While everyone else is searching for ways to cool off, devotees of "hot yoga" spend class sweating through a series of stretches and poses in a room designed to be even hotter than Africa in the summer.

"It's difficult to explain.... You're so at peace. It's well worth the suffering," Fessler said after a recent workout at Bikram Yoga Baltimore, a studio in Cockeysville, Maryland.

In the Cockeysville yoga studio, instructors crank up the temperature and keep the humidity level in the 30 percent to 40 percent range, which is ideal for Bikram yoga, a series of 26 postures and two breathing exercises.

About 20 people attended a recent noon class and within the first few minutes, everyone is sweating. It starts as beads of perspiration on foreheads. But most of them are drenched in sweat by the time the class members twist their arms and legs into the "eagle" pose.

Although it is known for being challenging, the Bikram style is helpful to those with joint problems and back pain.

"This kind of sweating is cleansing," an instructor says. "Your body starts to crave it."oppressively  (adv.)   闷热地；难忍地on purpose   故意地；蓄意地devotee  (n.)   献身者；热爱者workout  (n.)   运动；练习to crank up   转动；提高humidity  (n.)   湿气；湿度posture  (n.)   姿势；姿态perspiration  (n.)   流汗；汗drenched  (adj.)   浸湿的；湿透的to crave  (v.)   渴望；热望