By Allison Bond
NEW YORK (Reuters Health) - Couch potatoes looking for a reason to forgo working out in the evening may no longer be able to use difficulty sleeping afterward as an excuse, according to a recent study.
Researchers found that people who exercised in the evening reported sleeping just as well as those who weren't active in the hours before bed. People who worked out in the morning reported getting the best sleep, on average.
"Sleep recommendations suggest avoiding exercise prior to bed," said Matthew Buman, lead author of the study from Arizona State University in Phoenix. "We found evidence to the contrary suggesting that individuals need not avoid exercise at night."
He and his colleagues analyzed responses collected from 1,000 adults participating in the 2013 National Sleep Foundation Sleep in America Poll. The telephone- and web-based questionnaire asked participants how well they felt they slept, how long they slept each night, how much time it took them to fall asleep, and whether they felt refreshed after waking up in the morning.
The poll also asked participants about their exercise habits, such as whether they worked out regularly and, if so, whether they were active in the morning, afternoon or evening. Evening was considered to be within four hours of going to sleep.
Based on the types of physical activity participants performed regularly, like tai chi, running or yard work, workouts were categorized by intensity as light, moderate or vigorous.
People who exercised vigorously in the morning were 88 percent more likely to report good sleep quality than non-exercisers and 44 percent less likely to say they woke up feeling unrefreshed.
Moderate-intensity morning exercisers were 53 percent more likely to say they slept well overall, compared to people who didn't exercise.
There was no difference in any of the sleep measures between moderate or vigorous evening exercisers and non-exercisers, according to findings published in the journal Sleep Medicine.
Experts said the study's poll-based methods may not necessarily be the most accurate gauge of sleep quality, however.
"As strange as it may seem, self-reported sleep - whether good or bad - is not a very reliable indicator of what's actually happening by objective measures with a person's sleep," Dr. Matt Bianchi said. He directs the sleep laboratory at Massachusetts General Hospital in Boston and was not involved in the new study.
"For example, only half of people with sleep apnea will feel sleepy or non-refreshed about their sleep - and sleep apnea is a fairly dramatic kind of sleep problem. I take with a grain of salt any ‘survey'-based studies such as this one," Bianchi said.
Although the National Sleep Foundation's sleep hygiene recommendations don't preclude pre-bedtime workouts, they do advise sticking to relaxing exercises, such as yoga, in the evening hours.
Researchers said the online or printed resources to which some doctors direct patients advise against evening workouts.
"Generally, physicians do have patients get a sleep hygiene resource, and often not exercising close to bedtime will be on there," said Dr. James Mojica, director of the Spaulding Sleep Center in Cambridge, Massachusetts. Mojica, who is also a sleep specialist at Massachusetts General Hospital, was not involved in the study.
Representatives from the National Sleep Foundation were not available for comment.
It's important to remember that sleep is different for each person; what helps one person's slumber may lead to insomnia in someone else, researchers said.
"Sleep hygiene recommendations are just that - things that might work in general. They are not written in stone," Bianchi told Reuters Health. He recommends people who are having trouble sleeping be "thoughtful and introspective about finding patterns in their own lives."
"Each patient may find by trial and error the best combination of things to do or to avoid," he said.
SOURCE: bit.ly/1mFfirQ Sleep Medicine, online February 10, 2014.