And according to the BBC, some health professionals think the NHS should be doing more to promote the benefits of exercise - as it does for smoking cessation and reducing alcohol consumption.
The Beeb's health correspondent Adam Brimelow claims that while official figures claim that one quarter of men and half of women are missing the target - research suggests the real figure could be much, much higher.
Tracking data from devices fitted to volunteers suggests that only one-in-15 men and one-in-30 women could be meeting the guidelines of two-and-a-half hours of moderate exercise a week.
Dr Mike Loosemore, a sport medicine consultant at University College Hospital in London, is quoted as saying: "We have huge anti-smoking programmes. We have massive amounts of money being spent on obesity, and GPs are paid to check peoples' diabetes and cholesterol status.
"If we could get the population more active we could reduce the risk of bowel cancer by 60 per cent. We could reduce the risk of diabetes by 50 per cent. We could reduce the risk of breast cancer by 50 per cent, reduce mild to moderate depression by the same as taking Prozac.
"We could improve bone health, reduce falls in the elderly, reduce Alzheimer's by 30 per cent."
And public health expert and GP William Bird has set up a programme called Beat The Street to try to encourage more walking and moderate exercise.
He told the BBC: "People go to their offices, they drive there, they go on the escalator, they sit doing their emails in their work, they come home again, and then they just watch television.
"All that time they're causing damage to their bodies, so we just have to keep moving."
His programme sets parents and youngsters off around their neighbourhood looking for "beat boxes" to swipe their fobs against - so they can keep track of their activities.