Health and well-being

When the sun wakes up the brain: the superpowers of spring light

10/3/2026
4 min

Every year, spring brings a familiar feeling. The clocks move forward, the days grow longer, and suddenly we seem to have a little more energy. We feel the urge to go for a walk outside, open the windows, or finally tackle that famous spring cleaning.

It’s not just tradition or the simple desire to air out the house. In spring, something actually changes in our brain.

The arrival of the new season comes with a noticeable increase in daylight. And that light acts directly on the brain. As soon as it enters our eyes, it activates specialised cells in the retina that send signals to several brain regions responsible for mood, energy, and alertness.

The result? Our body slowly shifts back into “coming out of hibernation” mode.

A little chemistry of happiness

Natural light influences several hormones and neurotransmitters that play a key role in our well-being.

For example, exposure to morning light:

  • Stimulates the production of serotonin, often called the “happiness hormone”
  • Reduces the secretion of melatonin, the hormone that promotes sleep
  • Increases alertness and concentration

In practical terms, as daylight increases in the spring, our brain receives a stronger signal that it’s time to be awake, active and motivated.

It’s no coincidence that many people feel more optimistic and energetic at this time of year.

When light resets our internal clock

Light also plays a crucial role in regulating our circadian rhythm—our internal biological clock.

During the fall and winter, shorter days and lower light levels can disrupt this balance. Some people feel more tired, have difficulty waking up, or experience a drop in motivation.

With the arrival of spring, increased daylight helps recalibrate that internal clock. The brain receives a clear signal: the day starts earlier, daylight lasts longer, and the body gradually adjusts.

This process helps improve sleep quality, boost concentration, and support energy levels throughout the day.

An experiment that demonstrated the power of light

The influence of light on the brain has even been tested in a rather surprising experiment.

In the late 1990s, researchers installed powerful lighting in several nursing homes in the Netherlands. Common areas were equipped with ceiling lights reaching about 1,000 lux, while other facilities maintained lower lighting levels of around 300 lux.

For more than three years, nearly 200 residents were monitored and evaluated for mood, cognitive abilities, and independence.

The results were striking. Residents exposed to brighter lighting showed fewer depressive symptoms and maintained a better ability to perform certain daily activities, such as dressing or moving around.

This experiment clearly illustrates that light is not just useful for seeing; it can also act as a powerful stimulant for the brain.

A little morning sunshine

To fully benefit from this natural boost, timing matters.

Specialists recommend getting exposure to natural light as early as possible in the day. That’s when it is most effective at stimulating the brain and synchronizing our biological clock.

A few simple habits can make a difference:

  • Taking a morning walk
  • Drinking your coffee near a sunny window
  • Stepping outside for a few minutes before starting your day
  • Working near a source of natural light whenever possible

On the other hand, strong exposure to light in the evening (hint hint, from screens!) can send mixed signals to the brain and interfere with sleep.

The return of sunlight, and energy

In Quebec, as in the rest of the Northern Hemisphere, the difference in daylight between winter and spring is dramatic. After the winter solstice, days slowly begin to lengthen, with the increase accelerating around the spring equinox.

More light often means more serotonin, more energy, and a more stable mood.

So if you feel a bit like a bear emerging from hibernation these days, it’s normal! Your brain is probably just enjoying the return of the sun.

And sometimes, a single ray of light is all it takes to get the whole system moving again.

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