It used to be a badge of honor for high performers to say they barely slept.
Now, studies show that getting less than seven hours will almost undoubtedly send you to an early grave.
The risks of developing heart disease, obesity, and death increase by 83 percent, and 82 percent, and 40 percent, respectively.
And yet a startling one in three adults in the US are sleep-deprived.
Meanwhile, newer research shows that sleeping too much, around nine hours or more, is linked to an increased risk of death by 74 percent, stroke by 12 percent, and obesity by 37 percent.
![The solid line in this graph depicts the average risk of dying [the Y axis] based on sleep duration [the X axis]. The dash line represents the confidence intervals, which provide a range in which scientists can be sure the true risk of death lies](https://i.dailymail.co.uk/1s/2024/07/22/16/87628411-13653095-image-a-6_1721661925673.jpg)
The solid line in this graph depicts the average risk of dying [the Y axis] based on sleep duration [the X axis]. The dash line represents the confidence intervals, which provide a range in which scientists can be sure the true risk of death lies
The graph shows that sleeping fewer than around six hours vastly increases one’s risk of chronic diseases including diabetes, high blood pressure, heart disease, and stroke
The consensus, for the vast majority of US adults, is that the ideal amount of sleep is between seven and eight hours.
However, about 0.5 percent of the population has a rare genetic mutation that allows a person to function on around four to six hours of sleep.
But for the rest of us, risks of death from all causes are compounded when we get fewer than six and more than eight or nine per night.
Graphs showing the harms of unhealthy sleep – too little or too much – show there is a high risk of a range of health issues with six hours or fewer of sleep.
The same goes for getting more than eight hours of sleep, with risks increasing with every additional hours spent snoozing.
People who sleep too little are 14 percent more likely to have depression, around 108 percent more likely to have anxiety, a 37 percent increased risk of obesity to a 12 percent increased risk of stroke stroke
They have a 38 percent increased risk of heart disease, a 29 percent increased risk of high blood pressure, and and 23 percent higher risk of diabetes.
In 2017, an analysis of 40 studies into the risk of death by all causes linked to sleep duration found that both very short and very long sleep durations are associated with a higher risk of death compared to getting about 7 hours of sleep.
Getting between four and six hours of sleep increased the risk of death by a range of four to six percent.
Sleeping eight hours increased risk of death by three percent, nine hours by 13 percent, 10 hours by 25 percent, and 11 hours of 38 percent.
Another analysis in 2010 by UK and Italian researchers looked at 16 studies including nearly 1.4 million people.
They found that people who sleep less than the average seven hours per night had a 12 percent higher risk of dying compared to those who slept the ideal seven to eight hours.
People who slept more than the average – eight to nine hours – had a 30 percent risk of dying compared to those who slept the ideal amount.
The graph shows results of seven meta-analyses looking at the relationship between sleep duration and stroke risk. All seven analyses reported a significantly increased stroke incidence in both short and long sleepers
And in 2022, a cadre of Chinese scientists studied the risk of death from all causes associated with sleeping anywhere from five or fewer to more than nine hours per night.
The researchers found that sleeping fewer than five hours per day made people 40 percent more likely to die from any cause, whereas sleeping more than nine hours per day made them more than 74 percent more likely to die from any cause.
They studied more than 25,000 US adults who all had different sleeping habits and lifestyle factors that contribute both to poor sleep and chronic diseases.
A U-shaped relationship was found between sleep duration and all-cause mortality, with the lowest risk at 7 hours per day.
They also found that sleeping either too little or too much more than doubled the risk of heart issues.
Dr Chris Winter, a neurologist specializing in sleep in Virginia, told Dailymail.com that the reasons explaining the link between poor sleep and heart issues are ‘probably multi-factorial.’
He said that sleeping too little or too much causes the nervous system to malfunction, causing higher heart rate, high blood pressure, and elevated stress levels.
Poor sleep can also exacerbate inflammation in the body, a well-known risk factor for cardiovascular disease, stroke, dementia, and autoimmune diseases like rheumatoid arthritis.
Weight and metabolism are also impacted when a person sleeps too much or too poorly, as diet tends to suffer. Sleep’s effects on hormones mean people are likely to make unhealthier food choices.
Sleeping too much or too little, usually six hours or fewer and nine hours or more, is tied to increased risk of death from all causes, including death by heart disease and stroke
Dr. Beth Frates, director of lifestyle medicine and wellness in the Department of Surgery at Massachusetts General Hospital, said: ‘Most people focus on exercise and diet when it comes to weight management and a healthy heart, but few focus on sleep.
‘Working to find ways to clean up sleep hygiene may help people to extend sleep time to the recommended seven to nine hours per night. This could, in turn, lead to consuming fewer calories and even weight loss in people who are in the overweight category by BMI.’
In another study examining the risk to heart health published in the Journal of the American Heart Association, researchers found that middle-aged adults with conditions like high blood pressure, type 2 diabetes, heart disease, or stroke may face a higher risk of cancer and premature death if they sleep less than six hours a night.
They studied more than 1,600 adults aged 20 to 74, focusing on those with high blood pressure, diabetes, existing heart disease, and a history of stroke.
They underwent sleep studies in a lab from 1991 to 1998, followed by tracking their causes of death until the end of 2016.
During the study period, 512 people died, a third of whom died of heart attack or stroke, while a quarter died from cancer.
People with high blood pressure or diabetes who slept less than 6 hours had twice the risk of dying from heart disease or stroke compared to those who slept longer.
And those with heart disease or a history of stroke who slept fewer than six hours had three times the risk of dying from cancer.
Stroke risk is projected to jump by around 18 percent for every additional hour of sleep above the optimal duration of around seven or eight.
Another study published last year estimated sleep problems such as sleeping too little or too much quintuples one’s risk of stroke.
Dr. Phyllis Zee, director of the Center for Circadian and Sleep Medicine at Northwestern University’s Feinberg School of Medicine in Chicago told CNN: ‘Poor sleep can impair the natural blood pressure dipping that occurs during night time sleep and contribute to hypertension — an important risk factor for stroke and cardiovascular disease.’
The effects of poor sleep can be felt immediately, and after around three days of too little sleep, a person can develop hallucinations or psychosis.
It can also lead to an increased risk of death by accident or injury. Almost 20 percent of all serious car crash injuries among the general public are associated with driver sleepiness, independent of alcohol effects.
Compared to drivers who had slept for a regular seven hours, those who reported they’d slept fewer were 1.3 times more likely to crash, while those who slept five to six hours were nearly two times as likely to crash.
And sleep four to five hours quadrupled a person’s risk of being in a serious crash.
