Short & Sweet
A recent study by scientists at Canada’s McMaster University reports that it’s possible to get equal benefits while exercising for less time. The key is Intensity.
According to this latest research, doing 10 one-minute sprints on a standard stationary bike with about one minute of rest in between, three times a week, works as well in improving muscle as hours of conventional long-term biking less strenuously—you just have to be at about 95% of maximal heart rate when you do the sprints.¹
If biking is not your thing, try sprinting on the treadmill or in the pool, or going full-throttle on an elliptical trainer (better for your joints), the rowing machine or anything that gets your heart racing. But before you try this new approach, make sure you and your doctor discuss the level of heart rate intensity involved to make sure it is okay for you. If you are not sure how to find your maximum heart rate, click on this link to the American Heart Association: http://www.americanheart.org/presenter.jhtml?identifier=4736.
So in short, you do have enough time to benefit from exercise. So get moving!
¹Jonathan P Little, Adeel S Safdar, Geoffrey P Wilkin, Mark a Tarnopolsky, and Martin J Gibala. “A practical model of low-volume high-intensity interval training induces mitochondrial biogenesis in human skeletal muscle: potential mechanisms.” The Journal of Physiology, 2010; DOI: 10.1113/jphysiol.2009.181743