In April 2021, a study titled “The Relationship Between Sleep Duration, Sleep Quality, Cardiovascular Disease, and Mortality Rates” led by a team of scientists headed by Chun Shing Kwok was published in the journal “Sleep Medicine.” The results indicated that the risk of death or cardiovascular complications in individuals who go to bed early increased by 29% compared to those who sleep at normal hours (between 10 PM and 12 AM).
Is this true? Does going to bed early, which has always been encouraged, actually increase mortality risk? Let’s explore the research below.
1. Too Little or Too Much Sleep is Not Good
Specifically, experts investigated the relationship between sleep duration, cardiovascular disease, and mortality rates based on 74 studies conducted from 1970 to 2017, involving 3.3 million participants.
However, this is merely an epidemiological study. Epidemiological research can indicate correlations of observed phenomena but cannot prove causal relationships between related events.
In this study, the primary cause of death was identified as high blood lipids, high blood sugar, or other chronic diseases. Experts found that sleeping more than 8 hours is associated with an increased risk of cardiovascular disease. The risk increases by 17% if sleeping 9 hours and rises to 23% if sleeping 10 hours.
Experts found that sleeping more than 8 hours is associated with an increased risk of cardiovascular disease.
They also discovered a correlation where the longer the sleep duration, the greater the risk of early death; specifically, a 23% increase for 9 hours, a 52% increase for 10 hours, and a 66% increase for 11 hours of sleep.
Sleeping less than 7 hours also correlates with the risk of stroke, albeit at a lower level. Sleeping for 5 hours shows a 29% increase in stroke risk, which could reach 41% when sleeping for 10 hours.
So, what factors did this study rely on to indicate a connection between going to bed early and increased mortality risk?
After thorough and in-depth analysis, scientists pointed out the link between going to bed early and the risk of death from cardiovascular complications.
Therefore, after careful analysis, it can be seen that the actual causes leading to high mortality risk and the likelihood of cardiovascular complications in those who go to bed early have a certain relationship with underdeveloped economies and a lack of modern healthcare.
2. Is Longer Sleep Always Better?
Sleeping too little can cause many unforeseen health damages. But does the opposite—sleeping too much—lead to better health?
A comprehensive study led by Keele University in the UK analyzed the relationship between sleep and health among 3 million people. The final results revealed that individuals who sleep an average of 10 hours each night have a 30% higher risk of early death compared to those who only sleep for 8 hours.
Additionally, research indicates that the more one sleeps, the more burden it can place on the body, leading to higher susceptibility to diabetes, blood pressure issues, and even cancer, particularly in snorers and those who are overweight. Furthermore, excessive sleep can inhibit nervous system function and impair memory. Thus, it is evident that sleeping too much can also be detrimental to health.
So, what is the optimal amount of sleep? How can one achieve quality sleep?
According to various research findings, the National Sleep Foundation in the United States has summarized new sleep recommendations for people of all ages as follows:
- For nighttime sleep, most adults should aim for 7-9 hours each day;
- People over 65 years old may need slightly less sleep;
- Teenagers and young children require more sleep.
Of course, the timeframes provided are for reference only. The director of the Second Affiliated Hospital of Nanchang University, Mr. Liu Hao, pointed out that generally, the normal sleep duration for people is about 7.5 hours and not less than 6.5 hours. However, exceptions do exist. If you have a short but sufficiently deep sleep that allows your body to recover energy, there is no need to force yourself to sleep longer.
Sleeping too much can also place additional burdens on the body.
3. Quality is More Important than Sleep Duration
Sleep is closely related to health. Compared to sleep duration, the quality of sleep plays a more direct and crucial role. If sleep quality is not ensured, the body’s functions cannot operate normally, negatively impacting health and life.
If you frequently stay up late, compensate by sleeping during the day, or catch up on sleep during weekends; face high work pressure, have to work overtime at night, and often experience interrupted sleep… Unfortunately, these are symptoms of fragmented sleep that significantly affect sleep quality and overall health.
To improve sleep quality, pay special attention to the following factors:
- Sleeping Position: For healthy individuals, sleeping on the left side, back, or right side are all good positions. For those with heart disease or high blood pressure, avoid positions that compress the heart; lying on the right side is generally more beneficial for health.
- Sleeping Environment: The bedroom should be dark and quiet, and it’s advisable not to place too many electronic devices in the sleeping area. Avoid wearing bracelets, rings, necklaces, or dentures while sleeping to minimize the risk of sleep interruptions.
- Sleep Timing: Whether you are a night owl or an early riser, it’s important to balance your biological clock and maintain a regular work and rest schedule. This is the most crucial factor for health.
Sleep is the foundation of life. Do not naively believe that simply adding more sleep time will benefit health while neglecting sleep quality.
