I recently read a 2015
review article published in Sports Medicine, titled "Sleep and
Athletic Performance: The Effects of Sleep Loss on Exercise Performance,
and Physiological and Cognitive Responses to Exercise.”
Below I provide a
summary of the authors’ main points, followed by my 2 cents (interpretation of
the results) from a coach’s perspective.
Authors’ main points:
Although sleep is
considered critical to optimal performance, many athletes appear to lose
sleep prior to competition for various reasons, including noise,
light, anxiety, and nervousness. While there appears
sufficient evidence to imply complete sleep deprivation can have
significant negative effects on athletic performance, the effects of sleep
restriction (partial disturbance of the sleep–wake cycle) are more
conflicting; a concerning issue given that athletes are more likely to
experience this mode of sleep loss. The detrimental effect of sleep
loss on most aspects of cognitive function remains unequivocal, with only
minor conflicting findings present for the extent of the effects of mild
sleep restriction, findings that would predictably suggest negative
consequences for athletes requiring high neurocognitive reliance.
Much of the previous
research has reported that exercise performance is negatively affected
following sleep loss; however, conflicting findings mean that the
extent, influence, and mechanisms of sleep loss affecting exercise
performance remain uncertain. For instance, research indicates some
maximal physical efforts and gross motor performances can
be maintained. In comparison, the few published studies investigating
the effect of sleep loss on performance in athletes report a
reduction in sport-specific performance. The effects of sleep loss on
physiological responses to exercise also remain equivocal; however,
it appears a reduction in sleep quality and quantity could result in an
autonomic nervous system imbalance, simulating symptoms of the
overtraining syndrome. Additionally, increases in pro-inflammatory
cytokines following sleep loss could promote immune system dysfunction.
My 2 cents:
For those who read the fine print of this review article and saw that the several studies
that showed a decrease in performance were mostly in maximal power output
(i.e., 30-sec Wingate/cycling test), I would ask them to raise their hand
if that is a meaningful carryover into their own training (answer: most likely
not). Sleep deprivation (SD) vs. sleep restriction
(SR) is where the other significant findings of the article are contained, but
I also don’t think any of local amateur athletes are facing actual sleep deprivation.
In short, if it’s the night before a race and you don’t get much
sleep, then don’t worry about it, especially since there are very little (if at
all) cognitive aspects of endurance events, whereas team-sport athletes might
have other considerations depending on their position/demands, but even then
the results are mixed with no need to sound an alarm.
It’s important to note
that the article points out that physiological measures don’t always show
adverse effects from SR, so the authors postulate that central fatigue (as
in central nervous system fatigue/ self-talk) is most likely the mechanism,
especially if you factor that perceived exertion (effort) was diminished in
some studies. In other words, if the athlete believes that the sleep
restriction is going to have an adverse effect, then he/she might be
likely to create a self-fulfilling prophecy! Get the idea out of your
head, and do so with confidence, as the empirical evidence supports that
short-term SR likely won’t affect your endurance the following day.
Chronic sleep restriction is a separate issue not
addressed by this article, and I think we would all agree that at that
point there are going to be performance detriments (even with just a few days),
along with an increased chance for injury (i.e., relationship between
chronic muscular fatigue and injury). I can empathize with any athlete who doesn't get a solid night of sleep the night before a big game/race, but what’s probably more important is the sleep you get two and three nights before a significant effort.
Train hard!
Mike
