The Physiology of Naps and the Impact on Athletic Performance

Posted by Shelley Harper on May 22, 2017 9:43:00 AM

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Nap time

Whether you incorporate naps into your daily routine or choose to opt for them when you are overly exhausted, naps can have a profound affect on alertness and performance. But when should you nap and for how long? The answers to these questions depend on the individual, and the following will help you determine the perfect nap in terms of time and length that is best for you.

First off, what are the benefits to napping during the day? There are many studies on this topic, one of which found that motor memories are enhanced through daytime naps. Motor memory is extremely important in sport when trying to learn a new skill or technique to better one’s performance. A simple nap can help facilitate the learning of this new skill. Other benefits include improved alertness and performance immediately upon arising from short naps (20min or less) and are seen after the body adjusts from waking after a longer nap. Naps can be extremely beneficial to the tired athlete at the right time and place.

Physiology of Sleep

"Sleep is the time when the body recovers from the stresses loaded upon it, and the repair of muscle and connective tissue begins. Naps are an excellent tool for athletes in training and on game day as well." - Dan McCarthy, High Performance Consultant at USA Swimming

There are four non-REM (rapid eye movement) stages of sleep. Stage 1 is a drowsy period as you are falling asleep. This is followed by stage 2 (light sleep), stage 3 (moderate-deep sleep) and finally stage 4 (deepest level of sleep). Typically in a 20-minute nap you will reach stage 2, allowing you to enjoy the restorative benefits of sleep, without entering stage 3 or 4. These stages are hard to awaken from and may leave you feeling drowsy or even more tired than you were before your nap.

Lengths of naps have different benefits and drawbacks. In one study the benefits of 5-minute, 10-minute, 20-minute and 30-minute naps were compared. Results showed that a 10-minute nap provided immediate improvements in fatigue, vigor and cognitive performance, as it was not long enough to cause sleep inertia consequences. Sleep inertia is defined as feelings of sleepiness, disorientation and/or confusion after awaking from sleep. Analysis of this study found that a nap longer than 20 minutes resulted in immediate sleep inertia effects, but after this adjustment occurred, the longer nap yielded longer lasting benefits.

These discoveries are important in timing of naps for athletes. As an example, if you take a 30-minute nap within 30 minutes of a race, your body may still be in a state of sleep inertia and thus performance will be sub maximal. The last part of this blog will now explore the different types of naps that you can use to attempt to improve performance.

 

Different Types of Naps

There are a few main types of naps that can all be beneficial to performance. The commonly used term “power nap” generally refers to a nap around 20 minutes that is quick and has restorative benefits without symptoms of sleep inertia (drowsiness upon awakening). The next take on a power nap is called a caffeine nap. This includes consuming caffeine and immediately taking a 15-min power nap. Caffeine takes between 20 and 30 minutes to kick in, and thus you trick your body into resting and having the caffeine kick in upon your waking from your power nap. Studies show a reduction in sleepiness after these so called “caffeine naps”. Lastly, longer naps (>30min and closer to 60min) are put in a different category as the longer duration allows the sleeper to enter deep-sleep stages 3 and 4. However, these longer naps result in reduced performance immediately upon awakening due to sleep inertia (a decline in motor dexterity and a feeling of grogginess).

 


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Environmental Factor

Before you go take your afternoon nap, it is important to recognize the importance of external environments’ role in sleep. When an individual’s body is preparing for sleep, their internal temperature drops, explaining why sleeping in extreme heat or cold (external environment) can be difficult. Daylight is the main external cue that affects sleep, thus when taking a nap one should consider both temperature and lighting to best achieve a regenerative rest. It is important that athletes are educated in the physiological factors that affect sleep quality, helping guarantee that an afternoon nap will be beneficial to their performance. Try out different types of naps using the previous tips and find what works specifically for you. Happy napping!

 

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References:

 

  • RANEL VENTER, M Sport Sci Lecturer, Department of Sport Science, Stellenbosch University
  • Brooks A; Lack L. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? SLEEP 2006;29(6):831-840.
  • http://www.usaswimming.org/ViewNewsArticle.aspx?TabId=0&itemid=5631&mid=8712
  • Nishida M, Walker MP (2007) Daytime Naps, Motor Memory Consolidation and Regionally Specific Sleep Spindles. PLoS ONE 2(4): e341. doi:10.1371/journal.pone.0000341
  • Purves D, Augustine GJ, Fitzpatrick D, et al., editors. Sunderland (MA): Neuroscience. 2nd edition. Sinauer Associates; 2001.
  • Reyner and Horne (1997) . Suppression of sleepiness in drivers: combination of caffeine with a short nap. Psychophysiology. 1997 Nov;34(6):721-5.



 

Topics: Competition, Sleep