In this blog post, we will examine why 7 to 8 hours of sleep is really necessary and whether historical figures who functioned well on less sleep are exceptions.
These days, people everywhere are suffering from sleep deprivation. According to a recent study, the average daily sleep time for Korean high school students is just 5 hours and 27 minutes. This is the result of rapid growth during adolescence and academic stress, which prevent them from getting enough rest. As a result, many teenagers are experiencing chronic fatigue and stress, leading to a vicious cycle of declining academic performance.
We have often heard since childhood that “we need 7 to 8 hours of sleep per day.” This is not just advice but a scientifically proven recommendation for brain development and physical recovery. The U.S. Food and Drug Administration (FDA) also recommends this range as the appropriate amount of sleep for adults. While this is based on scientific evidence, it raises questions about whether this standard applies equally to everyone in real life.
In my case, even when I sleep much less than 7 to 8 hours, I often don’t feel any significant disruption in my daily life the next day. This made me wonder if it’s really necessary to strictly adhere to a set sleep schedule to maintain good health. Of course, some people might say, “Sleeping a little less for a day or two won’t cause immediate problems, but if that becomes a recurring pattern, it will undoubtedly have a negative impact on your health.”
Historically, there have been figures like Napoleon and Edison, who are said to have slept only 3 to 4 hours a day. They managed to live normally and achieve great things despite their short sleep duration. Does this mean such cases can serve as a general standard? Perhaps they were exceptional individuals with genetically lower sleep requirements.
What we should truly focus on is whether such exceptional cases can be applied to the general population. Even if they managed to overcome sleep deprivation in special circumstances, most people find it difficult to maintain physical and mental health without sufficient sleep. In fact, numerous studies have shown that sleep deprivation weakens the immune system and is closely linked to various chronic diseases such as cardiovascular disease, diabetes, and obesity in the long term.
Furthermore, sleep serves functions beyond mere rest. During sleep, the brain organizes information received during the day and stores what it deems important in long-term memory. This process must occur smoothly to maintain learning ability and creative thinking. Therefore, sleep deprivation can lead to various cognitive issues such as decreased concentration, impaired memory, and slowed thinking, which directly impact academic and work performance.
Therefore, it is important to examine whether there is such a thing as “adequate sleep time,” what the criteria are, and what problems arise when these criteria are not met. One of the most representative statistics showing the correlation between sleep time and health is the association between mortality and sleep time. According to a study by a world-renowned research team, people who sleep an average of 5 hours or less per day have a 21% higher mortality rate than those who sleep 7 hours per day. Conversely, those who sleep more than 10 hours a day also had a 36% higher mortality rate. This data shows that both too little and too much sleep can be harmful to health. In other words, there is a scientifically proven “optimal sleep duration,” which the FDA recommends as 7 to 8 hours.
So, what changes occur in the body when this recommended sleep duration is not met? First, during sleep, the nervous system removes waste products accumulated from daytime activities. If this process is not properly carried out, brain function declines, and over time, this can lead to nervous system damage. Additionally, sleep is the time when the body processes information and emotions accumulated throughout the day. If this time is not adequately secured, memory declines, and cognitive flexibility decreases. This inevitably leads to reduced work efficiency and learning ability.
Furthermore, sleep deprivation weakens the immune system, making individuals more susceptible to various infectious diseases, and disrupts hormonal balance, increasing the risk of chronic diseases such as obesity and diabetes. In fact, growth hormone and appetite-regulating hormones such as ghrelin and leptin are highly sensitive to sleep duration. Insufficient sleep can increase appetite, reduce energy expenditure, and lead to weight gain. Ultimately, sleep is an important physiological factor that determines both physical and mental health.
On the other hand, excessive sleep also has negative effects on health. According to recent studies, people who sleep more than nine hours a day have a higher risk of cardiovascular disease, depression, diabetes, and obesity than those who do not. In particular, a study published in the Journal of the American Heart Association in 2022 found that people who sleep more than nine hours a day have a 14% higher risk of developing cardiovascular disease than those who sleep seven hours, and also tend to experience slowed brain activity and increased daytime fatigue. This suggests that while sufficient sleep is important, excessive sleep can have the opposite effect.
Additionally, spending prolonged periods in bed can limit physical activity, leading to muscle loss, impaired metabolic function, and worsening mental health. Experts emphasize that both insufficient and excessive sleep should be carefully addressed as major factors that can harm health.
Based on the results of studies conducted so far, it is clear that both too little and too much sleep can have negative effects on health. However, in reality, many people suffer from insomnia or are unable to get enough sleep due to busy schedules at work or school. While some may rely on medication to address these issues, the ultimate solution lies in improving lifestyle habits. Maintaining a regular sleep pattern, avoiding excessive caffeine intake before bedtime, and reducing the use of electronic devices are habits that can help improve sleep quality. Above all, stress management is an essential factor for getting a good night’s sleep.
Ultimately, sleep is more than just a time to rest the body; it is an important factor that determines the overall quality of life. In the 21st century, we often talk about “well-being,” but we often overlook the most basic aspect of health management: sleep. To take care of ourselves and live a healthy life, we need to recognize the importance of sleep once again. Maintaining 7 to 8 hours of sleep every day is a small but powerful step toward a healthier and happier life.
