The sun rises in Windsor on the winter solstice last December. A general feeling of sadness and faded energy takes hold as the winter solstice moves toward January, often affecting our physical and mental health, our relationships with others, and our performance at work.

PHOTO PROVIDED BY JODY ERRICHETTO

For a season that’s supposed to be all about joy and celebration and the brightness of being, a long shadow of darkness seems to hover over some of us this time of year.

It’s really no mystery. It’s as predictable as the sunrise and sunset. In fact, it’s a genuine form of clinical depression that’s directly tied to the cycle of the sun. As the days grow shorter and our time in the sunlight wanes, at least one out every four people experiences some degree of seasonal affective disorder.

A general feeling of sadness and faded energy takes hold as the winter solstice moves toward January, often affecting our physical and mental health, our relationships with others, and our performance at work.

The sun rises in Windsor on the winter solstice last December. A general feeling of sadness and faded energy takes hold as the winter solstice moves toward January, often affecting our physical and mental health, our relationships with others, and our performance at work.

PHOTO PROVIDED BY JODY ERRICHETTO

The human body, like all living things, plants or animals, follows what are called circadian rhythms, an internal biological clock that regulates our 24-hour sleep-wake cycle. Those rhythms are sensitive to light. The transition to winter, with its late sunrises and early sunsets, breaks that rhythm, often depleting our energy and mood. Some barely notice the change. Others are deeply affected and may need treatment, including medication, to make it through winter.

Fortunately, there are some very easy, effective, non-pharmaceutical and reasonably low-cost ways to treat the condition, often by artificially recreating the natural light exposure we enjoy during the spring and summer months.

Full-spectrum light box. These compact devices, plugged into a regular outlet or laptop using a USB cord, recreate the light quality and intensity of a late spring, early summer sunrise. While an average lightbulb emits some 800 lumens, a full-spectrum light box emits some 10,000 lumens. Spending 20 to 30 minutes in the morning near a light box while you’re reading the paper, checking your emails or having breakfast is an easy way to boost your exposure to light and your mood. The devices are available for as little as $50.

Dawn-light simulator. These similarly priced devices also mimic the spring-summer sunrise, providing the same therapeutic benefits, but are set on a timer in your bedroom, gradually increasing in intensity before you wake and as you rise. Some people combine the use of these devices with the full-spectrum light box. A double dose of healthy light.

Reducing exposure to blue light. On the opposite end of the light-exposure spectrum, some lights are not good for you late in the day. The blue light from smartphones, laptops, televisions and similar devices also disrupts our circadian rhythm. After sunset, if we’re exposed to light that mimics sunrise, our brains think it’s morning and aren’t ready for a healthy night’s sleep. Blue-screen filters can be programmed to automatically switch on for many of those devices.

Good old vitamin N. Nature is still an important source of light during winter months, even though the intensity and quality of light is nowhere near what it is on a midsummer’s day. You’re not going to get that big dose of vitamin D, but there’s still enough healthy white light outdoors on a sunny winter’s day to reach your retinas and brain and have a therapeutic effect on your mood and overall immunity. So bundle up, get outside and soak up some sun.

Light alone isn’t the only answer to reducing the onset or symptoms of seasonal affective disorder. Managing your mood and general physical and mental health also requires a mindfully balanced diet and regular exercise. Bringing all of those things into the full light of day is the best way to stay healthy and happy all winter and year-round.

Mark Pettus, M.D., is the director of wellness and population health for Berkshire Health Systems.

Get up-to-the-minute news sent straight to your device.