Friday, September 24, 2010
Friday, August 27, 2010
Sleep more to weigh less?
It’s amazing that something we spend ⅓ of our lives doing is something that doesn’t even get a second thought. Sleep gets no respect these days. Most people have decided that sleep is replaceable with a few cups of coffee in the morning and a 5-hour energy with lunch. It’s not that we don’t want to sleep, it's that our hectic lifestyles get in the way. Sleep is universally enjoyable, but for whatever reasons we aren’t doing enough of it.
Historically, humans slept in sync with the rising and falling of the sun. As a result, the human genome is not adapted to the erratic sleeping patterns that are shaped by our hectic lifestyles. Even those that make time to get sufficient sleep often have trouble falling or staying asleep due to multiv-variate problems such as poor sleep hygeine, chronic stress, anxiety, medications or sleep disorders such as obstructive sleep apnea.
When it comes to the actual act of sleeping the prescription is pretty straightforward; get 7-9 hours of sleep every night. Numerous scientific studies have found that the optimal range for sleep in adults is between 7-9 hours daily. When we deviate from this prescription on a regular basis the chances of morbidities are greatly increased.
The most prominent issue surrounding sleep today is sleep deprivation, not sleep excess. You don’t have to be a genius to realize that what the studies conclude about sleep restriction is true; we’ve all been there. Sleep restriction decreases performance; both cognitive and physical across broad performance domains. Worse, sleeping less than 7 hours is repeatedly linked to a suppressed immune system, obesity, high blood pressure, depression, suicide, metabolic syndrome and insulin resistance among other morbidities.
In addition to increasing chances of insulin resistance, sleep deprivation has been linked to increases in a hormone called ghrelin. Ghrelin stimulates hunger and specifically cravings for carbohydrates. As if this wasn't problematic enough, ghrelin decreases concentrations of the hormone leptin. Leptin antagonistically reduces hunger and carbohydrate cravings providing a feeling of satiety (no wonder why poor sleep is linked to obesity).
So what is the moral of the story? Focus on getting enough sleep. Adequate sleep will promote a more advantageous hormonal profile that will keep body fat low. And as always, avoid insulin resistance like the plague.