After a long, gray winter, the first truly bright spring days can feel like a jolt of electricity. Suddenly you want to open the windows, scrub the house, and spend the afternoon in the garden. People have long called this feeling spring fever. Is there something real behind it?
Scientists think there may be a biological basis. Spring fever usually describes a boost in energy, vitality, and romance, along with a bit of restlessness, as winter ends. The likely key is light. Longer, brighter days affect your body's internal clock and the sleep hormone melatonin, and many people's mood lifts as daylight returns.
Light Sets Your Body Clock
Your body runs on a roughly 24-hour internal clock, and light is its most important signal. Melatonin, often called the hormone of darkness, is released at night and helps you sleep.
Light, especially blue light, shuts down melatonin production. The stronger and longer the light, the bigger the effect. Researchers note that in the past, people in cooler climates got little blue daylight in winter, relying on firelight and lamps that gave off mostly yellow light.
In spring, the days stretch out and the morning sun gets stronger. That shift in daily light helps explain why so many people feel more alert, lively, and ready to go.
The Winter Blues Lift
The spring lift is especially strong for people with seasonal affective disorder, often called SAD, who experience low moods or depression in winter. Seasonal mood changes are believed to be related to light, and one reason is that bright-light therapy works for many people with SAD.
Light therapy usually involves sitting near a special lightbox, much brighter than an ordinary lamp, for 30 to 60 minutes. Some people notice improvement within the first week. Even simple dawn simulators, lights that gradually brighten in the morning, have shown promising results. Experts caution against long exposure to direct sun or lamps that don't block ultraviolet light, because of skin cancer risk. If winter blues hit you hard, talk to your doctor about what might help.
Sunshine and Vitamin D
Sunlight does something else, too. When your skin is exposed to the sun's ultraviolet B rays, it makes vitamin D. For most people, sunshine provides far more vitamin D than food, roughly 80 percent compared with about 20 percent from diet.
In winter, especially in places far from the equator, there's less sunlight to work with. By the end of winter, vitamin D levels in the blood can be a third to half lower than at the end of summer. Questions about supplements are best taken to your doctor.
Not Everyone Gets the Boost
Here's the twist. Some people feel worn out in spring instead. This is called springtime lethargy, and it can bring tiredness, irritability, headaches, and sensitivity to weather changes. It may be a normal reaction to warmer temperatures, or it may be linked to allergies.
Germans even have a word for it: Frühjahrsmüdigkeit, or spring fatigue. By some estimates, 50 to 75 percent of people in Germany have experienced it, usually from mid-March to mid-April.
Whether spring makes you want to run a marathon or take a nap, it's a reminder of how closely our bodies follow the seasons. So step outside, soak up some morning light, and enjoy the flowers.
