Help at hand?

New Delhi, Aug. 3: Scientists have leaped closer to the goal of developing pills that mimic the effects of exercise on the body and help people who are unable, or unwilling, to exercise.

Researchers in the US have demonstrated through studies on mice that two drugs can improve exercise endurance in the rodents. One drug works only with exercise, the other does the trick even without exercise.

“It’s tricking the muscle into believing it’s been exercised,” said Ronald Evans, professor of molecular biology at the Salk Institute in La Jolla, California, and head of the 13-member study team. “It proves you can have a pharmacological equivalent of exercise,” Evans said. The study findings appeared in the journal Cell.

The researchers believe exercise-mimicking drugs could one day help patients with muscle diseases or frailty and patients with obesity in whom exercise is known to have a beneficial effect.

The drugs appear to genetically reprogram muscles so that they can use energy better and contract repeatedly without fatigue. Mice given a drug named AICAR ran on a treadmill 44 per cent better than untreated mice after four weeks of treatment.

“That’s as much improvement as we get with regular exercise,” said Mumbai-educated Vihang Narkar, team member and scientist at the Salk Institute. “This finding has potential to be further developed into therapeutics to mimic some of the cardiovascular benefits of exercise.”

But the findings have also kindled concerns that the drugs could be abused in sports to improve endurance limits.

“The chemical structures and synthesis process of these drugs are in the public domain,” Narkar said. “The abuse of these drugs will be an unfortunate consequence of this study.”

The Salk team has developed a test to detect these drugs in blood and urine and is working with the World Anti-Doping Agency to certify a test for use on athletes competing in the 2008 Beijing Olympics.

The mice who got AICAR displayed lowered fat and higher oxygen consumption, without a change in body weight.

A second compound code named GW1516 improved endurance even more dramatically — 77 per cent — but only when combined with exercise. This drug showed no effect on sedentary animals.

Both drugs lead to a variety of changes, leading to the improved endurance and fat-burning ability of muscle cells. But scientists caution that the drugs have not yet been approved for use in humans.

The drug that works in combination with exercise would allow people who like to exercise to get “more bang for your buck”, said Evans. “If you don’t like exercise, you love the idea of getting benefits from a pill,” he said.

But, he cautioned, such drugs “may also be used by athletes who want an edge”.