This new research could keep you up at night.
Middle-age adults who slept just six hours or less a night were 30% more likely to develop dementia in their late 70s compared with people in their 50s and 60s who snoozed for a solid seven hours, according to a study published in the scientific journal Nature Communications on Tuesday.
European researchers analyzed survey data from almost 8,000 U.K. adults over 25 years, starting when the subjects were in their 50s. It linked this data with dementia diagnoses, and found that people who consistently reported getting six hours or less of sleep on the average weeknight were more likely to be diagnosed with dementia almost three decades later. When broken down by decade, the 50-year-olds sleeping six hours or less had a 22% higher risk of dementia, and 60-year-olds were 37% more likely to be diagnosed. There was no general difference between men and women.
And this higher risk was independent of risks related to socioeconomic status, their risk of having a cardiovascular event like a heart attack or stroke, or behavioral and mental health factors, the study authors wrote. Indeed, previous research has suggested that obesity, high blood pressure and depression can also raise your risk of sleep problems and dementia.
Related: These are the 3 biggest sleep myths
Some limitations to this study include the fact that the subjects self-reported how much sleep they were getting. What’s more, most of the participants were white and better educated than the overall British population, the New York Times noted. The study also could not identify exact types of dementia, as it relied on electronic medical records for dementia diagnoses.
But the large size of the study population, as well as the fact that the researchers followed the subjects for decades, offers a compelling argument for a link between better sleep and better cognitive health.
This is important to note because more than a third of American adults are sleep-deprived, according to the CDC, which means they are getting less than the recommended seven hours of sleep every night.And the pandemic over the past year and counting certainly hasn’t helped, as stress over the toll COVID-19 is taking on physical and financial health has seen Google searches for “insomnia” hit an all-time high.
And here are more key reasons to seek a good night’s sleep.
Better sleep can lead to better sex — for middle-aged women in particular.
Women getting poor sleep were almost twice as likely to report sexual dysfunction, such as less sexual interest or less pleasure in sex, according to a new study published in Menopause: The Journal of The North American Menopause Society on Wednesday.
Up to 43% of middle-aged women report sexual problems, and more than one in four (26%) report having “significant” sleep symptoms that meet the criteria for insomnia, the report noted. So researchers evaluated the association between the quality of sleep and the length of sleep with sexual function in more than 3,400 women whose median age was 53 years old. And good quality sleep was linked with positive sexual activity.
Sleep quality was more important than sleep duration in that study, but other research has linked more sleep with more satisfying sex. A 2015 study in The Journal of Sexual Medicine found that women who slept just one extra hour were 14% more likely to engage in sexual activity. The Better Sleep Council suggests this is because sleeping well improves energy, self-esteem and overall mood, which could make you more interested in having sex.
As for the fellas, since most testosterone release happens in sleep, research suggests that men also benefit in the bedroom by spending more time in bed. Researchers from the University of Chicago found that men who were subjected to a week of sleep deprivation of less than five hours of sleep per night saw their testosterone levels drop by up to 15% the following day — which is far greater than the 1% to 2% drop in testosterone men normally experience due to aging each year.
Better sleep can make you a better investor.
A couple of years ago, two professors of finance curious about the impact of sleep on financial risk tested 126 upper-level students in economics and finance, who were familiar with the concepts of risk and reward. They tracked the students’ sleep patterns and gave them several tests to gauge their attitudes toward risk. And those who were sleep-deprived or suffering from other sleep disruptions incurred more risk than those who had more sleep.
And MarketWatch’s Mark Hulbert noted at the time that a previous report dubbed “Losing Sleep at the Market: The Daylight-Savings Anomaly” found that the stock market’s returns are significantly below normal, on average, on the Mondays following daylight-saving time shifts. And this is probably due to disrupted sleep as we adjust the clocks, especially when we spring forward and lose an hour by turning our clocks ahead in March.
“We have all struggled through a day after a poor night’s sleep, weighed down by weariness, fighting lethargy, and perhaps even facing despondency,” the authors wrote.
If you’re looking for tips to improve your sleep, these 4 sleep experts shared their own personal routines for catching Zs.
And MarketWatch has also listed several tips from the National Sleep Foundation for improving your sleep hygiene here, such as ways to create a relaxing bedtime ritual, or what to do if you’re tossing and turning and just can’t fall asleep.