Can more sleep help ease pain? Yes, says new study!

Chalk another one up for the benefits of sleep. Researchers at the Sleep Disorders and Research Center at the Henry Ford Hospital in Detroit have found that getting more sleep improves daytime alertness and reduces pain sensitivity in healthy adults.

The study was led by Timothy A. Roehrs, Ph.D. of the Sleep Disorders and Research Center at the Henry Ford Hospital and supported by the Fund for Henry Ford Health System. Roehrs and his colleagues studied 18 pain-free, but mildly sleepy volunteers.

For the study, the participants were randomly assigned to four nights of either their normal amount of sleep, or extending their sleep time to 10 hours in bed per night. Their daytime sleepiness was measured on days one and four using the Multiple Sleep Latency Test (MSLT), a tool that measures how quickly a person falls asleep. Their pain sensitivity was also measured using finger withdrawal latency pain testing to a radiant heat stimulus.

The first study to prove sleep reduces pain.

The results of the study were published in the Dec. 1 issue of the journal Sleep. It is the first research of its kind to prove that extended sleep in mildly sleep-deprived adults can significantly reduce their sensitivity to pain.

The results showed that the extended sleep group—those who slept more than normal—slept 1.8 hours more per night than the normal sleep group. It also showed that they experienced less daytime sleepiness. This increase in sleep time during the four nights correlated to increased daytime alertness, as well as less sensitivity to pain.

Regarding the pain test, the extended sleep group showed a greater tolerance for pain/reduced pain sensitivity. The length of time before participants removed their finger from a radiant heat source increased by 25 percent. The researchers noted that this increase in “finger withdrawal latency” is greater than the effect found in a previous study where participants used 60 milligrams of codeine.

In their report, the researchers stated that the results, combined with data from previous research, suggest that increased pain sensitivity in sleepy individuals is the result of their underlying sleepiness.

Timothy Roehrs, PhD, the study’s principal investigator and lead author said, “The results suggest the importance of adequate sleep in various chronic pain conditions or in preparation for elective surgical procedures. We were surprised by the magnitude of the reduction in pain sensitivity, when compared to the reduction produced by taking codeine.”
Read the press release for the study, “Extended sleep reduces pain sensitivity.”

Lack of sleep and an increase in strokes.

Roehrs’ study adds to growing evidence that more regular, restorative sleep can help reduce the risk of health problems, and the opposite is true, as well.

Last June, the University of Alabama at Birmingham released the results of a study that regularly sleeping less than six hours a night significantly increases the risk of stroke symptoms in middle-age to older adults who are of normal weight and at low risk for obstructive sleep apnea (OSA). That’s worth repeating: Less than six hours of sleep per night increases the risk of strokes in adults of normal weight and not at risk for OSA.
It seems that under six hours of sleep per night is the critical variable, but why? Let’s take a look at the study. The University of Alabama researchers followed 5,666 people  for up to three years who had no history of strokes or stroke-like symptoms, transient ischemic attacks (when blood flow to the brain stops for a brief period causing stroke-like symptoms), or high risk for OSA at the start of the study.

For a period of three years, the researchers followed and studied the subjects’ first stroke symptoms, stroke risk factors, depression symptoms, demographic information and other various health behaviors. What they found was—after adjusting for body-mass index (BMI)—there was a strong association between daily sleep periods of less than six hours and a greater incidence of stroke symptoms for middle-age to older adults, even beyond other risk factors. Interestingly, the researchers did not find any link between short sleep periods and stroke symptoms in overweight and obese participants.

Still, the connection between short sleep and strokes is worthy of great attention from the medical community and general public. I agree with the Alabama study’s lead author, Megan Ruiter, PhD., who said, “The results of the Alabama study provide a strong argument for increasing physician and public awareness of the impact of sleep as a risk factor for stroke symptoms, especially among persons who appear to have few or no traditional risk factors for stroke.”

It looks like the medical community is taking this message to heart, no pun intended. Another study announced in late July is going on at the Alberta Health Services and the University of Calgary. There, Dr. Patrick Hanly of the university’s Hotchkiss Brain Institute is leading a study to learn more about the physiological connection between sleep apnea and stroke—specifically, the brain’s blood flow response in people with and without sleep apnea.

For the study, participants with sleep apnea stay overnight in the sleep laboratory at Calgary’s Foothills Medical Centre, where their breathing and cardiovascular responses are continuously monitored while they sleep. The next day, their brain blood flow response to reduced oxygen levels is assessed while they are awake. Then, the participants receive supplemental oxygen during sleep for two weeks, and are tested again to see if their cerebral defense mechanisms have improved. The researchers are also studying people without sleep apnea to see if their cerebral defense mechanisms function better than in those with sleep apnea. Hanly and team’s theory is that it is the lack of oxygen, or hypoxia, that people with sleep apnea experience during sleep that impairs the body’s normal defense mechanisms in the brain. A better understanding of this connection will lead to better prevention and treatment strategies.

I applaud the work of the Alabama and Calgary researchers. It’s time we all wake up to the health benefits of regular, restorative sleep

For more information, read the University of Alabama at Birmingham study, “Under 6 Hours of Sleep Tops Risks for Stroke in a Low-risk Population.”

Is the quality of your sleep making you gain weight?

How many of us would like to lose a few pounds, but look for external ways—outside of our bodies—to lose weight?  Perhaps we should be looking more inward, not only at our personal diet and exercise levels, but the length and level, or phase, of our sleep.

Recently, I read an article in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology. In it, researchers from St. Luke's-Roosevelt Hospital and Columbia University in New York shed some light on the link between our length and phase of sleep, and hunger and weight gain.

The researchers investigated the effects of “sleep architecture” on hunger to determine whether specific stages of sleep—not just the duration of sleep—affect the appetite and food cravings in healthy adults.

What they found is compelling, and cause for further attention: the length of time of sleep, as well as the percentage of overall sleep in different sleep stages, are associated with decreased metabolic rate, increased hunger, and increased intake of calories, specifically from fat and carbohydrates.

For the study, head researcher Ari Shechter and his colleagues studied a random sample of 27 healthy adults between the ages of 30 and 45. The participants underwent two six-day periods of laboratory observation, during which they were slept different lengths of time.

During a "habitual sleep" phase, they were allowed to sleep for nine hours; in the "short sleep" phase, they were allowed just four hours of sleep. Each of the two sleep phase studies were separated by four weeks to make sure the participants fully recuperated, and the women were observed at the same phase of their menstrual cycle. The amount of time spent in each sleep phase—stage 1, stage 2, slow wave sleep (SWS), and REM sleep—was recorded.

For the first four days in both sleep phases, the participants ate meals to meet their energy requirements for weight maintenance. On day four, they rated their hunger and level of desire for different foods. On day five, their resting metabolic rate (RMR) was measured, and for the final two days of the sleep phase studies, the participants were allowed to select their own foods.

The researchers then compared the participants' sleep architectures in both the short sleep and habitual sleep conditions. They also analyzed the relationships between sleep architecture, resting metabolic rate, food intake and food desire ratings.

Shechter and his colleagues found that sleep duration is important, but sleep composition—the time and percentage of overall sleep spent in each stage—also plays an important role in the link between sleep and obesity.

Head researcher Shechter explained, “Any number of various factors like obstructive sleep apnea, certain drugs/medications, chronic exposure to short sleep duration, shift work, jet lag, and changes in the scheduling of the sleep episode, can affect sleep stage quantity and distribution. Our data may provide an explanation for the greater obesity prevalence observed within some of these conditions."

Read the full article, “Changes in Sleep Architecture Increase Hunger, Eating.”
The results of this study remind me of another study I blogged about not long ago on “social jetlag,” another reason for all of us to get more sleep.

Social jetlag is a modern syndrome caused by the discrepancy between our internal body clock and our social clock. And according to Professor Till Roenneberg, Ph.D. at the University of Munich’s Institute of Medical Psychology in Germany, that gap between how much sleep we need and how much we’re actually getting is contributing to our global weight gain and the growing worldwide obesity epidemic.

Each of us has a physiological clock, and that internal clock — also known as our circadian rhythm — is regulated by daylight and darkness to prompt us to go to sleep or wake up. We also have a social clock of things that make up our daily lives, such as our work schedules and social calendars.

The problem is, in our modern society of too-late work hours and too much time in front of computer screens, we are listening to our social clocks more than our physiological clocks, causing a greater sleep gap known as social jetlag. As a person’s circadian rhythm gets more out of whack, their physiological clock gets set later and later, keeping them awake into the night, and feeling chronically tired during the day.

In their study, Professor Roenneberg and his fellow researchers in Munich discovered that people with different weekday and weekend sleep schedules—i.e., those with more social jetlag — were three times more likely to be overweight. That is a significant increase worth repeating: Three times more likely to be overweight!

Furthermore, the body mass index (BMI) of the overweight participants tended to increase as the gap between their weekday and weekend sleep clocks widened.
I applaud the efforts of Roenneberg and his team for their work in particular, because they are bringing a public awareness of a growing syndrome that is affecting many people worldwide — not just shift workers or those with irregular work schedules.

So, why does social jetlag cause weight gain? One of the theories is that late hours encourage irregular meal times and late-night eating, when the body has more difficulty digesting and metabolizing food. That translates into body fat. Another is that chronically tired people are less likely to exercise and more likely to smoke and drink, further contributing to weight gain.

Whatever the causes, it is in all our personal best interests to become more aware of our own physiological clocks and get more restful sleep. Doing so can help us all maintain a healthy body weight, avoid many health problems, feel better and live happier, more productive lives.

So, now that you have this new knowledge about sleep, weight gain, I suggest you give yourself a wonderful personal gift: get more sleep, especially during the holiday season, when many people are overeating and busier than usual. Also spend more time outdoors and exercise. More and better sleep is one of the best gifts you can give yourself for the holidays.

Read Professor Roenneberg and his team’s full report entitled, “Social Jetlag and Obesity,” published in the May 10 issue of Current Biology.