A brief session on a bike can transform a person's DNA Stockholm - Arabstoday A series of experiments have revealed that just a few minutes of relatively strenuous exercise can dramatically change a person’s DNA. The changes are not to the code of life itself, but to its ‘punctuation’. These chemicals activate, silence and crank up genes and their actions. In the case of muscle, exercise appears to crank up the genes needed to burn fat and sugar and support the body. Just 20 minutes pedalling flat out on an exercise bike makes a difference, the journal Cell Metabolism reports. Researcher Juleen Zierath, of the Karolinska Institute in Stockholm, said: 'We often say that you are what you eat. 'Well, muscle adapts to what you do. 'If you don’t use it, you lose it and this is one of the mechanisms that allows this to happen.' Professor Zierath and colleagues from Denmark and Dublin began with two experiments in which healthy men who didn’t regularly exercise were put through their paces on an exercise bike. After they stopped, slivers of muscle were taken from their thigh and the DNA analysed from chemical changes. This revealed the changes to occur after just minutes. However, the gentle exercise won’t to. The person needs to be out of breath and while able to speak, have difficulty carrying out a conversation. Further experiments on cells in the test-tube linked the changes to the contraction of muscle. Coffee had a similar effect. But, unfortunately for those who would choose a cappuccino over a trip to the gym, it takes 50 to 100 strong coffees to mimic the effect of exercise on muscles.