Sport And Exercise Psychology: A Critical Introduction

processes. After that, a brief evaluation of some important conceptual and
methodological issues in this field will be provided.

Physical benefits of regular activity

Sedentary people can increase their level of physical activity in two main ways. On the
one hand, they can take up exercise classes or engage in such traditional fitness pursuits
as walking briskly, cycling, running or swimming. On the other hand, they can increase
their level of physical activity by adopting a lifestyle approach whereby they make active
choices to engage in exercise in everyday situations. For example, they might decide to
walk or cycle to work and/or to take the stairs to their office rather than using the
elevator. Regardless of the mode of physical activity chosen, a considerable volume of
research has accumulated on the health benefits of regular physical activity (see reviews
by Biddle and Mutrie, 2001; Berger and Motl, 2001; Landers and Arent, 2001).
Much of this research was summarised in the 1996 Surgeon General’s report (United
States Department of Health and Human Services, 1996). At least three key conclusions
emerged from this report concerning the physical health benefits of regular exercise.
First, people of all ages can derive significant health benefits from cumulative amounts of
moderately intense physical activity (e.g., thirty minutes of brisk walking or fifteen
minutes of running) undertaken on several days per week. This finding is important
because it shows that physical activity does not have to be strenuous in order to be
advantageous—a point to which I shall return later in the chapter. So, it looks as though
the popular phrase “no pain, no gain” is seriously mistaken. Interestingly, Mutrie,
Carney, Blarney, Crawford, Aitchison and Whitelaw (2002) demonstrated recently that a
self-help, active commuting intervention called the “walk in to work out” programme
was successful in increasing people’s walking behaviour (but not cycling) in travelling to
work. Research cited by the Surgeon General’s report also indicates that additional health
benefits can be achieved by taking part in physical activity that is of a longer duration or
of a more vigorous intensity than the minimal “thirty minutes a day” criterion. Second,
physical activity reduces the risk of premature mortality, coronary heart disease, high
blood pressure, colon cancer, obesity and non-insulin dependent diabetes mellitus. It is
also important for maintaining the health of people’s bones, muscles and joints—and is a
useful aid in the prevention of osteoarthritis. Thirdly, activities which develop muscular
strength (“resistance training”) should be performed at least twice per week in order to
yield significant fitness benefits. Ideally, at least eight to ten such exercises should be
performed at each session, with at least ten repetitions of the relevant exercise required
each time. In summary, physical activity is associated with a reduction in a number of
risk-factors for health. The magnitude of this relationship is quite strong and can be
gauged from the fact that the Surgeon General’s report (United States Department of
Health and Human Services, 1996) claims that the link between physical inactivity and
cardiovascular illness is approximately equivalent to that between smoking and coronary
heart disease.
What physiological mechanisms underlie these positive effects of physical activity on
health? Not surprisingly, the answer to this question depends on the type of medical
condition involved (see Ogden, 2000). For example, regular activity seems to reduce
coronary heart disease either by stimulating the muscles that support the heart or by

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