Much of the attention on nutrition and health has focussed on what we eat and how it affects the risk of various diseases. Less attention has traditionally been paid to the amount of physical activity we undertake. This is now changing as evidence continues to mount on the benefits of physical activity for the well-being of body and mind and the reduction of risk of chronic disease.

In a recently published EUFIC Review on the benefits of physical activity, Professor Ken Fox from Bristol University (UK), explains that many studies show that people, who are reasonably active, especially in middle to later life, are twice as likely to avoid premature death and serious illness. In fact, the protective effect is equivalent to that of avoiding smoking. The benefits of being physically active are many and include:

Reduced risk of obesity

Evidence is mounting that a reduction in levels of physical activity is a major factor in the increase of obesity. There are several studies that show the benefits of an active and fit lifestyle for the prevention of obesity. In particular, activity appears to help protect against the weight in typical of middle age.

Reduced risk of heart disease

People with an active lifestyle and a moderate level of fitness are half as likely to develop heart disease as their couch-potato peers. Obese people who are active have a reduced risk of heart disease and diabetes compared to their obese counterparts who do not exercise.

Diabetes

A lack of activity can be a risk factor for the development of Type 2 diabetes. Very active individuals have a 33-50% reduction in the risk of developing diabetes. And in people with diabetes, exercise has been shown to help control blood sugar levels.

Reduced risk of cancer

Moderate to vigorous physical activity reduces the risk of colon, colorectal, lung and breast cancers.

Muscle and bone health

Regular exercise leads to stronger muscles, tendons and ligaments and more dense bones. Weight bearing exercise (such as running, roller blading and dancing) has been found to improve bone density in adolescents, help maintain density in adult bones and slow the loss of bone mass that commonly occurs with age (osteoporosis).

Mental health

Several studies show that physical activity improves psychological well-being, the way in which we deal with stress and mental functioning (such as decision making, planning and short-term memory), reduces anxiety and promotes healthy sleep patterns. Evidence from clinical trials shows that exercise can be used to treat depression. In older people, physical activity may help to reduce the risk of dementia and Alzheimer's disease.

How much exercise do we need?

Previous recommendations for physical activity dictated a minimum of 20 minutes of quite vigorous physical activity daily for most people. Twenty years on, scientists and health professionals have realised that this level of activity is too demanding for the majority of people. It has also been found that we don't need to work so hard to get health benefits from being active.

New recommendations from the UK and the USA are for regular bouts of activity at moderate levels of intensity. For example, brisk walking on all or most days of the week for around 30 minutes will help to improve physical and mental well-being. Taking activity in smaller bouts - say 2 or 3 bouts of ten minutes each - can be almost as effective as doing it all in one go and can be easier to fit into today's busy lifestyles. For those who strongly dislike or are unable to do planned exercise, avoiding or reducing the time spent in sedentary activities may be just as useful. Simply standing for one hour instead of watching TV each day, for example, will expend the equivalent of 1-2 kg of fat per year.

Care needs to be taken in choosing the type of activity undertaken by people who are obese in order to avoid damage to joints from vigorous weight-bearing activities. Swimming and cycling are examples of activities that are non-weight bearing and may be better choices for very overweight individuals.

Adding years and quality of life

Regular physical activity has been found to add years to our lives (by reducing the risk of disease and ill health) and to add life to our years by improving quality of life (better mental health and improved flexibility and stamina). As research continues, the role of physical activity can be expected to receive much more attention for its role in health and well-being than it has received in years gone by.
For more information read the full review on http://www.eufic.org.

References

-- Biddle, S.J.H., Fox, K.R., & Boutcher, S.H. (2000). Physical activity and psychological well-being. London: Routledge.

-- Blair, S.N. & Hardman, A. (1995). Special issue: Physical activity, health and well-being - an international scientific consensus conference. Research Quarterly for Exercise and Sport, 66 (4).

-- Lee, I.M., & Skerritt, P.J. (2001). Physical activity and all-cause mortality: what is the dose-response relation? Medicine and Science in Sports and Exercise, 33, (Supp 6) S459-471..

-- Lund Nilsen, T.I., & Vatten, L.J. (2001). Prospective study of colorectal cancer risk and physical activity, diabetes, blood glucose, and BMI: exploring the hyperinsulinemia hypothesis. British Journal of Cancer, 84, 417-422.