Exercise enhancing pill in the pipeline

A pill which could help people exercise for longer is in the pipeline but is sure to cause controversy as it can apparently deliver some of the benefits of exercise, even for those who do not move a muscle.

Scientists in the U.S. say they now have two possible drugs which appear able to build muscle, increase stamina and even burn fat and say tests in mice found they were able to run 44% further which suggests humans may be able to do the same without prior training.

The concept is clearly controversial because of concerns such drugs could be misused in sport.

Lead researcher Professor Ronald Evans, from the Howard Hughes Medical Institute, and the Salk Institute in California, has produced a test which will allow the drugs to be detected in the urine and blood of competitors.

Professor Evans says the drugs could eventually help tackle muscle wasting diseases, or help improve the health benefits of exercise in people at risk of conditions such as diabetes.

The two drugs AICAR and GW1516, appear to have an effect on the master gene PPAR-delta which is involved in the building and regulation of muscle and also has the ability to control the activity of many other genes.

This ability in theory could have a wider effect on the way the body works.

By genetically altering mice to enhance the activity of the gene, led to the development of muscle which was much more likely to burn fat than burn sugar and it also made "marathon mice" who were able to run much further on a treadmill.

The researchers say a drug now needs to be produced which will create similar effects rather than conducting a genetic alteration.

The first version, a pill called GW1516, again produced the "fat burning" effect, but no change on exercise performance until the team started training the mice with long treadmill sessions - the mice given the drug were able to run 77% longer than those training without its benefits.

The latest drug, AICAR, goes one step further, finding a different way to act on the same muscle cell mechanism and this time, without any training, after just four weeks on the drug, they ran 44% further on their treadmills without any prior exercise.

Professor Evans says both versions could one day serve a purpose in humans and the most obvious potential was in conditions, such as diabetes, where exercise was a proven benefit.

Experts however have voiced concern over a drug that basically enhances training and the concept of a drug that improves endurance training for sports professionals.