Exercise during the second trimester of pregnancy can be very important in keeping up your energy level and for helping you sleep well at night. The key to exercise during pregnancy is to take it slow and steady. You should warm up, exercise, stop if you feel short of breath or are in pain, and slow down before you come to a complete stop. It is always wise to get your health care provider's stamp of approval before you begin an exercise program or if you want to change your program while pregnant.

How Hard Should I Exercise?

When you exercise, make sure you stay below 60% of your maximum heart rate. For most women, this means you should maintain your heart rate at less than 140 beats per minute. Keeping your heart rate in a good range is important when you exercise because your body moves more blood to your muscles and skin and may move less to your uterus. If exercise is too strenuous, there is a risk that less oxygen will reach the baby. If you stay below 60% of your maximum heart rate, you don't need to worry about harming your baby when you exercise. Remember to avoid overheating and keep yourself hydrated during any exercise.

What If I Have Been Instructed Not to Exercise During Pregnancy?

With all this talk about the benefits of exercise, there is also little harm in not exercising. Women who choose not to exercise also have healthy babies. Don't worry if your doctor has suggested that you not exercise. It is recommended that you abstain from exercising if you have a variety of pregnancy-related conditions, for example, placenta previa, toxemia, preeclampsia, or intrauterine growth retardation. If you have a history of spontaneous abortions or an insufficient cervix, it may also be recommended that you not exercise. The beneficial effect of protecting your baby by not exercising outweighs any good done by a few laps in the pool.

What Types of Exercise Are Appropriate During the Second Trimester of Pregnancy?

Aerobic activities such as running and swimming, relaxation techniques, and strength training are all appropriate during the second trimester of pregnancy, as long as you are aware of your limits and follow simple guidelines for safety. Month-by-month guidelines are given below:

4th Month

  • Weight training : As you begin your second trimester this month, your total blood volume has increased and the placenta and baby are growing. When you stand, blood can pool in your legs, causing you to become lightheaded or dizzy. For this reason it may be safer to do weight training exercises while seated.
  • Jogging and running : If you are a runner, you can safely continue to run in moderation. During your second trimester your uterus gets larger, causing your center of gravity to shift which makes you more prone to losing your balance. Therefore, pay close attention to where you're running, and be sure to run on flat ground with as few obstacles as possible.
  • Yoga : As you slowly get bigger and your joints loosen, your balance may be affected, putting you at risk of injury. Pay attention to your body and only do as much exercise as is comfortable. Your breathing should stay smooth, and if you find you cannot breathe easily and smoothly during positions, think about shifting into an easier version of the position, stretching or extending less, or staying closer to the floor.
  • Swimming : If you are a swimmer, you should be able to continue swimming into your second trimester without any difficulty. If you are new to swimming, start slowly by swimming gently for short periods of time, taking caution not to overexert yourself, and working up to longer workouts.

5th Month

As your belly gets bigger, you may find that your center of gravity has shifted and you're not as agile as you once were. Compensate by being more careful when you step. At this time you will also want to stop exercises that require you to lie on your back. As your uterus increases in size, lying on your back can put pressure on the inferior vena cava, the large vein that runs vertically the length of your abdomen and is responsible for returning blood to the heart.

As you progress in pregnancy, your body produces a hormone called relaxin, which is responsible for loosening joints in preparation for a growing baby, labor, and delivery. As your joints become looser, you are at more risk for sprains and strains. Your increased weight and the change in your center of gravity may cause you to lose your balance, also putting you at greater risk for injury. For this reason, it is better to avoid exercises that involve extreme stretches or those high-impact activities like aerobics and running that put a lot of stress on your joints and put you at risk for falls.

  • Yoga: As your pregnancy progresses and has a larger impact on your activity, it might be wise to consider joining a yoga class for pregnant women or buying a book of yoga poses that are safe for pregnant women.
  • Walking : As your gait changes because of the changes in your body shape, be sure to focus on your posture when walking and keep your hips tucked under to prevent arching your back due to the increasing amount of weight you're carrying in front. When you feel out of breath, slow down or stop, and rest. You shouldn't be huffing and puffing.
  • Swimming: If you are a swimmer, you should be able to continue swimming into your second trimester without any difficulty. If you are new to swimming, start slowly by swimming gently for short periods of time, taking caution not to overexert yourself, and working up to longer workouts.

6th Month

Your blood volume increases by 40% during pregnancy and your cardiac output (heart rate times amount of blood pumped per beat) increases by 30 to 40%. During exercise, your heart rate increases even more. Although research shows that women who exercise regularly have no increased risk of problems with their pregnancies, the key is still moderation. Don't push yourself too hard. Keep yourself hydrated and cool.

  • Weight training: You may want to decrease the duration or frequency of your workout, depending on how you're feeling. If you use free weights, be very careful to avoid blunt injury to the abdomen from dropping weights.
  • Yoga: Now that you're at the end of your second trimester, you may need extra balance support when doing standing poses. Avoid poses that stretch the abdominal muscles and that require you to lay on your back. Bend from your hips. If you feel discomfort, stop and reevaluate if there's an easier way to do the position.