Wednesday, December 21, 2011
Sleep: Is it Worth it?
When you have a family, a full-time job, church duties and other obligations (such as a blog to maintain) sometimes finding time to train can be difficult. So many, maybe even most, of us make up the time by getting up early so as not to interfere with these commitments in the evening.
It makes sense - when you don't have time, you just make time and sleep time is the easiest to steal it from. But recently studies have shown that people who sleep less tend to weigh more - more precisely, they tend to eat more. As a matter of fact, in one study the subjects who got only four hours of sleep ate 22% more calories the next day than those who who slept for eight hours.
So now we have a dilemma. You can get up early, but the price you pay is an extra 22% calories ingested later in the day. But if you don't get up early, you might get caught up in the events of the day, get overwhelmed with commitments and end up skipping your workout - but you didn't take in any extra calories.
The optimal solution is finding a time of day that wasn't before dawn and doesn't interfere with your other obligations or your bedtime - because staying up late is just as harmful as getting up early. I suppose that using your lunchtime to run can help, but how much of a workout are you getting in those 40 minutes?
Let's take another look at the numbers. By reducing your sleep from eight to four hours you take in 22% more calories. But why would you reduce your sleep time by four hours? You're probably not looking for more than a 90 minute workout. You're taking a shower anyways, so your looking at waking up less than two hours earlier. So...22% more calories maybe looks a little more like 11% (assuming that the relationship is linear). 11% more calories on top of say, 3,000 calories - which is probably more than you take in. That's an extra 330 calories per day. But you're putting in a 90-minute workout. We could use the conservative number of nine-minute miles at 100 calories per mile. That's 1,000 calories you've burned.
So, if you get up two hours early for a ten-mile run you should net 670 calories less than a day when you don't get up early to run. Is sleep worth it? Not by my calculations!