“capabilities to organise and execute the courses of action required to produce given
attainments” (Bandura, 1997, p. 3). According to this theory, exercise is beneficial
because it helps people in a practical way to increase their sense of mastery over their
behaviour. Some support has been reported for the theory that self-efficacy mediates the
relationship between exercise and health (see Bozoian, Rejeski and McAuley, 1994).
Questions for discussion
Which of these explanations do you think is most plausible? Why do you think the
“endorphin” explanation of exercise benefits is so popular given its shaky scientific
foundations? Can you think of any other ways (besides that of Bodin and Hartig, 2003) of
testing the theory that physical activity offers people some respite from the stress and
tedium of everyday life?
A third finding from relevant research is that regular physical activity seems to
enhance people’s sense of self-esteem. In evaluating research on this topic, Fox (2000)
reviewed thirty-six randomised controlled studies on the relationship between physical
activity and self-esteem. Of these thirty-six studies, twenty-eight (78 per cent) reported
evidence of positive changes in self-perception or self-esteem—especially with regard to
body image. Also, greater benefits were apparent among those who were initially
relatively low in self-esteem. Overall, these data led Fox (2002) to conclude that the
relationship between exercise and self-esteem is a “robust and significant finding” (p.
95). Unfortunately, the psychological mechanisms underlying this beneficial effect
remain largely unknown.
The fourth documented benefit of habitual exercise on mental processes concerns
apparent improvements in cognitive functioning—especially in the elderly. This
conclusion emerged from narrative (e.g., Boutcher, 2000) and meta-analytic reviews of
relevant research (Etnier, Salazar, Landers, Petruzzello, Han and Nowell, 1997). In the
latter review of 134 relevant studies, Etnier et al. (1997) discovered that exercise had a
small but significant positive impact (overall adjusted mean effect size of 0.29) on such
cognitive variables as memory, mathematical ability, verbal ability, reasoning skills,
reaction time and creativity. This beneficial effect was larger for chronic exercise (effect
size of 0.33) than for acute exercise (effect size of 0.16). More recently, Harada,
Okagawa and Kubota (2001) discovered a link between regular jogging and improved
performance on certain working memory tasks. Briefly, seven healthy students jogged for
thirty minutes a day (a recommended “dose” of exercise for health benefits—see previous
section), three times a week for twelve weeks. The joggers took a series of cognitive tests
at three different stages during the study: at the start, after six weeks, and again after
twelve weeks. For comparison purposes, seven sedentary participants also took these
cognitive tests. Results showed that after the study, the joggers scored significantly
higher than their sedentary counterparts on the cognitive tests. These results were
interpreted by Harada et al. (2001) as indicating that jogging somehow stimulates the
prefrontal areas of the brain. In summary, on the basis of the research findings reviewed
above, there seems to be strong evidence to support the age-old maxim “mens sana in
corpore sano” or “a healthy mind in a healthy body” (a motto which is attributed to
Does a healthy body always lead to a healthy mind? Exploring exercise psychology 223