The new guidelines (July 2011) in the UK include the following: The intensity we exercise primarily and light activities like walking and doing housework do not seem to have a positive effect on health of most people. In order for aerobic exercise to be beneficial, it must increase heart rate and cause perspiration. Everyone should get at least 150 minutes of exercise per week for moderate intensity aerobic exercise, but that’s really the bare minimum for the health benefits. If you do so after 150 minutes, you will gain even more health benefits.
Inactive time (time not standing, such as when going to the bathroom or in bed) is bad for everyone’s health, and no exercise can be detrimental to sitting too long. These guidelines are now much more relevant than those used in the United States, including recommendations for muscle building and bone strengthening activities like weightlifting and yoga.