Talk Test for Exercise in Pregnancy: How It Works

Pregnancy is the clearest case in all of exercise prescription where the number on a watch is the wrong tool. Heart rate at rest and during effort shifts over the course of a pregnancy, so formulas built on age stop describing anything useful. The American College of Obstetricians and Gynecologists resolves this by recommending perceived effort instead — and the talk test is the version you can run without knowing what perceived effort means.

What ACOG actually says

Committee Opinion No. 804 puts the reasoning on the page: “Because blunted and normal heart-rate responses to exercise have been reported in pregnant women, the use of ratings of perceived exertion may be a more effective means to monitor exercise intensity during pregnancy than heart-rate parameters.”

It then gives two ways to apply that:

• A rating. “For moderate-intensity exercise, ratings of perceived exertion should be 13–14 (somewhat hard) on the Borg ratings of perceived exertion scale.”
• The talk test. “As long as a woman can carry on a conversation while exercising, she likely is not overexerting herself.”

The federal Physical Activity Guidelines reach the same place by a different route: “During pregnancy, perceived exertion is often a better indicator of intensity than heart rate or estimated absolute energy requirements of specific activities.” They place moderate work at an effort of 5 to 6 on a 0 to 10 scale and describe the talk test as being able to carry on a conversation, but not sing.

How to run the talk test

• Can you speak in full, comfortable sentences? You are at or below moderate intensity.
• Can you talk but not sing? That is moderate — the band the guidance is aiming at.
• Can you manage only a few words before pausing for breath? That is vigorous. Ease off unless you were a habitual vigorous exerciser before pregnancy and your clinician has agreed you can continue.

Nothing about that requires knowing the Borg scale, though if you want the rating behind it, the Borg RPE scale calculator shows where 13 to 14 sits and what the neighboring numbers feel like.

How much, and of what

The 2018 federal guidelines reaffirm at least 150 minutes of moderate-intensity aerobic activity per week during pregnancy and the postpartum period, spread through the week. ACOG frames the same target as building toward moderate-intensity exercise for at least 20 to 30 minutes a day on most or all days, adjusted as medically indicated. Women who habitually did vigorous activity before pregnancy can generally continue it.

Its list of activities extensively studied and found safe starts with walking, stationary cycling, aerobic exercise and dancing. Strength conditioning is encouraged alongside aerobic work.

What to avoid, and one date worth getting right

ACOG advises avoiding contact activities with a high risk of abdominal trauma or loss of balance, and avoiding scuba diving outright, “because of the inability of the fetal pulmonary circulation to filter bubble formation”. Staying well hydrated and out of high heat and humidity matters most in the first trimester.

On lying flat, the two American documents differ and the difference is worth naming. The federal guidelines say to avoid exercises lying on your back after the first trimester. ACOG’s 2020 opinion is more specific: maintaining a supine position during exercise after 20 weeks of gestation may reduce venous return through aortocaval compression, and exercise should be modified accordingly. When two American sources disagree, this site follows the obstetric guideline written for the question.

Stop exercising and seek advice for any of the warning signs ACOG lists: vaginal bleeding, abdominal pain, regular painful contractions, amniotic fluid leakage, shortness of breath before exertion, dizziness, headache, chest pain, muscle weakness affecting balance, or calf pain or swelling.

This content is informational and does not replace prenatal care. Pregnancies with obstetric or medical complications need individual evaluation before starting or continuing a program. For the pulse-based view of the same question — and why it is the weaker one here — see target heart rate during pregnancy and RPE vs heart rate training.