As the mercury rises and the sun stakes its claim in the sky, so might a brighter mood, sparked not by the sheer joy of summer days but by better sleep. This is the recent finding from a team at Harvard-affiliated Brigham and Women’s Hospital, as reported by The Harvard Gazette. Scouring the sleep habits and mental health of over 6,600 individuals, the study links longer exposure to bright light to more stable sleep patterns, and in turn, to a decreased risk of depression.
"Getting consistent, regular sleep has wide-ranging effects on our health,” said Susan Redline, the Peter C. Farrell Professor of Sleep Medicine at Harvard Medical School and a senior physician in the Brigham’s Division of Sleep and Circadian Disorders, according to The Harvard Gazette. The effects on mood are comparable to the calming influence of a scenic view. Research, which explores the interplay between bright light therapy and the importance of sleep consistency, suggests that maintaining regular sleep shouldn’t be overlooked when considering mood enhancements.
Danielle A. Wallace, who led the research from the Division of Sleep and Circarian Disorders, leveraged data from the National Health and Nutrition Examination Survey spanning 2011 to 2014. Participants sported wrist devices to monitor bright light exposure—akin to daylight levels—and sleep regularity. Wallace told The Harvard Gazette, “We found that greater time spent in bright light was modestly associated with lower depression symptoms and that sleep regularity partly explained this association.” Indeed, Vitamin D entered the chat with its ties to bright light and sleep, but apparently chose to ghost when it came to depression symptoms.
But don't sunbathe in these findings just yet; the authors note the study's cross-sectional nature, meaning this isn't a cause-and-effect revelation. They acknowledge that depression symptoms may just as well direct a person's time under the sun. So, while we may feel urged to chase the daylight for a pick-me-up, it's a reminder to give due diligence to nuance and complexity before we lather on the sunblock of conclusions. This illuminating study was funded by the National Institutes of Health.
