Research in the medical journal the Lancet says lack of exercise is killing as many people around the world as smoking or obesity.
Dr I-Min Lee, the author of the report, says you only need to do a very small amount of physical activity to get benefits.
She explains that people should aim for 30 minutes moderate to intense physical activity a day but if that is not possible then "15 minutes is fabulous".
Lord Krebs, who chairs the House of Lords Science and Technology Committee, believes the the government "doesn't have a credible plan" to deliver the Olympic legacy to get people active.
He told the Today programme that he was surprised to find out that health professionals "were not aware" of the latest government health guidelines.
Get in touch with Today via
or text us on 84844.