There are 3 great ways to measure exercise intensity during your pregnancy – Heart Rate, RPE, and Talk Test. Different methods work best depending on how far along you are in your pregnancy. Below I will outline each method and when to use each one. It is most safe and effective to have a primary method and backup at each stage of pregnancy.
Heart Rate – Resting Heart Rate can raise 10-20bpm in the beginning stages of pregnancy so you can reach your max and target heart rates faster than if you were not pregnant. Monitoring your heart rate when performing cardiovascular exercise in the first 20 weeks is a good idea to ensure you don’t go over target. After 20 weeks, switch to RPE or Talk Test as your primary way of monitoring intensity. At weeks 20-28 HR is a good backup test, and after 28 weeks, HR checks lose their effectiveness.
Ideal Heart Rate Zone: Under 20yrs old: 140-155bpm; Age 20-29: 135-150bpm; Age 30-39: 130-145bpm
RPE– RPE, or Ratings of Perceived Exertion, is simply how hard you feel you are working. In weeks 20-28 of pregnancy, RPE is a more accurate way to measure intensity rather than Heart Rate. In late pregnancy (after 28 weeks) RPE is the best measure.
Ideal Borg Scale Zone for all Ages: 12-14 (Somewhat Hard). If you think in 10s, then on a scale of 1-10, exercise in the 5-7 zone. (5-Moderate, 6- Somewhat Hard, and 7- Hard)
Talk Test- The talk test is a great back up method in the first half of pregnancy and can be used as the primary method of determining intensity in the last 20 weeks.
How to use the Talk Test- When warming up, it should be becoming difficult to talk, but you can still make conversation. During cardio work, it should be hard to talk, but you can still make brief sentences. If you are gasping for air and cannot talk at all, you are working too hard.