Poor sleep is likely to make you feel grumpy and unfocused, but more importantly it puts you at risk for serious medical conditions such as obesity, type 2 diabetes and heart disease — and it shortens your lifespan.
A new study shows that sleep loss also increases your risk of cardiovascular disease by changing how your body metabolizes cholesterol.
Recently reported in Scientific Reports, University of Helsinki's sleep team studied the cholesterol metabolism of sleep-deprived people, measuring their gene expression and the levels of blood lipoprotein, a molecule that transports cholesterol through the blood. They assessed these factors for a small group of volunteers who only slept four hours per night for five days. The team also looked at longer-term effects on cholesterol metabolism using data from two large population studies with 2,739 participants.
The study found that people getting insufficient sleep have fewer high-density lipoproteins (HDL) — the "good" proteins that act as cholesterol scavengers to decrease accumulation of atherosclerosis within the walls of arteries — than people who get enough sleep.
“It is particularly interesting that these factors contributing to the onset of atherosclerosis, that is to say, inflammatory reactions and changes to cholesterol metabolism, were found in the experimental study and in the epidemiological data,” said first author Vilmo Aho, a graduate student at the University of Helsinki, in a recent news release.
The bad news is they showed that even a week of sleep deprivation had a significant impact. Aho explained in the release:
The experimental study proved that just one week of insufficient sleep begins to change the body’s immune response and metabolism. Our next goal is to determine how minor the sleep deficiency can be while still causing such changes.