By Dr. Ryan Neely, Ph.D.
By this time of the year, the holidays are over and we’ve had several months of cold, dark winter. With daylight savings about to strike again in March, it can be a bit of a slog waiting for the warmth and sunlight of spring and summer. Although the science is mixed, people generally do show shifts towards lower mood during the colder darker months (1). Fortunately, we can channel our inner bear and use the benefits of sleep to combat some of the late winter slump. There are also some simple behaviors that we can adopt that will help keep spirits up until the warmer days of spring.
In psychology, the term “affect” is often used as a way to describe mood, such that “positive affect” refers to essentially good moods, whereas “negative affect” refers to poor or depressed moods. Sleep has been shown in several studies to influence affect. For example, sleep onset latency and total sleep time have been shown to moderate a positive affect “bounce-back” effect following a day of high stress. Put more simply, falling asleep faster and staying asleep longer can help you wake up in a better mood even if your previous day was stressful (2). Another study reported a similar result - specifically that the quality of sleep on a given night for both healthy and depressed individuals was predictive of positive affect on the following day (3). These results suggest that putting extra attention on sleep quality and quantity can be a way to lift your spirits even when winter feels like it’s dragging you down. Interestingly, the effect seems to be bi-directional such that higher levels of positive affect can improve sleep quality, suggesting the possibility of a positive feedback effect (4).
If sleep can be a tool towards improving mood, there are some simple ways to improve sleep during the winter months that can improve your outlook. First, like many things in life, consistency is key. Keeping a consistent bed and wake time helps your circadian cycle stabilize so that you’re mentally and physically prepared to be asleep and awake at the appropriate times. Unlike summer months, especially for those in northern latitudes, keeping your sleep environment dark is often less of a challenge in winter. Instead, we may find ourselves needing to get a little extra sunlight during the day. Sunlight is a strong regulator of circadian cycles. One of the early pioneers of circadian research, Jürgen Aschoff, referred to sunlight as the “Zeitgeber,” or “time-giver” by which the body sets and resets its internal clock. Getting regular exposure to sunlight is a great way to maintain your circadian rhythm. It can also improve your mood and make you less grumpy - a 2008 study found positive correlations between exposure to bright light throughout the day and improved moods and social interactions (5). Finally, there is also some evidence to suggest that vitamin D supplementation during wintertime can have positive effects on affect (6).
If late-winter gloom feels like it’s dragging you down, try to give yourself the positive mood-boosting effects of a good night’s rest by focusing on consistent sleep behaviors. Additionally, aiming for regular exposure to sunlight can help regulate your circadian cycle and improve your outlook. And finally, just hang in there and summer will be here before you know it!
References
- Øverland, S., Woicik, W., Sikora, L., Whittaker, K., Heli, H., Skjelkvåle, F.S., Sivertsen, B. and Colman, I., 2020. Seasonality and symptoms of depression: A systematic review of the literature. Epidemiology and psychiatric sciences, 29, p.e31.
- Chue, A.E., Gunthert, K.C., Kim, R.W., Alfano, C.A. and Ruggiero, A.R., 2018. The role of sleep in adolescents' daily stress recovery: Negative affect spillover and positive affect bounce-back effects. Journal of adolescence, 66, pp.101-111.
- Bouwmans, M.E., Bos, E.H., Hoenders, H.R., Oldehinkel, A.J. and de Jonge, P., 2017. Sleep quality predicts positive and negative affect but not vice versa. An electronic diary study in depressed and healthy individuals. Journal of Affective Disorders, 207, pp.260-267.
- Steptoe, A., O'Donnell, K., Marmot, M. and Wardle, J., 2008. Positive affect, psychological well-being, and good sleep. Journal of psychosomatic research, 64(4), pp.409-415.
- aan het Rot, M., Moskowitz, D.S. and Young, S.N., 2008. Exposure to bright light is associated with positive social interaction and good mood over short time periods: A naturalistic study in mildly seasonal people. Journal of psychiatric research, 42(4), pp.311-319.
- Lansdowne, A.T. and Provost, S.C., 1998. Vitamin D3 enhances mood in healthy subjects during winter. Psychopharmacology, 135, pp.319-323.