This summer has brought two heat waves under out belt and there are more assuredly on the horizon. With intense heat comes danger and for kids preparing for fall sports, dedicated athletes and weekend warriors alike, taking care of yourself and heading warning signs when exercising is essential. Heat exhaustion and heat stroke are serious.Dr. Robert Masci is a cardiologist with Cardiology Associates with offices in Newton and Sparta, N.J. and Milford, Pa. and also a avid runner, cyclist and triathlete. A resident of Sparta, Dr. Masci can often be seen cycling or running in the area in preparation for a triathlon in Brant Beach this September. "If the heat index is over 100, exercise inside," he warns.Tune into the weather report on the radio, TV or internet and the heat index is given daily. It's an index that combines air temperature and relative humidity in an attempt to determine the human-perceived equivalent temperature."It's the temperature that your body feels," Dr. Masci explained.The body cools itself by perspiring and then that sweat evaporates. A very efficient system until humidity comes into play."When it's really humid outside, that sweat can't evaporate," Dr. Masci said.This can lead to overheating."The bottom line is if the heat index is below 90, you can work out outside," Dr. Masci said. "If it gets up to 100 or above, that's a danger zone."Dr. Masci said athletes should hydrate all day, workout in the early morning or late evening when it's cooler and "if you experience any signs of light-headedness, cramping or blurry vision, stop immediately."He said to start hydrating several hours before exercising and that a good way to know that your hydrated is if your urine is clear, "like diluted lemonade."Dr. Robert Pampin is a physician at Skylands Medical Group and a runner and cyclist."If you're really dedicated, make sure you try to get out in the early part of the day before the sun gets up and humidity gets you," he said. "Many athletes are guilty of not stretching enough and not realizing how many electrolytes they lose on a scorching day."He also urges athletes to take advantage of the new technology in athletic wear that wick sweat away from the body."If you feel light headed or dizzy, don't hesitate. Stop immediately and get in the shade," Dr. Pampin said.The father of athletes, Dr. Pampin can be recognized as the dad who always has a cooler at summer practices. For those who have a choice, he encourages selecting sports like mountain biking on hot days that take you on trails canopied by trees.Dr. Gregory Martin is a chiropractor in Sparta and former elite collegiate basketball player. One of his specialties is working with athletes and their bio-mechanics."When I was a kid, we'd have basketball practice on blacktop in the scorching sun. Now a days. we wouldn't think of that," he said.He urges his daughter, Marissa, who will be a freshman soccer player at Moravian College and son, Robbie, who is a high school football player to start hydrating hours before practice."Drinking plenty of water is so essential," he said, "If you're thirsty during practice, it's too late."Tracey Swenson, of Sparta, has competed in running races and triathlons all over the United States. She's even an Ironwoman which means she competed in the prestigious Ironman Triathlon in Hawaii.When it comes to training in the heat, she said she looks to exercise very early in the morning. This means doing some tag teaming with her husband, Kurt, as the couple are parents to seven-year-old twins, but they work it out."It's also important to be very well hydrated with both water and fluid replacement drinks such as Gatorade," Swenson said.Tony Lombardo is heading to Triathlon Nationals in a few weeks, so to give up the pivotal training on the bike, roads and in the pool because of a heat wave isn't an option.Also a running coach at Sparta High School and triathlon coach county-wide, he said, "As a triathlete you need to mimic conditions you may encounter on race day."That means training for the bike and run between 8 and 9 a.m. for sprint races like at the Lake Mohawk Triathlon. Lombardo tries to train in the evenings, but the challenge for triathletes is finding time to get in all three sports.Corrine Renshaw, of Oak Ridge, is a student at the Northwest Christian School, in Newton. She loves to run so much that she's qualified for the United States Track and Field Nationals in the 800 meter event — at age 10. She may be young, but her parents, Gary and Rhonda, are sure that she's always armed with a bottle of water as she prepares for her races and her training."My new favorite drink of choice is Raspberry or Lemon Fruit 2O," Renshaw said. Renshaw enjoys cooling off after a training session with a dip in her friend's pool or a surf in the ocean with boogie board in hand. "We've all probably had some experience with a little heat exhaustion," Dr. Masci said.The next step — if you don't stop — is that your body loses its ability to control its temperature and your core temperature rises too high. This can lead to heat stroke which can involve seizures and brain damage. He warns swimmers to make sure to hydrate too."Just because you're in the water doesn't mean that you aren't sweating. It can be deceiving," Dr. Masci said.To the die hard athlete who thinks he's Superman or she's Wonder Woman capable of withstanding any heat adversity Dr. Masci advises, "It's a negative return on the investment. You'll get out there and the heat will prevent you from having a quality workout and could result in a health disaster. Play it safe and hit the gym instead. Even if it's 80 degrees in the gym, that's a whole lot better than a heat index of 125."