Mais la polymyxine n'est pas du tout absorbée dans le sang du système gastro-intestinal et n'a d'effet que dans l'intestin et est utile pour le traitement des infections intestinales doxycycline prix Internet en y faisant des achats permettant d’économiser jusqu'à soixante-dix pour cent, tout en étant sûr de la qualité des produits pharmaceutiques.
Sports Science Exchange (2013) Vol. 26, No. 113, 1-4
SLEEP AND THE ELITE ATHLETE
Shona L. Halson
| Recovery Center | Australian Institute of Sport | Canberra | Australia
Sleep is essential for athletes, both for preparing for, and recovering from, training and competition.
Sleep disturbances in elite athletes can occur both during training and following competition.
Sub-maximal, prolonged exercise appears to be more affected by sleep deprivation than short, maximal efforts.
Sleep extension and napping can be effective means of enhancing performance in athletes.
Athletes should focus on utilizing good sleep hygiene to improve sleep and potentially athletic performance.
characterised by muscle atonia (lack of normal muscle tension), bursts of rapid eye movement and dreaming. Therefore, REM sleep
Although the function of sleep is not ful y understood, it is general y
is considered an activated brain in a paralyzed body.
accepted that it serves to recover from previous wakefulness and/or prepare for functioning in the subsequent wake period. An individual’s recent sleep history therefore has a marked impact on their daytime functioning. Restricting sleep to less than 6 h per
night for four or more consecutive nights has been shown to impair
cognitive performance and mood (Belenky et al., 2003), disturb
glucose metabolism (Spiegel et al., 1999), appetite regulation
(Spiegel et al., 2004) and immune function (Krueger et al., 2011). This type of evidence has led to the recommendation that adults
should obtain 8 h of sleep per night to prevent neurobehavioual
While there is considerable data available related to the amount of sleep obtained by adults in the general population, there are few
Figure 1. The progression of sleep stages across a single night in a normal
published data related to the amount of sleep obtained by elite
young adult volunteer is illustrated in this sleep histogram. The text describes
athletes. This appears to be a considerable oversight given that
the ideal or average pattern (Carskadon & Dement, 2011).
sleep has been recognized as an essential component of preparation for, and recovery from high-intensity training (Reilly & Edwards, 2007; Robson-Ansley et al., 2009; Samuels, 2008).
Recently it has been hypothesized that sleep and in particular slow-wave sleep (SWS, or deep sleep), is important for recovery in athletes.
SWS consists of stages 3 and 4 of NREM sleep. Evidence in support of this theory includes the synchrony of growth hormone release
with SWS in humans, the suggestion that optimum conditions for
Sleep can be defined as a reversible behavioural state where an
anabolism prevail during sleep, and studies showing SWS duration
individual is perceptually disengaged from and unresponsive to
to be proportional to preceding wakefulness (Shapiro et al., 1981).
the environment (Carskadon & Dement, 2011). Sleep is a complex physiological and behavioural state which has two primary states
Shapiro et al. (1981) investigated sleep prior to and following a 92
based on physiological parameters. These are rapid eye movement
km marathon in six subjects. Results indicated total sleep time
(REM) and non-REM (NREM) stages. An electroencephalogram
increased significantly over control times on each of the four nights
(EEG) where electrodes measure brain electrical activity is used
after the marathon. Wakefulness was greatest on the night of the
to identify the two states (Figure 1). NREM sleep is divided into
marathon, suggested to be related to muscle pain. The percentage
four stages (1-4) and is associated with a progressive increase
of SWS increased on both nights 1 and 2. The quantitative increase
in the depth of sleep (Carskadon & Dement, 2011). REM sleep is
in total sleep time and particularly in SWS and the qualitative shift
Sports Science Exchange (2013) Vol. 26, No. 113, 1-4
toward more stage 4 sleep immediately after metabolic stress
and total volume load and training intensity) following 24 h of sleep
supports the theory that sleep (particularly SWS) is important for
deprivation when compared to no sleep deprivation (Blumert et al.,
2007). However, mood state as assessed by the Profile of Mood States was significantly altered, with confusion, vigour, fatigue and
total mood disturbance all negatively affected by sleep deprivation.
There are two commonly used methods to assess sleep, Actigraphy and Polysomnography. Actigraphy is a non-invasive method of
While much of the research has focused on anaerobic
monitoring sleep and involves wearing wrist activity monitors, which
performance, reductions in endurance running performance
are devices worn like a wristwatch that continuously record body
have been observed following 24 h of sleep deprivation (Oliver
movement (usual y stored in 1-min epochs). Sleep diaries are also
et al., 2009). Interestingly, this occurred without any changes in
collected where participants record the start and end date/time for
physiological parameters and pacing.
all sleep periods (i.e., night-time sleeps and daytime naps). Data from sleep diaries and activity monitors are used to determine when
The mechanism behind the reduced performance following
participants are awake and when they are asleep. Essentially, all
prolonged sustained sleep deprivation is not clear; however, it
time is scored as wake unless (i) the sleep diary indicates that the
has been suggested that an increased perception of effort is one
participant was lying down attempting to sleep, and (ii) the activity
potential cause. While the above studies provide some insight
counts from the monitor are sufficiently low to indicate that the
into the relationship between sleep deprivation and performance,
participant was immobile. When these two conditions are satisfied
most athletes are more likely to experience acute bouts of partial
simultaneously, time is scored as sleep. Actigraphy is useful for
sleep deprivation where sleep is reduced for several hours on
understanding sleep patterns as it is non-invasive and relatively
easy to collect data over significant periods of time (commonly two
A small number of studies have examined the effect of partial sleep
The second method is Polysomnography (PSG) which is a sleep
deprivation on athletic performance. Reilly and Deykin (1983)
study in which body functions such as EEG, eye movements,
reported decrements in a range of psychomotor functions after
muscle activity and cardiac activity are measured. PSG provides
only one night of restricted sleep; however, gross motor function
information on sleep staging and is considered the “gold standard”
such as muscle strength, lung power and endurance running
for assessing sleep quality and quantity. PSG can be expensive
were unaffected. Reilly and Hales (1988) reported similar effects
and is labour intensive and is often used primarily for assessing
in females following partial sleep deprivation, with gross motor
functions being less affected by sleep loss than tasks requiring fast reaction times.
PERFORMANCE EFFECTS OF SLEEP DEPRIVATION AND SLEEP EXTENSION
The effect of 2.5 h of sleep per night over 4 nights was measured in eight swimmers (Sinnerton & Reilly, 1992). No effect of sleep loss was
observed when investigating back and grip strength, lung function
There are a limited number of studies which have examined the
or swimming performance. However, mood state was significantly
effects of sleep deprivation on athletic performance. From the
altered with increases in depression, tension, confusion, fatigue and
available data it appears that several phenomena exist. First, the
sleep deprivation must be greater than 30 h (one complete night of no sleep and remaining awake into the afternoon) to have an
Reilly and Percy (1994) found a significant effect of sleep loss on
impact on anaerobic performance (Skein et al., 2011). Second,
maximal bench press, leg press and dead lifts, but not maximal
aerobic performance may be decreased after only 24 h (Oliver et
bicep curl. Sub-maximal performance however, was significantly
al., 2009) and third, sustained or repeated bouts of exercise are
affected on all four tasks and to a greater degree than maximal
affected to a greater degree than one-off maximal efforts (Blumert
efforts. The greatest impairments were found later in the protocol,
et al., 2007; Reil y & Edwards, 2007). For example, peak power has
suggesting an accumulative effect of fatigue from sleep loss
been shown to be unchanged after 24 h of wake; however, they were
impaired after 36 h without sleep (Souissi et al., 2003). Isokinetic
From the available research it appears that sub-maximal prolonged
performance has also been shown to decrease significantly
tasks may be more affected than maximal efforts, particularly after
following 30 h of sleep deprivation (Bulbulian et al., 1996). Skein
the first two nights of partial sleep deprivation (Reilly & Percy, 1994).
et al. (2011) reported significant decreases in mean and total sprint time following 30 h of sleep deprivation in 10 male team sport
athletes. Blumert and colleagues (2007) examined the effects of 24
Another means of examining the effect of sleep on performance is
h of sleep deprivation in nine U.S. college-level weightlifters in a
to extend the amount of sleep an athlete receives and determine the
randomised counter-balanced design. There were no differences in
effects on subsequent performance. Mah et al. (2011) instructed
any of the performance tasks (snatch, clean and jerk, front squat
Sports Science Exchange (2013) Vol. 26, No. 113, 1-4
six basketball players to obtain as much extra sleep as possible
the morning and 32% reported waking up at night. Factors such as
following two weeks of normal sleep habits. Faster sprint times
thoughts about competition (77%), nervousness about competition
and increased free-throw accuracy were observed at the end of the
(60%), unusual surroundings (29%) and noise in the room (17%)
sleep extension period. Mood was also significantly improved, with
were identified as reasons for poor sleep (Erlacher et al., 2011).
increased vigour and decreased fatigue (Mah et al., 2011). The same research group also increased the sleep time of swimmers to 10 h
Therefore it appears that sleep disturbances in athletes can occur
per night for six to seven weeks and reported that 15 meter sprint,
at two time points: 1) prior to important competitions and 2) during
reaction time, turn time and mood all improved. The data from this
normal training. This sleep disruption during normal training may be
small number of studies suggests that increasing the amount of
due to a poor routine as a consequence of early training sessions,
sleep an athlete receives may significantly enhance performance.
poor sleep habits (i.e., watching television in bed), nocturnal waking to use the bathroom, caffeine use and excessive thinking/worrying/
planning. While not documented in the literature, anecdotal evidence
Athletes suffering from some degree of sleep loss may benefit from
also suggests that athletes such as footbal ers who compete at night
a brief nap, particularly if a training session is to be completed in
also have significant difficulties falling asleep post competition.
the afternoon or evening. Waterhouse et al. (2007) are one of the
only groups to investigate the effects of a lunchtime nap on sprint performance following partial sleep deprivation (4 h of sleep).
Athletes should focus on utilising good sleep hygiene to maximise
Following a 30-minute nap, 20 m sprint performance was increased
sleep. Strategies for good sleep include:
(compared to no nap), alertness was increased and sleepiness was decreased. In terms of cognitive performance, sleep supplementation
The bedroom should be cool, dark and quiet. Eye masks and
in the form of napping has been shown to have a positive influence on
earplugs can be useful, especially during travel.
cognitive tasks (Postolache et al., 2005). Naps can markedly reduce sleepiness and can be beneficial when learning skil s, strategy or
Create a good sleep routine by going to bed at the same time
tactics in sleep-deprived individuals (Postolache et al., 2005).
Napping may be beneficial for athletes who have to routinely wake
Avoid watching television in bed, using the computer in bed
early for training or competition and for athletes who are experiencing
sleep deprivation (Waterhouse et al., 2007).
Avoid caffeine approximately 4-5 h prior to sleep (this may vary among individuals).
According to a 2005 Gallup Poll in the USA, the average self-reported sleep duration of healthy individuals is 6.8 h on weekdays and 7.4
Do not go to bed after consuming too much fluid as it may result
h on weekends (National Sleep Foundation, 2006). However, the
sleep habits of elite athletes have only recently been investigated. Leeder et al (2012) compared the sleep habits of 47 elite athletes
Napping can be useful; however, generally naps should be kept
from Olympic Sports using actigraphy over a four-day period to that
to less than one hour and not too close to bedtime as it may
of age and sex-matched non-sporting controls. The athlete group
had a total time in bed of 8:36 ± 0:53 hr:min, compared to 8:07 ±
0:20 in the control group. Despite the longer time in bed, the athlete group had a longer sleep latency (time to fall asleep) (18.2 ± 16.5
Sleep is extremely important for numerous biological functions
min vs. 5.0 ± 2.5 min), a lower sleep efficiency (estimate of sleep
and sleep deprivation can have significant effects on athletic
quality) than controls (80.6 ± 6.4 % vs. 88.7 ± 3.6 %), resulting in a
performance, especial y sub-maximal, prolonged exercise. From
similar time asleep (6:55 ± 0:43 vs. 7:11 ± 0:25 hr:min). The results
the available evidence it appears that athletes may be obtaining
demonstrated that while athletes had a comparable quantity of sleep
less than 8 h of sleep per night and that increasing sleep (sleep
to controls, significant differences were observed in the quality of
extension) or napping may be useful to increase the total number of
sleep between the two groups (Leeder et al., 2012).
hours of sleep and thereby enhance performance.
While the above data was obtained during a period of normal training without competition, athletes may experience disturbed sleep prior to important competition or games. Erlacher et al. (2011) administered a questionnaire to 632 German athletes to assess possible sleep disturbances prior to competition. Of these athletes, 66% (416) reported that they slept worse than normal at least once prior to an important competition. Of these 416 athletes, 80% reported problems falling asleep, 43% reported waking up early in
Sports Science Exchange (2013) Vol. 26, No. 113, 1-4
Souissi, N., B. Sesboue, A. Gauthier, J. Larue, and D. Davenne (2003). Effects of
one night’s sleep deprivation on anaerobic performance the following day.
Allen, D.G., G.D. Lamb, and H. Westerblad (2008). Skeletal muscle fatigue: cellular
Eur. J. Appl. Physiol.
mechanisms. Physiol. Rev.
Spiegel, K., R. Leproult, and E. Van Cauter (1999). Impact of sleep debt on
Belenky, G., N.J. Wesensten, D.R. Thorne, M.L. Thomas, H.C. Sing, D.P.
metabolic and endocrine function. Lancet
Redmond, M.B. Russo, and T.J. Balkin (2003). Patterns of performance
Spiegel, K., E. Tasali, P. Penev, and E. Van Cauter (2004). Brief communication:
degradation and restoration during sleep restriction and subsequent
Sleep curtailment in healthy young men is associated with decreased leptin
recovery: a sleep dose-response study. J. Sleep Res.
levels, elevated ghrelin levels, and increased hunger and appetite. Ann.
Blumert, P., A.J. Crum, M. Ernsting, J.S. Volek, D.B. Hollander, E.E. Haff, and
G.G. Haff (2007). The acute effects of twenty-four hours of sleep loss on
Van Dongen, H.P., G. Maislin, J.M. Mullington, and D.F. Dinges (2003). The
the performance of national-caliber male collegiate weightlifters. J. Strength
cumulative cost of additional wakefulness: dose-response effects on
neurobehavioral functions and sleep physiology from chronic sleep restriction
Bulbulian, R., J.H. Heaney, C.N. Leake, A.A. Sucec, and N.T. Sjoholm (1996). The
and total sleep deprivation. Sleep
effect of sleep deprivation and exercise load on isokinetic leg strength and
Waterhouse, J., G. Atkinson, B. Edwards, and T. Reilly (2007). The role of a short
endurance. Eur. J. Appl. Physiol. Occup. Physiol.
post-lunch nap in improving cognitive, motor, and sprint performance in
Carskadon, M.A. and W.C. Dement (2011). Normal Human Sleep: An Overview.
participants with partial sleep deprivation. J. Sports Sci.
Principles and Practice of Sleep Medicine.
M.H. Kryger, T. Roth, and W.C.
Erlacher, D., F. Ehrlenspiel, O.A. Adegbesan, and H.G. El-Din (2011). Sleep habits
in German athletes before important competitions or games. J. Sports Sci.
Krueger, J.M., J.A. Majde, and D.M. Rector (2011). Cytokines in immune function
and sleep regulation. Handb. Clin. Neurol.
Leeder, J., M. Glaister, K. Pizzoferro, J. Dawson, and C. Pedlar (2012). Sleep
duration and quality in elite athletes measured using wristwatch actigraphy. J. Sports Sci.
Mah, C.D., K.E. Mah, E.J. Kezirian, and W.C. Dement (2011). The effects of sleep
extension on the athletic performance of collegiate basketball players. Sleep
National Sleep Foundation (2006). Sleep in America - Poll. Washington DC.
Oliver, S.J., R.J. Costa, S.J. Laing, J.L. Bilzon, and N. P. Walsh (2009). One night
of sleep deprivation decreases treadmill endurance performance. Eur. J. Appl. Physiol.
Postolache, T.T., T.M. Hung, R.N. Rosenthal, J.J. Soriano, F. Montes, and J.W.
Stiller (2005). Sports chronobiology consultation: from the lab to the arena. Clin. Sports Med.
Reilly, T., and T. Deykin (1983). Effects of partial sleep loss on subjective states,
psychomotor and physical performance tests. J. Human Mov. Stud.
Reilly, T., and B. Edwards (2007). Altered sleep-wake cycles and physical
performance in athletes. Physiol. Behav.
Reilly, T., and A. Hales (1988). Effects of partial sleep deprivation on performance
measures in females. Contemporary Ergonomics.
E.D. McGraw. London, Taylor and Francis: 509-513.
Reilly, T., and M. Piercy (1994). The effect of partial sleep deprivation on weight-
lifting performance. Ergonomics
Robson-Ansley, P. J., M. Gleeson, and L. Ansley (2009). Fatigue management in
the preparation of Olympic athletes. J. Sports Sci.
Samuels, C. (2008). Sleep, recovery, and performance: the new frontier in high-
performance athletics. Neurol. Clin.
Shapiro, C.M., R. Bortz, D. Mitchell, P. Bartel, and P. Jooste (1981). Slow-wave
sleep: a recovery period after exercise. Science
Sinnerton, S., and T. Reilly (1992). Effects of sleep loss and time of day in
swimmers. Biomechanics and Medicine in Swimming: Swimming Science IV.
D. Maclaren, T. Reilly and A. Lees. London, E and F.N. Spon: 399-405.
Skein, M., R. Duffield, J. Edge, M.J. Short, and T Mundel. (2011). Intermittent-
sprint performance and muscle glycogen after 30 h of sleep deprivation. Med. Sci. Sports Exerc.
Deposits and investments with Deutsche Bank AG are covered by two German protec- tion schemes: 1. Entschädigungseinrichtung deutscher Banken GmbH (EdB), the German pri- vate commercial bank’s statutory compensation scheme for depositors and in- vestors 2. Einlagensicherungsfonds des Bundesverbands deutscher Banken e.V. (BdB), the deposit protection scheme of the German private comm
Terapêutica da dor na cirurgia de cães e gatos: revisão Francisco Lima Silva Catarina Rafaela Alves da Silva Amilton Paulo Raposo Costa RESUMO Procedimentos cirúrgicos realizados em animais são comumente utilizados na prática veterinária, principalmente em procedimentos eletivos, como por exemplo nos casos de esterilizações, devido a seu principal objetivo de controle