Training Considerations for Women Runners

Eat enough for the training

Eating too little for the training is common and easy to miss. Sports medicine calls it low energy availability, and the syndrome it causes is Relative Energy Deficiency in Sport (REDs). A 2023 International Olympic Committee consensus statement describes it as poorer health and performance in women and men who take in too little energy for what their exercise uses¹.

It is a performance problem as well as a health one. In a 2025 review, 44.7% of 6,118 athletes in 46 studies had low energy availability, and across the 59 studies in the review, those athletes ran worse, responded less to training and missed more training with illness than athletes who ate enough². When running gets harder for no clear reason, check food and sleep first. Girls and young women who are still growing need intake to match output too, including food after hard practices.

If a doctor finds that eating too little has stopped your periods, the fix is more food. The 2025 triad update says periods stopped by an energy deficit can come back with a moderate increase in food intake, and that one period is not the finish line: ovulation and hormone levels do not recover until several normal-length cycles in a row³. Keep eating for the training until then. See the guide on daily nutrition.

Missed periods and the first signs of a bone injury

A period that stops, or comes fewer than nine times a year, is a signal and not a bonus of training hard. In a 2021 study of 183 competitive women distance runners aged 18 to 40, bone stress injury was 2.25 times as common in those with fewer than nine periods in the past 12 months as in those with regular periods. Women on hormonal contraception were not in the study⁴. A missed period also has causes other than eating too little, so it needs a clinician, not a guess.

Effort changes before pain does. Runs feel like a grind day after day with no heat or hard week to explain it. Next comes a low-level spot that feels off at the start of a run, eases and is gone afterward. Later the pain stays through the run and at rest, or goes after three days off and returns when you restart, which is the stress fracture pattern. See someone at the first spot: a clinician who treats runners puts the cost of catching it then at about two weeks, and of catching it late at about twelve. See the guide on stress fractures.

Take more care in any big hormonal shift: adolescence, the months after a baby and the menopause transition. Low estrogen from any cause raises bone stress risk, so adjust the load.

Your cycle and training

A 2026 review found that links between cycle phase and performance are weak, vary from study to study and differ from one woman to the next. It concluded that no phase is better or worse for everyone, and that the evidence does not support rigid training rules by phase⁵. So there is no phase to schedule hard days into.

Use your own record. For two or three cycles, note the first day of your period and how each run felt. If a certain week is reliably rough, move the hard session two or three days or trim it. If you feel good, run, whatever the calendar says.

Iron

Low iron can cost you speed, and a hemoglobin check can miss it. In a 2023 study of 126 university athletes in Japan, none was anemic, yet 22 of the 47 women (47%) had a ferritin of 30 ng/mL or less⁶. Ferritin is the blood marker of iron stores. A 2024 review of iron in female athletes found that iron deficiency lowered endurance performance by about 3% to 4% in high-level athletes, and that endurance improved with supplements in the studies it covered⁷.

If you are tired or slower than your training explains, tell your clinician about heavy bleeding and ask for a blood test that includes ferritin and your red blood cell count before you take iron. Studies and labs draw the line for low ferritin in different places, so take the number to a clinician.

Running in pregnancy

If you ran before you were pregnant, the 2020 guidance from the American College of Obstetricians and Gynecologists is that you can continue, and that a woman who was not exercising should start. It applies when there are no obstetric or medical complications, and the routine may need to change as your body does⁸. Ask your midwife or doctor before you start, continue or change running.

There is no research on how much high-volume running is too much in pregnancy, so let symptoms and fatigue set the load. If a run is followed by an afternoon on the couch, or you cannot manage the evening, your energy was too low for the load: cut back. The long run comes down first. Many runners move some of the work to the stair machine, the elliptical or the pool as the weeks pass, and some run to the end.

Keep lifting, at 12 to 14 reps to fatigue so loosened joints are not loaded as hard, with no one-rep max lifts. Start core work early.

Coming back after birth

Your doctor's check at six to eight weeks clears healing. It does not tell you when to run. An international panel of 118 clinicians and exercise professionals agreed that after at least three weeks of rest and recovery, an individual, gradual return can be considered, after screening for medical and psychological concerns, your current fitness and your training history⁹. A second panel agreed the program should start with run-walk, include strength training, and change with pelvic symptoms, sleep, mental health, breastfeeding or concerns about eating enough¹⁰.

Order the return: sleep and food first, then a visit to a pelvic floor physical therapist whatever the type of birth, then strength, then run-walk. Some clinicians build strength for about twelve weeks before the first run. The pelvic floor and the abdominal wall take months, not weeks, to recover. Pelvic symptoms such as leaking are a reason to change the plan and be seen, and they can appear years later if this step is skipped.

Start with a minute of running and a minute of walking, repeated, and build the running slowly. After a broken night, skip the long run and walk or bike instead. A setback costs more time than going slowly does, so a gradual return is the faster one. Bring speed work back after a couple of months of easy running, and expect to be slower than you were for many months, with a personal best a project of a year or more.

Eat more, not less. Breastfeeding adds an energy cost on top of the training and low estrogen raises bone stress risk, so give yourself a longer runway than you think before full training. See the guide on returning to running.

Perimenopause and menopause

Perimenopause can last up to ten years with no clear start. It is poorly researched and often misdiagnosed, so take questions about it to a menopause specialist. If you are slowing, rule out the ordinary causes first, in this order: food, recovery (are the easy runs truly easy?), then a blood test for iron, vitamin D and thyroid.

Make the training flexible. Three weeks building and one easier, or two and one, works better than a fixed block, and skipping or swapping a session on a bad day is part of the plan. Strength is the key piece: start with a small dose so soreness does not drive you off, then lift heavier. See the guide on strength training for runners.

Protect bone. Running and lifting build bone only moderately. Jumping, hopping and side-to-side movement are stronger signals, so add a short set of them, starting around 50 ground contacts before a run. Ask for a bone density (DEXA) scan when you enter early perimenopause, sooner if you dieted, ate too little or ran high mileage in your late teens and twenties.

Eat enough. Many women gain weight through the transition, and cutting calories to fix it makes the running harder and raises the risk of injury and bone loss. Eat for the training with enough carbohydrate and protein, and drink and sleep enough.

Heart rate and heat change. A heart rate that creeps up on a long run at a steady pace is normal in menopause, and edging into zone 3 late is fine. A dramatic change is a reason to see a doctor. Heat tolerance falls, so hydrate, add walk breaks and cool your body. Some days feel easy and some feel like running through cement, so judge by effort, as in the guide on heart rate zones. More on training from 40 on is in the guide on masters running.