Internal biological rhythms control our activity during the day. Circadian rhythms determine when we sleep and wake up, they affect the flow of hormones into the blood and changes in body temperature. How does it work, and can you tune your internal clock?
What Are Circadian Rhythms
Circadian rhythm is the body’s daily internal rhythm, which depends on the sun and changes within 24 hours. It’s necessary to clearly adjust all physiological aspects of the body to a certain time interval – 24 hours. Our internal clock is driven by several important genes that produce clock proteins that tell our cells what to do and what time it is.
Like all mammals, humans have an internal clock inside the brain. It’s one segment of the visual analyzer, the suprachiasmatic nucleus. It receives information from the eyes about the level of light and according to this information, arranges the work of neurons. Their signals are distributed throughout the body and coordinate its work.
How Light Affects a Person
We are much dependent on light: its availability, duration and intensity. The photosensitive cells of the eye (pRGC) “register” sunrise and sunset and then set the molecular clock to the correct time of day. By the way, even blind people can have normally functioning light-sensitive cells. So, blind people also need light, so that their internal mechanism can adjust their circadian regime.
At dawn, the brain commands the body to raise its body temperature – by 6 a.m. it’s at its lowest. The rise in temperature triggers the production of cortisol. At this time, the stress hormone enters the bloodstream in the amount needed to give you strength upon awakening. During the day, cortisol levels decrease. The production of the sleep hormone melatonin slows down in the morning. When darkness falls, on the contrary, its levels begin to rise. Throughout the night, it’s quite high, but only if a person has the opportunity to see changes in the brightness of sunlight during the day. That’s why people who work all day and play a lot via 22Bet login in the evening with artificial light without windows often have trouble sleeping.
Sleep and Wakefulness Mode
British professor Paul Kelly of the Institute of Sleep and Circadian Neuroscience at Oxford University argues that there is an ideal time to wake up in a good mood. It’s individual for every age:
- 20 years old – 9:30 a.m.
- 30 years old – 8:00 a.m.
- 40 years old – 7:30 a.m.
- 50 years old – 7:00 a.m.
- 60+ years old – 6:30.
Of course, we must also remember to go to bed on time. The National Sleep Association in Great Britain believes that an adult should get 7 to 9 hours of sleep, and after age 65, 7 to 8 hours. The older we get, the less melatonin our body produces. The changes begin after the age of 30-35. That’s why older people tend to wake up early.
The ability to concentrate also changes throughout the day according to circadian rhythms. It’s best to start working 2.5-3 hours after awakening. The optimal time to exercise is 4 hours before bedtime. As for the myth “don’t eat after seven” – it only works if you go to bed at 10 p.m. Since few people in their 20s go to bed earlier than midnight, a light dinner at 8:30 p.m. won’t be bad for young people. The ideal time for dinner in your 30s and 40s is 8:00 p.m. After 40, it’s better to eat dinner at 7:00 p.m., and after age 60 at 6:30 p.m. to leave more time for absorption of nutrients and avoid heartburn.