Though 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. It can lead to heat exhaustion or heat stroke. Warning signs include feeling lightheaded or dizzy, or experiencing nausea or muscle cramps. If you suffer more serious symptoms either during or after class, such as unusual weakness, fever, vomiting, or confusion, Consumer Reports advises going to the nearest emergency room.
Bikram hot yoga practitioners say the high temperature and humidity promote health. Studio owner Rich Pike says he hasn't had complaints of heat exhaustion and touts the benefits. He says, "Heat allows you to bend safely and be more flexible. What the sweating does is it eliminates toxins through your sweat."
Consumer Reports says that though the heat may help you stretch further, it can also cause you to overstretch, leading to possible joint or muscle damage.
Consumer Reports' advice: Whatever exercise you do, stop if you feel pain or heat exhaustion. Be sure always to drink plenty of water. And with any type of yoga, Consumer Reports says there are steps you can take to avoid picking up viruses or bacteria. Bring your own mat and towels. Cover any cuts or scrapes with an adhesive bandage, and use alcohol wipes to wipe down any surfaces, such as mats or blocks.