Not getting enough sleep increases the risk of heart disease, Alzheimer’s disease and even damages the immune system, study finds
- Researchers in New York tracked 14 adults who slept eight hours a night
- They asked them to reduce this by an hour and a half for six weeks in the study
- At the end, they found that these adults had more inflammation than before
- Scientists warned this suggested they were at higher risk for heart disease, Alzheimer’s and even immune system damage
Sleeping just six and a half hours a night increases the risk of heart disease, Alzheimer’s disease and even ages their immune systems, a new study finds.
Researchers at the Icahn School of Medicine, in New York City, reduced the normal eight-hour nighttime sleep schedule of 14 adults for six weeks and found that each ended with higher levels of inflammation. They said this increased the risk of chronic disease and warned it even caused permanent changes in the DNA of some cells.
According to official guidelines, adults need about seven to nine hours of sleep a night, with growing evidence that getting too much or too little is linked to a higher risk of chronic disease.
Experts not involved in the study said it was the first to reveal why sleep was so important to immune system health.
Researchers at the Icahn School of Medicine, in New York, deprived 14 adults of their normal eight hours of sleep every night for six weeks and found that they all had more inflammation in their bodies (stock image)
In the newspaper — published on Thursday in the Journal of Experimental Medicine – scientists recruited 14 adults who were about 35 years old and lived in New York City.
For the first six weeks, they each slept about eight hours a night, and at the end of the period, their blood was tested for immune cells.
Then each was asked to shave an hour and a half off their sleep for the next six weeks. The participants then went for a second blood test.
The results showed that there were more immune cells in the blood after sleep deprivation, indicating higher levels of inflammation.
They also noted that among stem cells that made immune cells, how their DNA was expressed changed, warning them of a loss of diversity in the system — a hallmark of aging.
How much sleep should I get per night?
How much sleep you need each night depends on your age.
The Centers for Disease Control and Prevention (CDC) say that newborns need the most, up to 17 hours a day, but this gradually decreases as a person ages.
They say that kids in school should get nine to 12 hours a night, and teens eight to 10 hours.
For adults, however, they recommend seven to nine hours.
From 65 years and older this drops to seven to eight hours.
Risks of insufficient sleep include:
- More chance of heart disease;
- Increased risk of type 2 diabetes;
- More likely to be obese;
- Difficulty concentrating at school;
- Greater chance of accidents.
Tests after sleep patterns returned to normal showed that immune cell levels also decreased, but the DNA appeared to be permanently ‘swapped’.
dr. Filip Swirski, a cardiovascular expert involved in the study, told NBC News: “The main message of this study is that sleep reduces inflammation and sleep loss increases inflammation.
‘In subjects who had undergone a sleep restriction, the number of immune cells circulating in the blood was higher. These cells play a key role in inflammation.’
He added that too much inflammation has been linked to heart disease and Alzheimer’s disease.
About the change in the DNA of immune stem cells, he said this equates to “accelerating” aging because it reduced diversity in them.
The study was small — only 14 people were involved — meaning more research is needed to support the findings.
dr. Stephen Chan, a heart expert at the University of Pittsburgh School of Medicine, said this was the first paper to show why sleep can be so important to the immune system.
The Centers for Disease Control and Prevention (CDC) say adults need about seven to nine hours of sleep each night. Children and teenagers need considerably more.
Not getting enough has been linked to a higher risk of many diseases, including heart disease, type 2 diabetes and obesity.
It can also affect concentration, leading to poor learning at school or an increased risk of accidents while commuting or at work.
But a growing body of evidence also suggests that too much sleep can be harmful and also increase the risk of Alzheimer’s disease.
In a paper published earlier this week, researchers in China warned that people over 60 who sleep more than eight hours are more likely to develop dementia.
Experts said the longer sleep was an important indicator that someone could be suffering from the disease, and they should be monitored.