By Dr. Zachary LaVigne, B.S., D.C.
January gets blamed for a lot. Low mood, low energy, low motivation. We point to cold weather, post-holiday whiplash, or the quiet pressure to suddenly have it all together. But there is a quieter factor shaping how your body feels this time of year, one that rarely gets named directly. Light.
Not candles or cozy lamps or the glow of your phone at midnight. Real environmental light, the kind your nervous system evolved to read like a clock.
Your body does not run on dates, planners, or resolutions. It runs on light and dark. For most of human history, winter meant shorter days, longer nights, and a natural slowing that required no effort. There was less light, more rest, and fewer demands after sunset. Today, winter still brings shorter days, but we override that signal completely. We spend our days under dim indoor lighting and our nights staring into bright screens. From a biological perspective, that creates a mismatch.
That mismatch often feels like low-grade jet lag without the travel. You wake up tired even after enough sleep. Your mood feels flat or heavy. Cravings shift. Motivation takes longer to arrive. Aches and tension linger. None of this means you are lazy, broken, or failing January. It means your internal timing system is confused.
Your brain uses morning light to set the rhythm for the entire day. Light entering your eyes early tells your nervous system when to release cortisol for alertness, when to raise body temperature, and when to begin the countdown toward melatonin later that night. When that morning signal is weak or missing, everything shifts later. Energy dips earlier. Sleep quality suffers. Mood and pain sensitivity follow.
Winter makes this especially tricky. Many people wake up in darkness, commute in darkness, and spend most of the day under lighting that is far dimmer than an overcast sky. Then at night, we flood our eyes with blue-heavy light from phones, tablets, and televisions. From an evolutionary standpoint, that looks like living in a cave during the day and standing next to a bonfire at night.
Seasonal mood changes often get framed as a mental health issue alone. Biology deserves equal attention. Light exposure directly influences serotonin, dopamine, sleep depth, immune function, and pain sensitivity. If your nervous system is already under strain from stress, poor sleep, or chronic tension, winter lighting patterns amplify every one of those signals.
The adjustment does not need to be dramatic. It needs to be directional. Morning light matters more than total daylight hours. Ten to twenty minutes outside shortly after waking can help anchor your rhythm. Cloudy days still count. Your eyes need brightness, not sunshine. A porch, sidewalk, balcony, or short walk is enough to send the message.
During the day, brighter environments support alertness and mood. Open the blinds. Sit near windows. Step outside when you can. Most indoor spaces are far dimmer than your nervous system expects, especially in winter.
At night, dimming helps the body downshift. Lower lights after sunset. Warm tones work better. Screens closer to your face matter more than overhead lights, so distance helps. This is not about perfection or abandoning modern life. It is about clarity.
January does not ask for reinvention. It asks for alignment. When light timing improves, sleep often follows. When sleep improves, pain sensitivity drops. Mood steadies. Energy returns without force. Winter is a quieter season by design. Your body still knows that. Give it the signals it expects, and January becomes something your nervous system can finally understand.