Train with your cycle
If you log your period in Apple Health, Strathlon can take your cycle into account*. It keeps your training plan steady and adds a few short notes in the places you already look, plus one optional change to your calorie target. Here's what you'll see through the month, and why it's built that way.
Built from your own log
Strathlon reads the periods you log in Apple Health, whether you use the Health app or a period tracker that saves there, once you've given it permission. It works on your phone, from roughly the last six months of logs.
From those dates it works out your typical gap between periods and expects the next one about that far after your last. The days you've logged flow count as your period, and the five or so days before your next expected period count as "pre-period". Strathlon sticks to what dates can show reliably, your period and the days before it, and it labels everything as an estimate on every cycle card.
Support during your period
On your Plan tab, a note headed Train by feel today: energy can dip on the first days, so it's fine to train by feel and go a little lighter, and moving usually beats resting completely because it can ease symptoms. Your session itself stays as programmed.
On your Nutrition tab, Eating around your period: iron-rich foods such as lean red meat, beans and leafy greens, staying hydrated, and leaning on protein and fibre if your appetite rises. Iron earns its place: low iron is common in women who train[5]. If you often feel unusually tired, ask your GP for a blood test before you consider supplements.
On your Progress tab, the Cycle & energy tile counts the day of your cycle from your last logged period and reads Water weight is normal. Many people hold a little extra water around their period, which nudges the scale up for a few days while body fat stays the same[4]. Once you've weighed in on enough period days, the tile tells you how much higher your own scale tends to read on them. Your logged period days are also shaded pink on your weight chart, so a bump lines up with its cause.
Push when you feel strong
The Plan note changes to Often a strong window: many people feel their best in this part of the cycle, so if you feel good, it's a great time to push your harder sessions.
That "if you feel good" matters. When researchers measure strength, power and muscle growth across the cycle, most find the differences between phases small and inconsistent[1], and a randomised trial found women gained the same strength and muscle from training whatever the phase[2]. So the note follows how you feel on the day.
Easier pre-period days
On the Plan tab, Pre-period — listen to your body: you may feel a bit flatter, so train by effort (RPE), and it's okay to trim a set. Sessions can feel harder before a period even when what you can lift stays the same[3]. Switch on Cycle-aware training guidance and the note goes a step further on these days and during your period: drop the last set of each lift if your energy is low, because progress is judged over the cycle, rather than one session.
On the Nutrition tab, Pre-period appetite is normal: hunger and cravings commonly rise in the days before a period. That's physiology rather than willpower, and a small, planned increase in food helps you stay consistent. If your calories are set at maintenance, the note keeps to the appetite reassurance and the protein-and-fibre tip. More on appetite across the cycle.
That planned increase is what Ease my targets in my pre-period week does. Switch it on and your daily calorie target goes up by about 100 kcal in the days before and during your period. The extra comes as about 25 g of carbohydrate, so your protein and fat targets hold steady and your macros still add up. The Nutrition tab, the Tracker and your AI coach all use the same eased figure. When your target is set for a goal, the Tracker also shows a short Eased note, so the change is easy to see.
The Progress tile changes its line to Your period may be near.
Your programme stays steady
- Your programme. Your sets, reps and weights stay as programmed. The notes suggest; you decide.
- Your protein and fat targets. The optional ease goes on carbohydrate.
- Good training, every week. The evidence favours consistent, well-run training adjusted on the day over rearranging your plan around cycle phases[1][2], so that's what Strathlon gives you.
Your coach, your terms
Strathlon keeps your period dates, flow, symptoms and history private, and the training suggestions on your Plan stay on your Plan. Your coach hears about your cycle through two switches you choose in Settings → Cycle-aware insights: one shares a general phase word such as "pre-menstrual", and the ease shares your adjusted calorie target with a note that it was deliberately adjusted. With both on, that note also gives your cycle as the reason. Every switch, explained.
One more thing worth knowing. A regular cycle is a good sign you're eating enough for the training you do. If your periods become irregular or stop while you're training hard or eating less, treat it as a reason to eat more and talk to your GP[6]. Energy availability and RED-S, explained.
References
Numbered sources for the specific findings above. Research on the menstrual cycle and training is younger and more variable than the general literature, which is why Strathlon keeps its cycle notes to suggestions and your programme steady.
- D'Souza AC, Wageh M, Williams JS, Colenso-Semple LM, McCarthy DG, McKay AKA, et al. Menstrual cycle hormones and oral contraceptives: a multimethod systems physiology-based review of their impact on key aspects of female physiology. Journal of Applied Physiology. 2023;135(6):1284–1299. A systems-physiology review finding most cycle-phase effects on performance small and inconsistent. PubMed 37823207 · PMC10979803 full text
- D'Souza AC, Van Every DW, Bhinder A, Elango S, Lamont GAC, Lees MJ, et al. Menstrual Cycle Phase Does Not Influence Training-Induced Muscle Hypertrophy or Strength: A Randomized Controlled Trial. Medicine and Science in Sports and Exercise. 2026. The randomised trial behind "the same strength and muscle whatever the phase". PubMed 42160459
- Dragutinovic B, Moser F, Notbohm HL, Ihalainen JK, Bloch W, Schumann M. Influence of menstrual cycle and oral contraceptive phases on strength performance, neuromuscular fatigue, and perceived exertion. Journal of Applied Physiology. 2024;137(4):919–933. Strength performance and perceived exertion across menstrual and oral-contraceptive phases. PubMed 39052822
- Kanellakis S, Skoufas E, Simitsopoulou E, Migdanis A, Migdanis I, Prelorentzou T, et al. Changes in body weight and body composition during the menstrual cycle. American Journal of Human Biology. 2023;35(11):e23951. Body weight and composition across the cycle: the source for the scale moving with fluid rather than fat. PubMed 37395124
- Pengelly M, Pumpa K, Pyne DB, Etxebarria N. Iron deficiency, supplementation, and sports performance in female athletes: A systematic review. Journal of Sport and Health Science. 2025;14:101009. Iron deficiency is common in active women; test before supplementing. PubMed 39536912 · PMC11863318 full text
- Mountjoy M, Ackerman KE, Bailey DM, Burke LM, Constantini N, Hackney AC, et al. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine. 2023;57(17):1073–1097. The basis for reading a change in your periods as a fuelling signal. PubMed 37752011
* Cycle-aware features use the periods you log in Apple Health, which Strathlon reads with the permission you grant. Cycle-aware insights starts switched on, and the other three switches start off, ready for you to choose. Everything here is an estimate and general information. If your periods are irregular, very heavy or painful, or have stopped, or if you're pregnant, talk to your GP or midwife.
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