Literature Review of Mood Alteration
Regular physical exercise is associated with
important cardiovascular and mental health benefits (ACSM, 2010; Deslandes et
al., 2009; Haskell, et al., 2007). However, only about 64.5% of adults in the
United States are physically active (at least 150 minutes per week of
moderate-intensity activity), and approximately 25.4% of adults have no
leisure-time physical activity (Centers for Disease Control and Prevention,
2010). Even though most of the general population know of the benefits of
regular physical exercise, they still are inactive (Deslandes et al., 2009); because
knowledge of exercise benefits does not necessarily encourage people to be
physically active, and long term health benefits are difficult to achieve in a
short period (Berger, 2009). Thus, novice exercisers may feel disappointment
with an apparent lack of expected benefits and drop out from a regular exercise
program. Therefore, novice exercisers may need to anticipate not only long term
health benefits, but also experience immediate psychological rewards, such as
improved mood states (Hallgren, Moss, & Gastin, 2010). These immediate
rewards could be noticeable and thus, motivate novice exercisers to continue
regular physical activity. In addition, specific exercise factors such as
exercise intensity and duration need to be examined to determine the
relationship between these exercise factors and mood changes (Berger, 2009).
Information about specific exercise factors will be useful in designing
exercise programs to maximize mood benefits from a single exercise session
(Berger & Tobar, 2011).
Theoretical Support of the Relationship Between Exercise and Mood Alteration
Hedonic and self-determination theory are two
popular theories applied to sport and exercise science. Those two theories may
explain the relationship of preferred exercise intensity and mood alteration.
According to the hedonic theory, people seek to enhance
or prolong pleasure and avoid or minimize pain (Williams, 2008). People are
more likely to make behavioral choices that increase their pleasure and tend to
avoid behavioral choices that decrease their pleasure or induce displeasure.
This theory can be applied to exercise choices. When people exercise at
prescribed intensity, they may feel less pleasure than when they exercise at
their preferred intensity. Prior studies (Ekkekakis & Lind, 2006; Lind et
al., 2008) support this hypothesis by showing participants felt less pleasure
when they exercised at 10% higher than their preferred exercise intensity.
Therefore, people are more likely to participate in and find pleasure in
exercising if they do so at their preferred intensity.
The self-determination theory (SDT) focuses on the
motivational implications of self-selected (autonomous) and dictated
(non-autonomous) behaviors (as cited in Vazou-Ekkekakis & Ekkekakis, 2009).
According to the SDT, autonomy is one of three basic psychological needs (the
others are competence and relatedness), which refers to the extent to which a
person feels free (perceives high flexibility and low pressure) to exhibit the
behavior of his or her choice, with an inner endorsement of his or her own
actions. SDT suggests that the degree of pleasure that individuals experience
when they act autonomously (in this case, when they set their own exercise
intensity) will likely be higher than that experienced when behavioral
parameters are externally controlled (when the intensity is prescribed).
Therefore, when participants can set their preferred intensity, they will
experience more pleasure and a more positive mood will occur than when they
exercise at prescribed intensity (as cited in Vazou-Ekkekakis & Ekkekakis,
Application to the Current Study
Based on the literature reviewed, the hedonic theory
and the self-determination theory both seem to be applicable for the
relationship between exercise and mood changes. According to hedonic theory,
people tend to choose activities to maximize their pleasure. When people
exercise at preferred intensity, they will achieve the maximum enjoyment, and
when exercisers feel more enjoyment, they will obtain more desirable mood
changes. According to the self-determination theory, when people can choose
their preferred exercise intensity, they will feel more pleasure, and obtain
more positive mood changes. Therefore, exercise enjoyment may be a mediator
between exercise intensity and mood states.