close to it. doi:10.1080/02640414.2011.585473
5. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. Step 5: 20 to 40 g of protein after training. doi:10.1186/s12970-017-0177-8
6. Dyson P. Low carbohydrate diets and type 2 diabetes: what is the latest evidence? Diabetes Therapy. 2015;6(4):411-424. Step 6: under 130 g of carbs a day counts as a low-carbohydrate intake (a table adapted from Feinman et al., 2015). doi:10.1007/s13300-015-0136-9
7. Singh M, Hung ES, Cullum A, et al., for the Scientific Advisory Committee on Nutrition. Lower carbohydrate diets for adults with type 2 diabetes. British Journal of Nutrition. 2022;127(9):1352-1357. Step 6: there is no agreed definition of a low-carbohydrate diet, people taking diabetes medicine may be at risk of low blood sugar, and the evidence does not cover children or type 1 diabetes. doi:10.1017/S0007114521002373
8. Medicines and Healthcare products Regulatory Agency. SGLT2 inhibitors: updated advice on the risk of diabetic ketoacidosis. Drug Safety Update, 18 April 2016. Step 6: eating very little raises the risk of ketoacidosis in people taking SGLT2 inhibitors. gov.uk

Related: Your targets

Fat

Your daily fat target, set from your current weight, with a floor so it is never squeezed too low.

Where you see it

1. Tap the ⓘ next to Fat on the Nutrition tab to see your fat per kg for the day.

How your fat target is worked out

Fat is set after protein and before carbs. A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Grams per kg. Fat is set from your current weight:

   • Fat = 0.9 g per kg of your current weight, inside the 0.5 to 1.5 g per kg range in the research^[1]

2. The 40 g floor. Fat never goes below 40 g a day. This is Strathlon's own setting: the research gives a range per kg, not a gram floor, so the floor stops fat being squeezed too low on low-calorie days. The nearest source is the range in step 1^[1].

3. On a tight day. If the calories run short, fat comes down first to keep carbs at their minimum, but not below 40 g (see Carbohydrates). On such a day the Nutrition tab's Fat ⓘ says your fat is below the usual range.

4. Why fat matters. Your body needs some fat to absorb vitamins A, D, E and K^[2], and in studies of men, low-fat diets lowered testosterone^[3].

References for this section

1. Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports (Basel). 2019;7(7):154. Step 1: 0.5 to 1.5 g of fat per kg a day for people building muscle, and the nearest source for the 40 g floor in step 2. PMC6680710
2. MedlinePlus Medical Encyclopedia, US National Library of Medicine. Dietary fats explained. Step 4: fat helps your body absorb vitamins A, D, E and K. MedlinePlus
3. Whittaker J, Wu K. Low-fat diets and testosterone in men: systematic review and meta-analysis of intervention studies. Journal of Steroid Biochemistry and Molecular Biology. 2021;210:105878. Step 4: in studies of men, low-fat diets lowered testosterone. doi:10.1016/j.jsbmb.2021.105878

Related: Your targets

Hydration

Drinking guidance on the Plan tab's day cards, the same for everyone, and the research behind it.

Where you see it

1. Open the Plan tab and tap the ⓘ on the day's drinking card.

Where the drinking guidance comes from

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. On training, activity and match days. The day's drinking card (Hydrate during on a gym day, Drink through both sessions on a double day, Hydrate before and after on a practice or activity day, Hydrate from the morning on a match day) follows the American College of Sports Medicine's fluid guidance^[1]:

   • Losing more than about 2% of your body weight in sweat can hold back your performance
   • Drinking before and during exercise helps keep the loss below that
   • In long or hot sessions, a sports drink can work better than water

2. On rest days. The Drink regularly card suggests 6 to 8 glasses of fluid a day, more if you trained hard the day before or it is hot^[2]. A drink with electrolytes can help after heavy sweating^[1].

3. Electrolyte drinks. The electrolyte cards on match days and long practices (see Supplements and caffeine) use the same fluid guidance^[1].

References for this section

1. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand: exercise and fluid replacement. Medicine and Science in Sports and Exercise. 2007;39(2):377-390. Steps 1 to 3: drinking before and during training so you lose no more than about 2% of your body weight, when a sports drink can work better than water, and electrolytes after heavy sweating. doi:10.1249/mss.0b013e31802ca597
2. NHS. Water, drinks and hydration. Reviewed 17 May 2023. Step 2: 6 to 8 glasses of fluid a day, more if you are active or it is hot. nhs.uk

Sleep

Your nightly sleep target: a range set by your age, with a nudge toward the top after a hard day.

Where you see it

1. Open the Plan tab and tap the ⓘ on the day's sleep card, or tap the ⓘ next to Bedtime reminder in Settings.

How your sleep target is set

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. The range. Your target depends on your age^[1]:

   • Adults: 7 to 9 hours a night
   • Under 18: 8 to 10 hours a night

   A joint statement of two US sleep bodies also says adults need 7 hours or more a night^[2].

2. After a hard day. For adults, after a gym day, a match day or a double day, the card says to aim for the top of your range. Athletes' sleep needs vary, so one fixed figure is unlikely to suit everyone^[3]. Which days count as hard is Strathlon's own setting.

3. The bedtime reminder. The bedtime reminder's lock-screen card shows tonight's sleep target from your plan, using the same range.

References for this section

1. Hirshkowitz M, Whiton K, et al. National Sleep Foundation's sleep time duration recommendations: methodology and results summary. Sleep Health. 2015;1(1):40-43. Step 1: 8 to 10 hours for under 18s, 7 to 9 hours for adults. doi:10.1016/j.sleh.2014.12.010
2. Watson NF, Badr MS, et al. Recommended amount of sleep for a healthy adult: a joint consensus statement of the American Academy of Sleep Medicine and Sleep Research Society. Journal of Clinical Sleep Medicine. 2015;11(6):591-592. Step 1: adults need 7 hours or more a night. doi:10.5664/jcsm.4758
3. Walsh NP, Halson SL, et al. Sleep and the athlete: narrative review and 2021 expert consensus recommendations. British Journal of Sports Medicine. 2020. Step 2: aiming for the top of your range after a hard day, because athletes' sleep needs vary. doi:10.1136/bjsports-2020-102025

Heart rate: your maximum and effort bands

Your estimated maximum heart rate, and the effort bands built from it that you see during workouts.

Where you see it

1. Tap the ⓘ next to Max heart rate on the Your targets card in Settings, or on the Target HR tile of a gym session.

How your heart rate figures are worked out

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Your maximum heart rate. Strathlon estimates it from your age with the Tanaka formula^[1]:

   • Max heart rate = 208 minus 0.7 × your age, rounded to the nearest beat

   It is an estimate for people of your age, and your own maximum can be higher or lower.

2. The effort bands. Each band is a share of that maximum, rounded down to a whole beat:

   • Lifting: 50 to 75%. This is Strathlon's own guide: no expert body sets a heart-rate zone for lifting, so treat it as a sign you are working, not a training zone. The nearest source is the guidance in the note below^[2]. Your heart rate turns red once it reaches the bottom of the band during your sets
   • HIIT finisher, from Phase 2: work intervals aim for 80% or more, the vigorous level in guidance from the American College of Sports Medicine (ACSM) and Exercise and Sports Science Australia (ESSA)^[2]
   • Sport training: 60 to 80%, the moderate to vigorous levels in that guidance^[2]
   • Match: 70 to 90%, the vigorous level in ESSA's guidance^[2]

   In that guidance, moderate is 55 to 70% (ESSA) or 64 to 76% (ACSM) of maximum heart rate, and vigorous is 70 to 90% (ESSA) or 77 to 95% (ACSM)^[2].

3. The warm-up. The warm-up's heart-rate target moves with your training phase: Phase 1 aims for 55 to 60% of your max heart rate, and Phase 2, Phase 3 and Maintenance aim for 60 to 70%, inside the moderate level^[2]. The gentler Phase 1 target is Strathlon's own setting.

4. During pregnancy. While a pregnancy is recorded, Strathlon sets no heart-rate targets and the Target HR tile shows none. It uses how hard the effort feels instead: you should be able to hold a conversation as you exercise^[3], at around 12 to 14 on the Borg scale of effort, which is somewhat hard: you can talk but not sing^[4].

References for this section

1. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. Journal of the American College of Cardiology. 2001;37(1):153-156. Step 1: maximum heart rate = 208 minus 0.7 × age. doi:10.1016/s0735-1097(00)01054-8
2. Fahey M, Brazg G, Henderson CE, et al. The value of high intensity locomotor training applied to patients with acute-onset neurologic injury. Archives of Physical Medicine and Rehabilitation. 2022. Table 1. Steps 2 and 3: its Table 1 reproduces the intensity levels of the ACSM (2018) and ESSA (2010): moderate 55 to 70% (ESSA) or 64 to 76% (ACSM) of maximum heart rate, vigorous 70 to 90% (ESSA) or 77 to 95% (ACSM). doi:10.1016/j.apmr.2020.09.399
3. NHS. Exercise in pregnancy. Reviewed 15 March 2023. Step 4: the talk test in pregnancy. nhs.uk
4. Sports Medicine Australia. Position Statement: Exercise in Pregnancy and the Postpartum Period. Updated 19 July 2016. Step 4: effort of 12 to 14, somewhat hard, on the Borg scale instead of heart-rate targets. sma.org.au (PDF)

Related: Your targets

Body mass index (BMI)

Your BMI: a quick weight-for-height ratio used as a rough health screen, and where Strathlon uses it.

Where you see it

1. Tap the ⓘ next to BMI on the Your targets card in Settings.

How your BMI is worked out and used

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. The formula. Your weight divided by your height squared:

   • BMI = weight in kg ÷ (height in metres × height in metres)

   If your scale or another app writes BMI to Apple Health, Strathlon shows that figure instead, so it may not match the height and weight in your profile.

2. What it cannot tell you. BMI can't tell muscle from fat, so a lean, muscular build can read overweight. That is why, with Use body composition on, Strathlon works out your BMR and your protein from your lean mass instead (see Daily calories and Protein).

3. The bands. The standard adult bands are healthy 18.5 to 24.9, overweight 25 to 29.9, and obesity 30 or more^[1][2]. NICE, the UK's National Institute for Health and Care Excellence, uses lower thresholds for people from some ethnic backgrounds, such as South Asian and Chinese^[1]. Strathlon uses the standard bands for everyone.

4. Where Strathlon uses it. Two of your targets look at your BMI:

   • A goal weight below a BMI of 18.5 for your height is planned only down to that weight^[1]
   • Above a BMI of 25, protein is counted on your goal weight or the weight at a BMI of 25 (Strathlon's own method, see Protein)

References for this section

1. National Institute for Health and Care Excellence. Overweight and obesity management (NG246). 2025. Recommendations 1.9.10 and 1.9.11. Steps 3 and 4: the BMI bands (healthy 18.5 to 24.9, overweight 25 to 29.9, obesity 30 or more), the lower thresholds NICE uses for some ethnic groups, and the lowest goal weight Strathlon plans for (BMI 18.5). NICE NG246, identifying and assessing
2. World Health Organization. Obesity and overweight, fact sheet. 2025. Step 3: the BMI bands (overweight 25 or more, obesity 30 or more). who.int

Related: Your targets · Body composition

Est. burn for a gym session

The Est. burn range on a gym session: a rough body-weight guide to what the session burns.

Where you see it

1. Open a gym day on the Plan tab and tap the ⓘ on the Est. burn tile.

How Est. burn is worked out

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. The estimate. Strathlon multiplies your weight by the energy cost of lifting and by the session's length:

   • Est. burn = MET × weight in kg × hours, given as a range
   • MET range by level: Beginner 3.0 to 4.0, Intermediate 3.5 to 5.0, Advanced 4.5 to 6.0
   • Length: a standard session for your phase, a 10-minute warm-up and your sets, about 36 minutes in Phase 1 and 45 minutes after that

   The MET ranges for each level are Strathlon's own setting. The nearest source is the 2024 Adult Compendium of Physical Activities, which lists the energy cost of weight training^[1].

   Rest between sets is counted at the standard 60 seconds, so choosing a longer rest does not raise the estimate. Setting Gym intensity to Light takes a fifth off the estimate and High adds a fifth: Strathlon's own settings.

2. How far to trust it. It is not your calorie target: your calories come from Daily calories. Watch calorie readings for weight training can be well off in either direction. In one test an Apple Watch read about twice the measured burn during weight training^[2]. In another, none of the wrist devices tested, an Apple Watch included, measured calories validly during weight training^[3], and a third found the Apple Watch 6 and two other wrist devices poorly accurate for calories in every activity tested^[4]. So treat both the estimate and the watch figure as a rough guide.

3. Gym and sport on the same day. On a day with both, Est. burn covers the gym work only. The sport's calories are the sport and activity bonus (see Daily calories, step 4).

References for this section

1. Herrmann SD, Willis EA, Ainsworth BE, Barreira TV, Hastert M, Kracht CL, Schuna JM Jr, Cai Z, Quan M, Tudor-Locke C, Whitt-Glover MC, Jacobs DR Jr. 2024 Adult Compendium of Physical Activities: a third update of the energy costs of human activities. Journal of Sport and Health Science. 2024;13(1):6-12. Step 1: the nearest source for the energy cost of weight training. PMC10818145
2. Yun JH, Ko JM, Lee TH. Criterion validity of smartwatches for measuring heart rate and energy expenditure during resistance exercise. Bioengineering (Basel). 2026;13(10):1099. Step 2: during weight training, an Apple Watch read about twice the measured burn. doi:10.3390/bioengineering13101099
3. Boudreaux BD, Hebert EP, Hollander DB, et al. Validity of wearable activity monitors during cycling and resistance exercise. Medicine and Science in Sports and Exercise. 2018;50(3):624-633. Step 2: none of the wrist devices tested, an Apple Watch included, measured calories validly during weight training. doi:10.1249/MSS.0000000000001471
4. Hajj-Boutros G, Landry-Duval M, Comtois AS, Gouspillou G, Karelis AD. Wrist-worn devices for the measurement of heart rate and energy expenditure: a validation study for the Apple Watch 6, Polar Vantage V and Fitbit Sense. European Journal of Sport Science. 2023;23(2):165-177. Step 2: the Apple Watch 6 and two other wrist devices were poorly accurate for calories in every activity tested, weight training included. doi:10.1080/17461391.2021.2023656

Related: “About Est. burn”

Daily steps and everyday movement

The Daily steps figure on Progress, and why everyday movement can matter as much as your sessions.

Where you see it

1. Open Progress and tap the ⓘ on Daily steps.

Why steps matter, in numbers

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Everyday movement differs a lot. How much you move outside your sessions differs a lot from person to person. In a study where adults ate about 1,000 kcal a day more than they needed for 8 weeks, those whose everyday movement rose the most gained the least fat^[1].

2. What 3,000 steps is worth. Walking at about 100 steps a minute takes about 3 times the energy you burn at rest, 3 METs^[2], so 3,000 steps at that pace is about 30 minutes. Working that out the way the Compendium's energy costs are used, METs × weight × time^[3]:

   • 3 METs × 70 kg × 0.5 hours = about 105 kcal, roughly 100 calories for a 70 kg adult

   So a change of 3,000 steps a day can explain the scale stalling while the training looks fine. Your calorie target allows for ordinary daily movement through the everyday activity factor (see Daily calories, step 3), so this figure is for watching your trend.

References for this section

1. Levine JA, Eberhardt NL, Jensen MD. Role of nonexercise activity thermogenesis in resistance to fat gain in humans. Science. 1999;283(5399):212-214. Step 1: everyday movement outside exercise changed a lot between people, and it made a big difference to how much fat people gained when overfed. doi:10.1126/science.283.5399.212
2. Tudor-Locke C, Aguiar EJ, Han H, et al. Walking cadence (steps/min) and intensity in 21 to 40 year olds: CADENCE-adults. International Journal of Behavioral Nutrition and Physical Activity. 2019;16:8. Step 2: walking at about 100 steps a minute is about 3 METs. doi:10.1186/s12966-019-0769-6
3. Herrmann SD, Willis EA, Ainsworth BE, Barreira TV, Hastert M, Kracht CL, Schuna JM Jr, Cai Z, Quan M, Tudor-Locke C, Whitt-Glover MC, Jacobs DR Jr. 2024 Adult Compendium of Physical Activities: a third update of the energy costs of human activities. Journal of Sport and Health Science. 2024;13(1):6-12. Step 2: energy costs as METs, used with your weight and the time. PMC10818145

Weight trend and predicted weight

Your weight trend on Progress, and the dashed line showing what your tracked calories predict.

Where you see it

1. Open Progress and tap the ⓘ on the Body weight chart or on Energy balance.

How the trend and the predicted line are worked out

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. The trend. Daily weight is noisy: water, food and salt move it from day to day. The trend cuts through that to show the real direction, so the weekly average matters more than any single day.

2. The predicted line. When you turn on the dashed predicted line, Strathlon starts from your first weigh-in and, over the days where both food and burn are logged, adds up what you burned minus what you ate:

   • Predicted weight = first weigh-in minus (total burned minus total eaten) ÷ 7,700

   7,700 kcal is the usual rule of thumb for 1 kg of body weight, and it overestimates for leaner people^[1]. The line runs to your last weigh-in.

3. Water from carbs. Eating more carbs stores more glycogen, which holds water^[2], so the scale can rise for a while with no fat gained^[3].

4. Energy balance. The Energy balance chart overlays what you ate, what you burned and your weight, using the same 7,700 kcal per kg rule^[1].

References for this section

1. Hall KD. What is the required energy deficit per unit weight loss? International Journal of Obesity. 2008;32(3):573-576. Steps 2 and 4: about 7,700 kcal per kg of body weight, and its limit: it overestimates for leaner people. PMC2376744
2. Fernández-Elías VE, Ortega JF, Nelson RK, Mora-Rodriguez R. Relationship between muscle water and glycogen recovery after prolonged exercise in the heat in humans. European Journal of Applied Physiology. 2015;115(9):1919-1926. Step 3: each gram of stored glycogen holds about 3 g of water. doi:10.1007/s00421-015-3175-z
3. Kreitzman SN, Coxon AY, Szaz KF. Glycogen storage: illusions of easy weight loss, excessive weight regain, and distortions in estimates of body composition. American Journal of Clinical Nutrition. 1992;56(1 Suppl):292S-293S. Step 3: eating more carbs raises scale weight for a while, and that gain is water, not fat. doi:10.1093/ajcn/56.1.292S

Training research behind your plan

The research behind why Phase 1 starts light, how smart pairing works, and the training glossary.

Where you see it

1. Open the Plan tab and tap the ⓘ on Phase 1 or on the Training Glossary, or tap Research behind smart pairing when you set up your sports.

The research, point by point

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Phase 1 starts light. Tendons get stronger more slowly than muscle^[1], so Phase 1 grooves clean movement and builds a base before the weights go up, which keeps the strain on your tendons in step with your strength.

2. Smart pairing. On a day with both sport and gym, the gym session trains different muscles from the ones your sport works hardest, so you are not hitting tired muscles twice in one day. Research on combining cardio with strength training found that running held back strength and muscle gains more than cycling did, and the more cardio people did, the more it held them back^[2].

3. From the training glossary. Three of the glossary's entries rest on research:

   • Tempo, written like 3-0-1: seconds to lower, pause, seconds to lift. Studies find similar muscle growth with reps lasting from about half a second to 8 seconds^[3], and rep speed makes little difference to growth^[4]
   • The lowering phase (eccentric) causes most of the muscle soreness after training^[5]
   • EPOC, the afterburn: after hard sessions such as heavy lifting or intervals, your metabolic rate stays raised for a while, and longer the harder you train. After easy exercise the effect is small^[6]

References for this section

1. Mersmann F, Bohm S, Arampatzis A. Imbalances in the development of muscle and tendon as risk factor for tendinopathies in youth athletes: a review of current evidence and concepts of prevention. Frontiers in Physiology. 2017;8:987. Step 1: tendons adapt to training more slowly than muscle (a review of young athletes). doi:10.3389/fphys.2017.00987
2. Wilson JM, Marin PJ, Rhea MR, Wilson SM, Loenneke JP, Anderson JC. Concurrent training: a meta-analysis examining interference of aerobic and resistance exercises. Journal of Strength and Conditioning Research. 2012;26(8):2293-2307. Step 2: adding cardio to strength training held back strength and muscle gains, running more than cycling, and more cardio meant more interference. doi:10.1519/JSC.0b013e31823a3e2d
3. Schoenfeld BJ, Ogborn DI, Krieger JW. Effect of repetition duration during resistance training on muscle hypertrophy: a systematic review and meta-analysis. Sports Medicine. 2015;45(4):577-585. Step 3: similar muscle growth with reps lasting from about half a second to 8 seconds. doi:10.1007/s40279-015-0304-0
4. Enes A, Piñero A, Hermann T, et al. How slow should you go? A systematic review with meta-analysis of the effect of resistance training repetition tempo on muscle hypertrophy. Journal of Strength and Conditioning Research. 2025;39(12):1331-1339. Step 3: rep speed (tempo) makes little difference to muscle growth. doi:10.1519/JSC.0000000000005302
5. Proske U, Morgan DL. Muscle damage from eccentric exercise: mechanism, mechanical signs, adaptation and clinical applications. Journal of Physiology. 2001;537(Pt 2):333-345. Step 3: the lowering (eccentric) phase causes most of the muscle soreness after training. doi:10.1111/j.1469-7793.2001.00333.x
6. Børsheim E, Bahr R. Effect of exercise intensity, duration and mode on post-exercise oxygen consumption. Sports Medicine. 2003;33(14):1037-1060. Step 3: after hard sessions your metabolic rate stays raised for a while, and longer the harder you train. doi:10.2165/00007256-200333140-00002

Related: Training phases

Supplements and caffeine

The supplement cards on the Nutrition tab, and the research behind each amount.

Where you see it

1. Open the Nutrition tab and tap the ⓘ on a supplement card.

Where the supplement amounts come from

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. Caffeine. The caffeine cards suggest:

   • 3 mg per kg of body weight, about 60 minutes before training or a match, or 45 to 60 minutes before a practice^[1]
   • No more than 200 mg in one dose and 400 mg a day from all sources, such as coffee, energy drinks and pre-workout^[2]

   Its effect on strength and power is small^[3][4]. The caffeine cards are not shown to under 18s or while a pregnancy is recorded, because the levels EFSA considers safe are lower for children and adolescents, and in pregnancy^[2]. Hiding the cards for those users is Strathlon's own rule.

2. Creatine. 3 to 5 g a day, every day, rest days included^[5]. On a match day the card says not to start anything new.

3. Whey and casein. Whey: 20 to 40 g after training, a practice or a match. Casein: 30 to 40 g before bed^[6].

4. Tart cherry. 30 ml of concentrate twice a day, from a few days before to 2 or 3 days after a match^[7]. Its effect on soreness and recovery is modest^[8].

5. Electrolytes. A sports drink at the warm-up and during matches, and in long or hot practices, to replace the salt you lose in sweat^[9].

6. During pregnancy. While a pregnancy is recorded, the supplements section asks you to talk to your midwife or doctor about supplements.

References for this section

1. Guest NS, VanDusseldorp TA, et al. International Society of Sports Nutrition position stand: caffeine and exercise performance. Journal of the International Society of Sports Nutrition. 2021;18(1):1. Step 1: caffeine at 3 mg per kg, about 60 minutes before. doi:10.1186/s12970-020-00383-4
2. European Food Safety Authority. EFSA explains risk assessment: caffeine. 2015. Summary of the scientific opinion on the safety of caffeine. Step 1: the caffeine limits for adults (no more than 200 mg in one dose and 400 mg a day), and the lower safe levels behind hiding the caffeine cards for under 18s and in pregnancy. efsa.europa.eu (PDF)
3. Warren GL, Park ND, Maresca RD, McKibans KI, Millard-Stafford ML. Effect of caffeine ingestion on muscular strength and endurance: a meta-analysis. Medicine and Science in Sports and Exercise. 2010;42(7):1375-1387. Step 1: caffeine's effect on strength is small. doi:10.1249/MSS.0b013e3181cabbd8
4. Grgic J, Trexler ET, Lazinica B, Pedisic Z. Effects of caffeine intake on muscle strength and power: a systematic review and meta-analysis. Journal of the International Society of Sports Nutrition. 2018;15:11. Step 1: caffeine's effect on strength and power is small. doi:10.1186/s12970-018-0216-0
5. Kreider RB, Kalman DS, Antonio J, et al. International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation in exercise, sport, and medicine. Journal of the International Society of Sports Nutrition. 2017;14:18. Step 2: creatine at 3 to 5 g a day, every day. doi:10.1186/s12970-017-0173-z
6. Jäger R, Kerksick CM, Campbell BI, et al. International Society of Sports Nutrition position stand: protein and exercise. Journal of the International Society of Sports Nutrition. 2017;14:20. Step 3: whey at 20 to 40 g after training, and casein at 30 to 40 g before bed. doi:10.1186/s12970-017-0177-8
7. Bell PG, Stevenson E, Davison GW, Howatson G. The effects of Montmorency tart cherry concentrate supplementation on recovery following prolonged, intermittent exercise. Nutrients. 2016;8(7):441. Step 4: tart cherry concentrate at 30 ml twice a day around a match. doi:10.3390/nu8070441
8. Hill JA, Keane KM, Quinlan R, Howatson G. Tart cherry supplementation and recovery from strenuous exercise: a systematic review and meta-analysis. International Journal of Sport Nutrition and Exercise Metabolism. 2021;31(2):154-167. Step 4: tart cherry's effect on soreness and recovery is modest. doi:10.1123/ijsnem.2020-0145
9. Sawka MN, Burke LM, Eichner ER, Maughan RJ, Montain SJ, Stachenfeld NS. American College of Sports Medicine position stand: exercise and fluid replacement. Medicine and Science in Sports and Exercise. 2007;39(2):377-390. Step 5: electrolyte drinks before and during matches and long practices. doi:10.1249/mss.0b013e31802ca597

Related: Supplements guidance

Pregnancy and breastfeeding

What changes while a pregnancy or breastfeeding is recorded: no calorie target, and published guidance instead.

Where you see it

1. Record a pregnancy or breastfeeding in Health & safety in Settings. The Plan tab then shows the guidance card, and its ⓘ opens the sources.

What the app does, and the guidance behind it

Strathlon doesn't design a programme for pregnancy or for the months after childbirth. It shows published guidance from UK health bodies and Sports Medicine Australia instead. A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. No calorie target. Trying to lose weight during pregnancy is not recommended, because it could harm the baby, and there is a lack of evidence about what the best weight change in pregnancy should be^[1]. You do not need a special diet while breastfeeding: eat a healthy, varied diet, and a daily vitamin D supplement is advised^[2]. So Strathlon sets no calorie target while either is recorded, and shows no goal weight during pregnancy. The box at the top of Daily calories lists what the app shows instead.

2. Activity in pregnancy. The Plan tab's pregnancy card shows:

   • At least 150 minutes of moderate intensity activity every week, and muscle strengthening activities twice a week^[3]
   • Choices that reflect how active you were before pregnancy and include strength training. Vigorous activity is not recommended if you were not active before^[4]
   • Effort, not heart rate: you should be able to hold a conversation as you exercise^[5], at around 12 to 14 on the Borg scale of effort, which is somewhat hard: you can talk but not sing^[6]
   • What to avoid, such as contact sports and scuba diving, and pelvic floor exercises every day^[5]
   • Signs to stop and seek advice. Sports Medicine Australia states that its list comes from national guidelines by consensus, not from systematic evidence^[6]

   This is why Strathlon shows no heart-rate target or training zone while you are pregnant (see Heart rate).

3. After childbirth. The Plan tab's after-childbirth card shows:

   • At least 150 minutes of moderate intensity activity every week, building back up to muscle strengthening twice a week, and pelvic floor exercises daily^[7]
   • After your 6 to 8 week postnatal check, and depending on how you feel, a gradual return to harder activity, building up from moderate to vigorous over at least 3 months^[4]
   • A gradual return to high-impact activity, and to activity that loads the pelvic floor, depending on how you gave birth^[6]
   • Moderate to vigorous exercise does not reduce breast-milk volume, change its composition or affect the baby's growth, given enough food and fluid^[6]

4. Other changes. The caffeine cards are not shown during pregnancy (see Supplements and caffeine). Your coach knows, and will point you back to your midwife, GP or health visitor for anything specific. Follow your midwife, GP or maternity team over anything the app shows you.

References for this section

1. National Institute for Health and Care Excellence. Maternal and child nutrition: nutrition and weight management in pregnancy, and nutrition after pregnancy (NG247). Section 1.2, recommendations marked [2025]. Step 1: trying to lose weight during pregnancy is not recommended, and there is a lack of evidence on the best weight change in pregnancy. NICE NG247
2. NHS. Breastfeeding and diet. Step 1: no special diet while breastfeeding, and a daily vitamin D supplement. nhs.uk
3. UK Chief Medical Officers (Department of Health & Social Care). Physical activity for pregnant women (infographic, text version). Published 7 September 2019, updated 16 July 2026. Step 2: activity guidance on the pregnancy card. gov.uk
4. UK Chief Medical Officers (Department of Health & Social Care). UK Chief Medical Officers' physical activity guidelines: physical activity during pregnancy and postpartum. Published 10 July 2026. Steps 2 and 3: the evidence behind the pregnancy and after-childbirth guidance, including strength training and the return to harder activity after the postnatal check. gov.uk
5. NHS. Exercise in pregnancy. Reviewed 15 March 2023. Step 2: the talk test, and what to avoid and what to do while pregnant, including pelvic floor exercises. nhs.uk
6. Sports Medicine Australia. Position Statement: Exercise in Pregnancy and the Postpartum Period. Updated 19 July 2016. Steps 2 and 3: how hard exercise should feel (12 to 14 on the Borg scale), the warning signs to stop, returning to harder training after birth, and exercise while breastfeeding. sma.org.au (PDF)
7. UK Chief Medical Officers (Department of Health & Social Care). Physical activity for women after childbirth: birth to 12 months (infographic, text version). Updated 16 July 2026. Step 3: activity guidance on the after-childbirth card. gov.uk

Health and safety checks

The readiness and eating questions in Health & safety, the age rules, and how each changes your plan.

Where you see it

1. Open Health & safety in Settings and tap the ⓘ next to the readiness check.

What each check does

A number in square brackets points to a source in the references at the end of this section. Where a figure is Strathlon's own setting, the text says so: no published source sets it.

1. The readiness check. These questions are based on the PAR-Q+, the Physical Activity Readiness Questionnaire for Everyone, a screening form used before people become more physically active^[1]. Strathlon asks its own shorter, plain-language version, so it is not the official form. If you answer yes to any question, Strathlon suggests checking with your doctor first and, until you confirm you are cleared, limits a calorie cut to 100 kcal on rest days and 125 kcal on training days. That limit is Strathlon's own safety setting.

2. The eating questions. The eating-concern questions follow the themes of the SCOFF screening questionnaire^[2]. If your answers flag a concern, your plan stays at maintenance, with no calorie cut.

3. Age rules. Strathlon is for 16 and over. Under 18, there is no fat-loss goal and never a calorie deficit, and the caffeine cards are not shown. These are Strathlon's own safety policy for young people who are still growing.

References for this section

1. Warburton DER, Jamnik VK, Bredin SSD, Gledhill N. The Physical Activity Readiness Questionnaire for Everyone (PAR-Q+) and Electronic Physical Activity Readiness Medical Examination (ePARmed-X+). Health and Fitness Journal of Canada. 2011;4(2):3-17. Step 1: the readiness check questions. Strathlon asks its own shorter, plain-language version of the PAR-Q+ questions, not the official form. doi:10.14288/hfjc.v4i2.103
2. Morgan JF, Reid F, Lacey JH. The SCOFF questionnaire: assessment of a new screening tool for eating disorders. BMJ. 1999;319(7223):1467-1468. Step 2: the eating-concern questions. If they flag a concern, your plan stays at maintenance. doi:10.1136/bmj.319.7223.1467

Related: Readiness check