Why Nap?

Even though we spend a third of our lives sleeping, scientists are still trying to learn exactly why people need sleep. In animal studies it has been shown that sleep is necessary for survival. For example, while rats normally live for two to three years, those deprived of REM sleep survive only about 5 weeks on average, and rats deprived of all sleep stages live only about 3 weeks. In humans, those who had been deprived of just one night’s sleep were shown to have a reduction in mental exertion. In real life situations, the consequences of being sleep-deprived are grave. Some speculation has linked sleep-deprivation to certain international disasters such as the Exxon Valdez oil-spill, Chernobyl, Three Mile Island and the Challenger shuttle explosion.

Taking this into the gym can mean that the ability to concentrate and focus can become compromised which means less of an effort and intensity in the workout (9). Hopefully it’s not leg day.

Athletes who suffer from sleep-deprivation have been shown to see a decrease in cardiovascular performance (10), that is, their time to exhaustion is quicker. Sleep- deprivation in studies has been shown to occur around 30-72 hours. For an athlete who has a full course-load, studies, mid terms and trains, sleep-deprivation can accumulate very rapidly.

Another study looked at cortisol and performance levels after staying up for an 8-hour period overnight. Performance declined and cortisol levels increased. For someone looking to pack on muscle and increase strength, this is bad news since the main focus is to minimize cortisol release as it’s a catabolic hormone (11).

From a fat loss perspective, sleep deprivation can impair fat loss through a decrease in levels of the satiety hormone leptin, and increases in the hunger hormone ghrelin. According to Dr. Van Cauter a professor of medicine at the university of Chicago, “One of the first consequences of sleeplessness is appetite dysregulation.” “Essentially, the accelerator for hunger [ghrelin] is pushed and the brake for satiety [leptin] is released.” “The leptin levels are screaming ‘More food! More food!’” What this means is that the hormone leptin is responsible for telling the body when it is full. However, with decreased production of this hormone, the body will crave calories (especially in the forms of carbs) even though its requirements have been met. For someone trying to diet, good luck!

Voluntarily sleeping less than 6 hours per night has been associated with an increased incidence of impaired glucose tolerance, according to a cohort analysis of the Sleep Heart Health Study (SHHS) reported in the Archives of Internal Medicine. (12) This may mean that a chronic lack of sleep can impair glucose tolerance, which can make body recomposition a difficult task. Most people have a hard enough time trying to regulate their carbohydrates and time them so that the body metabolizes them efficiently.

So, if you’re getting the required 8 hours of sleep, are you ok? Well, if this sleep is broken up, then its value decreases as the sleep cycle is interrupted. Deep sleep appears to be connected with the release of growth hormones in young adults. Many of the body's cells also show increased production and reduced breakdown of proteins during deep sleep. Since proteins are the building blocks needed for cell growth and for repairing bodily stress (muscle damage from strength training), uninterrupted deep sleep plays an important role in recovery and regeneration of the body.

Finally, adequate sleep and a properly functioning immune system are closely related. Sleep-deprivation compromises the immune system by altering the blood levels of specialized immune cells and important proteins called cytokines. These chemical messengers instruct other immune cells to go into action. As a result of being compromised, greater than normal chances of infections are likely to occur. And we all know that being sick can be a big-set back both in and out of the gym.

The Benefits of Napping

Hopefully, you are beginning to understand why taking a nap just might be beneficial, if you aren’t already snoozing sometime during the day. The question that needs to be answered is: how long do I nap for?

The Center for Applied Cognitive Studies states:

“"Studies show that the length of sleep is not what causes us to be refreshed upon waking. The key factor is the number of complete sleep cycles we enjoy. Each sleep cycle contains five distinct phases, which exhibit different brain- wave patterns. For our purposes, it suffices to say that one sleep cycle lasts an average of 90 minutes: 65 minutes of normal, or non-REM (rapid eye movement), sleep; 20 minutes of REM sleep (in which we dream); and a final 5 minutes of non-REM sleep. The REM sleep phases are shorter during earlier cycles (less than 20 minutes) and longer during later ones (more than 20 minutes). If we were to sleep completely naturally, with no alarm clocks or other sleep disturbances, we would wake up, on the average, after a multiple of 90 minutes--for example, after 4 1/2 hours, 6 hours, 7 1/2 hours, or 9 hours, but not after 7 or 8 hours, which are not multiples of 90 minutes. In the period between cycles we are not actually sleeping: it is a sort of twilight zone from which, if we are not disturbed (by light, cold, a full bladder, noise), we move into another 90-minute cycle. A person who sleeps only four cycles (6 hours) will feel more rested than someone who has slept for 8 to 10 hours but who has not been allowed to complete any one cycle because of being awakened before it was completed.... "

Power naps can be defined as “brief periods of daytime sleep lasting an hour or less.” They should be directed at targeting sleep stages 1 and 2, and take place in the afternoon. Dr. Claudio Stampi's, aka Dr Sleep (one of the worlds foremost sleep researchers), found that afternoon siestas were chockful of slow-wave sleep. The main benefit that is derived from these stages is restoration from mental fatigue or an increase in alertness. During a 10-20 minute nap the brain cells reset their sodium & potassium ratios when the brain is in Theta state. This state of mind is associated with a flow of ideas or a positive mental state. The sodium & potassium levels are involved in osmosis, which is the chemical process that transports chemicals into and out of your brain cells. After an extended period in the Beta state (when the brain is aroused and actively engaged in mental activities, it generates beta waves) the ratio between potassium and sodium is out of balance. This is the main cause of what is known as "mental fatigue". A brief period in Theta (about 5 - 15 minutes) can restore the ratio to normal resulting in mental refreshment. Stampi says, "Sleep charges your battery more at the beginning of the sleep cycle than at the end."