When should I exercise to sleep? (6/17/11)
Is Morning or Evening Exercise Better?
Exercise has multiple, generally positive effects. You can exercise to regenerate brain cells; to improve mental acuity; to control weight; to improve memory; to look younger and fitter. Some argue regular exercise can add about six to seven years to the average lifespan. The “best” times for these different actions, however, is not so easy to specify.
First, actions like eating, sleeping, resting, socializing, as well as the environment, powerfully affect one another. So changing the “exercise” part of the equation means looking at how physical activity – which researchers now realize includes standing and fidgeting – affects lots of other variables. For example, people metabolize a meal much more efficiently in the morning than the evening – which changes the results of exercise, too.
Then there’s what body clocks do. Some people are morning people, some people are night people. “Larks” and “owls” have different metabolisms, different job interests, and different abilities to adjust to our Lark Work World. Getting someone to exercise at 7 AM if they’re a lark is generally “no sweat”; getting an owl to do the same thing can be ghastly, equivalent to having many work out at 4 AM, the performance nadir point for much of the population.
And then we come to sleep.
A Brief History of Exercise Timing and Sleep
Though lots of people know the benefits of exercise, many, many people want to sleep better. Starting in the 1970’s, Professor Jim Horne at Loughborough University looked at exercise and sleep.
His first conclusion was that exercising – running on a track – worked best to aid sleep if done about 4-6 hours prior to bed time. The sense was that exercise somehow changed the temperature “trigger” on the sleep gate which told us to get to bed.
Horne tested this ideaby running his regular folks and more training athletes on the same track, and then having some pass at intervals through a cold shower. The sleep “inducing” exercise effect seemed to disappear when people got cooled by the shower.
Later studies by Janet Mullington showed an effect of hot baths, with a direct drug response curve – it appeared that the body’s quick cooling after the bath tends to send a signal to the brain to “go ahead and sleep.”
Others found that 4-6 hours prior to sleep was too long a time interval. Later it was discovered that professional athletes could work out right before sleep and fall asleep very quickly – unlike much of the rest of the population, which found themselves “energized” and kept up an hour or two by exercising close to bedtime.
Soon other studies, especially in older women, showed morning exercise aided sleep.
So now we come to the newest data, from Appalachian State (http://www.medicalnewstoday.com/releases/227554.php.)
Morning Exercise for Sleep
The latest study was done with healthy undergraduates. They exercised at 7 AM, 1 PM, or 7 PM, and then later went in for the night to the sleep lab.
Those who exercised in the morning demonstrated more sleep and particularly more deep sleep. The effects of later exercise were not so profound.
Is this study definitive? No. The sample size is small, the issue of body clocks not fully dealt with, the time of study short.
Yet it fits with other results. Morning exercise, many hours before Jim Horne’s students exercised to aid sleep, seems to do a somewhat better job.
It also fits with some things we know about body clocks. Morning light and morning exercise both reset circadian rhythms. Time rules life. Getting your body clocks in synch can be very helpful.
And morning represents the period after our great rest time – sleep. When we wake we are preparing for the day with higher steroid levels, greater platelet stickiness, increasing blood pressure. These effects appear to be heightened by morning exercise. Add morning light, with its improvement of mood and ability to set basic body rhythms, and morning exercise may be the ticket to improve sleep for many.
Other Exercise for Sleep
But physical activity itself appears helpful to health. Recent surveys put 43% of American adults as doing no exercise at all during an average day. Sitting is a risk factor for mortality. Much of the population, even the young population, hardly moves.
And people who are fitter sleep better. They have better moods. They feel, and are, more productive.
Plus, there are many other ways of learning how to sleep. And for people suffering from restless legs and leg kicks, the latter of which may afflict the majority of people over 65, evening exercise can prove even more helpful.
Move when you can – wherever you can. But morning exercise in morning light may be a bit more efficient in helping you sleep through the night.
Rest, sleep, Sarasota Sleep Doctor, well-being, regeneration, longevity, body clocks, insomnia, sleep disorders, the rest doctor, matthew edlund, the power of rest, the body clock, psychology today, huffington post, redbook, longboat key news