Football's Secret Sports Science: The Power of Sleep

Sleep could be the next frontier of sports science, with Europe’s top-flight teams turning to experts to recharge their multimillion-pound assets and gain a competitive advantage on the field. As reported by Mark Bailey of the Telegraph, teams such as Manchester United, Chelsea and Real Madrid are recruiting "sleep coaches" to help their players snooze better.

Why? Because, as Bailey put it, "Despite the boom in sports science services designed to improve every component of an athlete’s life, from nutrition and hydration to psychological wellbeing and physical conditioning, sleep is a subject which has often been neglected."

Studies published in the World Journal of Biological Psychiatry agree, stating, "Sleep is crucial for psychological functioning and daily performance."

Which is why teams are investing heavily in things like sleep kits, personalised mattresses, daily wellbeing questionnaires on smartphones and tablets and, according to the Guardian, even "snoozeboxes" and "sleep pods," which players can use to rest between training sessions.

The Daily Mail even cited the work of sleep coach Nick Littlehales as being partly responsible for the extended career of Ryan Giggs, saying "natural ability, a rigid conditioning programme and regular yoga" all helped, but it was the Manchester United legend's willingness to learn about his nocturnal activity that may have played a key role.

So what are the benefits of a good night’s sleep? Can having an expert invade your bedroom make that much of a difference? Finally, if all of the above does work, which players are embracing it, and what methods are they using to wield its power?

The Science of Sleep in Sport

Studies show sleep can impact everything from mental focus to energy and recovery. This is because, contrary to popular belief, players don't get fitter on the training ground. No, training merely provides the body with the necessary stimulus. It’s the period players spend sleeping when the body recovers and adapts, becoming faster and stronger.

That's because your immune system—the body’s defence mechanism that stops us becoming ill—recuperates. Your rejuvenating hormones, like human growth hormone (HGH), begin to naturally peak. Your muscles, tendons and ligaments repair and regrow. Even neurotransmitters—the chemical signals in the brain—are replenished.

But it appears the above is already known and being practiced in sports like basketball after Stanford University analysed the impact sleeping 10 hours a night had on athletes' performance after five to seven weeks. The players had only been sleeping six to nine hours previously, and what the study found was that their performance dramatically improved.

Not just a little, either.

"Shooting accuracy improved, with free-throw percentage increasing by 9.0 percent and three-point field goal percentage increasing by 9.2 percent ... Subjects also reported improved overall ratings of physical and mental wellbeing during practices and games."

The conclusion?

"Improvements in specific measures of basketball performance after sleep extension indicate that optimal sleep is likely beneficial in reaching peak athletic performance."

Could this be the secret to LeBron James' decorated career? Maybe, as ESPN.com reports he sleeps, "an average of 12 hours per day, compared to about seven hours for the average American."

Where does this nocturnal magic come from? According to research published in Frontiers in Systems Neuroscience, it’s closely related to our previously mentioned neurotransmitters.

Neurotransmitters are the chemicals that relay signals from a neuron to a target cell across a synapse within the body. Pretty much every function within the body is controlled (or impacted) by neurotransmitters, from emotional states to mental performance and our perception of fatigue and pain. They’re the brain’s little messengers, and if they’re not working correctly due to lack of sleep, you can’t expect to be effective come matchday.

Obviously, it’s hard to quantify just how much of an impact lack of sleep has on players, but there’s strong evidence to suggest it’s amplified when battling jet lag resulting from long-haul flights. Jet lag is a term used to refer to the disruption of circadian rhythms—our 24-hour physiological body clock that determines when hormones peak and dip—which can cause extreme fatigue.

Of particular importance during the 2014 FIFA World Cup in Brazil, research published in the Journal of Science and Medicine in Sport monitored the impact travelling 14,695 kilometers across 11 time zones had on players. It found through self-reporting questionnaires that, "Sleep disruption during and following long-haul air travel, together with exacerbated jet-lag symptoms may result in reduced player wellness. Consequently, player preparedness for subsequent training and competition may be impeded."

This is why the Daily Mail reported that England invested heavily in "support staff, hi-tech training facilities and luxury accommodation" during their 2014 World Cup campaign.

This was after their previous Brazilian World Cup in 1950 went down as "an object lesson in how not to win the World Cup" after the team arrived following a 31-hour flight, during which they made just four stops to refuel.

It’s also why the Daily Mail reported club managers were frustrated with the amount of distance their players had to travel during a fortnight of international fixtures. Most notably, Filipe Luis, Oscar and Willian—who all played for Chelsea at the time—and Liverpool's Philippe Coutinho travelled a total of 14,600 miles to compete with Brazil in Singapore, and Arsenal's Alexis Sanchez made a 14,500-mile round-trip journey to play for Chile in his home country.

Although articles—like that published in The Sun—that compare Arsenal and Bayern Munich’s travel habits might seem trivial, they could play a key role in the team’s success. All because in a sport where the difference between winning and losing is so small, the difference could be a business class flight compared to a premium economy one.

Train Hard, Sleep Hard

So why is sleep so important after periods of intense training?

The answer is complex—and sports science is still trying to understand the intricacies of it—but the short answer is because this is the time your body uses to repair, recover and regrow.

During a match, the body's oxygen usage skyrockets, and there is a dramatic increase in lactic acid accumulation in the muscles (that burning sensation you get as you tire). This, in turn, causes the body to pull alkaline reserves from bones and other mineral-dense sources.

Equally, tiny micro-tears are formed in the muscles when a person lifts weights, and the body’s molecular form of energy, adenosine triphosphate, is exhausted.

Needless to say, the human body has a lot to cope with, and the more miles a player covers on the pitch, the more sleep they will need. According to The Sun, this means Jurgen Klopp's Liverpool should have slept like babies over the Christmas period after totalling 464.8 kilometers in their first four matches, an average of 116.2 kilometers a match.

It is an idea supported by scientists from the University of Toronto who monitored the sleep patterns of six runners following a 92-kilometer ultramarathon. Results showed sleep time for each runner increased significantly compared to normal sleep patterns on each of the four nights after the marathon, illustrating the body’s desperate need for quality sleep to recover.

Using an electroencephalogram (EEG), which utilizes electrodes to measure electrical activity in the brain, they specifically found long periods of "deep sleep" were induced on the first two nights. This led researchers to conclude this objective and quantitative increase in total sleep time, and particularly deep sleep, supports the theory that it’s incredibly important for optimal recovery in athletes.

Again, reasons for this are incredibly complex, but one is that HGH peaks during deep sleep. HGH is a peptide hormone that stimulates cell reproduction, cell regeneration, growth and recovery and is thus one of the most revitalizing hormones in the body. So if a coach suspects his players are running on tired legs during the season, he should pay close attention to research published in the Journal of Clinical Investigation, which noted as far back as 1968 that, "sleep results in a major peak of growth hormone secretion."

Based on this, the 30 inflatable, portable sleep rooms called Snoozy pods that Swansea City’s head of sports science and fitness bought now seem like a pretty good idea. The Telegraph reported, "Each Snoozy pod comes with a double or twin bed and can be erected in just eight minutes."

But even putting "sleeping pods," snoozing experts and state-of-the-art facilities to one side, sleep represents a powerful tool available to each and every team. From the Sunday league amateur ranks to the top flight of the Premier League, it could be the most cost-effective secret to sporting success.

All quotes and information obtained firsthand unless otherwise indicated.