Your Winter Sleep Problem Explained 

You would think that with dark winter nights, you’d sleep better.

Dr. Tracey Marks, psychiatrist, explains why this often isn’t the case:

The long night of the…

…suprachiasmatic nucleus. That’s a part of your brain, and the reason winter can be a problem for it, is because reduced winter light sends weaker signals to your brain’s timing center (the aforementioned suprachiasmatic nucleus) that controls sleep, wakefulness, and how restorative sleep feels.

In particular, insufficient morning light delays melatonin suppression, so you stay sleepy longer and struggle to feel alert early in the day. And then, to make matters worse, bright indoor lighting at night tricks your brain into thinking it is still daytime, delaying sleep mode.

In short, these misalignments weaken the normal morning rise and evening fall of cortisol, leading to the classic “tired but wired” feeling. So, a lot of it is actually not about serotonin, although yes, altered light exposure does affect serotonin too, which coupled with the effects on cortisol levels, often results in bad outcomes for emotional regulation, stress tolerance, memory consolidation, and overall mental resilience.

The good news is that your brain can reset quickly: once you provide clear light and timing cues, your brain adapts faster than most people expect.

Here are 5 strategies to fix it quickly:

1. Morning light reset: get 10–15 minutes of bright light within the first hour of waking, ideally outdoors or near a window, or use a 10,000 lux light box if needed. However, even cloudy outdoor light delivers far more useful intensity than indoor lighting, giving your brain a strong “day has started” signal.
2. Evening light hygiene: reduce bright and blue light about two hours before bed by dimming lights, using warmer bulbs, enabling night mode on screens, or wearing blue-light blocking glasses. This is important, as bright ceiling lights, especially cool white LEDs or CFLs, can disrupt melatonin more than phones because you sit under them for hours.
3. Anchor your wake time: keep your wake time consistent within about 30 minutes every day, including weekends, to reduce sleep inertia and stabilize your rhythm.
4. Choose your movement timing: light movement in the early morning, such as a short walk or gentle stretching, acts as a circadian cue that boosts alertness when paired with light.
5. Enjoy supplement support: low-dose melatonin (0.3–0.5 mg) taken before bedtime can help shift your clock earlier, while magnesium glycinate supports relaxation and sleep quality.
   • Not mentioned in the video, but this writer also highly recommends bedtime l-theanine!

Do note also that you don’t need perfection—small, consistent changes can nudge your clock back into sync quite quickly and easily.

If you just pick one thing to focus on first, then morning light has the biggest ripple effect on energy, mood, hormones, and sleep—try it for one week and notice what changes!

For more on all of this, enjoy:

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Want to learn more?

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Sweet dreams!