variables. To illustrate, few studies have controlled for the expectations of participants
about the efficacy of exercise interventions. This is a pity because Desharnis, Jobin, Cête,
Lévesque and Godin (1993) found that when people were led to believe that they were
receiving exercise which had been designed to improve their well-being, their self-esteem
levels actually increased as much as those who had been involved in “real” exercise
interventions. In other words, there was a self-fulfilling prophecy among people who had
volunteered to take part in an exercise programme. For this reason, experimental controls
for placebo effects are mandatory in this field.
A second conceptual issue in this field stems from terminological confusion. For
example, researchers do not always treat physical fitness as a multidimensional construct
and may not distinguish between its different forms—aerobic and anaerobic fitness. In a
similar vein, the construct of “subjective well-being” is a semantic minefield. To
illustrate, it is sometimes defined by positive characteristics (e.g., the presence of feelings
of happiness or satisfaction) but on other occasions by the absence of “negative”
emotions such as depression or mood disturbance (see Berger and Motl, 2001). Clearly,
such conceptual vacillation leads to problems of measurement. Thus several reviewers
(e.g., see ibid.) have lamented the usage of idiosyncratic, unstandardised measures of key
variables (e.g., psychological wellbeing) in exercise psychology. This criticism also
applies to measures of affective constructs like anxiety and depression. Thus it is
debatable whether available psychometric measures of these constructs are sufficiently
sensitive to detect actual changes in these variables as a result of exercise interventions
(Buckworth and Dishman, 2002).
A third flaw affecting research on the effects of physical activity is that many
researchers in this field have combined results obtained from different participant
populations. This cavalier attitude is unfortunate because there are significant differences
between elite athletes, non-athletic university students, patients in psychiatric settings and
people being treated for coronary heart disease. The fourth problem encountered in this
field concerns the fact that few researchers have bothered to conduct “follow-up” studies
on their participants in an effort to assess the long-term effects of exercise activity. A
final difficulty is the relative neglect by researchers of possible negative consequences of
exercise. It is to this issue that we now turn.
Exploring some adverse effects of exercise on healthSo far in this chapter, we have argued that physical exercise is a healthy habit. But
research suggests that occasionally this habit can have adverse consequences. For
example, injury is a significant risk for people who exercise vigorously or who participate
in competitive sports (see Chapter 9). In addition, for certain vulnerable people
(especially young women), exercise is associated with specific psychopathologies arising
from eating disorders and distortions of body image (Buckworth and Dishman, 2002).
Furthermore, a variety of physiological health hazards have been found to be associated
with habitual physical activity and/or sport. These hazards include metabolic
abnormalities (e.g., hypothermia in swimmers or dehydration in marathon runners), blood
disorders (e.g., anaemia in endurance athletes) and cardiac problems (e.g., arryhthmia as
a result of prolonged vigorous activity). Unfortunately, as these conditions fall largely
within the realm of sports medicine, they lie outside the scope of this book. Instead, this
Does a healthy body always lead to a healthy mind? Exploring exercise psychology 225