The body was so exhausted that it couldn't even lift its hand, yet the brain seemed to have pressed the "acceleration button".The mundane tasks of work and life kept flashing by non-stop.
Finally, after a long wait until dawn, upon waking up, one felt dizzy and groggy, with heavy eyelids, as if one hadn't slept at all throughout the night.
The classic theory proposed by Matthew Walker, a world-renowned sleep expert and professor of neuroscience at the University of California, Berkeley, in his book "Why We Sleep" dissects three scientifically proven sleep techniques that challenge conventional wisdom.
These are not "superstitions" but scientifically validated "sleep enhancement" solutions that can help you fundamentally improve your sleep.
🔑 Technique One:
-- Adjust the body temperature and make it feel like "wanting to sleep"-
Professor Walker discovered that the decrease in the core body temperature (not the temperature felt by touching the skin, but the internal body temperature) is the key signal that causes us to feel sleepy.
Inside our bodies, there is a "circadian clock" that not only regulates "when to wake up and when to sleep", but also controls body temperature:
- during the day, the core body temperature is high, helping us stay alert;
- at night, the temperature gradually drops by 0.5-1℃, and it also releases heat through the hands and feet -
so many people feel their hands and feet getting warmer before going to bed.
In fact, this is the body sending a signal to the brain: "The heat has been dissipated, it's time to sleep."
If the core body temperature doesn't drop enough before going to bed (for example, if the body is excessively hot all over or the hands and feet are cold and unable to dissipate heat), the brain will mistakenly think that "it's not time to rest", and as a result, you will keep tossing and turning and unable to sleep.
How to do it specifically? Remember three things:
- 90 minutes before bedtime, take a bath or shower in water at around 40℃ for 10 to 15 minutes.
- Before going to bed, warm up your hands and feet (for example, by wearing thin socks) to help your body better "ventilate" itself;
- The temperature in the bedroom should be set at around 18.5℃. It should not be too hot nor too cold.
🔑 Technique Two:
-- Taming the excited brain--
In Professor Walker pointed out in his research that many people's insomnia is not due to "the body not wanting to sleep", but because "the brain is too anxious".
When we are under stress and thinking too much, the "sympathetic nerve" in our body gets activated - it's like the "accelerator", responsible for making us "fight or flee", causing the release of stress hormones (cortisol), speeding up our heart rate, and making our minds become more chaotic.
But to fall asleep, we need to activate the "parasympathetic nerve" - it's like the "brake", responsible for relaxing our bodies, aiding digestion, and helping us switch from the "tense mode" to the "relaxed mode".
And "physiological sighing" is currently known as one of the fastest methods to activate the parasympathetic nervous system - it can quickly expel excess carbon dioxide from the lungs through specific breathing rhythms, lower heart rate and cortisol levels, and help the brain and body calm down within a few minutes.
How exactly should one practice?
It can be used before going to bed or when waking up in the middle of the night. Just practice 3 to 5 times.
- The first deep breath: Take a slow breath through your nose, until you feel that your lungs are "filled" (you can feel your stomach slightly bulging).
- Second inhalation: Don't exhale! Then quickly take a small breath through your nose - this step is crucial as it fills the "empty spaces" in the lungs and allows the alveoli to fully expand.
- Slow exhalation: Breathe out slowly through your mouth, making sure to exhale completely (feeling your chest and abdomen slowly sinking down). The exhalation time should be longer than the inhalation time (for example, inhale for 2 seconds and exhale for 4 seconds).
🔑 Technique 3:
-- No matter how late you go to bed, get up at a fixed time--
Inside our bodies, there is a "master biological clock" (located in the suprachiasmatic nucleus of the brain), which needs external signals (such as light, meal times, and wake-up times) to "calibrate" itself, ensuring a stable "wake-sleep rhythm" every day.
Among all the signals, the time of waking up is the most crucial "calibrator" - just like a watch needs to be adjusted daily to be accurate, the biological clock also requires a fixed waking time every day to "align".
If you get up 3-4 hours earlier on weekends than on weekdays, it's equivalent to "resetting your body's internal clock" once a week. This phenomenon is known in sleep science as "social jet lag".
The body clock gets disrupted: One doesn't know "when to wake up" and "when to secrete melatonin (the sleep-inducing hormone)", which leads to catching up on sleep on the weekend, but then having insufficient melatonin secretion on Sunday night, resulting in insomnia.
By Monday morning, when the body clock hasn't "adjusted back", one will feel tired.
How to do it？
- Set a fixed wake-up time and stick to it without fail.
- Within one hour after getting up, expose yourself to sunlight for 5 to 15 minutes.
- Stick to it for at least one week and don't give up halfway.
Professor Walker's research tells us that sleep is not a passive state where one simply falls asleep when tired, but rather a physiological process that can be "actively shaped" through regulating body temperature, breathing, and rhythm.
