The Function of Sleep

We spend a third of our lives sleeping. During this rest, our muscles can relax and the brain processes all the impressions we have gathered throughout the day. The amount of stress hormones decreases and the level of growth hormone increases. Growth hormone is essential for the repair and growth of cells and tissues. During our sleep, we produce more new cells and more antibodies than when we are awake.

Sleep Pressure and Biorhythm

Your sleep is regulated by your brain and depends on two factors: sleep pressure and biorhythm. Sleep pressure (also known as sleep debt) indicates how much sleep the brain needs. The longer you are awake, the higher the sleep pressure. With high sleep pressure, you will experience a more intense and deeper sleep than with low sleep pressure. While you sleep, the sleep pressure decreases, and when you wake up, you start building up your sleep requirement again. Your biorhythm (also known as the circadian rhythm) has a 24-hour cycle and is regulated by your biological clock. This clock consists of a small group of nerve cells called the suprachiasmatic nucleus. This group of cells is located in the hypothalamus on a small piece of brain tissue about 20,000 nerve cells in size. It sits precisely above the point where the nerves from the eyes cross. The suprachiasmatic nucleus is strongly influenced by light and sends a signal to the pineal gland, which in turn releases the sleep hormone melatonin into our blood and cerebrospinal fluid.

Melatonin

Melatonin is a hormone that influences our sleep-wake rhythm. When it gets dark, our body starts producing melatonin. This continues for most of the night, after which the level decreases again in the early morning. Our sleep requirement averages 7 to 9 hours per night, but as we age, our natural melatonin levels decrease along with the need for sleep.

Insomnia

Although our need for sleep generally decreases as we get older, short nights can still be experienced as a problem. In addition to ageing, there are many other causes that can lead to insomnia, such as stress, PMS, menopause, alcohol use, and jet lag. Poor nights can manifest in difficulty falling asleep, trouble staying asleep, or waking up early. Lack of sleep is linked to both physical and mental health issues such as cardiovascular diseases, diabetes, anxiety, and depression. But a bad night's sleep can also result in poor concentration, moodiness, and forgetfulness the next day. It is therefore important to have or develop a healthy sleep rhythm. Here are some tips that can help you:

  • ensure a good night's sleep by keeping your bedroom cool and dark
  • use earplugs so you are not disturbed by noises during your sleep
  • maintain a good biorhythm by going to bed and getting up at regular times
  • try not to nap during the day to prevent insomnia at night
  • avoid phones, computers, and TV at least 2 hours before going to sleep
  • take a warm shower to relax before going to bed
  • do not eat after 8:00 PM and only drink water or herbal tea
  • engage in meditation or yoga before going to bed
  • take a melatonin supplement to help you fall asleep faster
  • avoid caffeine or only consume it in the morning

Author: Noëlle van Seggelen