It’s said that March 4 is the only day on the calendar that tells you what to do. That factoid, together with the warming trend in the weather, reminds me how important it is to get outside every day during daylight hours.

The energy from the sun not only warms us and provides light but also plays a role in our overall health. The study of how our body’s natural mental, physical and emotional cycles are affected by the sun and the moon is called chronobiology.

• Sleep: One of the chronobiological cycles you may have heard of is the circadian rhythm. The circadian rhythm regulates your sleep and wake cycle. In humans, there is a very strong natural rhythm that promotes wakefulness during daylight hours and sleeping at night. If you spend most of your time indoors and never see daylight, you may find that you have trouble sleeping at night, as electric lighting does not seem to be strong enough to stimulate and support this natural rhythm.
• Mood and mental health: Seasonal affective disorder, sometimes called seasonal depression, is a mood disorder that happens at the same time every year, generally in the winter. Experts believe that SAD may be related to hormonal changes in the brain. One of the hormones that regulates mood is serotonin, and sunlight tends to enhance its production. During the fall and winter, when there is less sunlight, the brain doesn’t make as much serotonin, and this may cause some people to feel symptoms of depression or sadness.
• Bone health: Vitamin D is very important for your bone health. While you can find vitamin D in some foods like fortified dairy products and mushrooms, the most natural source is the sun. Your body produces Vitamin D with sun exposure. It has even been found that bone density may fluctuate seasonally, with bones being stronger in the fall than they are in the spring. I know some people avoid the sun, and it’s true that overexposure increases cancer risk, but it only takes 5-15 minutes to produce enough vitamin D, and that is safe for many.
• Your weight: According to some researchers, morning light seems to help people keep the fat off. They say you need 20-30 minutes between 8 a.m. and noon, and the earlier you get it, the better it seems to work.

Good morning! Go outside!

• Sherry DeWalt is the healthy lifestyles coordinator for the CGH Health Foundation in Sterling.