Depression affects many adolescence and young adults and is the main reason of disability worldwide. There have been many drugs created to help combat one’s depression, yet they all come with negative side effects (Chen et al., 2017). Current research is showing that running can be its own kind of therapeutic treatment for depression. Research shows that running strengthens blood vessels, reduces plaque buildup within the veins and arteries, and strengthens capillaries (small blood vessels). Depression is also linked with smaller hippocampus (the area of the brain related to memory) volume resulting in memory, emotional and learning impairment. Depressed individuals also have lower blood flow to the hippocampus; therefore, if running increased the blood flow and strengthens capillaries then it may reduce or reverse the symptoms of depression.

A study by Chen et al., (2011) examined the effects running had on rats who were depressed. They hypothesized that the if the hippocampus changes when depression occurs, and exercise increases blood flow in the brain, then the increased blood flow in the hippocampus will reduces the symptoms of depression. The rats used in the study were randomly assigned to two groups, control group and chronic unpredictable stress (CUS) (i.e., water deprivation for 24 hours, a tail clamp 1 minute 3 times a day) group. After 4 weeks, 20 of 90 rats in the CUS group were chosen, for the next portion of the study, based on their significantly low sucrose level. Sucrose intake was measured by the total sugar water the rats drank in one week. The low intake of sucrose indicates anhedonia (the inability to feel pleasure); therefore, their lack of interest for the sugar water suggests depression. This is a core symptom of depression in humans. The 20 rats were split into 2 groups: 10 were assigned to CUS standard and the other 10 were assigned to CUS running. After the 8-week trials, the rats brain was hippocampus was analyzed.

The results show that after the 4 weeks of exercise the running group showed significantly elevated levels of sucrose consumption, suggesting their increased ability to feel pleasure and can take pleasure in their regular enjoyments. This also demonstrates that running revered depressive symptoms. The total volume of the CA1 and dentate gyrus increased significantly for those in the running group compared to the standard group. The total length of the capillaries in the CA1 and dentate gyrus also increased significantly for the running group compared to the standard group. The running groups had similar brain structure to the control group who did not experience depression. This suggests that the running improved the depressive behaviour and symptoms enough for the rats to be comparable to those in the control group who have never experienced depression. Improving blood vessels may be a way of treating depression; vascular density may be the underlying cause of depression improvement.

Other research has shown that the majority of the brain of depressed patients is not much different than healthy patients; however, the volume of the hippocampus in depressed patients is significantly lower. This study shows that the volume of the hippocampus in depressed rats increases after the 4-week running intervention; however, the mechanism behind how it changes is unknown. The increased blood flow and oxygen to the brain may raise metabolism and chemical activity; this could be the one mechanism. This also might be why antidepressants with vasodilators (a drug that relaxes smooth muscles, widening blood vessels) leads to greater depression reduction. Running has shown to be an effective therapeutic treatment for depressive symptoms. Running also improves cardiovascular function, therefore the mind and body can become healthy with one intervention. Running off depression may become a new therapy for individuals.