Rivulets of perspiration run down participants' bodies as an instructor calls for the correct form and to hold the position for another five seconds - this is "hotbox" yoga, something more commonly known as hot yoga.

Hot yoga is exactly what it sounds like - practicing the ancient art in a heated environment - a hot studio maintained at about 38 to 40 degrees Celsius at about 40 percent humidity.

The benefits of the practice are numerous and proponents say it is the single best form for weight loss, toning, strengthening, flexibility and a better sense of emotional well being. It stretches and strengthens every single muscle, ligament and joint in the body.

Weila Wu, owner and yoga instructor of Yoga Space, said hot yoga takes the ancient practice one step further.

"It uses the natural 'heat' the body generates from going through the postures and builds the body core temperature even more by completing the movements in a heated and humid environment," she said.

The hot yoga postures are also typically more physically challenging, according to Wu. "Hot yoga allows the practitioner to safely go deeper into each pose whilst under the watchful eye of a trained instructor, without increasing risk of injury."

"Your body becomes more flexible in the heat and since the poses are relatively difficult, the heat allows you to sink into the poses more deeply."

Hot yoga classes are typically 60 or 90 minutes of postures in combination with specific breathing exercises. The procedure pumps fresh oxygenated blood to 100 percent of the body, and the heat forms an integral part of this style of yoga as muscles and organs become more flexible and less susceptible to damage the warmer they get.

"Just as importantly, however, the sweating allows built up toxins to drain out of the body," Wu said. "Pollution from automobile traffic, heavy metals, processed foods and other toxins from living in a big city like Shanghai are flushed out through the body's natural cleansing system."

Another effect of this natural process is the promotion of weight loss. Practitioners exert a good deal of effort in class and consequently sweat profusely. This serves to facilitate the burning of calories and expedites weight loss.

The poses stretch not only the muscles but also squeeze and massage the internal organs, glands and the nervous system. This is carried out all in the proper order and is vital to correctly stretching and facilitating the outward growth of the whole body.

"Better still, is the soothing calm that one feels from the inner depths of one's soul after having spent even just an hour performing yoga. It is a feeling that none of us should be deprived of, and one that I personally would like to fill my whole life with," Wu said.

Tips for hot yoga

Drink plenty of water before, during and after the yoga class. It is recommended that one increase his or her daily water consumption by an additional 1.7 to 2.3 liters. Once you are drinking enough, your body will tolerate the heat better and you will actually enjoy it.

If you feel slightly disoriented or like you need a good nap after your first few classes, this is because your body has begun to cleanse itself as a result of the yoga practice.

After the first few classes this sensation will pass. The more you can relax after an honest effort during class, the more energized you will feel throughout the session and throughout the rest of your day.

If you begin to feel nauseous or disoriented during class, take a break; if really uncomfortable, leave the room and take a drink. You may be dehydrated. Know your body limitations.

Due to the thick concrete walls of most Chinese buildings, it is very difficult to find true hot yoga studios that can maintain a constant 40 degree Celsius temperature and humidity in Shanghai. Many studios call themselves hot yoga but the temperature may only be 34 or 36 degrees or even less. It takes a specially-designed room with heated floors and insulated walls to maintain the heat during Shanghai winters. Make sure of your choice.

Address: 3/F, 35 Gaoan Road (by Hengshan Road)
Tel: 021-6431-3164
E-mail: www.yogaspace.cn