{"id":56705,"title":"Cycling and sleep","description":"Sleep is a vital part of any cyclists life, but it's especially important for cyclists who are training for competitive events. This article looks at the science of sleep, why it's so important to the competitive cyclist and how they can ensure they gety good quality sleep.","content":"

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Published in<\/strong>: <\/span>RIDES & MORE<\/strong><\/a><\/p>

One of the most important recovery aids for cyclists is sleep. Yet many riders fail to get enough.<\/p>

In this article we're going to delve into the science of sleep, find out why it matters so much and look at how you can boost your performance from the comfort of your bed - by making sure you get good quality sleep.<\/p>

\"Sleep<\/p>

The mystery of sleep<\/h2>

You\u2019d think with all the advances in modern science that, by now, we\u2019d fully understand sleep. However, just as many features of our brains remain a mystery, so does sleep. For example, why we sleep at all remains a subject of conjecture. The reality is that the reasons why we sleep, how and when we sleep and what impact it has upon us evolved a long, long time ago.<\/p>

Our brains and sleep patterns have evolved from those of primates that first appeared 85 million years ago<\/p><\/blockquote>

Aspects of our sleep and our brains retain features from a time before the species of human beings even existed. Anatomically modern humans emerged in Africa approximately 300,000 years ago, which in earthly terms is yesterday. Our brains and sleep patterns have evolved from those of primates that first appeared 85 million years ago.<\/p>

In this section we\u2019ll dig into some fundamentals such as \u201cwhat is sleep?\u201d and \u201cwhy do we sleep?\u201d. It won\u2019t help you become a better cyclist to consider these questions, but it introduces some concepts that will be helpful and includes some interesting facts.<\/p>

ABOUT RIJDEN<\/strong>: <\/span>From cobbles to cross. Cycling\u2019s true heart<\/span><\/em><\/strong>. <\/span>Rijden grew from a passion for Flemish-style cycle racing, essentially cobbled classics, cross-winds, kermis races and cyclocross. We're a small UK independent that publishes a <\/em>free online cycling magazine<\/em><\/strong> and sustainable gifts for fans of cycling\u2019s classics and cyclocross. Read <\/em>more about Rijden<\/em><\/strong><\/a>.<\/em><\/p>

What is sleep?<\/h3>

The question \u201cwhat is sleep?\u201d seems pointless. Surely it\u2019s just the period of time when we are asleep. But how do you know when you\u2019re asleep, and what do we mean by sleep? When you\u2019re asleep, you don\u2019t know you\u2019re asleep. You can only know when you\u2019re awake.<\/p>

Have you ever been in a dull meeting, wondering whether it will ever end and not listening to the person droning on about how important they are? Your mind wanders to unrelated thoughts, and the next thing you know is that your head has dropped forward and you suddenly realise you\u2019d nodded off.<\/p>

What you do realise is that whilst you were awake, you hadn\u2019t heard a single word spoken by the boring speaker<\/p><\/blockquote>

It\u2019s unlikely you considered at the time whether this was sleep. You were probably more concerned with whether anyone else noticed. What you do realise is that whilst you were awake, you hadn\u2019t heard a single word spoken by the boring speaker.<\/p>

We\u2019ve all done it at some point in our lives. It\u2019s known as a microsleep. It's an interesting question as to whether you were awake when you had your eyes open, but were almost completely unaware of your surroundings and whether that brief moment of nodding off consisted of sleep.<\/p>

What\u2019s also interesting is that from a brainwave pattern perspective, there\u2019s very little difference between fully resting, but \u2018awake\u2019 and the light sleep known as Rapid Eye Movement (REM).<\/p>

The late Professor Jim Horne, an authority on sleep and author of Sleepfaring<\/em>, didn\u2019t consider REM sleep to be sleep at all. He categorised it as a period when neither sleep nor wakefulness are switched on. He likened it to a computer that had gone into screen saver mode.<\/p>

Why do we sleep?<\/h3>

As a parent and more recently grandparent of a boisterous, but very amusing four-year-old, I must have spoken the words \u201cyou need to go to sleep\u201d hundreds of times. In part because I know how important it is for infants to get their full quota of sleep, but also because I\u2019m exhausted and I\u2019m desperate for a rest. Why do I feel so tired looking after a small child when it's not physically exerting?<\/p>

We all know how important sleep is to us, and until I started researching this article, I'd never wondered why we sleep in a semi-catatonic state. It doesn't really make any sense. Nowadays, most of us don't have to worry about our safety whilst we're asleep.<\/p>

Go back millions of years to when we were evolving from other mammals into primates; then sleep was a potentially dangerous exercise. It left us vulnerable to our predators.<\/p>

This is especially true when we are in a deep sleep, where our ability to wake and respond to a threat is extremely diminished. Have you ever been woken from a deep sleep? It's not only an unpleasant feeling, but it's also extremely disorientating. It takes quite a few moments to realise what's going on and become fully functional.<\/p>

When they need to sleep, they close one eye, and the half of the brain it\u2019s connected to just goes to sleep<\/p><\/blockquote>

Dolphins face this problem, and they've evolved in an ingenious way to cope with potential threats whilst asleep and their constant need to swim and regularly surface. Each eye is connected to just one of the two halves of their brain.<\/p>

When they need to sleep, they close one eye, and the half of the brain it\u2019s connected to just goes to sleep. The other half stays awake. Dolphins, unlike most mammals, don't have REM sleep.<\/p>

It's probably just as well. REM sleep is when we dream. It's thought that dolphins don't dream. Imagine how confusing it would be to have one half of your brain assimilating information and trying to make decisions, whilst the other half is having a vivid dream.<\/p>

I wonder if primates\u2019 habit of living in packs and forming communities is what allowed us to enter a state of deep sleep. I can imagine members of the pack taking it in turns to guard their slumbering fellows. Maybe that's why we sleep through alternating cycles of deep and light sleep throughout the night.<\/p>

In a later section, we\u2019re going to look at the sleep cycles that operate throughout a human\u2019s day and what affects them, but first we\u2019ll consider what makes us tired.<\/p>

\"Gifts<\/u><\/a><\/p>

What makes us tired?<\/h3>

Curiously, physical exertion, despite what you might think, doesn\u2019t make us tired, or at least not sleepy. I know what you\u2019re thinking. How come I always feel really tired after a four-hour training ride? Obviously, strenuous physical exercise makes us feel weary, but it\u2019s not the physical aspect that makes us sleepy, but the mental one.<\/p>

It\u2019s the strain that our cortex has endured during the day that drives our need for sleep<\/p><\/blockquote>

It\u2019s the strain that our cortex has endured during the day that drives our need for sleep. The cortex is the largest part of the human brain and is responsible for higher-level functions, including memory, thinking, learning, reasoning, emotion, and language.<\/p>

The only time it switches off is when we go to sleep. Lie in a dark, quiet room, in a relaxed meditative state, and it\u2019s still \u2018purring away\u2019. How tired we feel at the end of the day depends upon how hard the cortex has had to \u2018work'.<\/p>

Work in this context consists of two elements: how hot the brain has become and how much information and decision-making the cortex had to process. The brain will normally be heated up during exercise as the body temperature rises. And cycling on the open road loads it with a huge amount of visual information, and conscious and subconscious decisions that it\u2019s constantly forced to make.<\/p>

This explains why I don\u2019t feel so tired after training on the turbo in the garage on a cold winter\u2019s night, compared with a summer\u2019s day riding through countryside. Sitting on a turbo requires little thought process, and as long as I've got my fan blasting cold air over me, my brain stays quite cool.<\/p>

The sleep cycle<\/h2>

The circadian cycle<\/h3>

The circadian cycle or rhythm is the natural internal clock that controls our wakefulness and sleepiness. It\u2019s slightly out of sync with the normal day, as it operates on a 24-hour-and-30-minute cycle.<\/p>

Not only does the circadian cycle influence our sleepiness, but it also affects our body temperature. Body temperature and alertness are at their lowest between 02:00 and 06:00 and reach a peak in the evening.<\/p>

a time before central heating when the air temperature would rise and fall with the rise and fall of the sun<\/p><\/blockquote>

Our bodies need to cool down to aid sleep. This probably reflects life in a time before central heating when the air temperature would rise and fall with the rise and fall of the sun.<\/p>

Ever wondered why you feel drowsy mid-afternoon? That\u2019s because your circadian rhythm has a dip around 15:00 to 16:00. Body temperature drops, and so does alertness. Figure 1 shows the circadian cycle starting from 4 am.<\/p>

\"FigureFigure 1 - the circadian cycle<\/em><\/p>

You may be interested to know that young men under thirty are most likely to have sleep-related vehicle accidents during the 02:00 to 04:00 period, whilst elderly drivers tend to have them during the mid-afternoon dip. It's an effect of the circadian cycle.<\/p>

The \u2018sleep hormone\u2019<\/h3>

Under normal conditions, the fact that the circadian clock is slightly longer than 24 hours doesn\u2019t matter, as its cycle is heavily influenced by the presence or absence of light. As days get longer and shorter, it adapts automatically. Deep within the brain of humans, there\u2019s a structure known as the pineal gland.<\/p>

Light from our eyes feeds into the gland, which then releases the hormone melatonin depending upon how much light it receives. If there\u2019s lots of light, melatonin is not produced, but if it\u2019s dark, then melatonin is released into the bloodstream.<\/p>

Melatonin has a soporific effect and is sometimes referred to as the \u2018sleep hormone.\u2019<\/p><\/blockquote>

Melatonin has a soporific effect and is sometimes referred to as the \u2018sleep hormone.\u2019 Our \u2018circadian clock\u2019 is not controlled by the presence or absence of light, but is effectively synchronised by it. The combination of the circadian cycle and the level of melatonin is a key component in how sleepy you feel.<\/p>

Whether melatonin is produced or not is dependent upon the brightness of light (the lux) and how close its colour is to daylight (spectral quality). The brighter the light and the closer to the colour of daylight, which is blue-tinged, the greater the suppressive effect on melatonin production.<\/p>

The stages of sleep<\/h3>

Once you start to fall asleep, you pass through various stages of sleep. Once you\u2019ve settled down for sleep, tucked in your teddy bear, finished reading a relaxing and calming book, hopefully you\u2019ll start to nod off.<\/p>

Based upon the study of \u2018brain waves\u2019 (using an electroencephalogram or EEG), sleep has been subdivided into the following five, or six if you include awake, stages.<\/p>

Stage 1<\/strong> is the first stage, and it\u2019s the drowsiness phase just before you drop into stage 2<\/strong>. Roughly half the time we spend asleep consists of stage 2. Both stage 1 and stage 2 are considered to be light sleep<\/strong>. It\u2019s quite easy to be awoken during these two stages.<\/p>

After a while, assuming you\u2019ve not been woken up, you\u2019ll slip into the first stage of deep sleep<\/strong>, stage 3<\/strong>, before finally stage 4<\/strong>. For this article, there\u2019s no need to consider the differences between stages 1 and 2, and 3 and 4. We\u2019ll just refer to them as light and deep sleep.<\/p>

There\u2019s a final stage of sleep that we\u2019ve already mentioned - Rapid Eye Movement (REM<\/strong>). It\u2019s the period during which we dream, although not always.<\/p>

As you can see from Figure 2, we don\u2019t just drop into a deep sleep and stay there for the next eight hours.<\/p>

\"TheFigure 2 - the nightly sleep cycle<\/em><\/p>

The brain\u2019s sleep cycle rotates around a very rough 90-minute duration. Having fallen into a deep sleep, the brain starts to reverse the process, going from deep to light sleep and occasionally waking up, even if we\u2019re unaware of it. You\u2019ll note that all of the deep sleep in this illustration occurs in the first half of the night. It\u2019s not an exact representation, but predominantly deep sleep occurs in the earlier period of sleep.<\/p>

Here\u2019s an approximate breakdown of how much time we spend in each of these stages:<\/p>

Light sleep - 35-65% (around 4 hours a night)<\/p>

REM - 20-25% (around 1.75 hours a night)<\/p>

Deep sleep - 10-20% (around 1.25 hours a night)<\/p>

\u2018Awake\u2019 - 5-20% (around 1 hour a night)<\/p>

Why is sleep important to cyclists?<\/h2>

It\u2019s obvious that sleep is incredibly important to all human beings; why else do we desire sleep so much when we\u2019re tired? To be contrary for a moment, why do I crave chocolate sweets sometimes, if they\u2019re not particularly good for me?<\/p>

We feel as if we\u2019re zombies and function poorly<\/p><\/blockquote>

OK, we know that sleep is really important because all the textbooks say so and because we know from personal experience what happens when we sleep poorly or have a late night. We feel as if we\u2019re zombies and function poorly. I find I\u2019m extremely clumsy the morning after a restless night.<\/p>

I might crave chocolate, but if I resist temptation, once the desire has passed, I feel no ill effects. That\u2019s not the case with lack of sleep. In this section, we\u2019re going to consider what sleep, and in particular deep sleep, does for our bodies whilst we are in the land of nod, especially for cyclists undertaking regular and often vigorous exercise.<\/p>

\"ImageSleep is vital for recovering from training and improving fitness<\/p>

You get fitter when you're asleep<\/h3>

You've just been out on the Sunday ride. Four hours of riding, some significant climbs, the odd sprint and you're back home with a coffee to catch up on the day's cycling action.<\/p>

Strava informs you that your fitness has improved by two points. It's lying to you. You're no fitter now than you were when you set off. How can this be?<\/p>

the body releases pulses of human growth hormone<\/p><\/blockquote>

It's because fitness gains are made whilst you're asleep. As you drop into deep sleep, the body releases pulses of human growth hormone (HGH). During deep sleep, around 50-70% of your daily growth hormone is released, driving muscle repair and tissue regeneration.<\/p>

It's this overcompensation that leads to the much sought-after fitness improvements. Without proper sleep, you won't get faster. Worse, you could actually get slower.<\/p>

You\u2019ll get slower without it<\/h3>

Without sufficient sleep, glycogen levels aren't replenished, testosterone, which is critical for fitness gains, drops and muscle damage goes unrepaired.<\/p>

Not only will you not improve if you don't get good sleep, eventually you\u2019ll go slower<\/p><\/blockquote>

Not only will you not improve if you don't get good sleep, eventually you\u2019ll go slower<\/p>

Additionally, the stress on your body of poor sleep will cause your cortisol levels to rise. We\u2019ll come back to the role of cortisol, the \u2018stress hormone\u2019, later<\/p>

Your immune system needs it<\/h3>

Proteins called cytokines are used by the body when it's fighting an infection. Not getting enough sleep can lower how many of these protective cytokines are made. Additionally, levels of antibodies and cells that fight infections are lowered during times when you don't get enough sleep.<\/p>

Miss that precious sleep, and you're at heightened risk of picking up a cold or a more serious infection that can ruin your training and racing plans.<\/p>

You need it to lose weight<\/h3>

Insufficient sleep causes the levels of the proteins ghrelin, which makes you feel hungry, to increase and leptin, which makes you feel sated, to reduce.<\/p>

You'll end up craving high-calorie foods and struggle to lose weight<\/p><\/blockquote>

You'll end up craving high-calorie foods and struggle to lose weight. If you're putting in the kilometres and the weight's not shifting, it might be due to poor sleep.<\/p>

Memory retention<\/h3>

You've just got back home from a great cyclocross skills session. Your head is buzzing with all the knowledge the coach has imparted and, in your mind, you replay your attempts to master the off-camber corners.<\/p>

But how will you remember all this new information and what's the best way to ensure you really have mastered these new skills?<\/p>

You won't be surprised, given the topic of this article, that the answer is a good night's sleep. This is when the brain lays down its memories, which consist of two types - declarative and procedural.<\/p>

Declarative memories are associated with conscious learning, such as remembering what the coach said, whilst procedural relates to the subconscious learning of a new skill through practice, such as learning to walk or ride a bike. Our brain subconsciously learns how to perform the skill better through repetition.<\/p>

If you want to improve your cycling skills, you need a good night's sleep afterwards. This suggests that rather than one long skills session a week, you'd be better breaking it up into a number of shorter sessions throughout the week.<\/p>

\"Read<\/u><\/a><\/p>

Good sleep for cyclists<\/h2>

What is cortisol and why\u2019s it important?<\/h3>

A lot has been written about cortisol recently. Much of it suggests that cortisol is \u2018bad news\u2019 and you should do your best to reduce the presence of this \u2018stress hormone\u2019 in your body. The reality, unsurprisingly, is that cortisol has its benefits as well as its downsides.<\/p>

It has many important roles, but let\u2019s first look at how it balances against melatonin. If melatonin is the \u2018sleep hormone\u2019, then cortisol is the \u2018awake hormone\u2019. As one rises, the other falls. Cortisol and melatonin are usually in sync based on our circadian rhythm. Cortisol peaks in the morning to wake us, and melatonin rises at night to help us feel sleepy.<\/p>

As well as helping to make us feel awake, cortisol is produced by the adrenal glands in response to stress. This includes physical stress from training, mental stress, and lack of sleep.<\/p>

Cortisol regulates blood sugar and blood pressure levels, maintains heart and blood vessel functions, suppresses the immune system after it has completed its job, neutralises inflammation, increases fat breakdown and more. In short, it has a vital job to perform.<\/p>

The problems occur when too much cortisol is produced because the body is constantly under stress<\/p><\/blockquote>

The problems occur when too much cortisol is produced because the body is constantly under stress. For example, regularly training too long and too hard will keep cortisol levels high. Because of the relationship with melatonin, there\u2019s a reasonable chance that your sleep will suffer, which in turn further raises the cortisol.<\/p>

Overly high cortisol levels can also impact the release of HGH and the beneficial effects of melatonin on the body. The result can be poor recovery, immune system suppression and detrimental effects on numerous vital organs.<\/p>

If your body is chronically stressed, your adrenal glands have to keep secreting more and more cortisol. Eventually, they become exhausted, and cortisol production drops as they develop Adrenal Fatigue Syndrome (AFS), which can take weeks or months to overcome.<\/p>

The symptoms of \u2018cortisol overload\u2019 and ultimately Adrenal Fatigue Syndrome include:<\/p>