Did you know that your body has its own internal network of clocks? These biological clocks help you feel alert during the day, hungry at mealtimes, and sleepy at night. Keeping your body’s daily cycles, or circadian rhythms, in sync is important for your health.
“Circadian rhythms are big influencers in the body,” explains NIH’s Dr. Michael Sesma, an expert in circadian biology. “They affect almost every part of your physiology in one way or another. Learning how the rhythm is generated is critical for understanding health.”
“Many of your body’s functions and normal daily activities—like sleeping, waking, eating, and going to the bathroom—are patterned around this 24-hour cycle,” Sesma explains.
Your biological clock’s “settings” are determined by specific genes. These settings can affect body temperature, blood pressure, activity level, inflammation (your body’s protective response to injury or infection), fertility, mood, and brain functions. Even the timing of health-related events can be related to your biological clocks. For instance, heart attacks are more likely to occur early in the morning, when the level of a hormone called cortisol starts its daily rise.
Circadian rhythms can influence eating habits, digestion, and metabolism (how our body uses and stores energy), too. Researchers have found that eating later in the day, closer to when melatonin is released, can disrupt the body’s natural rhythms. This can lead to increased body fat and weight gain, which are often associated with obesity, heart disease, and diabetes.
Time of day has also been shown to impact the effectiveness and side effects of certain medications, including those used to treat cancer.
Be mindful about how you may be altering your circadian rhythms. “Our around-the-clock society creates challenges for our internal clocks,” Sesma says. “There are lots of modern situations that can disrupt our rhythms, and some may contribute to health problems.”
For instance, shift workers who must be on the job after the sun goes down are at odds with their biological clocks. They may be tired at work and have trouble falling or staying asleep during daylight hours after work. Studies show that shift workers have increased risk for heart disease, digestive disturbances, cancer, depression, and other health problems.
Traveling across time zones can also disrupt your circadian rhythms. The brain has trouble adjusting when the time of day suddenly changes. The result is jet lag.
Keep Your Inner Clocks on Track
- Stick to a regular sleep schedule every day of the week.
- Sleep in a dark, quiet, and comfortable place.
- Avoid heavy meals two to three hours before bedtime.
- Avoid caffeine, nicotine, and alcohol late in the day.
- Exercise daily, but not within two hours of bedtime.
- Limit the use of electronics with bright screens before bedtime.
