一个人的衰老不仅仅反映在外表上，尽管面部可以通过护肤、医美等方法来延缓衰老。然而，判断一个人是否真正开始变老，还有一个常被忽视的衰老变化——Sleep.

随着年龄的增长，与年轻时相比，一个显著的变化是睡眠质量的改变。Changes in sleep patterns mark the process of aging. If you don't experience any of these, it proves you're still very young!

A sign of aging begins with sleep.

Reduction in sleep duration

How many hours do you sleep each day? 7 hours, 6 hours, or 5 hours? As people age, their sleep duration indeed decreases. Many people sleep 8 to 9 hours when they are young, but as they get older, they wake up after sleeping only 6 to 7 hours.

根据《美国睡眠医学会》的数据来看，婴幼儿所需的睡眠时间最多，As people age, their sleep duration tends to decrease.

A clinical study published in the Journal of the American Medical Association found that sleep duration significantly decreases with age.

比如，**从中年阶段（36_{50 岁）到晚年阶段（71}83 岁），总睡眠时间平均每 10 年减少 27 分钟。**这一变化主要发生在 50 岁之后。换句话说，After the age of [X], the total sleep duration decreases by [Y] minutes every [Z] years.

Experiencing fragmented sleep.

"Waking up more frequently during sleep" and "always waking up in the middle of the night and then struggling to fall back asleep" — this kind of "fragmented sleep" is particularly prominent among middle-aged and elderly people. Why are middle-aged and elderly people more prone to fragmented sleep? It's not just humans; in fact, many animals also experience fragmented sleep as they age.

2022 年 2 月，斯坦福大学医学院的研究人员在国际《科学》期刊上发表的一项研究发现：The activity of "neurons" in the brain can control states of wakefulness and sleep. As one ages, neurons become more easily triggered, leading to over-excitation, which in turn results in "fragmented sleep."

The study selected two groups of mice of different ages and used light to stimulate specific neurons, recording the results using imaging techniques.

Group: Young mice (months)

Group: Aged mice (months)

研究发现，During the aging process, neurons transition into a hyperexcitable state, and it is precisely this change that leads to older mice being more prone to fragmented sleep.

Research screenshots

The duration of deep sleep has decreased.

As people age, many experience a reduction in deep sleep time, such as feeling like they haven't slept even though they have.

上述《美国医学会杂志》发表的临床研究指出，正常衰老过程中，睡眠阶段的变化包括觉醒次数和觉醒时间增加，以及**深度慢波睡眠减少。**例如：从青年阶段（16_{25 岁）到中年阶段（36}50 岁），深度慢波睡眠的百分比从 18.9% 降至 3.4%，被较浅的睡眠所取代。

Research indicates that the decline in growth hormone secretion with increasing age is closely related to the reduction in deep sleep. From early adulthood to middle age, there is a significant decrease in growth hormone secretion (a reduction of micrograms per year); after the age of , growth hormone secretion further decreases by micrograms per year.

Methods to Improve Sleep Quality

Try it for people who have poor sleep

Wearing socks to sleep.

Does wearing socks affect sleep quality and duration? A study published in the "Journal of Physiological Anthropology" in 2021 on the "Impact of Wearing Socks on Sleep" found that wearing socks while sleeping can effectively improve sleep quality.

Research experiments have found that compared to people who do not wear socks when sleeping, those who wear socks while sleeping:

Sleep onset time: reduced by . minutes

Number of awakenings during sleep: decreased by . times.

Total sleep duration: increased by an average of minutes.

Sleep efficiency: increased by .%

研究指出，这主要和睡眠时人体的肢体温度有关，小腿和脚等部位的温度，通常易受外界环境影响。Wearing socks can help maintain a comfortable and warm sleeping environment.

Cover with a heavy quilt.

A heavy quilt leads to sound sleep.

A study published by Swedish researchers in the Journal of Sleep Research found that sleeping with a heavier blanket increases the release of melatonin, promoting better sleep. The experimental study discovered that compared to using a lightweight blanket, using a weighted blanket could increase the concentration of melatonin in saliva by approximately %.

Soak your feet before going to bed.

If you don't like wearing socks to bed, you can also soak your feet before sleeping, as the principle is similar.

2024 年 3 月《整合与补充医学期刊》上发表了一项分析研究指出：Soaking feet in warm water for an hour before bedtime is a method that can significantly improve the sleep quality of the elderly.

水度 **40℃、Length of foot soak不超过 20 分钟、water level高于脚踝 10 厘米，**满足这 3 个条件时，泡脚对于提升睡眠的效果最佳。

Don't use your phone before going to bed.

In 2019, a sleep assessment organization in the United States conducted a sleep data survey on over a thousand people and found that: scrolling through your phone for a few minutes before bed can keep your body excited for several hours. On average, it takes an hour to fall asleep after playing with your phone for a few minutes before bed. This is because the blue light emitted from the phone screen increases people's alertness, thereby prolonging the time it takes to fall asleep.

Do some sleep-inducing exercises.

2024 年 7 月，《英国医学杂志在线·体育与运动医学》发表的一项研究发现：Perform these exercise movements within the hour before bedtime to significantly extend your sleep duration.

Research Screenshot, Translated by Health Times

squats：模仿坐椅子的动作，膝盖不超过脚尖。

calf：站立抬起后脚跟，使小腿肌肉收缩，然后脚跟慢慢回到地面。

Lift knees and expand hips：站立膝盖抬高，直腿髋关节伸展。

Just take a few minutes each time, and do it every few minutes. This can extend the night's sleep time by nearly a few minutes.

Source: Science China, Health Times

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