No sweat: Is exercising inside or outside better for you?
Alex Treadway/National geographic/Getty By Teal Burrell In the dark days of winter, opting to run on an indoor treadmill rather than braving the cold may seem tempting. But does it bring the same effects? One thing that could make the treadmill easier is the lack of air resistance – you don’t have to displace the air in front of you when you run on the spot. To make up for this and ensure an indoor workout isn’t too easy, some people religiously set the treadmill’s incline to 1 per cent. That figure originated from a 1996 study that found runners doing a 7-minute-per-mile pace used similar amounts of energy to run over ground as they did on a treadmill with a 1 per cent incline. However, at slower speeds, there were no differences in the energy costs of running over ground or on a flat treadmill. So at an easy pace, there is no need to touch the incline dial – the treadmill isn’t any easier than outside. Many people think the “dreadmill” feels harder, not easier. Runners on a treadmill asked to replicate a pace they had previously run on a track, for example, jogged more than 2 minutes per mile slower. Irene Davis at Harvard Medical School, who studies the biomechanics of running, has seenthe same thing – people find that comfortable paces suddenly seem less so on the mill. She blames the treadmill forcing you to maintain one speed,