Circadian rhythm and sleep - how to control it
The human body follows an internal timekeeping system known as the circadian clock. This internal clock regulates the body's natural "circadian rhythm," daily sleep-wake cycles, hunger and digestion, hormonal activity, and other bodily processes. Origin - etymology The word circadian comes from the Latin phrase "circa diem", meaning "about a day", referring to the way most circadian rhythms reset automatically every 24 hours. Circadian rhythms are driven by physical cues to stay awake such as light exposure, human interaction, and scheduled meal times. What is the circadian rhythm The circadian clock consists of a cluster of about 20,000 neurons known as the suprachiasmatic nucleus (SCN). The complex is located in the hypothalamus at the base of the brain. When the eyes perceive light during the day, they trigger signals that travel down a neural pathway to the SCN, which lets the brain know it's time to wake up. The SCN then releases a series of hormones, including cortisol, ensuring you are awake and alert for your 9:00am meeting. The body uses light and other signals, called "zeitgebers" (German for "time giver" or "synchronizer") to determine whether it is day or night and synchronize circadian rhythms accordingly. Light is considered the most important zeitgeber for the circadian rhythm. Even when our eyes are closed, the eyes still perceive light and activate signals in the SCN. Other zeitgebers include physical activity, food intake, body temperature, and social interaction. Circadian rhythms regulate the production of different hormones throughout the 24-hour cycle. When the sun rises in the morning, the body produces cortisol, a hormone that makes us feel refreshed and alert. After waking up, a healthy person will feel increasingly tired throughout the day until the sun goes down, when the feeling of fatigue peaks. As the sun begins to set, the pineal gland will release melatonin, a hormone that reduces wakefulness and alertness. Circadian rhythms also regulate hunger and digestion, body temperature, mood, fluid balance, and other important physiological processes. For most healthy adults, the circadian clock resets every 24 hours. However, there are variations in when people feel tired or alert throughout the day. How to Change Your Sleep Schedule Your sleep rhythm will evolve and change with age. For example, older people tend to sleep and wake earlier in the day than younger people, while babies sleep in multiple phases throughout the day and night. People may want to change their circadian rhythms and sleep-wake cycles for different reasons. Some need adjustments after starting a job that requires them to work late nights or early mornings. In order to effectively change your circadian rhythm and sleep-wake cycle:
- Wake up at the same time every day: Sticking to a regular sleep schedule will help reset your circadian rhythm. If you go to bed and wake up at the same time every day, your body will learn to adjust to the new rhythm.
- Bright light: Exposure to bright artificial lights can reorient circadian rhythms quite effectively. Exposure to artificial light for a long period of time works especially well for shift workers or those whose work schedule includes waking up late at night and/or early in the morning.
- Increase Melatonin: In addition to the natural hormone produced in the pineal gland, melatonin is also available by prescription in supplement form. Melatonin supplements were not developed to treat insomnia, but to help rearrange circadian rhythms when the time is right. Always consult your doctor before taking supplements.
- Different meal times: Circadian rhythms regulate when we feel hungry and how we digest food. Some studies have found that advancing or delaying meals can change the way your circadian rhythm regulates these processes, causing you to feel alert and tired at different times than you're used to.
- Exercise: Proper exercise can improve the quality and duration of sleep, while a healthy sleep-wake cycle ensures more strength and endurance when you work. However, exercise is also stimulating if you exercise too close to sleep.
- Caffeine : Caffeine also has a half-life of 10 of 5 hours in a healthy adult, meaning it takes an average of 5 hours for the body to eliminate half of the caffeine consumed. For best results, consume a moderate amount of caffeine for the first few hours when you are awake, but stop consuming it at least 5-7 hours before bed.
