Recent studies have shown lack of sleep is linked to obesity, diabetes, heart disease and even affects the body’s ability to manage pain. But the exact reasons have not always been fully understood.
That is changing as scientists dig deeper into the underlying processes that occur while the body is at rest. In a study published in the journal Nature, researchers in Boston took a deeper look recently and discovered how sleep has the ability to protect the heart.
They found that when sleep is sound there is a link between the brain, bone marrow and blood vessels that protect against the development of atherosclerosis or a hardening of the arteries. This further demonstrates the importance of getting quality sleep and could help protect against heart disease, the leading cause of death among men and women in the U.S.
"We've identified a mechanism by which a brain hormone controls production of inflammatory cells in the bone marrow in a way that helps protect the blood vessels from damage," said Filip Swirski, associate professor at Harvard Medical School. "This anti-inflammatory mechanism is regulated by sleep, and it breaks down when you frequently disrupt sleep or experience poor sleep quality. It's a small piece of to a larger puzzle."
Scientists used a group of mice genetically engineered to develop atherosclerosis and divided them between ones allowed to sleep normally and those whose sleep patterns would be disrupted. The mice with disrupted sleep had progressively larger arterial lesions and had fatty deposits up to one-third larger than the control group. Those same mice also had twice the level of certain inflammatory cells than the control mice and lower amounts of hypocretin, a hormone produced in the brain thought to be critical to regulating sleep and wake states.
The sleep disrupted mice that were given additional hypocretin had fewer inflammatory cells and smaller atherosclerotic lesions than the other sleep deficient mice. But researchers cautioned that more work is needed to validate the findings before hypocretin could be used therapeutically, especially in humans.
"This appears to be the most direct demonstration yet of the molecular connections linking blood and cardiovascular risk factors to sleep health," said Michael Twery, Ph.D. “Circadian biology refers to the 24-hour internal body clock that governs the expression of many genes in most every tissue and the regulation of sleep and wake cycles. Understanding the potential impact of poor sleep and circadian health on blood cell formation and vascular disease opens new avenues for developing improved treatments."