A slew of new studies recently presented at the European Study of Cardiology has found that getting too little or too much sleep is associated with significantly increased risk for cardiovascular issues such as hardened arteries, heart attacks, strokes, heart failure and more.
"We spend one-third of our lives sleeping yet we know little about the impact of this biological need on the cardiovascular system," Dr. Epameinondas Fountas, one of the authors of a meta-analysis, stated in a news release.
In one of the studies, the researchers looked at 11 studies with more than one million participants, and the findings suggest that, when it comes to cardiac disease, the lowest risk is six to eight hours of sleep per night. Anything less is associated with an 11 percent increased risk for dying from coronary heart disease or stroke at some point in the follow-up period of about 9.3 years. Anything more than that is associated with a 33 percent increase in risk.
In another study presented, people wore waist-band monitors for one week to track their sleep patterns. The results suggest that those who got less than six hours of sleep per night or who had woken up a lot had about 27 percent more atherosclerosis, which refers to hardening in the arteries that can lead to blockage or narrowing and contribute to heart failure, strokes or aneurysms.
Another study presented at the European Society of Cardiology conference looked at a group of 798 50-year-old men from Gothenburg, Sweden, who answered a 1993 survey on how long they slept. Twenty years later, those who had slept less than five hours per night were found to have double the risk of a cardiovascular event.
Most of us know the consequences of not getting enough sleep. But, according to the Centers for Disease Control and Prevention, one in three adults still don't get the recommended at least seven to nine hours per night — the amount considered optimal for good cognitive performance, safety and brain health.
And these studies aren't the first to call out the spectrum of issues with which sleep deprivation is associated. Sleep deprivation can prevent one's immune system from functioning normally, which can lead to illnesses, and long-term sleep deprivation can, therefore, also increase one's risk for chronic illnesses like diabetes and heart disease.
According to a 2017 by researchers at the Marche Polytechnic University in Italy, sleep deprivation can even cause parts of the brain’s synapses to be “eaten” by other brain cells. Astrocytes — abundant glial cells in the brain that clean out worn-out cells and debris so electric impulses can be transferred smoothly between neurons — are more active when we’re deprived of sleep, so they break down more of the brain’s connections than necessary.
Another recent study found that not getting enough sleep can actually alter genes in ways that promote obesity and impair metabolism. And more research has shown that sleep deprivation can lead to inflammation, which, in turn, can contribute to the risk of cardiovascular disease.
"More research is needed to clarify exactly why, but we do know that sleep influences biological processes like glucose metabolism, blood pressure, and inflammation — all of which have an impact on cardiovascular disease," Fountas said. "Having the odd short night or lie-in is unlikely to be detrimental to health, but evidence is accumulating that prolonged nightly sleep deprivation or excessive sleeping should be avoided."
AnnaMarie Houlis is a multimedia journalist and an adventure aficionado with a keen cultural curiosity and an affinity for solo travel. She's an editor by day and a travel blogger at HerReport.org by night.