To celebrate the renewal of our partnership with sleep and comfort brand, Mammoth, we recently put athletes’ questions on sleep science and the relationship between sleep and performance to Mammoth ambassador, Dr Nicola Barclay, who is a renowned Lecturer in Sleep Medicine at the University of Oxford.

Q: Given that Japanese hotel rooms tend to be smaller than average, and that athletes at this year’s Olympics and Paralympics will be spending more time in their room due to COVID restrictions, how do they ensure that there is a distinct difference between rest and recovery, and time for sleep?

A: Whilst the rooms may be small, it is important to have distinct areas for wakefulness and activity, and rest and sleep. If you can, make sure that your waking activities are out of the bed; perhaps watch TV in a chair or sit at a desk for working. Don’t use the bed for these waking activities.

There is a bit of psychology involved here in making these distinctions, and the important thing for being able to get to sleep quickly is ‘stimulus control’. What we mean by this is that we need to control the associations we have with our bed as a place for sleep and sleep only. Imagine if we are watching TV in bed, working on a laptop, playing on our phones or tablets, maybe even working out on the bed, we are building up psychological associations between the bed as a place of wakefulness and activity. It’s no surprise then, that when we want to use the bed for sleep, we have trouble switching off. The bed should only be entered when we are ready to get to sleep.

This rule follows if we wake up in the night too. If we are awake and starting to worry and think about the next day, or whatever happens to be going through our minds, we need to get up, get out of bed, move to a different part of the room until we are sleepy enough again that we are literally about to drop off to sleep.

We use a 15-minute rule here. If we’re in bed lying awake and alert, and it feels like 15 minutes has passed, get up out of bed! There isn’t always space to do this in one room. So what can we do if space is restricted? Well, we can sit on the edge of the bed, sit on the floor near the bed, or even just sit the other way round, at the foot of the bed. But importantly, don’t put your head on the pillow until you are ready to fall asleep.

What’s also important for optimising sleep is having a set routine. Our brains love routine, and when a routine is disrupted, the brain doesn’t know what it should be doing. Is it time to be awake, is it time to go to sleep? If we sometimes go to bed a little later, or we try to get an early night, or sleep in on weekends, overtime this lack of consistency wreaks havoc with our brain’s automatic process for switching off and getting to sleep.  

Light is also important and is perhaps the most important ‘zeitgeber’ – time giver. Light entrains the brain’s master body clock. When we wake in the morning, it is best to get an immediate hit of bright light – outdoor light if possible, but if that isn’t possible, light from the window will be fine – stand or work by the window to get as much natural light as possible. And when evening approaches, make sure to turn the lights down, or have just a little lamp on in one corner of the room. The hormone melatonin is secreted by our brains in dim light conditions, and tells our brain it’s nighttime and time for sleep. Whereas bright light inhibits melatonin and makes it harder for us to get to sleep. So, make sure the lights in the room are dim a couple of hours before your typical bedtime to ensure you keep your melatonin rhythm in sync.

Temperature is also important. Sometimes hotel rooms can get a bit stuffy, so maybe we want to alter the temperature control throughout the day. Temperature is also a time cue to our biological clock, and changes in ambient temperature tell our brain the time of day. Our brain and body also have their own characteristic temperature pattern that rises when we wake up in the morning, peaks in the late afternoon and evening, and starts to cool off as evening approaches. We then have our coolest point in the early morning a few hours before we wake up. Making sure the room is cool in the evening mimics the body’s natural cooling process and can start to make us feel sleepy.

Q: What advice can you give to athletes for overcoming jetlag?

A: It’s first important to understand that it is easier to travel west, than it is to travel east. This is because travelling west requires us to extend our waking day and go to bed later, which we can relatively easily control, whereas travelling east requires us to try to get to sleep at an earlier clock time, a time when we are just not sleepy yet.

Let’s imagine we are travelling from the UK to Japan. According to our UK body clock, we might arrive in Japan say around 1pm, but according to the local time in Japan it is already 10pm – bedtime according to the clock. We will find it very hard to get to sleep for the night when our internal clock still thinks it is 1pm in the afternoon. When we travel home from Japan, this will be a little easier as on the first day home we will simply have to stay up a little later than we are used to – that is, we have to delay our rhythm.

We are able to delay our biological clock by about 1.5 hours per day in the new time zone. But to phase advance we can only achieve about 1 hour phase shift per day. If we are travelling east from the UK to Japan, which is nine hours ahead, it will take us nine days to fully adjust, that is to fully advance our rhythm to the new time zone. If we are travelling west, from Japan back to the UK, we will be able to phase delay our rhythm to the new time zone within six days.

Q: What tips do you have for being able to sleep on a plane?

A: You only want to sleep on a plane if it works with your schedule for minimising jet lag. If the plane journey is in your biological night, or if it is also nighttime at your destination, then by all means sleep on the plane.

But if it is your biological day and not a useful time for your new schedule, by which I mean you will arrive within daytime at your destination, don’t sleep on the plane. So assuming its nighttime by your biological and destination clocks, and you do want to sleep on the plane, what can you do to ensure you get some sleep? First you need to make sure you’ve ditched that coffee at the airport, to stop any unhelpful alerting effects. Then when you’re on the plane use ear plugs, use an eye mask to stop unwanted light telling your brain it is daytime. In fact, you could start reducing light exposure even in the airport by wearing blue-light blocking glasses. Also, be sure not to have an alcoholic drink on the plane!

Q: How do you manage nerves and ensure good sleep the night before competing?

A: The night before a competition is going to be pretty stressful; you’ll be excited, nervous, perhaps a bit of both. There is enough to be worrying about and it is counterproductive to also add worrying about sleep to the mix. We know that stress interferes with sleep, but you’d probably be surprised to hear that one night of poor sleep actually has very little impact on performance the next day.

So, if you sleep poorly the night before a competition, don’t stress it. What is more important is the sleep in the weeks leading up to the competition. If you have a stable sleep routine in the weeks before competing, optimising the bedroom environment, being strict with caffeine and alcohol intake, making sure you have enough opportunity for sleep, then you’ll have a strong basis for performance, even if you have a poor night before your competition.

There may be some tendency to want to ‘bank’ sleep, so to extend your sleep period, perhaps getting an early night. Sometimes this can be difficult if we have trained our brains that there is a specific time for sleep. But if we have followed the rules of stimulus control, going to bed early and getting to sleep quickly can be achieved. The brain will think ‘ok, so I’m in bed, all I do here is sleep’, and you may be able to get in an extra half hour or so.

The key thing really is, don’t stress about your sleep. You will get some, and it will be enough. The real decrements on performance come when we get consistently poor or insufficient sleep, one night won’t knock us.

Q: What does an optimum bedtime routine look like?

The bedtime routine really starts from the moment we get up in the morning. In order to sleep well, we need to manage effectively what we do and the time we do things during the day. This comes down to caffeine use, timing of meals, timing of exercise, light exposure, and allowing wind down time.

Let’s take each of these in turn. Caffeine has a half-life of around five hours, meaning its effects take five hours to reduce by half. IF we had a double espresso at 5pm, by 10pm we still have the equivalent of a single espresso shot keeping us alert. Would we really want to have an espresso at 10pm? I always recommend no caffeine after midday. 

Timing of exercise impacts on sleep. Vigorous activity in the hours leading up to bedtime simply delays sleep onset. When we exercise our body temperature increases, we’re highly alert, and exercise stimulates the release of dopamine, noradrenaline, and serotonin. Whilst these are all great hormones for mental and physical health, they are part of the wake-promoting system. Higher circulating levels of these monoamines as a result of exercise in the evening will make it hard for your brain to quieten the wake-promoting system, making it hard to get to sleep.

We’ve already highlighted light exposure as perhaps the most important time giver for our biological clock. It’s really important to make sure that light levels are dim in the 2-3 hours leading up to bedtime, to allow your brain to secrete melatonin, which prepares our brain for sleep.

It is vitally important to factor in wind-down time before you intend to go to bed. You can’t expect your brain to go from wake to sleep without a nice, calming transition. We don’t stop a car driving at 30mph to an immediate stop – we gradually slow down, and that’s exactly what we need to do to get to sleep. For 1-2 hours before bed, dedicate quiet, relaxing time, have a bath, read a book, watch TV – perhaps a programme that is not too stimulating. Do mindfulness or light yoga or stretching. But just make sure you factor in at least one hour before you get in bed. And make sure you do this in dim light!

You might want to even get ready for bed, put pyjamas on, brush your teeth, before you start your wind-down time. Then at the end of the wind-down, you can simply get in bed. No need to turn on the bathroom light to brush your teeth, no need to wake yourself up to get changed. You’re done.

Q: How much does the time at which you eat affect your sleep?

A: Timing of meals is important. There is some research to suggest that consistently having an early breakfast is associated with early bedtimes. At the other side of the day, eating a late meal close to bedtime delays sleep onset. It’s no surprise that there is an association between later sleep times and later mealtimes. Eating meals close to bedtime also increases your core body temperature, and we already know that getting to sleep is easier when the brain and body is starting to cool. But it’s also important to consider what you eat before bed. There has been some research to show that eating carbohydrates that have a high glycemic index close to bedtime (say an hour prior to bedtime) may delay sleep onset; whereas when high GI carbohydrate rich meals are consumed four hours before bedtime, sleep onset is faster. The bottom line is, have your last meal of the day around four hours prior to bedtime, and ensure high GI foods are consumed early.

Q: Is it important to track or log your sleep?

A: I am in two minds about tracking sleep. It is very useful when an individual has difficulties with sleep, to track their sleep over say two weeks, to get an idea of what is going on. Check the rhythmicity of bedtimes and waketimes, to see how fragmented sleep is, or to see the presence of a sleep disorder. When an individual has difficulties with sleep, sleep tracking can be useful to get a bit more information about what may be going on and how to fix it. It can also be useful in training to determine the circadian rhythm of the athlete, to get an idea of their habitual wake up and bedtimes, and this is information can then be used to set optimal training times. Ideally each individual will have training times that coincide with their own timing of optimal alertness, and importantly allowing enough time for sleep. So sleep tracking for a couple of weeks can be useful in setting training programmes.

However, Sleep tracking is not useful when we don’t have a problem with sleep, or when we are not setting training programmes, and it can actually create a sleep problem. Firstly, if you are wearing a sleep tracker on your wrist, you already will sleep differently. Maybe you’re lying still in bed you may wiggle your arm more as you really want your tracker to know that you are not asleep, that you’re fighting sleep. But more importantly, most sleep trackers are not good at really detecting sleep from wake – they measure movement rather than sleep, and we move a lot when we actually are asleep. No sleep trackers can accurately tell you whether you are in deep or light sleep, or NREM or REM sleep. The problem with this is that most sleep trackers will give you a ‘sleep score’ when you wake up, and the accuracy of these is far from optimal.

The score that we get is not a good reflection of the sleep we actually obtained. Importantly, that perception of how our sleep was becomes even more influential than the actual sleep we got.

One study looked at the effect of providing completely false feedback about a night’s sleep on subsequent daytime behaviour, mood and sleepiness. Half of a group of people were given sleep trackers, and the following day their tracker told them their sleep was poor – which was completely made up – and half of them were told their sleep was good.

The group that was told their sleep was poor the night before reported more sleepiness and fatigue and impaired daytime function, decreased alert cognition the following day. All based on fake feedback. This is to some extent what sleep trackers tell you – fake feedback. And it’s staggering that this can influence how we feel and behave the following day, regardless of how good our sleep really may have been.

A related problem is something called orthosomnia – this simply means the desire for perfect sleep. Many individuals are obsessed with sleep tracking, and want to ensure that their sleep is perfect. When this is done using trackers that can’t track sleep well, we end up actually having more problems with our sleep than if we didn’t track it in the first place.

In brief: track your sleep if you already have sleep difficulties and you work with a sleep specialist to see what is going on and what needs to be done to optimise sleep. Or use short term if you want to determine the timing of your circadian rhythm, and understand more about the ideal timing of sleep and wake to optimise performance.

But using sleep trackers for a long time when you’re a good sleeper has the potential to disrupt the good sleep that you are already getting.

Q: What is the relationship between sleep and motivation?

A: Studies that have looked at total and partial sleep deprivation have consistently shown that lack of sleep impairs cognition, alertness, decision making and motivation. But it is rare that anyone really experience total sleep deprivation to the extent implemented in lab studies.

Real world differences in sleep quality and quantity are associated with small changes in performance and motivation, but not to the extent that you would expect. However, there is a growing body of research looking at the effect of banking sleep on performance and motivation.

It is actually likely that athletes need more sleep than non-athletes, given the role of sleep in bodily repair and cellular regeneration, so the recommended 7-8 hours of sleep for a typical adult should probably be increased in athletes.

But even with an increased need for sleep, studies have shown benefits of banking even more sleep. One study looked at a sleep extension of one hour across four nights and showed benefits in reaction time (important for tactical sports), decision making, physical performance and motivation levels. Importantly, these effects were even maintained four days after the sleep extension when individuals resumed their normal sleep schedules. So, banking sleep in the nights leading up to a competition can improve many domains of motivation and performance, even if the night before a competition is poor.

Q: How can sleep quality help with the handling of anxiety?

A: Sleep is not only optimum for our physical health but also important for our mental health. We know that there are strong bidirectional associations between poor sleep and anxiety. Poor sleep increases anxiety the following day, and also high anxiety makes it difficult to sleep well – we can see how this can create a vicious cycle.

The good thing is that improving our sleep can help us manage the stresses that come up the following day: good sleep helps us regulate our emotions, makes us more resilient in stressful situations, improves our interpersonal functioning and helps our decision making. All of these things are likely to reduce anxiety.

Good sleep is rich in REM, and this is the stage of sleep associated with vivid dreaming. It’s also thought that this sleep stage helps us deal with emotions, and readies us for dealing with stressful situations. Dreams may actually be helping us have a run through, a little practice dealing with things that are on our minds. We actually see REM sleep alterations in individuals with depression, and it’s thought that prolonged poor sleep disrupts REM to the extent that we have difficulty dealing with the day-to-day things in our lives. Our brain then compensates by trying to get more REM sleep, sooner in the night, and more intense.

But what about the impact of anxiety on sleep? Of course, if we go to bed worrying and anxious, we’re not setting the right tone for sleep. In bed is not the place to be worrying. So as part of stimulus control, we need to get out of bed and deal with worries and anxiety elsewhere. Ideally, we want to have dealt with anything that is on our minds before we even get into bed. I have dedicated ‘worry time’ scheduled in to my day, a time when I can deal with all my worries. Factor this in. and if you are worrying in bed, get up, get out and write down those worries to deal with in the morning.

Q: In an ideal world, when would be the best time for athletes to train, leading up to a competition?

A: I know it’s not always easy for athletes to pick their own training times, but if possible, it would be ideal to train not necessarily at your peak performance time, but at the actual time of your competition. You want to do your training within those timings, to make sure that you are ready, that your body is ready and will respond at that particular circadian phase, and work together with your own biological clock.

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