By Angela J. Grippo, Ph.D.
A common New Year’s resolution is to begin, or improve upon, an exercise routine. Of course, this is a wonderful goal because exercise has many benefits, such as increasing muscle strength, keeping our hearts healthy, staving off chronic diseases, and helping us shed a few unwanted pounds.
But did you know that exercise is also very good for our brains?
In fact, in addition to the many physical benefits of exercise, another great reason to step up our exercise routines is to improve our mood and ability to cope with stress.
Moderate aerobic exercise can serve as a great mood booster. For instance, patients with mild to moderate depression engaged in a 12-week exercise program involving one of three exercise routines. The routines consisted of moderate intensity, low intensity, or placebo exercise (flexibility regimen) at frequencies of either five or three days per week (Dunn et al., 2005). The patients on the moderate-intensity routine showed greater improvements in their mood when compared to the low-intensity and placebo groups. Interestingly, there was no difference in mood improvement between those individuals who exercised three days per week versus five days per week.
Research from animal studies, such as with rodents, also provides evidence that exercise can change mood and behavior. For instance, stressed mice will display behavioral signs of “depression” by consuming less of a sugary drink than un-stressed mice. This lowered consumption of a sugary drink is indicative of the animals deriving less pleasure from an experience that used to be pleasurable (drinking the sweet beverage), which is a common sign of stress and depression. But if the mice are allowed to exercise in a running wheel for three weeks, they do not display as pronounced of a change in consumption of the sugary drink – indicating improvements in behavior, emotion, and ability to cope with stress (Solberg et al., 1999).
Exercise can even improve behavioral and emotional responses to social stress. For example, a unique rodent that is used to study social stress and emotion is the prairie vole. Prairie voles live on prairielands in family groups, with mothers and fathers raising their young together. The animals also form very strong social bonds – just like humans. Social stress, such as separating the prairie voles from their family or friends, leads to changes in behavior and emotion that look like depression. For instance, these rodents also derive less pleasure from drinking a sugary beverage as a result of social stress. (Grippo et al., 2011).
However, if prairie voles are allowed to exercise in a running wheel for four weeks while they are separated from family or friends, they show improvements in behavior and emotion and can better handle mild stress (Ihm et al. 2013). Because prairie voles show many unique social traits that mirror humans (such as forming long-lasting social bonds), and they also show many biological similarities to humans (such as similarities in the way the brain regulates hormones, blood vessels, and the heart), this research involving rodents can apply to humans. It suggests that we, too, can benefit from the stress-buffering effects of exercise.
Why does exercise have stress-buffering and mood-elevating effects? One reason might be the way in which exercise changes communication in the brain. Regular exercise can encourage new cell growth in the brain (Olson et al., 2006 discuss many studies that have demonstrated this effect) – which is critical for adequate brain communication, emotional reactivity, and our ability to cope with stress.
So, start a new exercise routine in 2014 (after talking with your doctor to be sure this is the right choice for you). Not only will you see improvements in your muscle strength and cardiac fitness, but your brain will thank you as well! A regular, moderate exercise routine can have immense benefits on our mood and our ability to handle stress.
Angela Grippo is an Associate Professor of Psychology at Northern Illinois University. She teaches courses about neuroscience and the brain. Her research is focused on the interactions of emotions, social interactions, and the heart, including the psychological and biological underpinnings of the link between mood disorders and cardiovascular disease. She uses prairie voles as an animal model.
References
Dunn, A.L., Trivedi, M.H., Kampert, J.B., Clark, C.G., & Chambliss, H.O. (2005). Exercise treatment for depression: efficacy and dose response. American Journal of Preventive Medicine, 28, 1-8.
Grippo, A.J., Carter, C.S., McNeal, N., Chandler, D.L., LaRocca, M.A., Bates, S.L., & Porges, S.W. (2011). 24-Hour autonomic dysfunction and depressive behaviors in an animal model of social isolation: implications for the study of depression and cardiovascular disease. Psychosomatic Medicine, 73, 59-66.
Ihm, E., Dotson, A., Jadia, N., McNeal, N., Murphy, R., Schultz, R., Wardwell, J., Wegner, A., & Grippo, A.J. (2013). Reversing the effects of social stress through environmental enrichment and exercise: an animal model. Animal Behavior Conference, Bloomington, IN.
Olson, A.K., Eadie, B.D., Ernst, C., & Christie, B.R. (2006). Environmental enrichment and voluntary exercise massively increase neurogenesis in the adult hippocampus via dissociable pathways. Hippocampus, 16, 250-260.
Solberg, L.C., Horton, T.H., & Turek, F.W. (1999). Circadian rhythm and depression: effects of exercise in an animal model. American Journal of Physiology – Regulatory, Integrative and Comparative Physiology, 45, R152-R161.
