How Does Sunlight and Seasonal Affective Disorder (SAD) Affect Mental Health?

An autumnal leaf rests on a wooden table top which looks like a bench. We look at it from above and see on the floor more brown autumn leaves on the ground beneath.

by | 25 Oct 2023

This weekend the clocks in the UK go back as British Summer Time officially ends. With the nights getting longer, days getting shorter, and weather becoming colder and more overcast, winter can have quite the impact on our mental health.

Some people, you might be one of them, are more sensitive to the effects of the seasons. This can be a condition that is known as Seasonal Affective Disorder. We’ve outlined what this condition is below although it’s important to always be properly diagnosed by a doctor.

 

SAD – what is it?

Seasonal affective disorder (SAD) is a type of depression that occurs during the fall and winter months when the days are shorter and there is less sunlight. It is also sometimes referred to as seasonal depression or winter depression. SAD is a recognised mental health condition and can be debilitating for those who suffer from it.

Some common symptoms of SAD include:

  • Low mood and feelings of hopelessness
  • Lack of energy and fatigue
  • Difficulty concentrating
  • Increased appetite and weight gain
  • Changes in sleep patterns, such as sleeping more than usual

SAD is believed to be caused by a lack of sunlight, which can disrupt the body's internal clock and circadian rhythms. The reduced sunlight during fall and winter months can also affect the production of neurotransmitters in the brain, such as serotonin and melatonin, which play a role in regulating mood, sleep, and appetite.

While SAD is most often associated with the autumn and winter months, some people can experience seasonal affective disorder during the summer months. This is known as summer SAD, and its symptoms can include anxiety, insomnia, and decreased appetite.

 

Why does sunlight support our mental health?

Many studies have shown the number of benefits sunlight can have on our mental health. Sunlight helps our mental well-being in a number of ways. Sunlight exposure helps the production of vitamin D, a nutrient that plays an important role in our brain function and mental health. Research has found that low levels of vitamin D are associated with an increased risk of depression, anxiety, and other mental health conditions.

As well as this, exposure to sunlight triggers the release of serotonin, a neurotransmitter that regulates mood and contributes to feelings of well-being. Increased exposure to sunlight is associated with increased serotonin levels, which can improve mood and reduce symptoms of depression.

Warm weather also plays a role in our mental health. Warm weather can also promote physical activity, which is known to have numerous mental health benefits, including reducing symptoms of depression and anxiety. During summer months, we can enjoy more green spaces and research has shown plants and nature are likely to have a positive effect on mental health.

Sunnier countries often produce foods that are associated with healthier mental well-being. Being outside and getting active is good for mental health and this is undoubtedly easier when the weather is dry and warm, but not too warm. Research suggests, healthy eating patterns, such as the Mediterranean diet, are associated with better mental health than eating patterns we might find in the Western diet.

As other research has suggested, exposure to sunlight, spending leisure time in green spaces, and physical activity each had a positive impact on people’s mental health, including depression, anxiety, and stress states. Specifically, moderate physical activity in an external environment with sunlight exposure or green space was found to be an important factor. The study found that exposure to the natural environment through sunbathing and exercise is important for people’s mental health.

 

What's best for mental health - cold or warm temperatures?

Conversely, while many of us enjoy the warmer weather and find it helps our mental health, it is more and more common for people to struggle with anxiety regarding the newly heightening temperatures since climate change is having an effect on the mental health of many.

In fact, many have experienced a link between recent heatwaves and a negative impact on mental health. Studies have shown that higher temperatures increase emergency department visits for mental illness, suicide ideation, and poor mental health. Surprisingly, cold temperatures reduce negative mental health outcomes while hot temperatures increase them. So there’s good news as we enter wintery days; colder weather is actually linked to improved mental health for many.

If you are concerned you or someone else might be struggling with SAD or anxiety regarding climate change, do seek medical advice from your GP.

If you struggle with the winter months, help is at hand. We’ve come up with 10 top tips to help us all get through the colder days to come.

 

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