It is said that if the health benefits of exercise were available as a pill, all doctors would prescribe it and just about everyone would take it. That says something. There are few things that are almost universally beneficial, yet exercise appears to be one of them. Documented benefits of regular exercise include lower resting blood pressure; heart rate; waist circumference; abdominal and total body fat; and markers of inflammation; along with increased cardiovascular fitness; muscle strength; bone density; and insulin sensitivity.
Exercise is also considered to help regulate appetite and food intake, with active people better able to achieve a balance between the two so as to avoid unintended weight gain. In addition, lots of research has shown that active people have lower risks of illness and of dying prematurely compared to inactive people of the same body size, at all body sizes. And there are also well-documented psychological benefits, with both moderately- and highly-active people less than half as likely to perceive themselves as highly stressed as those who are inactive. Sounds good? So, just how much exercise are we talking about to get these benefits and how do we go about getting it?
The first thing to understand about exercise (or physical activity) is that some is better than none, and even small amounts can be beneficial. Secondly, the amounts needed for health improvement are generally much lower than the amounts needed for fitness or athletic performance. Current guidelines state that most health benefits can be obtained from 150 minutes of moderate physical activity per week, or 30 minutes on most days (1).
This amount doesn’t have to be done all at once, although it is best done in blocks that are at least 10 minutes in duration. So that means doing 3 bouts of 10 minutes, 2 bouts of 15 minutes, or one bout of 30 minutes on most days. Suitable activities include walking, jogging, cycling on a flat surface, and mild gardening, like raking leaves. Vigorous exercise counts as double the time, meaning that the required amounts are only half those set for moderate exercise, i.e. 75 minutes per week. Suitable activities for vigorous exercise include running, fast cycling, heavy gardening such as digging soil, and playing singles tennis.
Both moderate and vigorous activities should involve the major muscle groups of the body in a continuous way for the relevant period of time (i.e. without stopping). This demands more from the heart and lungs, and helps to strengthen both of them. So 150 minutes of moderate activity or 75 minutes of vigorous activity per week is the first objective.
The second involves muscle-strengthening exercise. Guidelines recommend doing strengthening exercises for each of the major muscle groups of the body at least twice each week (1). So, that could be done by training all of the main muscle groups in a single workout, twice per week, or by sub-dividing the body into different sections and training some of those sections on one day and the others on a different day. How you divide up the body is not that critical, but doing muscle-strengthening exercises is particularly helpful to long-term strength, balance, hormonal health and also bone density.
For Best Results
A key point in doing muscle strengthening exercises is to do each exercise to the point of fatigue while still keeping good form. This helps to give the best results in terms of gaining strength and muscle tone. Rather than stopping after a certain number of movements (repetitions), ideally keep going until the muscle tires out and can’t produce any more repetitions with good form (2). Try to use a weight for each exercise that produces fatigue within a timeframe of 60 to 90 seconds, because that helps to increase the enzymes in the body that fuel strength-oriented exercise. In other words, don’t use a weight that is so easy that it takes several minutes for the muscle to get tired. From experience, I’ve found that it’s really worth learning how to do each exercise correctly so as to be confident in doing it to that point of muscle fatigue.
Children & Adolescents
Recommendations for children and adolescents are actually higher than those for adults when it comes to exercise. Both are recommended to get at least 60 minutes of moderate or vigorous activity every day, and vigorous activity is advised on at least 3 days of the week.
- US Department of Health and Human Services. 2008 Physical Activity Guidelines for Americans. Available at www.health.gov/paguidelines
- Giessing J, Eichmann B, Steele J, Fisher J. (2016). A comparison of low volume ‘high-intensity-training’ and high volume traditional resistance training methods on muscular performance, body composition, and subjective assessments of training. Biol Sport. 33(3),:241–249.