‘Sleep-deprived workers cost £0 billion a year in lost productivity’ (Independent). ‘People who sleep less than six hours are four times more likely to catch a cold’ (Telegraph). ‘Brits tend to sleep naked’ (Daily Mail). OK, forget that last one, but it seems hardly a day goes by without the media claiming that our lack of shuteye has reached epidemic levels. And while British newspapers rarely shy from hyperbole, this time the stats back the headlines: recent research by Aviva Health found that we Brits are some of the worst sleepers on the planet, with 37 per cent of us reporting insufficient rest. (The top nations when it comes to sleep are India and China.) What’s more, things are seemingly getting worse. According to the latest figures from the Sleep Council, the average Brit now gets just six and a half hours sleep a night, with over a third of us snatching just five to six hours – a seven per cent rise on the numbers in that group three years earlier. Increased use of smartphones , social media, emails and texting have eaten into our sleep time. And as this is when most of our physical and mental recovery takes place, it’s of particular concern to runners.
‘Insufficient sleep, especially over a period of time, results in decreased speed and power output,’ says Shona Halson, senior recovery physiologist at the Australian Institute of Sport and one of the world’s leading experts on sleep in athletes. Halson has worked with elite runners, the pro cycle team Orica-Scott and many world-class swimmers, including Rio gold medallists Kyle Chalmers and Bronte Campbell. ‘It also leads to reduced reaction times, compromises your immune system and is detrimental to cognitive ability, which is important when it comes to factors like pacing,’ says Halson.
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When Halson evaluated the sleep of athletes for the 12 days before – and then during – a six-day netball tournament, she found the top two teams slept, on average, an hour longer each night before and during the competition. They also gave a higher rating to the quality of their sleep.
In the US, Stanford University sleep researcher Cheri Mah conducted studies that showed when college swimmers increased their sleep time to 10 hours a night from their typical six to nine they slashed an average of 0.15 seconds from their reaction times off the starting block, and similarly improved turn time, 15-metre sprint time and kick rate. Another study, in the Journal of Pediatric Orthopaedics, surveyed injury rates among athletes and of all the factors studied, sleep (or lack thereof) was the strongest predictor of injury – greater even than training load. And research at The University of Toronto, Canada, also found sleep deprivation can compromise the recovery of muscle tissue post-injury.
Like its Australian counterpart, the English Institute of Sport has invested in this once-neglected aspect of recovery and performance. In the build-up to the Rio Olympics, Luke Gupta studied sleep patterns in more than 400 elite GB athletes. His finding that 50 per cent of boxers were getting insufficient sleep resulted in an upgrading of the ‘sleep environment’ in Team GB’s boxing training base. In came bigger beds; sheets, duvets and pillows had to be made from breathable fabrics; and materials selected to create a hypo-allergenic barrier to allergens were fitted to each bedroom.
‘On average, the boxers were sleeping for 24 minutes longer each night,’ says consultant coach Richie Woodhall. ‘Over the course of an Olympic training cycle, it could be as much as 29 or 30 days’ extra sleep. That can be the difference between winning a medal or going out in the first round.’ It paid off, as they hit their medal target.
While you were sleeping
So how exactly does sleep result in performance benefits? And outside the environs of an Olympic training camp, what strategies can we implement to maximise sleep?
Much of sleep’s beneficial effect on performance can be ascribed to the cocktail of hormones released while you’re between the sheets. The key ingredient is human growth hormone (HGH), which helps to repair and rebuild muscles by stimulating the liver and other tissues to make a protein called insulin-like growth factor 1 (IGF-1). Lack of sleep equals lack of HGH production equals restricted muscle growth. This is bad news for those overly partial to a postrace/run tipple, because alcohol has long been known to stall your secretion of HGH, with research published in The Journal of Clinical Endocrinology Metabolism showing alcohol decreased HGH secretion by 25 per cent.
‘Sleep can also affect your eating habits,’ says Halson. Again, it’s down to hormones. Rising levels of the hormone ghrelin signal that it’s time to start eating, while increased levels of the hormone leptin tell you that you’re full. And a German study, published in the Journal of Sleep Research, showed that just one night’s broken sleep significantly raises ghrelin levels, explaining why you crave seconds of macaroni cheese when tired. The study also found that two nights or more of poor sleep reduces leptin levels. This helps to explain why decreased sleep is associated with increased weight – bad news for running performance.
Related: What to eat to help you sleep better
There’s also a psychological impact. We all know anecdotally that a bad night results in lack of running motivation, and every step we do take feeling that bit tougher. In research published in the journal Sleep, subjects completing the same tasks before and after undergoing sleep deprivation achieved the same results, but perceived that the workload had increased significantly. Another study, published in Perspectives on Psychological Science, found increased perception of task difficulty when tired. Athletes suffering from insufficient sleep considered their drills to be more difficult, and those with frequent awakenings avoided the most challenging exercises.
The mechanisms behind this aren’t yet fully understood, but University of New York sleep specialist Mindy Engle-Friedman believes it’s down to your brain determining whether it has the resources to complete a task, or whether those resources need to be conserved for tasks of higher priority. Essentially, says Engle-Friedman, sleep deprivation alters perception of this resource distribution and leads to your brain making things feel tougher. Lack of sleep also results in greater stress and anger, draining energy reserves required for running. In
a study published in the journal Emotion, when sleep-deprived participants were shown emotionally negative images, activity levels in the amygdala – an area in the brain that controls emotions – were up to 60 per cent higher than levels in those who were rested. Sleep deprivation appears to cause the amygdala to overreact to negative stimuli because it becomes disconnected from brain areas that normally moderate its response.
How long were you awake in the night
Like many things sleep-related, the release of HGH as we snooze is governed by our circadian rhythms. ‘This clock of ours, deep within the brain, regulates our internal systems, including sleeping patterns,’ says Nick Littlehales, a leading sleep consultant who has worked with many runners, including Team GB Olympic sprinter James Dasaolu and former elite marathoner Mara Yamauchi. ‘Our body clock also regulates things like alertness, mood and digestion in a 24-hour process evolved to work in harmony with the Earth’s rotation. Our internal clocks are set by external cues, chief among them being daylight.’ Of particular relevance here is the secretion of the sleep-inducing hormone melatonin in response to the transition from light to dark, but recent research has revealed that the functioning of our bodies is affected far more extensively by circadian rhythm than was previously thought. In fact, we now know that one in every 10 genes in human DNA operates in 24-hour cycles. Understanding those cycles won’t just help you sleep better, it’ll help you optimise energy levels and performance when you’re awake.
In Littlehales’ book Sleep (Penguin), he features a 24-hour clock showing key biological markers throughout the day. Around 2-3am is the time of your deepest sleep; 5pm is when your cardiovascular efficiency and strength are at their peak; around 10.30am is when you’re at your most alert. This varies among individuals, however, with people generally falling into one of three categories – larks, night owls or in-betweeners. ‘We call it your chronotype,’ says Littlehales. ‘Essentially, your sleep characteristic.’
Your chronotype doesn’t just indicate what time you want to go to bed and get up – it highlights when your body is best equipped to perform functions guided by circadian rhythms. Chronotype is genetic and you’ll probably be aware of yours already, but if you’re unsure, use the Munich questionnaire online assessment for a definitive answer. Know your chronotype and plan your runs in harmony with your natural rhythms – you’ll reap the rewards. ‘Studies show that training to suit your chronotype results in better sporting performance and fewer injuries,’ says Littlehales.
Cycles are also crucial while you sleep, says Littlehales. ‘In a clinical sense, 90 minutes is the way you measure sleep,’ he says. ‘It takes 90 minutes to run through a sleep cycle, of which around 20-25 per cent is deep sleep.’ Consequently, Littlehales’ R90 programme, which he uses with both elite and recreational athletes, breaks sleep down into numerous 90-minute cycles, with the aim of waking at the end of a sleep cycle, when the body and brain find waking easiest. How many cycles should you aim for per night? ‘Your optimum is a very personal thing but, broadly speaking, five cycles, totalling seven and a half to eight hours is sufficient for optimum physical and mental recovery,’ says Littlehales. ‘But the R90 programme is more about reintroducing the idea of polyphasic sleep, where you give your mind and body multiple chances of recovery – and not just a night.’
Many elite runners, including Mo Farah, Paula Radcliffe and numerous East Africans nap during the day when training, and studies have show daytime naps restore alertness and enhance performance. In fact, a NASA study on military pilots and astronauts found that a 40-minute nap improved performance by 34 per cent.
Related: How to fit in quality sleep around a hectic schedule
Of course, while napping may be de rigueur in Rift Valley training camps, it’s generally frowned upon at your desk. However, according to Littlehales, your middle-of-the-day physical and mental regeneration doesn’t necessarily have to mean actually going to sleep – just slowing things down can be enough. ‘All you need to do is zone out,’ says Littlehales. ‘You don’t even need to leave your desk. Listen to relaxing music or a mindfulness app. Focus on breathing so that, mentally, you’ve left the room. If you can drift like this for just 15 minutes a couple of times a day, it can really help you to mentally and physically recover.’
If you do have an opportunity for a genuine nap, take it, and consider this nutritional strategy to bounce back into the day: ‘Consume caffeine just before napping so that when you wake up, you can get back into it a lot quicker, as caffeine will be peaking in the bloodstream,’ says Dr Sophie Killer, lead performance nutritionist for the British Olympic track and field team. ‘Have a coffee, nap for 20-30 minutes and you’ll wake up alive and kicking.’
Eat, sleep, repeat
Nutrition plays a role in maximising sleep beyond napping, too, though Gupta cautions that the research on some foods that supposedly encourage sleep is equivocal at best. ‘While it’s accepted that avoiding some foods and drinks – for instance, caffeine – can help sleep, there are fewer studies on foods that can facilitate it,’ he says. ‘There is, however, some research to suggest that foods high in melatonin – tart cherries, walnuts, tomatoes – may help sleep.’ Rice, tomatoes, barley, sweetcorn and bananas are further melatonin-rich foods.
Halson reiterates the importance of not eating – or drinking – too much prior to bed to avoid alarm calls of nature in the night, but also cautions against swinging too far the other way: ‘I know a lot of athletes who go to bed hungry because they’re trying to lose or maintain weight,’ says Halson. ‘They believe it’ll help with fat burning but restricting calorie intake has a negative impact on sleep.’ Again, however, it’s not a case of the more the better: a study by Killer found that switching to a high-carbohydrate diet during intense training didn’t significantly improve sleep.
What you eat can help the beneficial processes that occur while you sleep, though. Professor Luc van Loon of Maastricht University, the Netherlands, who specialises in protein synthesis, stresses the importance of evening protein ingestion on building muscle. He has studied the effect of protein on muscle repair, regeneration and growth via muscle biopsies, and concluded that consuming 40g of casein protein around 30 minutes before sleep is effective. Casein-rich foods include milk, cottage cheese and yoghurt.
Littlehales is the architect of cycling outfit Team Sky’s sleep kits, which the team take to all their races – they have helped Bradley Wiggins and Chris Froome claim four Tour de France titles between them. The kits comprise portable beds made up of two or three mattress toppers – thickness of foam and number depending on the weight of the athlete – with a body comforter on top. This is wrapped in a removable, washable cover, combined with a shallow pillow and linen, all squeezed into a bespoke backpack.
‘They were important because the riders would sleep in a different, often poor, hotel each night,’ says Littlehales. ‘We could control their racing gear and their nutrition, but not their sleep.’
A portable sleep kit may seem excessive for destination races, but if you want to kip like an elite before the Torquay 10K you can purchase a custom-made one from The importance of pre-race sleep. Of more value would be applying the science to your home set-up, starting with your mattress. ‘My first piece of advice is to spend £300 on a mattress every couple of years rather than £1,000 every 10 years,’ says Littlehales. ‘They can degrade fairly rapidly so frequency of changes is preferred.’
He suggests adding a body comforter or a mattress topper, which should be washed regularly to minimise chances of infection. You should also use hypoallergenic and breathable bedding (Microvent linen pack, from £95), whether you have allergies or not, to keep out potential impediments to sleep and regulate temperature. And while it may not be the case for all things bedroom-related, when it comes to sleep, size matters: ‘Go for the biggest bed you can fit into your room,’ says Littlehales. ‘Double beds are really designed for one person; in fact, a super-king mattress is the minimum size a couple of runners should consider for their own space and a good night’s sleep.’ This extra cost should focus on the mattress because, as Littlehales says, the frame is basically decoration.
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You could also consider a PJ upgrade: Under Armour’s Athlete Recovery Sleepwear (currently available only in the US, but should be here soon) claims to use ‘the world’s most advanced sleep system that actually rebuilds your body while you rest.’ A soft, bioceramic print on the inside absorbs the body’s natural heat and reflects Far Infrared (FIR) – a type of energy on the infrared spectrum that has several benefits for the human body – back to the skin. Independent studies by researchers from Harvard Medical School and Massachusetts General Hospital, both in Boston, US, have found that sleeping environments could be improved by FIR.
Halson offers more traditional advice: ‘There are many interventions that can help a runner sleep, including eye masks and ear plugs, temperature of the room, noise and light,’ she says. ‘Staying off bright-light devices like smartphones is useful, too. That light stimulates the body clock and tells you to stay awake. You want as dark a room as possible in the hour before bed because it primes the body for sleep.’
Made to measure
So how do you know if all this is working? Dropping off face down in your cornflakes is obviously one measure, but in the more technical sphere, sleep-tracking features are now near-omnipresent on fitness watches. These track movement, with a certain amount corresponding to being awake and stillness registering as sleep. However, there’s debate on the accuracy of the data they produce. One study found wrist actigraphy, as it’s known, ‘can be quite accurate when it comes to estimating information such as total time asleep, sleep percentage and how long after sleep waking occurs’. But critics argue they mistake motionlessness for sleep, and more recent research, published in the International Journal of Behavioural Nutrition and Physical Activity concluded that the majority of smartphone sleep apps ‘overestimated or underestimated’ sleep. ‘Although relatively cheap and convenient to use, there are very few sleep-monitoring devices that have been shown to validly assess sleep against gold standards of sleep assessment,’ says Gupta. Still, because that gold standard involves two nights in a lab with electrodes attached to your head to measure brain activity, you may want to settle for the slightly less accurate, wrist-based option. It’s also very useful to keep a sleep diary (see below) to track your sleep patterns over the longer term.
Put all this together and perfecting your sleep can join training and nutrition as the third crucial element of a complete plan for improving your running. Sweet dreams.
How well did you sleep last night
Ask these questions over seven days to form the basis of a good sleep diary, says sleep expert Luke Gupta.
1/ What time did you go to bed?
2/ The secret to achieving the elusive runners high?
3/ How long were you awake in the night?
4/ What to eat to help you sleep better?
5/ Eat, sleep, repeat?
6/ How well did you sleep last night?
Now calculate your sleep duration and efficiency (time asleep ÷ time in bed x 100). Scores below 80 per cent indicate poor sleep.
Sleep cycle
A sleep cycle takes 90 mins. The stages alternate between REM (rapid eye movement) and NREM (non-rapid eye movement).
NREM
As we fall asleep, we enter NREM, accounting for 75 per cent of a night’s sleep. This comprises:
N1: This is where you’re between being awake and falling asleep – light sleep.
N2: The onset of sleep; you become disengaged from your surroundings. Breathing and heart rate are regular; body temperature drops.
N3: The deepest, most restorative sleep, blood pressure drops; breathing is slower; muscles relax; blood supply to your muscles increases; tissue repair occurs.
REM
REM accounts for the other 25 per cent; it begins about 90 mins after you fall asleep and recurs roughly every 90 minutes thereafter; the periods grow longer later in the night. This period supports optimum daytime performance and is when the brain is most active (most dreams occur), and your body is immobile as your muscles are ‘turned off’.
