Washington: Aerobic exercise can help alleviate excessive daytime sleepiness among depressed individuals, according to a new study led by an Indian-origin scientist.
Researchers looking at blood samples identified two biological markers for the condition, called hypersomnia, which is characterised by sleeping too much at night as well as excessive daytime sleepiness, in those with Major Depressive Disorder. Exercise reduced the levels of the two biomarker proteins, resulting in reduced excessive sleepiness. “Hypersomnia, as well as insomnia, have been linked in the development, treatment, and recurrence of depression,” said senior author Madhukar Trivedi, Director of University of Texas Southwestern Medical Centre’s Centre for Depression Research and Clinical Care.
“Sleep disturbances are also some of the most persistent symptoms in depression. Identifying these biomarkers, combined with new understanding of the important role of exercise in reducing hypersomnia, have potential implications in the treatment of major depressive disorder,” said Trivedi. People with hypersomnia are compelled to nap repeatedly during the day, often at inappropriate times such as at work, during a meal, or in conversation.
They often have difficulty waking from a long sleep, and may feel disoriented upon waking. Researchers had previously found a negative loop in which sleep, inflammation and depression interact and progressively worsen. The results of the current and previous research on insomnia suggest that exercise may be resetting this negative feedback loop, said Trivedi. More than 100 subjects ages 18 to 70 who had Major Depression Disorder were randomly assigned to two types of aerobic exercise to determine the effects of exercise on their depression.
Researchers examined four biomarkers – brain-derived neurotrophic factor (BDNF) and inflammatory cytokines called tumour necrosis factor alpha, and two interleukins, IL-1 beta and IL-6, from blood samples collected before and after the 12-week exercise intervention. Researchers found that reductions in two biomarkers, BDNF and IL-1 beta, are related to reductions in hypersomnia. “Identification of biomarkers that uniquely predict or correlate with improvements in hypersomnia and insomnia is an important step toward more effective treatment of MDD,” said lead author Chad Rethorst, assistant professor of Psychiatry with the Centre for Depression Research and Clinical Care at UT Southwestern Medical Center. The study was published in the journal Translational Psychiatry.
