Hot Yoga is just the beginning.

The concept of practicing yoga in a heated room started in the late 1970s when a man named Bikram brought his version of yoga to America. Hot Yoga was a marketing coup; over subsequent decades, it has become wildly popular. And now this craze has permeated the entire fitness arena, with the likes of Hot Pilates, Hot Spin, Hot Barre and Hot TRX cropping up everywhere. Gyms and fitness centers are warming their classrooms from 90 to 117 degrees, and everybody is ernestly sweating their way through “intense” workouts.

Is hotter better? Let’s examine some of the myths and concerns behind this sizzling trend.  

First, it’s important to remember that traditional yoga in India was practiced at dawn and dusk--not in the midday heat—for good reason. Gently stretching our muscles is desirable; over-stretching ligaments and tendons is not. At higher temperatures, you feel more flexible than you really are, making it easier to over-stretch and get hurt. 

In America, our fitness regimens are fueled by the notion that the more we sweat, the better the workout—the more calories we burn, the quicker we lose weight, the faster we get in shape. There’s also the belief that a good sweat removes toxins from our systems. Actually, sweating is merely the body’s mechanism for cooling down, not cleaning out. Most of what you sweat is water--with some salt, potassium and electrolytes—so what you’re losing is just water weight. True toxin elimination comes from the kidneys, liver, and colon, so if that’s what you want, look for natural cleanses or talk to your physician.

Everyone from our mothers to the Mayo Clinic has warned us to be careful when exercising in high temperatures. Extreme heat puts dangerous stress on the body. Heat stroke can be deadly. If an exercise studio is full of sweaty bodies, the temperature can easily top 100˚ F, at which point it’s difficult to cool down. You need to stay hydrated and watch for feelings of exhaustion, light-headedness, nausea, confusion, or muscle cramping, during or after practice—all signs that it’s time to stop immediately.

Exercise in extreme heat is not for the wise or faint of heart: A 90-minute Hot Spinning class, for example, is the equivalent of riding a bike full speed up a hill in 110-degree heat. Increased risk factors include age, pregnancy, diabetes, heart disease and lung disease. If you’re pre-menstrual, menopausal, prone to migraines and/or taking medication, it can exacerbate symptoms or side-effects. An additional concern: Hot, humid conditions are breeding grounds for bacteria, so don’t share mats or towels, and cover any cuts or scrapes. If you borrow a mat, wipe or spray it clean.

Medical science tells us there’s actually no correlation between hot exercise and fitness benefits, and in fact there are some risks. So while hot-hot-hot is trending, the safest way to a get intense sweat is the old-fashioned way--working a little harder, or switching up your routine to add a new and more challenging exercise to your regimen.