The return to standard time for most of the country won't come for a few more weeks, leaving many looking forward to the Nov. 3 "fall back" that rewards us the option of an extra hour's sleep.
But even as shorter days make us want to hibernate, sleep scientists have been churning out several new studies that underscore just how important - and difficult - it can be to get a decent amount of shuteye.
Although it's clear that sleep is important in preserving mental function, and restoring and growing everything from the immune and nerve systems to bones and muscle, researchers remain uncertain about just how much sleep debt we build up over time and how much can be done to recover that lost sleep with extra snooze time down the road.
First, a team from the Penn State University College of Medicine and several other institutions took a look at catch-up sleep - typically sleeping in on weekends after a workweek of reduced sleep. The study appeared Oct. 9 in the American Journal of Physiology-Endocrinology and Metabolism.
They put 30 healthy volunteers on a sleep-lab schedule that mimicked a sleep-restricted workweek, followed by a weekend with extra recovery sleep. And they found that the volunteers' sleepiness, which had increased during the week, did go back to baseline levels after getting the recovery sleep.
And blood tests showed that inflammation that increased during sleep restriction, and a hormone that is a marker for stress both went down after the recovery sleep. However, results from a test that assessed volunteers' ability to pay attention declined during the work-week period and did not improve after the catch-up sleep, suggesting that not all the effects of sleep lost during a workweek can be made up over a single weekend, the researchers said.
They also stressed that while the study gives some insight into a weekly cycle, it does not address possibly more significant health effects brought about by sleep loss over a longer time frame.
Another study of sleep patterns in adults 45 and older found that sleeping too little (less than six hours a night) or getting too much sleep (10 hours or more) both are linked with chronic diseases such as heart disease, obesity and diabetes.
The report by researchers at the Centers for Disease Control and Prevention appeared Oct. 1 in the journal Sleep. Short sleepers, who made up about 31 percent of the participants, reported a higher incidence of the chronic diseases, as well as mental stress, compared to optimal sleepers who made up 64 percent of the study group and who got an average of 7 to 9 hours sleep per each 24 hour period.
Similar effects, but even more pronounced, were found in the long-sleepers who made up just 4 percent of the study group.
The study included 54,000 people from 14 states.
A third report, published last year by scientists at the University of Pittsburgh, shows that the sleep habits of the elderly, once thought to be much shorter and with earlier bedtimes, are actually much the same.
Based on telephone interviews with nearly 1,200 retired people over the age of 65 and living in western Pennsylvania, the researchers found that three quarters of them said they slept an average of more than 6.75 hours a night, and most of them slept between the hours of 11 p.m. and 7:30 a.m.
Only about 25 percent said they slept less than 6.7 hours a night, had difficulty sleeping at night and experienced problems with daytime sleepiness. Among that group, interviews showed the sleep problems were more likely to be tied to illness or medicines the seniors were taking than old age.
The study was published in the journal Healthy Aging and Clinical Care in the Elderly.
Contact Scripps health and science writer Lee Bowman at BowmanL@shns.com.
Distributed by Scripps Howard News Service, www.shns.com.