How much physical activity is important?

The current government recommendation for ensuring good health is that a minimum of 30 min of moderate intensity physical activity is taken on at least five and preferably all days of the week. In addition to planned activity, see increasing the activities of daily living may also make a valuable contribution e.g. using the stairs instead of the lift. It is interesting to note that those that 'fidget' can expend anything from 150-850 kcal extra per day as a result of this 'spontaneous activity'.1

This may help to explain the difference between those who seem to be able to avoid weight gain compared with those that are susceptible to weight gain. A practical strategy is to ask patients to reduce periods of inactivity e.g. going for a family cycle instead of watching a video, building a 15 min walk into a sedentary day job. Asking individuals to track the time they spend in active and non-active pursuits will provide a clear picture of their overall activity levels and will provide direction for the improvements that could be made.

While the benefits of activity in helping to maintain weight and to prevent weight regain cannot be overstated, it is important that individuals are clear about what can be achieved in terms of weight loss through activity alone e.g. it would take one hour of brisk walking to expend the energy equivalent of a mars bar! The guideline of 30 minutes moderate activity (e.g. brisk walking) is based on improving cardiovascular fitness but to aid weight loss the duration and intensity would need to be increased. For example, subjects in the National Weight Control Registry who have been successful at maintaining the weight that they lost, report activity levels equivalent to 610 minutes/week of brisk walking.43 This may seem a lot to an individual who is inactive – getting started is the key; then work on gradually increasing the level of activity. The International Association for the Study of Obesity has recently produced the following consensus statement on how much physical activity is enough to prevent unhealthy weight gain.

"The current physical activity guideline for adults of 30 minutes of moderate intensity activty daily, preferably on all days of the week, is important for limiting health risks for a number of chronic diseases including heart disease and diabetes. However for preventing weight gain or regain this guideline is likely to be insufficient for many individuals in the current environment. There is compelling evidence that the prevention of weight regain in formerly obese individuals requires 60-90 minutes of moderate intensity activity or lesser amounts of vigorous intensity activity. Although definitive data are lacking, it seems likely that moderate intensity activity of approximately 45-60 minutes/day, or 1.7 PAL (Physical Activity Level) is required to prevent the transition to overweight or obesity. For children, even more activity time is recommended. A good approach for many individuals to obtain the recommended level of activity is to reduce sedentary behaviour by incorporating more incidental and leisure-time activity into the daily routine. Political action is imperative to effect physical and social environmental changes to enable and encourage physical activity. Settings in which these environmental changes can be implemented include the urban and transportation infrastructure, schools and workplaces."44