The National Day holiday is halfway through, and many people have shifted from the initial joy of vacation to feeling holiday fatigue. Some even exclaim, "Taking a vacation is more exhausting than working!"

In fact, many people are just "pretending to be on vacation." While maintaining regular schedules during workdays, they begin staying up late and engaging in revenge bedtime procrastination during holidays. Although it appears they are resting, their bodies are still "working overtime."

Those experiencing "ineffective rest" have disrupted these 5 body systems:

**1. Hormonal Disruption**

The sudden late nights and delayed sleep during holidays cause hormones in the body to stage a "collective protest." Our body's "biological clock" controls hormone release, metabolism, and sleep cycles.

Melatonin, an important sleep-regulating hormone, can have its secretion rhythm disrupted by just one night of revenge bedtime procrastination. To restore it to timely and adequate secretion, it takes several days or even one to two weeks of waking up at fixed times and exposure to sunlight to gradually recalibrate, like adjusting a stubborn clock.

Besides melatonin, there's the stress hormone cortisol, which should drop to its lowest levels at night but becomes abnormally elevated due to staying up late. This sudden disruption causes daytime fatigue and unusual nighttime alertness, creating a vicious cycle of "wanting to sleep but being unable to."

**2. Brain Disruption**

Many people experience difficulty concentrating, memory decline, and slow reactions after staying up late. This is actually brain disruption caused by sleep deprivation.

During deep sleep, the brain converts short-term memories from the day into long-term memories. Staying up late severely disrupts this process, leading to memory problems. This cognitive decline requires sufficient, continuous, quality sleep to gradually repair - simple catch-up sleep cannot compensate for it.

Additionally, during sleep, the brain clears metabolic waste accumulated during the day through the "glymphatic system," including β-amyloid proteins associated with Alzheimer's disease. Staying up late means this "garbage" accumulates, causing potential long-term damage to neurons. Restoring this process requires sustained, regular sleep.

**3. Endocrine Disruption**

Sleep is the golden time for endocrine regulation, and sudden staying up late or delayed sleep during holidays leads to endocrine disorders. This explains why many people experience oily skin, acne breakouts, and dull complexion after staying up late.

For example, sleep deprivation from staying up late causes leptin levels (appetite suppression) to decrease and ghrelin levels (hunger sensation) to increase. This is why people especially crave high-calorie, high-carbohydrate foods after staying up late. This hormonal disruption continues to affect appetite and weight, increasing risks of central obesity and insulin resistance. Restoring normal appetite and metabolism takes even longer.

**4. Emotional Disruption**

Holidays should be joyful, so why do some people become more irritable, angry, and anxious? This is mainly because sleep is closely related to emotional regulation centers (such as the amygdala and prefrontal cortex).

Sleep deprivation from staying up late lowers the threshold for emotional management, making people more prone to negative emotions. Recovery from this emotional imbalance requires not only sleep but sometimes active psychological adjustment.

**5. Immune System Disruption**

Some people catch colds and fevers during holidays but recover when returning to work, joking about having a "natural workhorse constitution." The reason behind this is actually decreased immune system function during holidays.

Sleep is the "charging" time for the immune system. Research shows that even just one night of sleep deprivation significantly reduces immune cell activity, thereby decreasing the body's ability to fight viruses and bacteria. Rebuilding a strong immune defense requires weeks of regular sleep and routine.

**What Time Constitutes Staying Up Late? Not 11 PM, Not 12 AM**

What's the difference between people who sleep at 10 PM versus those who sleep at 11 PM or midnight?

A 2021 study conducted jointly by the National Key Laboratory of Cardiovascular Diseases at Fuwai Cardiovascular Hospital of the Chinese Academy of Medical Sciences and The Chinese University of Hong Kong, covering 26 countries and over 136,000 middle-aged and elderly people, found that going to bed after 10 PM is considered late sleep. People who sleep late daily and have insufficient sleep are more likely to be obese and have excessive waist circumference, and daytime napping cannot offset this risk.

The study included 136,000 participants aged 35-70, with an average age of 51. Based on their daily bedtimes, they were divided into 5 groups:

Group 1: 6 PM - 8 PM bedtime Group 2: 8 PM - 10 PM bedtime Group 3: 10 PM - 12 AM bedtime Group 4: 12 AM - 2 AM bedtime Group 5: 2 AM - 6 AM bedtime

The study found that compared to people who went to bed between 8-10 PM, those who went to bed after 10 PM had a 20% increased risk of both obesity (BMI) and abdominal obesity (waist circumference). Among them, people who fell asleep after 2 AM had a 35% increased obesity risk and 38% increased abdominal obesity risk.

Additionally, the study confirmed that sleeping less than 5 hours per night constitutes severe sleep deprivation, with a 27% increased obesity risk. Even taking an afternoon nap cannot compensate for nighttime sleep deprivation damage.

In other words, going to sleep before 10 PM can significantly reduce obesity risk, while sleeping after 10 PM can be considered late sleep. For those wanting to relax slightly during holidays, it's best not to exceed 11 PM and try to ensure sleep during the golden period from 11 PM to 3 AM.

**5 Methods to Restore Body Order**

**1. Avoid Revenge Sleep-in** Even if you sleep very late, don't wake up more than 2 hours later than your usual time the next morning. For example, if you usually wake up at 7 AM, sleep until 9 AM at most. This protects your biological clock from excessive deviation.

**2. Golden Time for Afternoon Rest** Take a 20-30 minute short nap between 1-4 PM in the afternoon. This efficiently restores energy without affecting nighttime sleep.

**3. Light Reset for Biological Clock** After waking up the next morning, get exposed to outdoor natural light for 15-20 minutes as soon as possible. Sunlight is the strongest signal for calibrating the biological clock, effectively telling your body: "A new day has begun!"

**4. Remember to Disconnect Before Sleep** Stay away from phones, computers, and other electronic devices one hour before bedtime. Blue light suppresses melatonin secretion, keeping you awake.

**5. Moderate Daytime Exercise** Engage in moderate exercise during the day (such as brisk walking, jogging, or yoga) to help improve nighttime sleep quality, but avoid vigorous exercise within 4 hours of bedtime.