Weeks into the shelter-in-place order, people may struggle to find the motivation to get up. Many people might be scared to leave their homes, or intimidated by new social distancing rules. The feeling of being stuck inside can worsen moods and exacerbate stress. These changes in mood—though heightened by the Covid-19 pandemic—are a common experience, especially during the winter months. When trapped inside, many people present worsened mood and mental health symptoms. But why does this happen? The answer can be found in the sun.
Sunshine has often been used as a representation of happiness and positivity. It turns out this depiction is highly accurate, as sunlight does have a direct relationship with your mood. It has been shown that the more sunlight there is, the more elated feelings a person experiences. Furthermore, studies have found that decreased exposure to sunlight corresponds to an increase in mental health distress, as well as an overall change in mood and cognition. 
Also associated with changing amounts of sunlight, Seasonal Affective Disorder (SAD) is a depressive disorder that fluctuates with the seasons and shows how much of an impact the sun can have on mental health and well-being. According to the American Psychological Association, symptoms of this disorder include pervasive sad moods, irregular sleep patterns, fatigue, and craving carbohydrates.  Although they share similar symptoms, Seasonal Affective Disorder (SAD) is more severe than just the “winter blues,” as it interferes with a person’s daily activities and functions.
understanding the mechanism
The changes in mood experienced in the recent winter months have a biological basis related to sunlight. Sunlight impacts the release of serotonin and melatonin, which are neurotransmitters that help regulate sleep and emotions. Levels of serotonin, commonly associated with happiness, increase when you are exposed to sunlight and can explain why your mood improves when it is sunny outside.  Conversely, the lack of sunlight causes the body to change its cycle of melatonin production, which is involved in sleep. This affects how, when, and how much melatonin is produced which can be linked to other symptoms of SAD, such as irregular sleep patterns and fatigue.
Another neurotransmitter, glutamate, is also affected by sunlight. A 2018 study examined mice to test the biological effects of exposure to sunlight and found that sunlight affects how the brain functions.  They noticed that the UV rays created urocanic acid in the body, which traveled in the bloodstream to the brain, and caused neurons to produce more glutamate. This increase in glutamate changes how neurons communicate, which alters brain functions and could have an effect on motor learning, memory, and mood improvement. This study reveals the mechanisms behind how sunlight affects the brain; understanding these mechanisms could have a significant impact on developing ways to combat these fluctuations in mood.
improving your mood
Now more than ever it is important to seek out natural light. Although no one can control the shelter-in place orders, there are ways to help alleviate the symptoms caused by staying inside. The best way to improve your mood is by simply getting outside and maximizing the intake of available sunlight. Take advantage of sunny days by going for a walk—making sure to maintain a distance of 6 feet from other people to avoid spread of the virus. If it is too cold, simple things like opening your blinds or sitting by a window to let in some natural light can help as well.
Even when you cannot go outside, there are simple things that can be done in your home to improve your mood. It is important to find ways to take time for yourself and dive into self-care. Sitting under blankets and watching movies all day may sound amazing, but it is also important to exercise and maintain a healthy diet during these times. Although finding the motivation to do so may be difficult, a balanced diet provides essential nutrients and exercise produces endorphins—both of which are associated with elevated moods.  Other activities that reduce stress can also help improve your mood. Try putting on some upbeat music, creating a cozy space, and immersing yourself in an activity like journaling that helps you relax and enjoy yourself.
Although more difficult to accomplish, there are technologies often used in the treatment of SAD that can help relieve symptoms caused by less sunlight. These technologies include mechanical light boxes and dawn simulators that work by simulating natural light, helping to regulate the mechanisms associated with SAD. Light boxes emit intense light—around 100 times brighter than typical indoor lighting.  Sitting near them for 30 minutes every morning helps relieve SAD symptoms caused by lack of sunlight. Dawn simulators are similar, but they work by gradually increasing the intensity of light over a period of time .
Finally, if you are really struggling, do not be afraid to reach out. UCLA has many mental health resources on campus, such as CAPS, with people who can provide professional assistance.
Sunlight affects the biological mechanisms that help regulate mood, meaning that staying inside and reducing your sunlight intake can worsen your mood during these already stressful times. Although these are difficult times, there are things that can be done—like going outside and taking time for yourself—to help you overcome the “winter blues” and get through these stay-at home orders.
by Fiona Osborn