If it’s dark when you’re off to work in the morning and when you return home at night (and you’re not getting out during the day), you may already be feeling the effects that the lack of sunshine is having on your energy, mood, appetite, and sleep patterns. Now that we’ve changed the clocks back, here are some important things to know about how your sleep can change with the shorter, darker days ahead.

  1. You’re wired to feel sleepier when it’s dark out. Your body’s internal clock is dictated by light because the circadian biological clock is controlled by a group of cells in the hypothalamus that respond to light and dark signals. Light is the cue that turns the internal clock genes on and off, affecting your circadian rhythms. Circadian rhythms can influence sleep-wake cycles, hormone release, body temperature and other important bodily functions. These internal biological clocks regulate the timing of periods of sleepiness and wakefulness throughout the day. So the longer it’s dark outside, the more likely your body thinks it’s time to get ready for sleep.
  2. Darkness influences your hormones. When you wake up in the morning and open your curtains to let sunlight in, that exposure to light through your eyes sends signals to your brain that it’s time to raise your body temperature and produce hormones like cortisol, which regulates many functions in the body. Exposure to light also delays your body’s release of other hormones, like melatonin, which is associated with sleep onset. Melatonin is produced in your body when brain signals receive the message through your eyes that it’s dark out. This could be one of the reasons why you feel sluggish as the sky darkens early on winter afternoons but it’s nowhere close to bedtime.  Melatonin levels rise in the evening and stay elevated throughout the night to help you fall asleep and stay asleep.
  3. Less sunlight can lead to depression symptoms. You may have heard of Seasonal Affective Disorder (SAD), a type of depression that’s associated with the change in seasons. While you might be thinking you’re just in a “fall funk” because summer is over and the weather is cooler, it’s a good idea to talk to your doctor if you find yourself feeling down more often than not, don’t want to do the things you love, and are feeling lethargic. Your doctor can evaluate you to get an idea of whether you’re suffering from SAD and need light therapy, psychotherapy, or medications. Or, they might suggest changing up your diet, adjusting your exercise routine, taking a vitamin D supplement, or spending more time outdoors in the sunlight. It’s important to open up blinds and let sunlight in your home and get outside during the day for sun exposure. Eat lunch outside or take your coffee break in the park, schedule some walks or runs outdoors, and just keep up with your regular exercise schedule. Exercise will not only help alleviate stress and anxiety, but it can help you fall asleep and get better quality sleep.
  4. Your food cravings have changed. Is it our imaginations, or are we really hungrier for hearty, heavy “comfort” foods as the weather gets cooler and the days are shorter? I broached this topic with D. Milton Stokes, MPH, RD, owner of One Source Nutrition, LLC, a nutrition counseling and consulting firm in Connecticut, in a winter weight gain story I wrote last year for DailyBurn. He said it’s not the colder weather that leads us to overeating during the winter months, but it’s the behaviors we’re conditioned to and the temptations we’re exposed to during the winter months. (Like everything from leftover Halloween candy straight through to Super Bowl Sunday parties and every event in between). That “hibernation theory” that we need more calories to get us through harsh winters doesn’t hold up he says. And if your sleep patterns have changed—you’re not getting enough hours or your sleep isn’t high-quality shuteye—that could affect your body’s hunger hormones and make you more inclined to overeat as well. Try to stick to your regular healthy eating plan, and minimize sugar and caffeine, especially in the afternoon as they can affect your body’s ability to fall asleep at night. Check out our Guy’s Guide to Healthy Eating for some ideas on how to get started.


“Body Clock and Sleep.”  ||  National Sleep Foundation

“Circadian Rhythms.”  ||  National Institute of General Medical Sciences

“Seasonal Affective Disorder.”   ||  MayoClinic.org

“9 Tips to Ward Off Winter Weight Gain.”  ||  DailyBurn.com/Life