Seasons Change — and So Does Your Body

If you feel gloomy in the cold weather, you’re not the only one. The reason you may feel depressed in the winter has to do with the amount of sunlight that reaches your brain. Sunlight prevents the production of melatonin (the sleep hormone that makes you tired) and, when you don’t get enough of it, you may feel groggy. Seasonal affective disorder (SAD) is a mood disorder characterized by depression that occurs at the same time every year. While medications are available to treat SAD, many people with this disorder benefit from making their home environments sunnier and brighter, getting outside and exercising regularly. “The light we get from being outside on a summer day can be a thousand times brighter than we’re ever likely to experience indoors,” said melatonin researcher Russel J. Reiter, PhD, of the University of Texas Health Science Center. “For this reason, it’s important that people who work indoors get outside periodically, and moreover that we all try to sleep in total darkness. This can have a major impact on melatonin rhythms and can result in improvements in mood, energy, and sleep quality.”