Recent research revealed that people who don’t get enough sleep are at greater risk of stroke and heart attack but the reasons are not clear, at least until now. A new study found that people who sleep for less than 7 hours per night have lower blood levels of three physiological regulators (so-called microRNAs), which influence which genes are turned on, play a key role in maintaining vascular health.
The findings could potentially lead to new tests for sleep deprived patients concerned about their health, the authors said.
The average person living in the UK sleeps for between 5.78 and 6.83 hours per night (a mean of 379.4 minutes). Compared with the global average (6.9 hours), this means that many of us miss out on the recommended amount of sleep by at least 100.6 minutes. The average UK resident is getting around 34.5 minutes less sleep a night than those in other countries adding up to 210.2 hours a year (or an incredible 8.76 days).
For the new study, which is the first to explore the impact of insufficient sleep on circulating microRNA signatures, Dr. DeSouza and his team from the University of Colorado, took blood samples from 24 healthy men and women, age 44 to 62, who had filled out questionnaires about their sleep habits. Half slept 7 to 8.5 hours nightly; Half slept 5 to 6.8 hours nightly.
They measured expression of nine microRNAs previously associated with inflammation, immune function or vascular health.
They found that people with insufficient sleep had 40 to 60 percent lower circulating levels of miR-125A, miR-126, and miR-146a, (previously shown to suppress inflammatory proteins) than those who slept enough.
In another recent study, DeSouza’s group found that adult men who sleep 6 hours per night have dysfunctional endothelial cells – the cells that line blood vessels – and their arteries don’t dilate and constrict as well as those who get sufficient sleep.
MicroRNAs are small molecules that suppress gene expression of certain proteins in cells. The exact function of circulating microRNAs in the cardiovascular system, and their impact on cardiovascular health is receiving a lot of scientific attention, and drugs are currently in development for a variety of diseases, including cancer, to correct impaired microRNA signatures.
Ultimately, he said, it’s possible that microRNAs in blood could be used as a marker of cardiovascular disease in people with insufficient sleep, enabling doctors to glean important information via a blood test rather than current, more invasive tests.
For now, DeSouza says, the takeaway message for those burning the midnight oil is this:
“Don’t underestimate the importance of a good night’s sleep.”
Hijmans et al. 2019. Insufficient sleep is associated with a pro-atherogenic circulating microRNA signature. Experimental Physiology. DOI: 10.1113/EP087469.