Having selected your exercise, you now have to consider how often and how long you should exercise to achieve a health benefit for your heart. The most authoritative guidelines are those from the US National Institutes of Health (1996) which state that:

“Children and adults alike, should set a goal of accumulating at least 30 minutes of moderate-intensity physical activity on most - and preferably all - days of the week”.

This means that if you cannot manage to do all your exercise at once, you can do it in smaller chunks throughout the day. For example, a brisk 15-minute walk to work in the morning and then again in the evening, means you have accumulated 30 minutes of moderate activity. But what do we mean by moderate intensity?