increasing the electrical activity of the heart itself. Also, it lowers blood pressure, thereby
decreasing the chances of a stroke. Furthermore, because exercise improves glucose
metabolism, it is associated with a reduction in people’s susceptibility to diabetes (a
medical condition in which one’s body either fails to produce enough insulin to power the
muscles or else uses prevailing insulin inefficiently). Put differently, physical exercise
can act like insulin for people who suffer from diabetes (Weston, 2002). Finally, regular
exercise strengthens the skeletomuscular system by improving joint and muscle
flexibility. On account of these benefits, people who exercise regularly are “functionally
younger in these various physical capacities and aerobic power than their sedentary age-
mates” (Bandura, 1997, p. 407). By contrast, sedentary adults age twice as fast as nature
intended (O’Brien Cousins, 2003).
Psychological health benefits of regular physical activityIn accordance with the intuitive insights of William James (see beginning of chapter),
regular activity appears to produce a number of mental as well as physical health benefits
for people of all ages. The purpose of this section is to summarise some of these
psychological (affective and cognitive) benefits (but see Buckworth and Dishman, 2002
for a more extensive review). Before doing so, however, an important caution must be
expressed. Briefly, due to their ephemeral nature, the affective aspects of people’s
exercise behaviour—namely, their feelings, moods and emotions—are difficult to
conceptualise and measure. As a result of this problem, research in this area is bedevilled
by semantic confusion. For example, consider the phenomenology of “feelings”. Is a
feeling of something (e.g., fatigue after a run) the same as a feeling about something
(e.g., apprehension before a race)? Clearly, many definitional issues need to be clarified
in this field (see Gauvin and Spence, 1998). Therefore, for the purpose of the present
chapter, I shall use the term “mood” to refer to an emotional state that is characterised by
the experience or anticipation of either pleasure or pain (Buckworth and Dishman, 2002).
Accordingly, one can be in a “positive” mood (when anticipating pleasure) or a
“negative” mood (when anticipating pain).
To begin with, research suggests that people who perform moderate amounts of
physical activity regularly (e.g., at least three times a week for approximately thirty
minutes each time) tend to experience significantly improved mood states (as measured
by such self-report instruments as the Profile of Mood States, POMS; McNair, Lorr and
Droppleman, 1992) and/or reductions in anxiety (e.g., Berger and Motl, 2000; Folkins
and Sime, 1981). In a meta-analysis of forty studies on this topic, Long and van Stavel
(1995) reported that exercise had a significant effect on anxiety levels—with an effect
size of 0.36 standard deviations relative to control conditions. Other research shows that,
in practical terms, self-rated levels of state anxiety (see Chapter 3) are lowered by about
one-quarter of a standard deviation within twenty minutes of participation in acute bouts
of continuous exercise such as cycling, swimming or running (O’Connor, Raglin and
Martinsen, 2000). More generally, Berger and Motl (2000) recommend that in order to
maximise exercise-induced mood enhancement, the physical activity undertaken should
be enjoyable, aerobic, non-competitive and performed at moderate intensity for at least
twenty to thirty minutes. This relationship between exercise and mood is complex,
however, because it is mediated by several factors. For example, consider the intensity
Does a healthy body always lead to a healthy mind? Exploring exercise psychology 221