A plan that changes with you
Every body runs on its own calendar. Pregnancy, breastfeeding, hormone therapy, contraception and cycles that change all shape what good advice looks like. Here's exactly what Strathlon does in each case, and where it hands over to national guidance and to your midwife or GP.
Guided support through pregnancy
Turn on I am pregnant in Settings → Health & safety. The switch is there on every profile, whatever sex is recorded. A one-time note then helps you decide what to do with your current programme. Ending it is the recommended choice, so that when you're ready you start fresh from the shape you're in then, and you can keep it if you prefer. Everything you've logged stays exactly where it is.
From then on, your Plan tab shows the UK's national activity guidance for pregnancy, word for word, with the source named against every line. It includes, for example:
- "Throughout pregnancy aim for at least 150 minutes of moderate intensity activity every week."[1]
- "Do muscle strengthening activities twice per week."[1]
- The NHS talk test: you should be able to hold a conversation as you exercise.[2]
- The NHS's own list of activities to take care with or avoid[2], and a list of symptoms to stop for and get advice about[7].
Effort is guided by how it feels, using the talk test, as the guidance recommends. Your calories stay at what you burn, and your weight goal is set aside for the pregnancy, in line with NICE's guidance on weight during pregnancy[3]. The Nutrition tab points you to your midwife or doctor for eating guidance, and if you use the Supplements section it adds one line: "Talk to your doctor or midwife about supplements during pregnancy."
Logging keeps working as normal: your meals, weight and activity, your history and your Progress tab. If you use the AI coach, it's told about your pregnancy with every message, so its answers follow the guidance on your Plan tab and point you to your midwife or GP for anything specific to you. Their guidance always comes first.
Back to activity after birth
Turning on I am breastfeeding works in a similar way. The Plan tab shows the UK Chief Medical Officers' guidance for after childbirth: aim for at least 150 minutes of moderate activity a week, build back up to muscle strengthening twice a week, restart gradually, start pelvic floor exercises as soon as you can, and "You can be active while breastfeeding."[4] Your calories stay at least at what you burn while breastfeeding is recorded.
When you're ready, and once your pregnancy and breastfeeding switches are off, the guidance card offers Start a new programme if you ended your old one.
Cycle features on your terms
On a profile that records testosterone therapy, cycle features start switched off, because periods often stop or become irregular on masculinising therapy. If you still have periods, turn on I still menstruate in Settings → Cycle-aware insights and everything works exactly as it does for everyone else.
Calories tuned to hormone therapy
The optional hormone therapy question in Settings → Body & stats covers masculinising therapy (testosterone), feminising therapy (oestrogen) and HRT for menopause, which uses your standard calorie estimate. For masculinising or feminising therapy, when Strathlon is working from an estimate of your body composition rather than a measured body-fat percentage or lean mass, it starts from the standard resting-calorie figure for your height, weight and age and adds a small, capped adjustment, because hormone therapy gradually changes body composition. It deliberately moves the estimate half of the way, because a cautious estimate is the safer one. For some people the adjustment comes to zero: on oestrogen with female sex recorded, for example, your figure stays exactly as it was. Your minimum daily calorie floor stays the same in every case. Tap the (i) beside your BMR in Settings to see exactly what was applied to you.
Strong through every life stage
Strathlon builds your workout plan, your targets and your coaching from your own profile and logs at every age, so they follow you through perimenopause and beyond. The cycle notes follow the periods you log, so as your periods change, the notes change with them, and they appear whenever there's a logged period to work from. The hormone therapy question above includes HRT for menopause as its own answer.
Strength training is worth keeping up at every age: it's linked to better bone density, studied especially in women after the menopause. Why lifting matters. Talk to your GP about new or unusual bleeding and about symptoms that are affecting your daily life.
Notes that follow your log
Strathlon's cycle notes follow the bleeding you log in Apple Health, whatever contraception you use. On many hormonal methods that bleed is a withdrawal bleed rather than a true period, and research suggests the natural hormone swings are often flattened or replaced by steadier levels[5], so you may find the notes less relevant. You can switch Cycle-aware insights off whenever you prefer.
Forecasts from your own dates
Strathlon learns your typical gap from the periods you've logged over roughly the last six months. It keeps that between 21 and 40 days, and uses 28 days until you've logged two periods. Notes for your period appear on the days you've logged flow, so they always match your log. The pre-period notes are a forecast, so with a cycle that varies they can arrive a little early or late. The estimate runs for 40 days from the start of your most recent logged period and starts again when you log your next one, and you can switch Cycle-aware insights off any time you'd like a break.
If your periods become irregular or stop while you're training hard or eating less, treat it as a sign to eat more and ease the training load[6], and talk to your GP. The same goes for periods that are very heavy or painful. Energy availability and RED-S, explained.
References
The pregnancy and after-childbirth guidance quoted above is shown in the app with its source on screen; these are the same sources. The rest are numbered sources for the specific findings mentioned.
- UK Chief Medical Officers (Department of Health & Social Care, United Kingdom). Physical activity for pregnant women (infographic, text version). Published 7 September 2019, updated 16 July 2026. GOV.UK
- National Health Service (NHS, United Kingdom). Exercise in pregnancy. Reviewed 15 March 2023. NHS
- National Institute for Health and Care Excellence (NICE, England). NG247 Maternal and child nutrition: nutrition and weight management in pregnancy, section 1.2. NICE NG247
- UK Chief Medical Officers (Department of Health & Social Care, United Kingdom). Physical activity for women after childbirth: birth to 12 months (infographic, text version). Updated 16 July 2026. GOV.UK
- 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. PubMed 37823207 · PMC10979803 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. PubMed 37752011
- Sports Medicine Australia. Position Statement: Exercise in Pregnancy and the Postpartum Period. Updated 19 July 2016. A consensus list drawn from national guidelines, as the statement itself says. sma.org.au
This explains how the app behaves and is general information. Strathlon is a general fitness and wellbeing tool. If you're pregnant, have recently given birth, or have any question about your periods or your health, follow your midwife's, health visitor's or GP's guidance.
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