Pregnancy Exercise Heart Rate

Guidance has moved away from a fixed limit

For many years the standard advice was to keep your heart rate below 140 beats per minute during pregnancy. That specific limit has largely been withdrawn from major guidelines, because it was not based on strong evidence and because it treated every pregnant person as identical regardless of fitness.

Current guidance from most obstetric bodies instead recommends around 150 minutes of moderate-intensity activity per week for people with uncomplicated pregnancies, with intensity judged by how the effort feels rather than by hitting a numeric ceiling.

The ranges shown here are a reference for what moderate intensity typically looks like, not a limit imposed on you.

The talk test is more useful than a number

The most practical way to gauge intensity in pregnancy is whether you can hold a conversation.

At moderate intensity you can talk in full sentences but could not comfortably sing. You are working, breathing harder, and slightly warm. This is the zone most guidance points to.

At vigorous intensity you can only manage a few words at a time. Some people who exercised at this level before pregnancy continue to, but that is a conversation to have with your midwife or doctor rather than a general recommendation.

If you cannot speak at all, that is a signal to ease off regardless of what any monitor says.

Why heart rate readings shift in pregnancy

Resting heart rate typically rises by 10 to 20 beats per minute during pregnancy, mostly in the second trimester, as blood volume and cardiac output increase. This means your heart rate at any given effort will be higher than it was before pregnancy — and that is expected, not a warning sign.

It also means percentage-based zones calculated from a pre-pregnancy baseline no longer describe the same effort. This calculator uses your current resting rate for that reason, but the underlying point stands: perceived exertion is more reliable than the number during pregnancy.

Activities that suit pregnancy well

Walking is accessible at any fitness level and easy to scale. Swimming and water aerobics take weight off joints and are often the most comfortable option later on. Stationary cycling removes the balance risk of a road bike. Prenatal yoga and Pilates support flexibility and pelvic floor strength. Modified strength training with lighter loads is generally well tolerated.

Generally advised against are contact sports, activities with a meaningful fall risk such as skiing or horse riding, scuba diving, hot yoga, and exercising at high altitude if you are not acclimatised. Lying flat on your back for extended periods is usually discouraged after the first trimester because it can restrict blood flow.

Stop and seek advice if

Stop exercising and contact your midwife or doctor if you experience vaginal bleeding, regular painful contractions, fluid leaking from the vagina, chest pain, calf pain or swelling, dizziness or faintness, severe headache, muscle weakness affecting balance, or shortness of breath before you have started exerting yourself.

These are the warning signs listed in standard obstetric guidance. None of them means something is certainly wrong, and all of them warrant checking rather than pushing through.

Before you start

Exercise in pregnancy is well supported for most people, and is associated with benefits including better sleep, reduced back pain, and lower risk of gestational diabetes. But “most people” is not everyone.

If you have a multiple pregnancy, placenta praevia, a history of preterm labour, pre-eclampsia, cervical insufficiency, significant anaemia, or any heart or lung condition, exercise recommendations change. Speak to your midwife or doctor before starting or continuing a programme — they can give advice grounded in your particular pregnancy, which no calculator can.

Common Questions