How Do Seasons Affect Memory and Thinking?

Fact checked by Olga Sadouskaya, MD
Clinical Pharmacologist, Chief Medical Officer

Do you feel that you can’t focus on anything when it’s autumn or winter outside? Well, you’re not making it up. Seasons can have a very real effect on your memory and focus.

Let’s take a closer look at several ways in which seasons affect brain function.

Seasonal affective disorder (SAD)

Seasonal affective disorder is a type of depression that usually begins in the autumn months, and continues throughout the winter. Scientists believe that it’s caused by a lack of sunlight: in winter, days are shorter and people tend to spend more time indoors. SAD is more prevalent in regions with long, dark winters.

The most well-known symptoms of SAD include losing interest in things that the person normally enjoys, being tired despite sleeping a lot, and overeating.

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Seasonal affective disorder can also have an impact on memory and thinking. Like other types of depression, SAD can make it hard to focus, remember things, and make decisions.

Note that seasonal affective disorder isn’t always limited to the cold, dark months of the year.

It’s also possible to have SAD that occurs in the summer months. Contrary to the “winter blues” that typically makes people feel sleepy and sluggish, summer-onset SAD manifests itself as insomnia and anxiety. These symptoms can also influence your cognitive processes.

Fortunately, SAD can be treated with light therapy, antidepressants, talk therapy, or a combination thereof.

People may be smarter in the summer

Seasonal affective disorder is a well-known phenomenon. However, recent studies suggest that seasons influence the human brain in other ways, too.

A 2018 study by Lim et al. investigated how older adults’ cognitive skills fluctuate throughout the year. The researchers also measured the expression of genes in the subjects’ brains and the amount of proteins related to Alzheimer’s disease in their spinal fluid.

The study found that older adults demonstrate much better cognitive skills in the late summer and early fall. Gene expression and the concentration of Alzheimer-related proteins also showed similar seasonal patterns.

A person writing in a notebook to demonstrate seasonal changes in memory

Do seasonal changes also occur in younger people? A 2016 study by Meyer et al. provided an answer to this question by keeping 28 young, healthy volunteers in a lab for 4,5 days, scanning their brain activity, and asking them to do two cognitive tasks. There was no sunlight or other seasonal cues in the lab.

The researchers found that the subjects’ attention skills were at their highest in the summer and at their lowest in the winter. The volunteers’ short-term memory seemed to be best in the fall and worst in the spring.

Both studies show that people’s cognitive skills seem to be better in the summer and autumn months.

However, the researchers couldn’t pinpoint what causes these seasonal changes. There may be a variety of factors that play a role: sunlight, physical activity, the amount of time typically spent outside, and many others.

It remains unknown whether the same seasonal fluctuations occur in all regions of the world and in all cultures (the studies were conducted in North America and Europe). For example, the Meyer et al. study took place in Belgium, where students typically have holidays in July and August. This may mean that they’re simply well-rested in the summer and tired of studying in the winter.

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It isn’t just about the brain

In 2015, a team of scientists led by Xaquin Castro Dopico found seasonal fluctuations in the expression of 23% of human genes. For example, genes that promote inflammation tend to be more active in winter. And since the immune system plays a role in regulating mood and behavior, seasonal changes in inflammation levels may be linked to changes in cognitive skills.

Books as a metaphor for seasons affecting thinking and productivity

More research is needed to explain the exact biological mechanisms behind this. But we can be pretty sure that our brain isn’t a standalone organ. On the contrary, it’s affected by many processes that happen in our body. And some of these processes seem to be regulated by seasonal factors.

As of now, there isn’t much we can do to fine-tune gene expression.

How to cope with seasonal changes in cognitive function

If you feel that seasons strongly affect your thinking, your memory, or your ability to focus, you can take some steps to feel better.

  • Establish a regular sleep schedule. Most adults need between 7 and 9 hours of sleep. While it’s tempting to spend rainy autumn days in bed, remember that too much sleep can have a negative impact on your memory and concentration.
  • Stay physically active. If the thought of jogging on a winter morning makes you cringe, work out at home or at a gym. Physical activity helps reduce stress and increase your energy levels.
  • Enjoy the outside. Natural scenery is known to speed up recovery from stress, reduce mental fatigue and increase concentration. In addition to that, you’ll get some sunlight and vitamin D.
  • Stick to a healthy diet. It’s common for people to eat more high-calorie and high-carb foods in the winter, but try to resist this temptation. Instead, you can try healthy and nutritious comfort foods like soups and other warm flavorful dishes.
  • Talk to your doctor. They can check if you have hypothyroidism, a vitamin D deficiency or any other condition that can influence your cognitive functioning.
  • Ask a mental health professional for help. Seasonal depression can’t always be cured with self-help alone. You may need talk therapy, exposure to a special lamp or even medications to get through your least favorite time of the year.

Conclusion

More research is needed to learn exactly how seasons influence our brain function. However, there’s no doubt that the change of seasons can greatly affect people’s memory and thinking in positive and negative ways.

If you find it hard to function during a particular season, try implementing some proven self-help techniques and never hesitate to talk to a medical professional.

November 11, 2022