In short. Training and fertility are linked non-linearly: moderate regular load raises the chances of conception (normalises insulin, regulates the cycle, helps maintain a healthy weight, lowers chronic stress), while excessive load reduces them through the mechanism of relative energy deficiency in sport (RED-S), when the body switches off ovulation as a survival strategy. The safe corridor for those planning is 2–6 hours of moderate activity a week; more than 10–12 hours of intense work (HIIT, long runs, competitive CrossFit) is the risk zone. The first sign of overtraining is a disrupted or missing cycle; it is reversible in 2–6 months after load and nutrition are corrected. When planning IVF the priority is strength work and moderate-intensity cardio, without HIIT or heavy twists during stimulation (risk of torsion in enlarged ovaries). Kegel exercises do not affect fertility directly but strengthen the pelvic floor for the upcoming pregnancy and birth. The main criterion is not hours but the state of the cycle and how you feel.
The short answer
Moderate regular training raises the chances of conceiving. It normalises insulin, lowers chronic stress, regulates the cycle, helps hold a healthy weight.
Excessive training lowers the chances of conceiving. It raises cortisol, depletes reserves, breaks the cycle and can stop ovulation.
The line between “helps” and “hinders” is individual, but it is visible through body signals. Let us look at where it runs and how not to miss it.
When exercise really helps with conception
More than 10–12 hours of high-intensity load a week while planning pregnancy switches off ovulation through RED-S – and the first sign of overtraining is not fatigue but a disrupted or missing cycle, which returns 2–6 months after load is reduced.
1. Normalises insulin sensitivity
Insulin resistance is one of the common causes of PCOS and anovulation. Strength training and moderate-intensity cardio improve cell sensitivity to insulin within weeks. In women with excess weight and a disrupted cycle, this often brings ovulation back.
2. Lowers cortisol
Chronic stress raises cortisol, and high cortisol suppresses progesterone – the hormone without which conception is impossible. Moderate load, especially outdoors, lowers baseline stress. It is not only swimming and yoga that work – moderate-paced strength training also does.
3. Helps hold a healthy weight
A BMI of 18.5–25 is statistically the best range for conception. Both excess weight (25+) and underweight (<18.5) reduce fertility, though through different mechanisms. Regular training plus adequate nutrition keep weight in this corridor.
4. Improves egg quality
This is less obvious, but according to reproductive specialists, women with regular moderate activity face poor oocyte quality less often. Probably through the same insulin and cortisol pathways, plus improved ovarian blood flow.
When exercise starts to hinder
This is called “relative energy deficiency in sport” – RED-S. The essence: a woman spends more calories than she gets, or gets them but under such stress that the hormonal system decides “now is not the time for pregnancy” and switches off ovulation.
Signs that you have overtrained
- Irregular or missing cycle. The main red flag. If the cycle slipped during intense training or a strict deficit – that is not “just because”, that is the body cancelling fertility.
- Constant fatigue despite sleep. You wake up already tired.
- A drop in libido. The hormonal system lowers reproductive activity as a whole.
- Trouble recovering. After a regular session, muscles hurt for 3–4 days instead of 1.
- Frequent colds. Immune function dips.
- Anxiety, insomnia. High cortisol on top of a deficit.
If 2–3 signals are present, that is RED-S. Time to roll back.
What kind of load triggers it
- More than 10–12 hours of intense load a week (HIIT, competitive CrossFit, marathon training).
- Calorie deficit of more than 500 kcal a day without medical supervision.
- Daily training without rest days.
- The combination of “I train a lot and eat little” – most often subconscious, especially in women after a diet.
Important: for one woman 8 hours a week is the norm, for another it is excess. The criterion is not in hours but in what is happening with the cycle and with how you feel.
What to do if the signals are there
Step 1. Reduce load
Not stop, but reduce. Remove anything intense: HIIT, competitive sessions, marathons. Keep 2–3 sessions a week of 45 minutes at low-to-moderate intensity. Add walking, stretching, yoga.
Step 2. Increase food
No fasting. Protein 1.2–1.6 g per kg of weight, fats at least 30% of calories (female hormones are made from cholesterol), carbs by how you feel. Remove the deficit completely. If there is excess weight, address it later, after the cycle is restored.
Step 3. Give the cycle time
The cycle returns in 2–6 months. If amenorrhea has lasted a long time, it may take up to a year. Observe: the first regular cycles appear as a signal that the system has switched back on.
Step 4. Go to a doctor
If the cycle has not returned in 3 months – see a gynaecologist-endocrinologist. Check hormones: FSH, LH, oestradiol, prolactin, progesterone, thyroid (TSH, T3, T4), cortisol. This often helps pinpoint what has slipped.
IVF and training – a separate story
If you are in an IVF protocol, the rules change.
- Before the protocol – usual preparation routine: moderate training, normalising weight.
- In stimulation – intensity is reduced. The ovaries enlarge and there is a real risk of torsion under impact load. Remove jumping, HIIT, heavy twists. Keep walking, yoga, swimming.
- From transfer to the hCG test – the most cautious mode. No shaking, no lifting, no heating the body (sauna and hot baths are banned). Walking, breathing, Kegel.
- After a positive test – switch to pregnancy mode, see the first trimester article.
The specifics of your protocol – with your reproductive specialist. The general logic: less load than usual. If you are a regular runner and you have conceived after IVF, most protocols recommend excluding running and any impact load in the first 12 weeks; after clearance you can gradually return. More on this – in the running during pregnancy article.
A practical minimum for those planning
If the cycle is regular, weight is in range and you feel well – the ideal baseline is already there. What is worth adding or adjusting:
- 3 sessions a week of 45 minutes – strength plus moderate-intensity cardio.
- Pelvic floor and breathing daily for 5–7 minutes – this skill will be useful right after a positive test.
- At least 7 hours of sleep – critical for ovulation.
- Folic acid 400 mcg a day at least 3 months before planning.
- Walking 7–10 thousand steps a day as a baseline.
What to remove if it has been there:
- Regular training to exhaustion.
- Strict diets with a deficit of more than 500 kcal.
- Daily cardio sessions of 60+ minutes.
- Alcohol on the eve of training and during the implantation window.
The bottom line
Training itself almost never gets in the way of conception – what does is its combination with underfeeding, chronic stress and ignoring body signals. A healthy training routine is one after which you feel better, sleep deeper, recover well and have a regular cycle.
If you want to build a preparation plan for your specific situation, an intro session is from 1 400 roubles online. Together we look at where you are now, what is worth changing before planning, and build a routine for the next 3–6 months.
You can start the Before-pregnancy programme without a session – it has a base structure for 3 months.
