Any type of aerobic exercise during pregnancy helps increase your body’s ability to process and utilize oxygen, which is important for you and your baby. But swimming is great exercise because it uses both large muscle groups (arms and legs). And although it’s a low-impact activity, swimming provides good cardiovascular benefits and allows expectant women to feel weightless despite the extra pounds added by pregnancy.
Swimming also improves circulation, increases muscle tone and strength, and builds endurance.
Swimming helps counteract the increased back strain from your expanding belly. Pregnancy forces the spine and shoulders to round forward and the pelvis to tilt out of alignment, but swimming gently strengthens the muscles and offsets this tendency. The water also protects you from overheating and supports your joints and ligaments as you exercise, preventing injury.
If you swim, you burn calories, feel less fatigued, sleep better, and are better equipped to handle pregnancy’s physical and emotional challenges. Swimming also helps you keep your weight within a healthy range, and some women say swimming also makes them feel less bloated.
Swimming is one of the safest forms of exercise. If you swam regularly before pregnancy, you should be able to continue without much modification. Just be sure you know the signs to stop exercising when you’re pregnant.
If you didn’t swim or exercise at all before pregnancy, it should still be okay for you to swim, but check with your doctor or midwife first. You need to start slowly, stretch well during a gradual warm-up and cooldown, and be careful not to overexert yourself.
When you’re in the water, it can be easy to forget to stay hydrated. James M. Pivarnik, Ph.D., of Michigan State University, says that while there is no official recommendation for how much water pregnant women should drink while exercising, a good guideline is to drink one 8-ounce glass before you start your swim, one glass for every 20 minutes of exercise, and one glass after you get out of the pool. In hot or humid weather, you need more.
If you have the energy, swim for at least 30 minutes on most, if not all, days of the week. Swimming first thing in the morning may counteract nausea and energize you for the rest of the day.
Your pregnancy won’t require you to cut down on swimming as you grow because it’s easy on expectant moms. And because the water’s buoyancy reduces the effects of gravity on your body, you can even lie on your back to do the backstroke without risking the impaired blood flow such exercises can cause on dry land.
You probably won’t need to modify your regimen, but think about getting a maternity swimsuit so you’re more comfortable as your belly expands.
The breaststroke might be the most beneficial stroke in the third trimester because it lengthens the chest muscles and shortens the back muscles, two areas that typically become misaligned as your body changes during pregnancy, says Julie Tupler, RN, certified personal trainer and founder of Maternal Fitness, a fitness program for new and expectant moms in New York City. Use a snorkel to relieve the pressure on your neck created when you bob up and down for air.