Scientists Find Sweet Spot of Sleep Time Associated with Healthy Aging

We’ve all heard about the importance of diet and exercise for healthy aging. But how about sleep? As someone who ranks a comfy pillow as one of her most valuable possessions, I was delighted to read a new study about how getting the right amount of quality sleep — between about six and eight hours per night — is associated with reduced risks of disease and premature death.

Led by scientists at Columbia University and several other institutions, the study built on publicly available data from the UK Biobank, a massive ongoing research program tracking 500,000 people. They asked all participants to report information about their sleep habits, and then paired that with a deep analysis of MRI scans and biological samples. The result: people who regularly got less than six hours of sleep or (sadly) more than eight hours of sleep had more advanced biological aging compared to those in the shuteye sweet spot. Accelerated aging occurred at all levels: structural, functional, and molecular.

According to the paper, this is the first study to link sleep duration with biological aging, while also establishing clear associations with disease and mortality. “Our results underscore the systemic biological adverse associations of disturbed sleep and provide a compelling framework for more targeted and thoughtful attention to sleep disturbance as a potential signal of emerging health issues,” the authors report.

Indeed, one of the reasons the scientists chose to focus on sleep is that, unlike our genetics or family histories, it’s something we may be able to change. Study author Junhao Wen (a neuroscientist who struggles to sleep well) told Nature that the team looked for genetic variants associated with abnormal sleep and didn’t find many. “Sleep might be more environmental,” Wen said. “It’s a strong message for the public that this can be modifiable.”

Thanks to the UK Biobank data, scientists were able to show that sleeping the right amount is important for organ health, the immune system, and the metabolism. They drilled down into data representing 23 distinct biological aging clocks. Molecular results showed that sleeping too little or too much had negative consequences that could be tracked in protein changes across the lungs, brain, liver, skin, and immune system.

If you haven’t already, make sure you’re following those sleep hygiene recommendations. Sweet dreams, all!

Short Takes

It’s hard to believe, but until now, hantavirus diagnostic tests used in the U.S. were not capable of detecting the rare Andes strain associated with human-to-human transmission. Wired has a great report of how researchers at the University of Nebraska, where most of the American passengers from the Hondius cruise are quarantining for up to six weeks, quickly pushed to develop a test that could detect this specific viral strain.

Scientists from Europe studied the microbial population found in tumors and in bile from patients with pancreatic cancer. They determined that while a healthy pancreas contains very few microbes, pancreatic tumors have a more robust microbiome that closely resembles that found in bile. The catalog of microbes detected could lead to future development of biomarker tests that could be used to diagnose and stage pancreatic cancers.

Finally, two interesting stories about DNA-based identification of people from the past:

First, scientists analyzed genomes from nearly fifty 17^th-century inhabitants of St. Mary’s City, the first English settlement in Maryland, to understand their genetic legacy in this country. By pairing those 400-year-old genomes with modern data from 23andMe, they were able to trace their local origins in England and Wales as well as to identify more than 1.3 million descendants of the settlers. They also propose identities for three of the original St. Mary’s residents based on genomic data.

In a second story, researchers used DNA data to identify the remains of four sailors who died in 1845 after a disastrous Arctic expedition that got stuck in ice for almost two years. All 129 members of the expedition died, but only two others have been identified based on their remains.