After months of exercising indoors on stationary bikes, treadmills, resistance machines or ellipticals, people should spend their summer months in the water to get a great cross-training workout, says Selen Razon, an exercise psychologist at Ball State University.

“Summer is great for swimming, and swimming is great for cardiovascular health,” she says. “Because one in four women in the U.S. dies from heart disease, women should take advantage of the opportunity for swimming in summer — even as a recreational activity.”

And if you are tired of hefting dumb bells, water aerobics is a great resistance exercise, strengthening bones, says Razon. “Women are at greater risk for developing bone-thinning diseases and should take advantage of water aerobics in the summer,” she says. “The added benefits include greater oxygen intake and increased heart rate. Before you know it, you strengthen your bones, burn extra calories and tone your body in the pool.”

Razon says that getting outside will provide an instant boost since studies have show that outdoor activities have 50 percent greater positive effect on mental health than going to the gym.

However, as the weather improves, heat and humidity will increase. So, she suggests:

• Exercising before 10 a.m. or after 3 p.m. to beat the heat;

• Applying sunscreen when exercising outdoors during daylight hours;

• Checking weather forecasts;

• Skipping exercise during a heat advisory;

• Stopping your exercise if you feel weak, lightheaded or nauseous.