lack of sleep effects

Poor sleep quality linked to lower physical activity

poor sleep

A new study shows that worse sleep quality predicts lower physical activity in people with post-traumatic stress disorder (PTSD).Results show that PTSD was independently associated with worse sleep quality at baseline, and participants with current PTSD at baseline had lower physical activity one year later.

Further analysis found that sleep quality completely mediated the relationship between baseline PTSD status and physical activity at the one-year follow-up, providing preliminary evidence that the association of reduced sleep quality with reduced physical activity could comprise a behavioral link to negative health outcomes such as obesity.

“We found that sleep quality was more strongly associated with physical activity one year later than was having a diagnosis of PTSD,” said lead author Lisa Talbot, postdoctoral fellow at the San Francisco VA Medical Center and the University of California, San Francisco. “The longitudinal aspect of this study suggests that sleep may influence physical activity.”

Study results are published in the July 15 issue of the Journal of Clinical Sleep Medicine, which is published by the American Academy of Sleep Medicine.
“This study adds to the literature that shows that better sleep leads to healthier levels of exercise, and previous research has shown that better sleep leads to healthier food choices,” said American Academy of Sleep Medicine President Dr. Timothy Morgenthaler. “It is clear that healthy sleep is an essential ingredient in the recipe for a healthy life.”

The study involved data from the Mind Your Heart Study, a prospective cohort study of 736 outpatients recruited from two Department of Veterans Affairs (VA) medical centers. PTSD was assessed with the Clinician-Administered PTSD Scale (CAPS). At baseline participants rated their sleep quality overall during the last month, and at baseline and again one year later they reported how physically active they have been during the last month. Of the 736 military veteran participants, 258 had current or subsyndromal PTSD.

According to Talbot, the results suggest that behavioral interventions to increase physical activity should include an assessment for sleep disturbance.
“The findings also tentatively raise the possibility that sleep problems could affect individuals’ willingness or ability to implement physical activity behavioral interventions,” she said. “Sleep improvements might encourage exercise participation.”

The research was performed in collaboration with principal investigator Dr. Beth Cohen of the San Francisco VA Medical Center and the Department of Medicine at the University of California, San Francisco. Research funding was provided by the National Heart, Lung, and Blood Institute (NHLBI) of the National Institutes of Health (NIH), the Irene Perstein Foundation, and the Mental Illness Research and Education Clinical Center of the U.S. Veterans Health Administration.

According to the National Center for PTSD of the U.S. Department of Veterans Affairs, PTSD symptoms such as nightmares or flashbacks usually start soon after a traumatic event, but they may not appear until months or years later. Symptoms that last longer than four weeks, cause great distress or interfere with daily life may be a sign of PTSD.

Source: science daily

Could lack of sleep cause a fatal mistake?

Behind the controls of the Metro-North train that derailed in New York earlier this week was a tired driver, according to new reports that engineer William Rockefeller fell asleep at the wheel.

Could lack of sleep cause such a fatal mistake?

Biologically speaking, experts said, yes. Sleep deprivation affects the brain in multiple ways that can impair judgment, slow reaction times and increase the likelihood of drifting off during monotonous tasks.

“When you’re sleep deprived, your brain reverts to a teenager — it’s all gas and no brake,” said Michael Howell, a neurologist at the University of Minnesota, Twin Cities. “Suddenly the part of the brain that says, ‘Let’s think through this,’ is not functioning well.”
The purpose of sleep has long mystified scientists, said Maiken Nedergaard, a neuroscientist at the University of Rochester Medical Center in New York. In an evolutionary conundrum, lying unconscious for hours on end makes people and other animals vulnerable to predators. Yet, not sleeping for long enough can actually lead to dementia and death. Chronic sleep-deprivation can cause obesity, diabetes, heart disease and other ills.

Studies have shown that exhausted people do worse on tests of memory and have more trouble learning. Tired basketball players sink fewer free throws. Even golfers who fail to get enough shut-eye take more strokes to finish a round.

“Almost everything researchers have looked at,” Howell said, “they’ve demonstrated is impaired if you don’t get enough sleep.”

When it comes to accidents, sleep matters because failure to get enough rest hampers functioning of the brain’s frontal lobes, which are responsible for executive judgment, or the ability to pay attention and make good decisions.

In overtired people, Howell said, imaging studies have shown that there is less blood flow to these areas in the front of the brain and brainwaves there move more slowly.
The result is a compromised ability to respond to things, along with a faulty tendency to do things you shouldn’t have done. When the frontal lobes aren’t working efficiently, people also have more difficulty paying attention during boring tasks, such as driving a car on a highway or operating a morning commuter train.

Early morning hours, like when the Metro-North train crashed, are some of the most vulnerable times for sleepy accidents, Howell said, especially for people whose circadian rhythms favor a later sleeping schedule and make it biologically difficult to function well after waking up with an alarm clock at 5 a.m.

Reports that Rockefeller had been driving for 20 minutes since his last stop and felt zoned out before the accident suggest that he probably fell asleep before the crash, Howell added.

Recently, scientists have begun to piece together an even more nuanced understanding of why sleep is so restorative. In a study published in Science this fall, Nedergaard and colleagues injected mice with a green dye that allowed them to track the movement of cerebrospinal fluid, the liquid that surrounds the brain.

As our brains do their work throughout the day, previous work had shown that cerebrospinal fluid collects the waste products of normal metabolism and functioning. Then, a network of tiny channels works like a dishwasher to regularly flush out the dirty fluid and send it to the liver for detoxification.

The new study found that sleeping facilitated the flushing of this toxic fluid, which was much slower to drain in sleep-deprived rodent brains. Nerve cells are very sensitive to the presence of waste, Nedergaard said. When surrounded by contaminated fluid, communication at the cellular level likely slows down.

Source: mashable