After screening 415 collegiate athletes and non-athletes for depression, Tamara Hew-Butler, an exercise physiologist and sport scientist, found that depression rates were much lower among athletes at 9.8 percent compared with non-athletes at 32.9 percent.
Exercise stimulates serotonin, norepinephrine, and brain-derived neurotropic factor (BDNF)—a brain protein linked to mood—all of which play a crucial role in the acute antidepressant effects of exercise, Hew-Butler said.
While these benefits occur across various forms of exercise, sprint interval training brings an added benefit: lactate production.
After high-intensity exercise, lactate is released from the muscle and enters the blood-brain barrier, triggering the release of more BDNF, which benefits people with depression, who often have lower BDNF levels.
During short, intense bursts of exercise, the body produces lactate as a by-product of glycolysis, the process that breaks down glucose for quick energy. Animal studies have shown that lactate has antidepressant-like effects and improves resilience to stress through several signaling pathways.
So short sprint training (sSIT), just 5 second “all out” bursts, has been shown to significantly ease depression, improves aerobic fitness, and boosts mood in just two weeks. A study on women with Major Depressive Disorder found that six, 10-minute sessions of sSIT over two weeks significantly reduced depression scores.
The training consisted of only 3 to 12 "all-out" sprints of 5 seconds, with 30-45 seconds of recovery between them.
In another article I will reference the benefits of high intensity interval training (HIIT) in slowing cancer progression.