This article will cover the following:
- What is seasonality?
- Physical effects of seasonality
- Psychological effects of seasonality
- Coping with seasonality: some tips and tricks
Ogni frutto ha la sua stagione.
Every fruit has its season.
Tuscan proverb
What is seasonality?
Seasonality (to vary or depend on the season or time of year) occurs in basically every species and man-made system on this earth, which should serve to remind us of nature’s all-powerful staff: the four seasons.
In this article, we’re going to try and understand how we are both physically and psychologically affected by seasonality, and what we can do to cope.
In order to find some answers, I’ve looked at a number of studies on the subject, which I’ll regroup for you here. They’re quite an interesting read and will quench your thirst for more details beyond what I give you here in this article. Voilà:
- Grimaldi et. al. | Indoors illumination and seasonal changes in mood and behaviour are associated with the health-related quality of life | Link here
- Ilona Merikanto | Influence of seasonal variation in mood and behaviour on cognitive test performance among young adults | Link here
- Brooks et. al. | Nature-related mood effects: Season and type of nature contact | Link here
- Harris & Dawson-Hughes | Seasonal mood changes in 250 normal women | Link here
- Denissen et. al. | The Effects of Weather on Daily Mood | Link here
- Scand | Seasonal variation of mood and behaviour in a healthy middle-aged population in Japan | Link here
- Madden et. al. | Seasonal Changes in Mood and Behvaiour | Link here
- Video: Ruth M. Benca | Lecture at the University of Chicago: Seasonality, Mood, and Migration (View on YouTube)
Physical effects of seasonality
On a physical level, what science tells us for sure is that seasonal changes affect our energy levels, duration and quality of sleep, and eating habits.
Energy levels
Generally, we have less energy in the autumn and winter, which is partially due, strangely enough, to indoor illumination [1]. If you’re up early in the morning before sunrise, or working past dark, you’re depending, to a certain degree, on artificial light sources to sustain your energy and focus. Because our natural body clock runs on natural light for indications on when to get up in the morning and when to go to sleep in the evening, relying on indoor light sources in the wintertime when the days are shorter makes it difficult to sustain energy in both the body and mind past daytime hours. And if your indoor area is poorly lit, it makes it even harder to do so.
On the other hand, we may also find we have less energy in the summer when it is particularly warm, because the intensity of sunlight is positively correlated with tiredness (5). Hence, we can conclude that extreme excess or lack of sunlight can both have a negative effect on our energy levels.
Sleep in the winter vs. sleep in the summer
Duration of sleep is inversely correlated with the length of the day, so hours of sleep will vary by season [2]. Of course, the shorter days and colder weather that come along with winter cause us, on average, to sleep longer - our bodies are trying to store heat and go along with the aforementioned internal clock that functions based on daylight. It then follows that we sleep less in the summer, when the days are longest. The warmer weather also makes it more difficult to fall asleep and stay asleep. For instance, if it’s so hot that we’re laying in bed sweating, it’s virtually impossible for our body and mind to enter into deep sleep, because our nervous system - and our skin - is actively busy trying to keep us cool.
Seasonal eating habits
Our eating habits are strongly correlated with one main physical and psychological factor: hours/ quality of sleep, and mood. Studies mentioned in Professor Ruth M. Benca’s [8] lecture at the University of Chicago show that we can have tendencies to eat more in both the winter and the summer: that would run true with our lack of sleep affecting our eating habits in the summer, and our worsened mood affecting our eating habits in the winter.
People with SAD (Seasonal Affective Disorder, learn more here) experience the effects of seasonality on both their weight and appetite [2]. In a study conducted in Japan [6], individuals living in the Northern part of the country, who were more affected by affected by cold, hot, humid, or cloudy weather and short days, were also more likely to develop SAD, or exhibit behavioural characteristics of SAD: “Our findings indicate that middle-aged men and women living in the northern part of Japan (Akita and Sapporo) show a similar trend in mood and behavioural change to that observed in SAD patients. They sleep more, feel worse, eat more, and gain weight in winter.”
Psychological effects of seasonality
Psychologically speaking, seasonal changes affect us in all kinds of ways. We’ll focus on how the lack of sunlight and extreme weather can affect our moods. I’ll also touch upon how seasonal changes can affect our cognitive abilities.
Lack of sunlight
According to research by Landsowne and Provost back in 1998 (5), Vitamin D3 was proven to influence serotonin levels in the brain, which is important to know because a) serotonin is the so-called “happiness chemical”, but also because b) we produce Vitamin D3 in our skin when we are exposed to sunlight. So, it follows that the less sunlight we are exposed to, the less Vitamin D3 our bodies will produce. That’s why we may feel more low in the fall and winter when compared to spring or summer, ceteris paribus.
The sensitivity of our moods in relation to (lack of) sunlight are also tied with our genetics, and in what kind of a climate we’ve lived for most of our lives. Obviously, bodies adjusted to grayer climates may not be as affected by less sun, but for someone having lived their whole life in a warm and sunny climate, mood swings are more likely in the case of having to transition to gloomier weather (7).
Extreme weather
It’s important to mention that worsened moods don’t necessarily have to be associated with cold weather and the winter. In the case of Choshi and Kagoshima, two cities in the South of Japan, a middle-aged sample population of residents studied (6) showed worsened moods in the month of June, corresponding to the rainy season with high humidity and less hours of sunshine. That means that extreme weather of any kind - humidity, high rainfall, storms, extreme cold, extreme heat - is capable of worsening our mood, or just plain and simple, causing confusion and turbulence in our minds as we’re trying to adjust to whatever is going on outside.
Seasonality and cognitive abilities
In a study testing cognitive performance of students in school based on different times of the year, it was found that seasonality does in fact affect our cognitive abilities - this is something interesting to take into account for schools when they decide during what time of the year testing periods should take place, or which months of the school year should be the most academically intense. According to some additional findings presented by Professor Benca in her university lecture on seasonality, mood, and migration, there are consistently higher graduation rates in the spring, not only because that’s traditionally when students tend to graduate, but also because spring is a season in which students, across the board, experience higher energy levels and better moods, which increases their motivation and productivity [8].
Seasonal decreases in sleep duration and increases in negative moods were correlated with worsened auditory attention and short-term memory, which makes sense: If you’re sleeping less and experiencing symptoms of depression or anxiety, you’re less likely to be able to focus and absorb information. According to the study, SAD-like symptoms, especially with respect to weight and appetite, also had a “significant effect on working memory, auditory attention, and short-term memory”.
Coping with seasonality: some tips and tricks
Even though we are consistent in our daily lives, it’s important to acknowledge the changes, big and small, in our external environment that are beyond our control and may influence our ability to follow that same routine throughout the entire year. In this case, the four seasons are our main villain… but they don’t have to be!
Try living seasonally
Living seasonally just means living like any other species does - that is, in harmony with nature and its four seasons. You are accepting of changes in your mental and physical state caused by changes in weather, and you do not try to repress them or fight them, but rather let them play out as they are supposed to. They are your body’s natural reaction to this seasonal change. When you start living seasonally, you begin to exercise gratitude for the way you evolve and adapt to nature’s cycle as a human being: that may mean that, in the winter, you are less active and prefer to get cosy and reflect on life from behind your window; and in summer, you may feel like a dandelion flying through the wind, high on life and hungry for adventure, always with lots of energy in your pocket. In a way, living seasonally gives us an opportunity to explore different versions of ourselves throughout the year-- how cool is that!
Spend time in nature (yes, even in the winter)
Contact with nature is proven to positively affect our mood [3], so get out there and frolic on Mother Earth’s playground! Regardless of the season you’re in, nature contact retains its benefits… I know what you’re thinking… yes, even in the winter! In fact, a study [3] showed that showing an image of nature in summer to an individual in the winter was not as elevating as having that same individual go outside and spend some time in actual nature. It doesn’t have to be for a long time, but breathing fresh air or feeling the cold on your skin is sometimes the most refreshing and exhilarating thing you can do for yourself when you’ve spent your entire day cuddled up in a blanket on your bed.
How does seasonality affect you? We’d love to hear. Is there anything in particular that helps you cope?