Serotonin is a chemical messenger in the brain that is a key player in regulating several functions such as mood, appetite and the circadian rhythm. Serotonin also converts to melatonin with lower light intensity. As mentioned above, melatonin is a hormone that regulates the sleep-wake cycle and signals the brain that it’s time to sleep.

Less daylight exposure during winter months leads to the conversion of serotonin into melatonin earlier in the evening, since it gets dark earlier. As a result, this untimely melatonin release causes a disruption in the sleep-wake cycle. For some people this can cause moodiness, daytime sleepiness and loss of appetite regulation, typically leading to unhealthy snacking. People with seasonal affective disorder often crave foods rich in simple sugars, such as sweets, because there is an intimate connection between carbohydrate consumption, appetite regulation and sleep.

In winter, most people leave work when it’s turning dark. For this reason, light therapy is typically recommended for those who experience seasonal affective disorder, or even shorter periods of seasonal funk.

This can be as simple as getting some light shortly after awakening. Try to get at least one hour of natural light during the early morning hours, preferably about one hour after your usual morning wake-up time when the circadian clock is most sensitive to light. This is true no matter what your wake-up time is, as long as it’s morning. For people living at northern latitudes where there’s very little sun in winter, light therapy boxes – which replicate outdoor light – can be effective.

You can also improve your sleep quality by avoiding stimulants like coffee, tea or heavy meals close to bedtime. Exercising during the day is also good – it increases serotonin production and supports circadian regulation. A balanced diet of complex carbs and healthy proteins supports steady serotonin and melatonin production, and practicing downtime before bed can reduce stress.

Taking these small steps may help the circadian rhythm adjust faster. For the millions with mood disorders, that could mean happier times during what are literally the darkest days.

This article is republished from The Conversation, an independent nonprofit news site dedicated to sharing ideas from academic experts. It was written by: Lina Begdache, Binghamton University, State University of New York. If you found it interesting, you could subscribe to our weekly newsletter.

Read more:
Seasonal depression: small things you can do every day to cope

Seasonal affective disorder: your eye colour might be why you have the ‘winter blues’

Lina Begdache does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.