CINCINNATI -- Hot yoga classes are soaring in popularity, as Lady Gaga, Madonna and other celebrities swear by it, along with legions of yoga practitioners.
While it comes with an array of benefits like helping you sweat out toxins and release anxiety, is exercising in extreme heat harmful?
Consumer Reports medical experts, like Dr. Orly Avitzur, advise using caution when practicing hot yoga.
Julienne Pepe has taken traditional yoga classes for years, so she decided to try a hot Bikram Hot Yoga class.
"During the class I felt lightheaded, fatigued, weak," Pepe said.
Normally, Pepe feels energized after a yoga class, but not after hot yoga.
"I was completely exhausted, just depleted," she said.
Bikram Yoga requires a heated studio, where the heat is turned up to 105 degrees Fahrenheit, and the humidity is kept around 40 percent.
Avitzur believes Pepe became dehydrated and was beginning to suffer heat exhaustion.
"While there is little specific research on hot yoga, we do know that exercising in extreme heat can cause a number of uncomfortable and even dangerous symptoms," Avitzur said.
Warning signs of heat exhaustion and heat stroke include feeling lightheaded or dizzy, experiencing nausea or getting muscle cramps.
"While the heat may help you stretch further, it can also cause you to overstretch, leading to possible joint or muscle damage," Avitzur said.
Bikram Yoga consists of a series of 26 postures and two breathing exercises. Bikram practitioners say the high temperature and humidity promote health. Cincinnati Bikram studio owner Chelsea Young says she hasn't had complaints of heat exhaustion and touts the benefits.
"You are going to get an amazing cardiovascular workout in there because of the heat, but at the same time it's not pounding on your joints," Young said.
Young, who has had two ACL reconstructive surgeries, credits Bikram Yoga for her recovery. She never thought she'd be able to sit on her knees again.
She encourages her clients to stay hydrated, and uses the rule of drinking water equal to two thirds of your body weight in ounces. So if you're 140 pounds, you need about 93 ounces of water per day. She also advises that students work at their own pace.
"You have to take it easy," Young said. "We always say to our beginners, 'just relax and breath and stay in the room.' You've got to acclimate your body to the heat."
Experts say you should check with your doctor before trying hot yoga if you have high blood pressure, heart disease, osteoarthritis, or if you dehydrate quickly.