While we know that physical activity boosts mood, reduces depression and combats fatigue – especially for those with chronic illness – research from the University of Illinois suggests that part of the reason for this effect is due to the way mastery of over our goals makes us feel.
According to Edward McAuley, a professor of kinesiology and community health at the University of Illinois and lead author of the study, while depression and fatigue are closely linked, interventions to reduce fatigue do not always result in reductions in depression. On the other hand, when depression is reduced, fatigue is typically lifted.
As depression and fatigue are both highly susceptible to changes in a person’s sense of his or her own ability to achieve a certain goal, which is known as self-efficacy, McAuley and his colleagues wanted to determine if self-efficacy was the factor that helped explain just how physical activity helps to reduce depression and fatigue.
“The conviction that you can jog down the block or climb several flights of stairs without stopping is an example of self-efficacy” (McAuley, 2016).
“Our argument was that physically active individuals would have higher self-efficacy, which in turn would result in reduced depression and reduced fatigue,” McAuley explains (McAuley, 2016).
To test this hypothesis, the researchers reanalyzed data from two previously published studies – the first involving breast-cancer survivors and the second focusing on individuals diagnosed with multiple sclerosis. Both studies included self-report questionnaires, but the second used different measures of health status, physical activity, self-efficacy, depression and fatigue. It also required that participants record their physical activity with an accelerometer worn during waking hours for seven days, and it tested them again on all measures after six months.
So did higher levels of physical activity increase feelings of self-efficacy?
In both groups the higher the levels of physical activity were, the more self-efficacy was increased and this effect also corresponded to lower levels of depression and fatigue. Even more convincing was that when the researchers controlled for the influence of self-efficacy on depression and fatigue, they found that the effect of physical activity on both depression and fatigue was significantly reduced (McAuley et al., 2016).
“What we’re showing is that the relationship between physical activity and reductions in fatigue in breast-cancer survivors and people with MS can be explained in part by the effect of physical activity on mastery experiences. That sense of accomplishment, or situation-specific self-confidence, serves to reduce depression, which in turn reduces fatigue” (McAuley, 2016).
The takeaway, McAuley notes, is that physical activity influences depression and fatigue through the mechanism of increased self-efficacy. And this is an important finding as physical activity programs can be designed specifically to enhance self-efficacy and, in turn, well-being (McAuley, 2016).