This is the column that those of you who love your sleep have been waiting for.
Recently, the importance of sleep has had a bit of renaissance. Huffington Post founder Arianna Huffington wrote a book called The Sleep Revolution, corporate offices have invested in nap spaces and new technology offers numerous ways to track your sleep patterns. Sleep is in, so does the science support the recent hype?
Nearly 30% of Americans sleep less than six hours a night, a tenfold increase from 50 years ago. That’s not good, as low amounts of sleep have been associated with a higher risk of mortality, increased chronic diseases and poorer exercise performance. While scientists can’t give specific recommendations, eight hours of sleep a night is sufficient for most people.
Conversely, to study the effects of a lack of sleep, researchers typically use one of two different protocols: 24 hours of no sleep and multiple days of less than six hours of sleep. Unfortunately, studies specifically done on ultrarunners are lacking; however, the existing data makes a compelling case that sleep can aid or hinder athletic performance. For instance, subjects who do not sleep for 24 hours have poor working memory, decreased motor performance, poor decision-making and response inhibition, all of which cause a reduction in cognitive performance and are associated with decreased physical performance. Exactly how the lack of sleep and psychological factors interact is not entirely clear. How the lack of sleep alters specific physiological aspects of performance is more straightforward.
Interestingly, it seems that the lack of sleep affects some physiological systems more than others. High intensity short exercise bouts, typically referred to as anaerobic exercise, are not affected by sleep deprivation. Whether looking at the ability to cycle all-out for 30 seconds or at weight lifting performance, sleep deprivation (up to 60 hours) is not detrimental. Conversely, subjects who haven’t slept for 24 hours typically have worsened aerobic performance, which is more relevant to ultrarunners. The decrease is significant, with most studies finding about a 10% shorter time to exhaustion during an exercise test following a single night of no sleep. The effects of chronic sleep deprivation on exercise performance are less well characterized, but several potential mechanisms exist to suggest negative consequences, including alterations in hormone levels, glucose metabolism and appetite.
Less sleep is bad for you. Is more sleep better? Can a nap or an earlier bedtime translate to better performance on the trails?
In those who are sleep deprived, the nap has restorative superpowers. In one study, athletes were forced to sleep for only four hours. Subjects were randomly assigned to either take a 30-minute nap or stay up. Subjects who napped did better on both physiological and psychological testing, improving sprint times, overall mood and reaction times. Similar data from case studies supports the notion that sleep deprived athletes show large improvements in mood and physical performance after naps. In practice, runners may want to plan strategic naps to recharge for difficult sections of a course, or for a mental boost to help reach the finish line during events lasting more than 24 hours.
What about everyday sleep? Is there an advantage to forcing yourself to spend a little more time in bed? Again, we don’t have research about ultrarunners, but we do have some convincing initial studies in other athletes. Mah and colleagues found that after 5-7 weeks of forcing the Stanford basketball team to sleep more than 10 hours a night, psychological and physiological performance was improved in areas such as free throw shooting, sprint times and psychological well-being. Importantly, the players perceived that practices and competition went better and thought of themselves as better players. Ultrarunners may also use habitual extended sleep to feel like a workout went well, or feel as prepared as possible for an upcoming race.
In summary, while much of the science on sleep is not specific to ultrarunners, the data does suggest that more daily sleep, and possibly napping during long events, is beneficial, while not at all likely to be detrimental. The data consistently shows that a lack of sleep leads to poor performance in skill-based activities, which is reversed by naps or more daily sleep. Ultrarunning certainly has a skill component: jumping over rocks, looking for ideal foot placements and skillfully navigating all of the food and injury aspects of race management. Many times we cannot control how much sleep we get, due to early start times or long events, but preparing in a way that allows full mental and physical restoration is in our control by sleeping more than adequate amounts. Sleep away, and let more time in bed lead to less time on the trail come race day.
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