Walking could be a better workout than running when all factors are taken into consideration, say scientists.
Though you have to do it for longer, it seems brisk walking has all the health benefits of running and more, without the risk of over-stressing your heart (and getting sore knees).
The study suggested that walking 4.3 miles would use up as much energy as running three, but would take you over twice as long (38 minutes compared to just 15 minutes running).
As long as you walk for long enough to use up the same energy as you would running, your risk of developing heart disease, high blood pressure, diabetes and cholesterol all lowers. In fact, walking was found to be more effective than running at lowering these risks.
[Related: Five ways to be a better runner]
Researchers at Lawrence Berkeley National Laboratory in California studied and compared the health of 33,060 runners and 15,045 walkers aged between 18 and 80.
Study leader Dr Paul Williams commented: "Walking and running provide an ideal test of the health benefits of moderate-intensity walking and vigorous-intensity running because they involve the same muscle groups and the same activities performed at different intensities.
"People are always looking for an excuse not to exercise but now they have a straightforward choice to run or to walk and invest in their future health."
[Related: Give yourself a health MOT in five minutes]
If you've got the running bug it's good to know that it can help prevent many health conditions.
But if you're not such an active sort, are injured or just prefer a good walk, you can be safe in the knowledge that even though you don't end up as red-faced and sweaty at the end, you're still helping your heart.