SINGAPORE - Want to push yourself in a low oxygen environment? Or pump iron into the wee hours of the morning? It is possible now with a gym that simulates high altitudes and a 24-hour gym chain in the heartland.
At Altitude gym in Bukit Timah, which opened last November, members work out in a simulated environment that is at least 3,500m above sea level. That is just below the top of Japan's Mount Fuji.
Inside a 800 sq ft air-tight chamber, oxygen levels are kept at 14 per cent, compared to 21 per cent outside.
A compressor system here produces nitrogen-rich air, displacing the oxygen inside the chamber.
Inside, up to 15 people can exercise at any one time on the spin bikes, treadmills and other fitness equipment provided.
The gym also conducts classes in yoga, circuit training, combat conditioning and physical training in this environment.
Altitude has seen 160 clients so far. Of this, 90 are members, who pay $100 to $200 a month.
Says the gym's managing director, Mr Stanley Tan, 42: "Exercising here, you are teaching your body to use oxygen more efficiently.
"This enhances athletic performance, and has many other benefits like lowering cholesterol levels and helping with weight loss," he adds.
"Famous athletes such as Tiger Woods, Michael Phelps and David Beckham have also trained under such conditions. In fact, many athletes will tell you it's the secret to their success."
While doctors endorse some benefits of altitude training, they also warn customers against pushing themselves too hard.
Says sports physician Benedict Tan, chief of Changi General Hospital's department of sports medicine: "It is safe to exercise at the gym if users follow the right safety protocol. In any case, common sense should prevail. Don't push yourself if you feel unwell."
Dr Ong Joo Haw, a registrar at Khoo Teck Puat Hospital's Sports Medicine Centre, says: "Since the 'ascent' is not graduated, there can be risks of altitude-related problems."
Symptoms of these problems, he says, include nausea, dizziness, undue fatigue, altered mental status, chest tightness and shortness of breath.
Says Dr Ong: "In such cases, exercise should cease immediately. The involved individual should be removed from the facility and given prompt medical attention."
So far, Altitude reports, there have been only two occasions where a member felt nauseous while exercising.
But Mr Stanley Tan explains that both members forgot to eat proper meals prior to exercise.
At least one trainer supervises every five members at all times, he adds.