If the warm weather has you itching to get out and play ball, go for a bike ride or hit the hiking trails, put that energy to work.
Do it — just don't overdo it, fitness experts say, especially if you've been a couch potato all winter long.
"Don't do too much too soon," says Dr. Frank B. Kelly, an orthopaedic surgeon in private practice in Macon, Ga., and a spokesperson for the American Academy of Orthopaedic Surgeons. "You shouldn't pick up where you left off last fall."
Kelly notes that every spring and summer as the temperature rises, so does the incidence of sprains, strains, torn ligaments and broken bones, along with heat-related illnesses.
"The number of sports-related injuries that show up in the ER spikes as soon as the weather warms up," he says.
Summer activities such as baseball, softball and tennis all carry their own risks, including arm and shoulder problems. Even golfers get injuries, such as back strain and carpal tunnel syndrome, that can send them to the clubhouse.
Injuries tend to rise in people who are out of shape and push themselves too hard, says Kelly. That's why it's essential for beginners to start slowly. Bike 10 or 15 minutes that first day instead of an hour. Golf nine holes instead of 36. Walk instead of sprint. Gradually work your way up to a more challenging workout.
If you're trying to lose weight for beach day , keep in mind that slow and steady wins the race. If you overdo it with exercise and get injured, you'll be out of the race altogether.
And everyone should warm-up before physical activity to help prevent injury, emphasizes Kelly. Spend five to 10 minutes walking or doing a lighter version of your favorite activity. Golfers, for instance, can hit some easy shots at a practice facility.
Summer sports and recreational activities also carry the potential dangers of heat exhaustion and heatstroke.
Dehydration increases the risk of these heat illnesses, particularly in people who are not used to the heat. In one of the most famous examples of this, Minnesota Vikings football player Korey Stringer died in 2001 from heatstroke on the second day of training camp in stifling heat and humidity.
Don't miss these Health stories
More women opting for preventive mastectomy - but should they be?
Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.
- Larry Page's damaged vocal cords: Treatment comes with trade-offs
- Report questioning salt guidelines riles heart experts
- CDC: 2012 was deadliest year for West Nile in US
- What stresses moms most? Themselves, survey says
- More women opting for preventive mastectomy - but should they be?
'Hype over hyponatremia'
In the last few years, much attention has been paid to a condition called hyponatremia that arises when athletes consume so much water that sodium levels in the body become highly diluted. Some marathon runners have died from it.
But experts say most people — except for endurance athletes — don't need to worry too much about hyponatremia.
"It's so rare," says Walt Thompson, a professor of kinesiology and health at Georgia State University in Atlanta and a spokesperson for the American College of Sports Medicine (ACSM).
When exercising in hot, humid weather, the far greater danger to athletes and exercisers is from not drinking enough, he says.
W. Larry Kenney, a professor of physiology and kinesiology at Penn State University and a past-president of the ACSM, agrees and says he worries about the impact of the "hype over hyponatremia."
Exercisers who don't drink enough in hot weather can develop headache, nausea, dizziness and goose bumps, which are all red flags for heat exhaustion. The condition can progress to potentially fatal heatstroke, in which a person can become confused and lose consciousness.
So how much should you drink? Some people sweat a lot more than others, so Kenney advises weighing yourself before and after activity. Do this a couple of times to see how much water weight you lose from sweating that you're not adequately replacing.
Once you know how much water you're losing, you'll know how much you need to drink to replace it.
If you exercise for an hour and lose 2 pounds, for example, you need to drink a liter of fluid to compensate, he says. Here's the math: For every kilogram (2.2 pounds) you lose, drink 1 liter (33.8 ounces) of water. Ideally, drink every 15 minutes during activity, Kenney advises.
If you're exercising more than an hour, consider a sports drink, which contains sodium to replace lost electrolytes and carbohydrates for fuel, he says.
When enjoying summer sports and fitness, it's also best to engage in the activity in the morning or late afternoon, when the sun isn't so hot, says Kelly. And wear light-colored, loose-fitting clothing, a hat, sunglasses and, of course, sunscreen.
Play it safe so you don't get sidelined with injuries, heat illnesses or sunburn. That way, you can enjoy your favorite outdoor activities all summer long.
Smart Fitness appears every other Tuesday.
© 2013 msnbc.com