My doctor told me to keep my Heart Rate below 140. Is this accurate?

Not necessarily. It’s important to note that heart-rate response to exercise varies throughout pregnancy, and from one individual to another. Blunted, exaggerated, and normal linear responses may all be seen at different stages during the same pregnancy. This means that heart rate is NOT an accurate way to monitor exercise intensity during pregnancy. Unfortunately, the guideline to “keep your heart rate below 140 beats per minute” is still one of the biggest prenatal exercise myths out there (and regrettably, we hear it most often from doctors). This is an outdated ACOG guideline from 1985 when almost no research existed about exercise during pregnancy. ACOG eliminated this guideline in 1994 after research revealed the issues with variable heart-rate responses to exercise and replaced it with the guideline to use Rate of Perceived Exertion (RPE) instead. This relies on women listening to their bodies and gauging their intensity by how they feel, which is a much more accurate method.