When temperatures rise, many people swim to beat the heat. But swimming does a lot more than give relief from hot weather. It is a great workout for the whole body.

Health experts at the University of California, Berkeley write on their website Berkeley Wellness that swimming is "an ideal way to stay in shape."

Swimming is a high-cardio but low-impact exercise.

Cardiovascular exercise is often simply called "cardio." Cardio involves the heart, lungs, and circulatory system. The Berkeley experts say swimming is great for your cardiovascular system. It increases your heart rate and exercises your lungs without putting stress on the rest of your body.

Some high-cardio exercises, such as running, can improve your health but can also be hard on your body. Swimming, on the other hand, is so easy on the body that people often use it to heal from injuries.

A former competitive swimmer, Paul Waas, now coaches a team of swimmers. He says that swimming is easier on the body than other sports because it is low-impact. For this reason, it is a common exercise for people who are in rehabilitation -- or “rehab,” for short.

"Well, swimming is a lifelong sport. It's a non-impact sport. And you know, it's horizontal rather than vertical. So, it's great for a lot of rehab from running injuries and things like that.”

A mother with two daughters on Coach Waas’s swim team agrees. Paloma says that for her girls swimming has been easier on the body than some other sports.

"So far, I think it's been good for their bodies. It's a lot of exercise, as you know. But it spares their knees, their joints, etc. But it's rare to get injured in swimming."

The coach adds that swimming is a great exercise for kids who grow a lot in a short amount of time. Again, here is Coach Waas.

“One of the things swimming is really good for is kids who go through really intense growth spurts. Their bones might be hurting and they're aching all the time. And then they get in the pool and, you know, they can float and stretch out a little bit and it relieves that as well.”

Swimming is also good for people with disabilities, or with chronic conditions such as arthritis and back pain. People who are overweight can find relief swimming. Their weightlessness in the water can help them to avoid injury as they exercise.

As we said earlier, swimming is an all-body workout. It works small muscle groups that often get ignored in other workouts. As you move in the water, many small muscle groups are working to help keep you balanced and upright.

However, swimming is not without any risk of injury. Many types of swimming use repetitive arm movements. Over time, the repeated movement can cause shoulder and neck injuries. This is especially true if the stroke is not done correctly.

To reduce the chances of getting hurt, swimmers can use different kinds of movements in the water. For example, they can mix standard swimming strokes with running in water, treading water and other water exercises.

The researchers at University of California Berkeley warn that another downside to swimming and other water workouts is that they are not weight-bearing exercises. So, they do not help to strengthen bones.

To make sure your bones are getting the exercises they need, the researchers suggest combining swimming with a weight-bearing exercise. Common weight-bearing exercises are dancing, walking, running or jumping rope.

Paloma, the mother we heard from earlier, adds that she was concerned about this issue. Her older daughter, Pryia, has mostly been a swimmer. So, playing, what she calls a “terrestrial sport,” has helped give her daughter a good balance.

“This year our older daughter has done more, what I call ‘terrestrial sports’ -- contact with the earth. And I think it’s been actually good for her to have the mix because she only has been a swimmer, primarily."

"And so you can be in swimmer shape but your muscles are not being challenged. So, it helps to really balance out. If you’re a basketball player all year, that’s not great for your body, but if you swim half the week and do other sports, I think that’s a good balance.”

But for many swimmers these downsides seem manageable when compared to the health benefits. Coach Waas agrees.

"You know, swimming can have some … some injuries from high repetition. But, in general, it's one of the safest and healthiest sports out there."

Besides the great workout you can get from swimming, Paloma brings up another important way it can help. It can help to keep you alive.

"My husband and I believe that swimming is a life skill. If it's a life and death situation, you can swim your way out of it. And as such, we really wanted them to be strong swimmers.”

Her daughter Pryia knows that swimming is good for her body. But perhaps the reason she likes to swims is more basic. It’s just fun.

"The water, of course, it keeps you cool while you're swimming. Also, you get a whole different way to use your muscles. And, overall, it's just fun to do because you get to stay in the water a lot."