The change of season does not make our body switch from one state to another overnight. But changes in daylight, temperature, daily routines and activity can influence some of our normal biological rhythms.

As summer gives way to autumn, daylight gradually decreases and the pattern of natural light changes. This can interact with the circadian rhythm — the internal timing system that helps regulate sleep and wakefulness. Light and darkness are among the most important environmental signals that help keep this system synchronized.

Light helps set our internal clock

Our brain uses the cycle of light and darkness as a cue for when it is daytime and when it is time to prepare for sleep. Natural light affects the timing of the circadian system and is linked to the release of melatonin, a hormone involved in regulating the sleep-wake cycle.

As daylight patterns change, some people may notice small differences in when they feel sleepy, when they wake up or how easily they adapt to a new daily schedule. These changes are not necessarily the same for everyone.

Our daily activity can change too

The seasons can influence how we spend our days. Weather, temperature and available daylight may affect how much time we spend outdoors, how active we are and how much time we spend sitting.

A systematic review and meta-analysis of 17 studies found evidence of seasonal differences in sleep, sedentary behaviour and physical activity, although the researchers noted that the available evidence remains limited.

In other words, seasonal change is not only something we notice outside. It can also indirectly shape the way we organize our days.

What about mood?

This is where some nuance is important. Some people report seasonal changes in mood, energy, sleep or social activity. That does not mean that every change in mood during autumn or winter is depression.

Research on seasonal mood changes in the general population is mixed. A systematic review of 41 studies found substantial variation between studies and concluded that there is some evidence for seasonality in clinical depression, but not a simple, universal pattern affecting everyone.

There is, however, a recognized condition called seasonal affective disorder (SAD), a form of depression associated with seasonal patterns. In its more common winter pattern, symptoms usually emerge in late autumn or winter and may include persistent low mood, loss of interest, changes in sleep and social withdrawal.

That is very different from simply needing a little time to adjust to autumn.

How can we help our body adjust?

There is no need for a special “reset” or drastic change. A few simple habits can help maintain a stable daily rhythm:

- Keep reasonably consistent sleep and wake times.


- Make use of natural daylight during the day.


- Maintain regular physical activity, even if that means a daily walk.


- Try not to let changes in weather completely eliminate movement from your routine.


- Give yourself time to adjust when your daily schedule changes.

Consistent sleep timing, physical activity and exposure to natural daylight are also among the practical habits recommended for supporting healthy sleep-wake patterns.

When is it worth seeking professional help?

A small change in energy or mood around a seasonal transition is not necessarily concerning. But if persistent changes in mood, sleep or daily functioning develop — particularly if they recur each year or significantly interfere with everyday life — it is worth speaking with a healthcare professional.

Seasonal change is a normal part of our environment. Our bodies do not need to “fight” autumn; they mainly need time and consistent daily signals to adapt.

What to take away

From daylight and sleep to activity and mood, seasonal changes can affect people in different ways. These changes are not necessarily intense and do not automatically indicate a health problem. Paying attention to your body's signals, maintaining a stable routine and seeking help when changes become persistent can make the transition easier. https://healthpont.com/seasonal-changes-and-the-body/