The Nordic October gloom brings more than just gray skies. As daylight shrinks—Helsinki and Stockholm see under ten hours by late October—bodies produce more melatonin, leaving many feeling drowsy and craving sugar.

For professionals, these seasonal changes can erode productivity: the NIH lists difficulty concentrating, irritability, and poor decision-making among the symptoms of seasonal affective disorder.

“People need light and warmth, and when there’s none, the body will try to replace them with something else,” says Sonia Wahlroos, founder and CEO of Nordic Nutritionist. Here are her five evidence-based strategies to stay focused and energetic through the “winter blues.”

1. Prioritize sleep like a strategic asset

Winter often disrupts the sleep-wake cycle. Prolonged lack of daylight can delay sleep timing, fragment rest, and heighten sensitivity to blue-light screens—creating a vicious cycle of poor sleep, according to a study on Antarctic research crews in winter.

Rather than surrender to fatigue, says Wahlroos, use the season to reset routines. Shifting bedtime an hour earlier—around 10 p.m.—aligns rest with natural drowsiness and improves recovery, as the deepest sleep occurs in the first half of the night. “When it gets dark, you get sleepier—allow yourself to go to bed earlier,” she notes. Aim to wake up without an alarm. Reconsider how you think about sleep: is it a cost or an investment in cognitive capital?

2. Eat warm, high-quality fuel

Reduced daylight disrupts appetite-regulating hormones, often triggering cravings for sugar and refined carbohydrates. “The best way to fend off sugar cravings is to give your body the right kind of nutrition,” says Wahlroos.

She recommends warm vegetable soups, whole grains such as quinoa, and protein-rich meals to steady blood sugar and keep the body warm. Avoid long gaps between meals—hunger encourages impulsive snacking. Carbohydrates can be especially tempting in darker months, so limit simple sugars and refined grains. If summer indulgence already stretches over a few months, adding a carb-heavy winter means most of the year is spent off track, she warns.

3. Hydrate—But don’t rely on coffee

Cold weather often blunts thirst cues, yet mild dehydration can mimic fatigue. Drink two to three liters of water daily; herbal teas or warm lemon water add comfort.

A word of caution on coffee: “If you struggle to get out of bed, caffeine alone won’t fix the problem,” says Wahlroos. She warns that afternoon or evening coffee can disrupt deep sleep cycles, worsening seasonal fatigue instead of relieving it.

The National Sleep Foundation advises avoiding caffeine at least 6 hours before bedtime because it lengthens sleep latency and decreases slow-wave sleep.

4. Supplement smartly: Vitamin D and omega-3

Sunlight in Nordic countries plunges below four hours a day by December, insufficient for natural vitamin D synthesis.

The Finnish Food Authority recommends daily supplements, but Wahlroos suggests even higher doses in winter, even up to 100 µg (4,000 IU), well above the standard 20 µg guideline for people who spend time outdoors.

Her second recommendation is high-quality omega-3s, guessing that few people receive enough such fatty acids from fish. A review of more than 170 academic studies links omega-3 intake to improved learning, memory, and cognitive well-being.

5. Seek light and movement daily

Grey weather can make outdoor activity less inviting, but exercise remains essential, Wahlroos says. She adds a caveat: while gym sessions build strength, they cannot replace the benefits of natural daylight. Her advice: keep up routines such as evening walks or bike rides, even alongside regular gym workouts.

Between the lines, staying active isn’t just about daylight and exercise—it’s also about nurturing social connections. After the interview, Wahlroos adds one more tip: “See people! Organize something fun!”

Dark months need not dim performance. With small adjustments—better sleep, smarter fuel, outdoor light, and social connection—professionals can protect energy, focus, and decision-making well into winter.