Is A 120 Heart Rate Easy To Exceed During Exercise While Pregnant?

Exercising at a moderate intensity for 30 minutes per day most days of the week while pregnant is recommended by the American College of Obstetricians and Gynecologists (ACOG). A heart rate of 120 beats per minute is an indication of a moderate intensity prior to pregnancy, but it may not be the best intensity measure during your pregnancy, because it may be too easy to achieve.

Pregnancy Changes

ACOG used to recommend against exceeding 140 heart beats per minute when exercising during pregnancy, Mayo Clinic reports. Recommendations were updated in 2002 to no longer include heart rate limitations. When you are pregnant, your blood volume doubles, making your heart work harder, pumping more blood to your uterus and growing baby. All of this extra work can increase your resting heart rate from around 70 beats per minute to 80 or even 90 beats per minute, according to "Prenatal and Postpartum Exercise Design." Also, as you approach the end of your pregnancy, your maximum heart rate may decrease. All of these changes make it easier for you to reach and exceed 120 beats per minute during exercise, which is why heart rate is an unreliable measure of exercise intensity.

Workout Intensity

Instead of using your heart rate to measure workout intensity, the American College of Sports Medicine (ACSM) recommends using the Borg Rating of Perceived Exertion, or RPE, scale. This is a 10-point scale where level 1 is sitting and level 10 is all-out effort. During your pregnancy, you should try to reach level three or four, which feels similar to carrying a couple bags of groceries into your house from the car. ACOG says you should be able to speak normally throughout your workout and you should never exercise to the point of exhaustion.

Benefits

Exercise during pregnancy is healthy and provides benefits for you and your baby. It helps reduce backaches, constipation, bloating and swelling, according to ACOG. It can also improve your mood, help you sleep and may even improve your ability to cope with labor. Babies born to mothers who exercise have lower birth weights, lower body mass indexes at birth, lower heart rates and improved heart rate variability.

Precautions

Certain activities, such as contact sports, water skiing, scuba diving and those that have an increased risk of falling, such as gymnastics or horseback riding, are not appropriate during your pregnancy. For everything else, check with your doctor first, but you should be able to continue your normal routine. Drink water before, during and after your workout and meet your daily calorie requirements. Avoid exercising in the heat or humidity, wear a supportive bra and don't lie flat on your back after your first trimester. Stop exercising and call your doctor if you feel dizzy or short of breath, get a headache, chest pain, muscle weakness, calf pain or swelling or feel contractions. Also tell your doctor if you feel a decrease in the baby's movements or see any blood or other leaking fluid.