Just how hot is hot? The American College of Sports Medicine recommends temperatures of 68 to 72 degrees, while celebrity trainer Tracy Anderson has found a temperature of 86 with 65% humidity ideal for safety and improving fitness without sacrificing performance. Bikram yoga is performed in 105-degree temperatures. A recent class at Pure Yoga on the Upper East Side of NYC offers classes at 110 degrees “by popular demand,” with an increasing number of elite clientele refusing to take fitness classes in rooms under 90 degrees.

Yoga instructors feature prominently. Loren Bassett, a Manhattan yoga teacher who “lovingly” refers to some of her followers as “insane,” teaches “America’s toughest workout” according to Marie Claire magazine, with spaces selling out weeks in advance. As students attempted to circle the room holding bodies parallel to the earth with hands and feet on purple gliding discs, she comments “You’re crawling through the desert in search of the oasis of a better body.” This approach and the trend of seeking ever hotter temperatures is arguably incongruent with yoga, which entails simultaneous non-attachment to outcomes and a complete embrace of the present, whether the temperature is 60 or 100 degrees.

Are these classes safe? As long as participants are highly fit and well-hydrated, University of Connecticut kinesiologist Douglas Casa says that benefits max out at around 100 degrees (higher temps jeopardize safety). If you work as hard as you would in cooler temperatures, you’ll burn more calories. But many are unable to sustain the same intensity in high heat, meaning they might as well work harder in cooler temperatures. What about detox? “A hoax,” says Dr. Casa. “I don’t think there’s any inherent advantage to sweating more. Some people just like the feeling.”

According to Ayurveda, the indigenous system of Indian medicine said to be yoga’s sister science, the fiery types often drawn to such extreme exercise are merely exacerbating existing heat. Such exercise aggravates pitta, a quality of passion, heat, and excitement common to Type A personalities that in excess can short-circuit one’s nervous system and result in increased irritability, anger, and the development of related illness or disease. Anger, hostility, and aggression have been associated with Coronary Heart Disease. Ayurveda would prescribe nourishing and cooling activities to balance out the extreme striving for more heat. This may include gentle and moderate yoga, yoga nidra, cooling pranayama, and meditation.

Yet the notion of balance to extreme heat-seekers is sacrilege. For one student arriving earliest to snag the spot directly under the heating vent, “I feel like it totally pushes me to the edge, and nothing else can bother me the rest of the day after surviving hell.”

What do you think about the extreme heat fad?