Chapter 8: Physical Activity and Exercise
The Impact of Physical Activity on Stress
One of the most eminent stressors in students’ lives is academic stress (AS).1 Students report experiencing AS at predictable times each semester with the greatest extent at the end of a semester, resulting from taking and studying for exams, grade competition and the large amount of time invested in studying.2–5
The effectiveness of AS as a psychosocial stressor is well established regarding repercussions on physiological and psychological health.6 It has been shown that AS has negative implications on physiological health variables, such as immune functions (suppresses cellular immunity while preserving humoral immunity)7 and neuroendocrine functions (increase in adrenocorticotropic hormone levels and cortisol levels, when perceiving high stress).8 Furthermore, in AS periods, different effects on psychological parameters can be detected, such as increased anxiety,9 poor sleep quality,10 a negative effect on well-being,11 increased negative affectivity12 and increases in the prevalence of depressive symptoms.13 Based on these findings, it can be assumed that times of high AS (ie, examination periods) have a negative impact on health-related physiological and psychological outcomes.
Evidence suggests the relationship between stress and sleep quality to be bidirectional: 1) high stress levels have negative effects on sleep quality14 and 2) poor sleep quality affects subsequent stress levels.15 Regarding the effect of stress on sleep quality, a growing body of research suggests that high stress levels negatively influence sleep quality.16 Taking AS as the stress-evoking situation, a study conducted by Lund et al10 found that students with higher stress levels also report poorer sleep quality and more negative mood and illness. Regarding the reverse effect of sleep quality on stress, studies have shown that sleep deprivation (ie, poor sleep quality) potentiated stress responses of the hypothalamic–pituitary–adrenal (HPA) axis (ie, cortisol secretion) in a similar way as real stress does17 and that reactivity to a psychosocial laboratory stressor after sleep deprivation was increased compared to that in normal sleeping participants. These effects have also been shown for psychological stress outcomes, as participants with poor sleep quality showed significantly more fatigue and lower behavioral alertness.17,18 These results were also confirmed in a longitudinal approach with student’s sleep quality and duration predicting mood and self-esteem, showing direct and indirect effects on academic performance.19
Well-being is commonly defined as the optimal functioning that enables an individual to live an effective life and to accomplish satisfaction in life and genuine happiness.20 It has been found to be inversely related to perceived stress in students,21 meaning that students show decreased well-being in high stress periods, whereby poor well-being also has a negative e