Watching sport can make you fitter, according to research Sunday that said viewing other people exercise increases heart rate and other physiological measures as if you were working out yourself.
The study, published in the international journal Frontiers in Autonomic Neuroscience, showed that when watching a first person video of someone else running, heart rate, respiration, skin blood flow and sweat release all increased.
They returned to normal at the conclusion of the "jog".
Researchers said that importantly, for the first time, it was shown that muscle sympathetic nerve activity increased when people watched physical activity.
"Recording this nerve activity provides a very sensitive measure of the body's physiological responses to physical or mental stress," said one of the lead researchers Vaughan Macefield, from the School of Medicine at the University of Western Sydney.
"We know that the sympathetic nervous system -- which supplies the heart, sweat glands and blood vessels, as well as other tissues -- increases its activity during actual exercise.