As the days get shorter, wetter, and greyer, you may have noticed a shift in how you feel—and you’re not alone.

With fewer daylight hours and dreary weather, it’s common to experience changes in mood, energy, and sleep. But why does this happen, and what can we do about it?

The Light We Need, But Don’t Get

Our bodies are wired to respond to light, and not just for our daily rhythms. As well as a circadian rhythm, which controls our 24-hour sleep-wake cycle, we also have an annual rhythm. This is influenced by the changing levels of daylight throughout the year, similar to how animals adjust their behaviour seasonally—like bears preparing for hibernation.

Natural sunlight plays a key role in both these rhythms, helping to regulate melatonin (the hormone that makes us sleepy) and our body’s overall energy levels.

During the summer, longer days help keep everything on track. But when the days shorten, and we’re exposed to less light—particularly in the morning—our body clock gets disrupted. This makes it harder to wake up because melatonin levels stay elevated for longer.

Light and Mood: Why We Feel Different

Light doesn’t just impact our sleep—it also plays a huge role in serotonin production. Serotonin is a neurotransmitter that boosts mood and helps you feel happy and energetic. Less sunlight, especially during the winter, can mean reduced serotonin levels, which is why many people experience a drop in mood, energy, and motivation.

This is also linked to Seasonal Affective Disorder (SAD), a form of depression that occurs during the darker months. But even without SAD, the shorter, darker days can still make us feel more sluggish and irritable. It’s not just in your head—this mood shift is your body’s response to reduced light intake.

Less Light, Less Energy

As daylight decreases, so can your energy levels. Less daylight can correlate with less energy, as our body is naturally inclined to slow down when we’re exposed to less light. In fact, many of us may even feel the urge to sleep for longer during the winter, much like animals that enter a form of hibernation during the colder months.

Waking up in the dark can be particularly challenging. With no sunlight to cue your body to wake up, you might feel groggy and slow to start your day. This lack of energy often carries over into the afternoon, leaving you less productive and motivated.

What You Can Do

While we can’t control the weather, we can take proactive steps to adjust to these seasonal changes and make the most of the shorter days:

• Maximise daylight exposure: Spend time outside during daylight hours, especially in the morning. Even a short walk can help reset your body’s internal clock and boost your mood.

• Use artificial light: If you can’t get enough natural sunlight, consider using a light therapy box or a dawn simulator. These devices can help replicate the effects of sunlight and support your circadian and annual rhythms.

• Stick to a routine: Try to maintain consistent sleep and wake times to keep your rhythms in sync, even if the darker mornings tempt you to stay in bed.

By understanding why we may feel a little different in the winter months, and taking proactive steps to adjust our light intake, we can help boost our mood and productivity and make the most of the shorter, darker days.