Sleep Strategies for Strength, Speed, and Size

TAGS: sleep studies, sleep for recovery, sleep deprivation, physical performance, Greg Potter

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elitefts™ Sunday Edition

In 1964, 17-year-old Randy Gardner set the sleep deprivation world record, clocking 264 hours under the beady eye of Stanford sleep researcher Dr. Dement. His parents must have been so proud. Gardner experienced impaired short-term memory and concentration, hallucinations, paranoia, and deluded behavior. After a couple days of catch-up sleep, Gardner appeared to undergo no further negative consequences of his experiment, as corroborated during multiple sleep analyses.

In this model of acute sleep deprivation, an otherwise healthy, young adult suffered no durable, negative consequences. But is this applicable to the rest of us?

Thirty to 45 percent of the U.S. population exhibits sleep and wakefulness problems (Hossain & Shapiro 2002). In light of this, what are the effects of sleep deprivation, and are there negative effects of insufficient sleep on health and physical performance outcomes? If sleep quality and duration prove to be important, what strategies can we use to optimize sleep?

Why we sleep

Numerous theories exist as to why we sleep, but the exact functions of sleep remain contentious. While most hypotheses hold that sleep serves the same role across mammalian species, few animals have been studied (Siegel 2005).

As sleep is divided into stages, the roles of sleep likely depend upon the stage in question. Non-rapid eye movement (NREM) sleep appears to play a role in the restoration of the nervous system and energy conservation. Rapid eye movement (REM) sleep seems to be important in local brain regeneration and modulating emotions. REM sleep appears to prepare animals for waking behavior; animals awakened from NREM sleep demonstrate impaired sensorimotor function in comparison to those awakened from REM sleep (Horner et al. 1997).

The fact that sleep debt accumulates suggests an essential role of sleep. During sleep deprivation, humans can't perform at high levels for prolonged periods (Binks et al. 1999), and sleep deprivation in flies can cause death more quickly than food deprivation (Rechtschaffen 1998). This observation can discount neither the effect of the stimulus used to prevent sleep nor the fact that sleep deprivation will differentially affect various species.

There is a growing body of evidence that implicates poor sleep in increasing all-cause mortality (Galicchio 2009), blood pressure (Lusardi et al. 1999), insulin resistance (Nedeltcheva et al 2009) and impaired immunity (Cohen et al. 2009). Shift work also has an array of harmful consequences on many health and performance parameters. Consecutive night shifts are associated with a significantly increased risk of accident and injury (Folkard and Tucker 2003). However, a detailed analysis of these effects is beyond the scope of this article, which will now examine the role of sleep in modulating body composition and athletic performance, culminating in how we can improve our sleep.

Sleep and body composition

Early work suggested that sleep deprivation could impact variables associated with body composition. One to two nights of complete sleep deprivation was associated with elevated 24-hour urinary nitrogen excretion (Scrimshaw et al. 1966), which might be expected to impair lean body mass accrual. Sleep deprivation also appears to elicit changes in appetite-related hormones that could influence food intake and body composition. During caloric restriction, sleep deprivation has been associated with increases in the orexigenic hormone, ghrelin, and reductions in the anorexigenic hormone, leptin (Spiegel et al. 2004). Acylated ghrelin has been demonstrated to blunt energy expenditure and increase hunger, food intake, fat mass retention, and hepatic glucose production (Nogueiras et al. 2008). Finally, a single night of complete sleep deprivation has been demonstrated to produce changes in brain activity that could motivate food acquisition in response to food images, independent of blood glucose and pre-scan hunger ratings (Benedict et al. 2012).

In a meta-analysis of 36 studies, Patel and Hu (2008) found that short sleep was strongly associated with current and future obesity in children. Findings among adults were more mixed, with 17 of 23 studies demonstrating independent associations between short sleep duration and obesity. The longitudinal studies examining adults exhibited unanimously unfavorable associations between short sleep duration and future body mass, although this relationship declined with advancing age.

A small study of overweight adults has recently demonstrated that sleep deprivation can impair fat loss at the expense of lean body mass loss (Nedeltcheva et al. 2010). Body composition changes were measured during fourteen days of caloric restriction. Participants were allowed 8.5 or 5.5 hours of sleep opportunity, respectively. After a wash-out period averaging seven months, they returned to experience the same dietary protocol, but this time were assigned to the other sleep condition.

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Sleep deprivation significantly reduced the fraction of body mass lost as fat by 55 percent and significantly increased the loss of lean body mass by 60 percent. Sleep deprivation also produced higher hunger ratings and an increase in respiratory exchange ratio, thereby suggesting impaired fat oxidation. Total energy expenditure was calculated to be virtually identical during the two, fourteen-day periods. However, resting metabolic rate was significantly lower after the sleep-deprived condition.

The authors hypothesized that sleep deprivation during caloric restriction increases ghrelin-modulated changes in hunger, substrate oxidation, and energy metabolism. Sleep deprivation-induced catabolism of lean body mass may be a homeostatic strategy that provides gluconeogenic substrates to support increased needs of the waking brain and other glucose-dependent tissues (Boyle et al. 1994).

Sleep timing also appears to be relevant to body composition. Baron et al. (2011) divided 52 participants according to the time at which they went to bed. One group tended to fall asleep at around 00:30 and the other slept at around 03:45. Total sleep duration between groups was similar. The group that slept later consumed significantly more fast food and calories at dinner. After controlling for sleep timing and sleep duration, higher energy intake after 20:00 was associated with higher body mass indices. To summarize these findings, shorter sleep durations appear to predispose most individuals to future weight gain and curtail fat loss efforts. Falling asleep later is also associated with unfavorable body compositions.

Sleep deprivation and exercise

Increasing sleep opportunity has been shown to improve a number of outcomes related to athletic performance. Four days of sleep extension to ten hours per night reduced daytime sleepiness (Carskadon and Dement 1982), which might be expected to hinder performance. Kamdar and colleagues (2004) also found this as well as faster reaction times and improved moods after sleep extension. However, not all studies support these beneficial effects of sleep extension (Carskadon and Dement 1979).

Restricting sleep to four hours per night for twelve days also appears to reduce optimism and sociability (Haack and Mullington 2005), which is not conducive to positive training environments and also produced significant increases in subjective measures of pain and discomfort, which could further impair motivation.

There is a reciprocal relationship between exercise and sleep. Impaired sleep may hinder exercise performance and training adaptations. Likewise, inappropriate exercise programs may thwart sleep. Intensified training eliciting overreaching or overtraining has been shown to negatively impact sleep in case studies (Halson et al. 2006).

Sleep deprivation and training adaptations

Sleep deprivation has been shown to impair the immune and endocrine systems (Reilly and Edwards 2007), which are crucial to recovery from exercise. Acute sleep deprivation has been shown to lower testosterone and aggression in men (Cote et al. 2012), which could reduce motivation in training and blunt adaptations due to the stimulatory effect of testosterone on muscle protein synthesis. Disrupted sleep has been associated with reductions in resting heart rate and core temperature (Vaara et al. 2009), aerobic capacity, and aerobic enzyme activity (Vondra et al. 2001).

Sleep deprivation and team sport athletes

Sleep deprivation is commonplace in some team sport athletes (Richmond et al. 2004). Sleep deprivation-induced disruption of circadian rhythms has been implicated in the success of NFL teams. Smith et al. (1997) found a consistent pattern of superiority favoring West Coast teams, who tended to win both home games and games on the East Coast. East Coast games were played at night, and West Coast teams had not adjusted to the three-hour time difference between coasts. It probably felt like they were playing games in the late afternoon, which has been suggested as a more optimal time of day for physical performance (Winget et al. 1985).

Ten male team sport athletes endured thirty hours of sleep deprivation during two consecutive day exercise bouts (Skein et al. 2011). On the second day of testing, sleep deprivation worsened mean sprint times during an intermittent sprint protocol and the distance covered during self-paced exercise on the second day. In spite of identical dietary intakes, this was associated with reduced muscle glycogen concentration in comparison to those who had slept normally.

In a study of male collegiate basketball players, Mah et al. (2011) had players maintain their sleeping habits for two to four weeks before a five- to seven-week period where athletes slept as much as possible at night, with the goal of exceeding ten hours. Total sleep duration significantly increased by around 110 minutes, and this was associated with significantly faster timed sprints and reaction times and superior shooting accuracy in free throw and three-point field goal percentages.

However, this study did have its flaws in that sprint times appear to have been taken by hand, and there was neither a control group nor a crossover arm within the study design. As improvements in both daytime sleepiness and mood are evident after sleep extension, independent of pre-existing sleep debt (Carskadon et al. 1986), it may be that these basketball players had not actually accumulated a sleep debt previously but that sleep extension in itself is ergogenic, although this is equivocal.

Sleep deprivation and strength and power training

Research into the effects of sleep deprivation on strength and power training is in its infancy, but some research suggests negative effects. For example, sleep deprivation has been demonstrated to impair sub-maximal strength training performance and increase ratings of perceived exertion (Reilly and Piercy 1994). Napping has also been shown to improve sprinting times and reaction times in the sleep deprived (Waterhouse et al. 2007). Therefore, sleep deprivation appears to negatively affect certain exercise modes and have a mechanistic basis for impairing training adaptations. Actively trying to prolong sleep seems to improve performance in some instances as well.

Sleep recommendations

The National Sleep Foundation provides the following generic recommendations:

  • Ages 1–3 years old, 12–14 hours per night
  • Ages 3–5 years old, 11–13 hours per night
  • Ages 5–10 years old, 10–11 hours per night
  • Ages 10-19 years old, 8.5–9.25 hours of sleep per night
  • Adults, 7–9 hours of sleep per night

There are exceptions to these rules, as truly ‘short sleepers’ do exist. However, even if you believe you are one of them, their prevalence is low enough to suggest that you probably aren’t.

Sleep hygiene: Behavioral strategies to improve sleep

Daytime

  • Manage stress. Numerous options are available including breathing techniques, progressive muscle relaxation, and meditation.
  • Get outside during daylight hours. Exposure to bright light outside will help increase melatonin secretion later in the day, aiding sleep onset. Melatonin exerts other beneficial effects within the body, such as antioxidant activity, that contribute to the beneficial effects of sleep.
  • Exercise early in the day. Strenuous exercise-induced elevations in hormones such as the catecholamines exert stimulatory effects that may hamper sleep. For this reason, avoid exercising too late.
  • Avoid inactivity. A study of 591 children demonstrated that children who were less active during the day took significantly longer to fall asleep. Moreover, the more active children also slept for longer durations (Nixon et al. 2008).

Nighttime

  • Establish a regular nightly routine. Try to go to bed and rise within one-hour from one day to the next.
  • Have a warm bath around one hour before bed. Heat dissipation from the skin of the hands and feet predicts shorter sleep onset duration (Krauchi et al. 1999). Declines in core body temperature facilitate sleep, which ends when it begins rising (Raymann et al. 2005). Increased sleepiness and shortened sleep latencies are evident following warm baths and foot baths, provided that they’ve increased skin temperature (Horne and Reid 1985).
  • Sleep in a cool room to encourage reductions in body temperature. In warm environmental conditions, use a fan or a cool shower. Conversely, if the sleeping environment is too cold, warm up through added clothing or the use of warm blankets.
  • Sleep in a quiet room. ‘White noise,’ such as that created by a fan, can help drown out any unpredictable noise pollution.
  • Sleep on a firm mattress. Poor mattresses may encourage poor sleeping postures that may both be a distraction and compromise musculoskeletal health. If you lie on your side, some find placing a small pillow between the knees more comfortable. Likewise, if you lie on your back, a small pillow beneath the knees may be better than nothing.
  • Minimize light exposure, especially to blue spectrum light, during the hours preceding sleep. Photoreceptors in the eye have been demonstrated to modulate melatonin secretion rhythmicity. This is not evident when the eyes are covered (Dijk et al. 1991). Short wavelength light of around 460 nanometers suppresses melatonin levels most dramatically (Brainard et al. 2001). Shorter wavelength light induces a significantly greater heart rate for twenty minutes after light exposure and increases melatonin suppression, core body temperature, and heart rate (Cajochen et al. 2005).

These effects are related to autonomic nervous system balance, as increased sympathetic nervous system activity would explain these effects. Light elicits a dose-dependent alerting response, and an intensity of just 100 lux will elicit half of the maximum alerting response to light at 9,100 lux over six hours (Cajochen et al. 2000). To put this into perspective, the intensity of light indoors in the home is roughly 200 to 500 lux. At 12:00 p.m. outdoors on a spring day, it may be around 81,000 lux. Therefore, minimize all light in the bedroom, including light from computers, televisions, and alarm clocks. If you need one, choose one that does not emit blue light.

If you use your computer late at night, see if you can alter the brightness settings so as to try and attenuate the effects of light. An online program named f.lux exists that adjusts the computer display color depending on your location and the time of day. If the lights in your home are adjustable, dim the lights progressively over the course of the evening. If you don’t find it distracting, an eye mask can be useful when in bed. If you do, shutters that completely block out light in the bedroom can be a worthwhile investment. Finally, amber-tinted glasses, which block blue light, worn for three hours before bed have shown to improve sleep (Burkhart and Phelps 2009).

  • Embrace ‘paradoxical intention.’ Try closing your eyes and focusing on staying awake. This might quite literally bore you to sleep and is effective in reducing sleep onset latency in individuals with sleep onset difficulties (Ascher and Efran 1978).
  • Read shortly before bed with the caveat that the content isn’t excessively stimulating. If you’re stumped for ideas, I’d strongly recommend Hard Times by Charles Dickens. There may be no better cure for insomnia.
  • Consider using ‘earthing.’ Ober et al. (2000) performed a randomized, four-week study of sixty individuals who had experienced sleep disturbances and chronic pain for at least six months. Participants slept on conductive carbon fiber mattress pads, half of which were connected to the ground outside. The majority of ‘grounded’ subjects experienced pain relief and enhanced sleep. More research is needed into this realm, but early research and anecdotal reports are favorable. For those unwilling to go to such lengths to acquire a mattress, get outside in your bare feet shortly before bed, provided weather permits.

Other considerations

  • Lose weight. Increased adiposity increases the likelihood of sleep apnea.
  • Take a note from behavioral psychology and use your bedroom for sleeping and sex only to avoid associations between the room and not sleeping.
  • Avoid napping during the day unless you are a shift worker. If you must, limit naps to less than 45 minutes and avoid napping beyond the early afternoon.
  • Shift workers should try to keep working hours as invariant as possible, and napping in the face of an accumulating sleep debt has been shown to benefit health in many ways from improved cognition to enhanced reaction time.
  • If you have accumulated a sleep debt during the week and have the opportunity to pay it off at the weekend, do so.

Nutritional strategies to help improve sleep

Pharmacological means of improving poor sleep will not be addressed here in light of their possible side effects, which include altered brain chemistry, constipation, dependence, drowsiness, memory loss, odd sleep walking behavior, and rebound insomnia.

  • The amino acid l-tryptophan is converted to serotonin in the brain, which is a precursor to melatonin. Reductions in plasma tryptophan elicit sleep disturbances (Markus et al. 2005). L-tryptophan ingestion has been demonstrated to reduce sleep onset latency by 45 percent (Hartmann 1982). A high l-tryptophan diet has been demonstrated to reduce ratings of sleepiness and increase task-related brain activity the following day (Markus et al. 2005). Foods rich in l-tryptophan include milk products, meat, eggs, and green, leafy vegetables. Of relevance to athletes, eggs and whole milk products are digested slowly and therefore may supply amino acids over a longer period, attenuating muscle protein degradation during sleep.
  • To produce the same effects as l-tryptophan supplementation, eat a high glycemic index (GI) meal before bed. In a comparison of consumption of isocaloric quantities of high versus low GI rice four hours before bed, sleep onset occurred 48.6 percent sooner in the high GI group (Afaghi et al. 2007). Consuming the high GI meal four hours before bed was superior (with sleep onset occurring 38.3 percent sooner) to consuming the same meal one hour before bed. It is thought that insulin promotes muscle uptake of branched chain amino acids (BCAA), increasing the free l-tryptophan:BCAA ratio (Afaghi, O’Connor and Moi Chow 2007). Insulin could also reduce serum free fatty acid concentrations, reducing l-tryptophan competition for albumin transport. The peak in the free l-tryptophan:BCAA ratio typically occurs two to four hours after meals, suggesting this may be an appropriate time at which to consume the day’s final meal. Work examining the insulin index also demonstrates that some of the amino acids in animal products can be highly insulinogenic. Therefore, if you’re on a low carbohydrate diet, these same effects can probably be achieved through selection of protein sources such as whey.
  • Montmorency tart cherries may help improve sleep courtesy of their melatonin content. A recent randomized, double-blind, placebo-controlled, crossover study that saw participants consume tart cherry juice concentrate for seven days found significant increases in urinary melatonin content, time in bed, and total sleep time (Howatson et al. 2012).
  • Ensure that your final meal is easily digested. Discomfort resulting from gas and bloating is hardly conducive to deep sleep.
  • Do not drink or eat excessively late in the day so as to minimize the likelihood of visiting the bathroom late at night. A survey of sleep habits of Australian athletes found that waking during the night to urinate was a major source of disturbed sleep.
  • Consider supplementing up to 800 milligrams of magnesium glycinate or malate. Begin with lower doses, as higher ones can exert laxative effects. Magnesium supplementation may also attenuate sleep deprivation-induced declines in anaerobic threshold and peak oxygen uptake (Tanabe et al. 1998).

Herbal strategies to improve sleep

  • Patients who had experienced sleep disturbances for at least four weeks (Vorbach et al. 1966) were administered 600 mg valerian ethanol extract daily for 28 days in a double-blind, randomized, controlled trial. By 28 days, the valerian group experienced superior measures of sleep and mood, and other studies have reported reductions in sleep onset latency (Leathwood and Chauffard 1983). Valerian use should not be accompanied by alcohol or barbiturate use, and as with all herbal sedatives, valerian’s use is contraindicated among pregnant or nursing women.
  • German chamomile, which can be consumed as a tea, is a mild sedative. There is a dearth of research on chamomile and sleep, but chamomile tea was found to effectively induce sleep in ten of twelve patients with myocardial issues (Gould et al. 1973).
  • Inhalation of lavender oil has also been shown to improve sleep (Hardy et al. 1995). It should be noted that lavender oil potentiates the sedative effects of other substances including alcohol (Atanassova-Shopova and Roussinov 1970).
  • Kava administration at doses of up to 600 mg has been shown to improve sleep (Emser and Bartylla 1991).

A word on drugs

  • Avoid drugs such as nicotine shortly before bed.
  • Treat caffeine with caution. Caffeine antagonizes adenosine in the brain, which promotes sleep, and increases excitatory neurotransmitter release. In a review paper, Bonnet and Arand (1992) concluded that consuming above 100 mg caffeine within two hours of bed prolongs sleep latency, impairs slow wave sleep, and reduces total sleep duration. Caffeinated coffee produces these same negative effects, which demonstrate a dose-response relationship (Karacan et al. 1976). A single cup of coffee (1.1 mg caffeine per kilogram of body mass) consumed thirty minutes before bed had negligible effects on sleep. Two cups (2.3 mg per kilogram) produced detrimental effects on initial sleep, and four cups (4.6 mg per kilogram) negatively affected all measures of sleep. The negative effects of caffeine appear to be partly due to melatonin secretion (Shilo et al. 2002). Individuals with the lowest habitual caffeine intake demonstrate the greatest impairments in sleep measures in response to caffeine ingestion (Hindmarch et al. 2000).
  • Don’t abuse alcohol. Alcohol is metabolized rapidly and thus exerts different effects across the duration of a bout of sleep. The negative effects of alcohol are dose-dependent. Feige et al. (2006) compared ‘normal’ consumption to alcohol ‘abuse’ (as ordained by blood levels). ‘Normal’ consumption had negligible effects on sleep parameters, but alcohol ‘abuse’ reduced sleep latency, REM sleep, and awakening frequency; suppressed light sleep; and increased slow wave sleep during the early hours of sleep. During subsequent sleep, this dose resulted in an increase in light sleep. Another placebo-controlled study compared the effects of bourbon to vodka (Rosenhow et al. 2010). Participants drank to achieve a breath alcohol level of 0.10 percent (the legal limit for driving in most states in the US is 0.08 percent). Both bourbon and vodka significantly decreased the amount of time that people slept and the proportion of time they spent in REM sleep. Alcohol also increased nighttime awakening and subsequent drowsiness the following day.

Conclusions

Sleep is something that we should all strive to improve if we value our health and performance. Try a few of these recommendations if you struggle to sleep well and you may just be recompensed with a kick-start in body composition and performance progress.

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