Tennis, Swimming Keep Heart and Mind in the Game

Variety is the spice of life — and also of exercise routines. Research shows that tennis and swimming can challenge your body, and your brain, in new ways.

On the tennis court, you get a great mental workout, said Mark Kovacs, executive director of the International Tennis Performance Association. That's because on the court, your brain has to switch gears frequently: "You have to keep your arms and legs moving to get to the ball, make contact with the ball, figure out where to hit it and then get to the next shot. It's not a one-off event like hitting a golf ball and walking a long distance before you have to do something again."

Attention improves too. "The visual process of having to recognize the ball coming at you quickly can transfer to your life off the court. Your brain has to recognize situations quickly and find ways to deal with them." 

Both mental skills can decline after people retire because they're not using those skills as much.

In the swimming pool, you don't need to chase after Michael Phelps' world records in order to get a boost. All you have to do is get into the pool.

One small Australian study found that being submerged in warm water to the level of the heart increased blood flow through the brain's cerebral arteries by 14 percent. In this case, those tested were in a tank that pumped in warm water, not the usual conditions found in community swimming pools. The authors added that more research needs to be done, but that swimming and other aquatic sports might have the potential to improve vascular health and cognitive function.

And don't forget, health experts say: The most important outcome of adding variety to your workouts is adherence. According to a University of Florida study done in 2000, people who had a varied exercise program were more likely to keep working out — and they enjoyed it more.