Sleep and Stress
Most insomniacs know why they can't sleep: they think too much. Their minds go too fast and they never stop. Insomnia, anxiety and an overactive mind go together. Many people first realise that stress is affecting their health when they have trouble sleeping. When they go to bed, the unfinished thoughts of the day crowd in on them. Whenever we are doing nothing, our thoughts naturally default to what we've just done or what we're about to do."At last", says the brain. "A chance to think without interruption."
Unfortunately, the luxury of uninterrupted thinking is incompatible with sleep. Even if
people fall asleep through sheer exhaustion – because they're too tired to continue
thinking – they often wake a few hours later and pick up their thoughts where they left
off.
Meditation disarms the thoughts and emotions that keep us awake. Meditators commonly use it as a way of falling asleep, and people often learn meditation for this purpose alone. Meditation triggers the Relaxation Response, which is the biological process that takes us towards sleep. If you are at all tired, and if you meditate lying down you are very likely to fall asleep. You would no longer be meditating but this would still be a good outcome. We can all do with more sleep than we usually get.
We know the value of diet and exercise for good health, but we almost completely ignore our need for sleep. Animals can last for weeks without food, but deprive them of sleep and they die within days. It is also crucial for normal health. People who sleep well tend to live longer, happier and healthier lives than those who sleep badly.
Poor sleep comes in various forms. Sleep-onset insomnia is when people have trouble falling asleep. Sleep maintenance insomnia is when people fall asleep readily but are awake for much the night. Other people have shallow, restless, unsatisfying sleep, and most of us get less sleep than we need. A few sleep problems benefit from medical interventions, but most are caused by stress or ageing.
Poor sleep impairs many biological functions that are most active in sleep. These include digestion, immunity, growth and repair. The brain also needs good sleep for learning and memory consolidation. However the most obvious effect of poor sleep is that we feel sleepy and unable to cope during the day, which is a source of stress in itself.
DAYTIME SLEEPINESS
Most of us now try to get by with a lot less sleep than our bodies and minds need. Feeling tired much of the time is now as normal as being overweight, and with similar detrimental effects on our health. Under ideal conditions we usually sleep around 9 hours over a 24-hour period. Nowadays we sleep about an hour and half less than people did a century ago, and each decade our average sleep time and quality continues to decline.
Poor sleep is often deadly. When we're exhausted, we easily can fall into a 'micro-nap' without realising it. In these situations, no amount of coffee or will power can stop the onset of sleep. We can fall asleep with our eyes open while doing routine tasks in bright, noisy surroundings.
This often happens while driving. We can easily travel a kilometre or two on the freeway during a micro-nap. According to some estimates, falling asleep at the wheel kills hundreds of thousands a year worldwide. It contributes as much to road fatalities as alcohol does.
Tired people suffer the same kinds of cognitive impairment as people who are drunk. Staying awake for 24 hours has the same effect on test subjects as three shots of whisky. Like drunks, tired people lack self-awareness and tend to overestimate their coping abilities. They confuse keeping going with doing things properly. Because their brains are operating on the lowest possible setting, they can't see alternative courses of action, or foresee outcomes. They often fail to respond to, or even notice, anything unusual. Both the Exxon Valdez oil spill disaster and the Chernobyl nuclear meltdown were attributed to having sleepy men in control. They didn't believe what they were seeing.
WHY WE SLEEP
Many biological functions are designed to do their best work when we are asleep. The Relaxation Response is the opposite of the Stress Response. In recognition of its many functions, it is also called The Rest, Digest and Repair Response. It works best when cortisol levels are low and when the body is still.
During the day, the demands of thought and action get priority, and other functions are put on hold. When we sleep and apparently do nothing, the priority shifts from action to the restoration of homeostatic balance. The processes of digestion, immunity, growth and repair come to life and can work uninterrupted by physical movement. In fact their circadian peak of maximum efficiency occurs around midnight to 3 am, exactly opposite the cortisol peak at midday.
In sleep the body repairs the damage of the day. For this purpose, growth hormone is produced in massive amounts compared to other hormones because its work is so crucial. Growth Hormone is essential for repair work in every cell of the body, and for the generation of new cells, and its production peaks in the deepest levels of sleep. The digestive and immune systems require a huge turnover of new cells daily, and these suffer if growth hormone production is disturbed.
Bad sleep upsets our ability to fight infections. Immune function operates on a daily rhythm in step with the sleep/wake cycle. A single night of bad sleep can cause our levels of killer T-cells to drop by a quarter. These are the cells responsible for killing off infected cells, including some cancers. In contrast, animal species that sleep the most tend have the strongest immune systems and the fewest parasites.
In sleep, the body lays up supplies. It builds up the nutritional substances within cells in preparation for the following day. Resting muscles are able to refuel their depleted supplies of glycogen or 'muscle-sugar' for example.
Poor sleep disturbs the processes of digestion, metabolism and the excretion of waste products. Digestion is the extraction of nutrients from food. Metabolism is their use within the cells of the body. Excretion gets rid of unwanted by-products and dead body parts. These processes take many hours from start to finish, and they work best if they are uninterrupted by physical or mental activity. This is why it feels natural to rest after a meal. It gets the process underway.
An insomniac is likely to have high cortisol levels even when asleep. Cortisol prevents the uptake of metabolic resources by the cells. It increases insulin resistance and causes blood sugar imbalances. In fact severe tiredness mimics the first stages of diabetes.
Sleep deprivation can also make us fat. Short sleepers and poor sleepers are more prone to obesity. As the production of growth hormone declines with stress and age, we convert energy to fat instead of muscle. Poor sleep also increases the production of grhelin, a gastric hormone responsible for hunger and our tendency to over-eat. You may notice how you often feel hungry when you wake up: that is the effect of grhelin.
There is also a neurological explanation for the way that poor sleep makes us feel miserable. It makes brain cells less sensitive to serotonin, the feel-good hormone whose activity is enhanced by Prozac and other antidepressants.
THE BRAIN NEEDS GOOD SLEEP
The brain needs good sleep for learning and memory. At night, free from the onslaught of stimuli, the mind is able to review the events of the day. Since we use the same brain areas to both perceive the world and to process what has happened, we can't do both at once. We need time to digest it all.
In dream sleep, which occurs just below the surface of consciousness, we review and evaluate the day's events in real time along with their full emotional content. In deep sleep, on the other hand, we strip the same events down to their essentials and code them into long-term memory.
This process prunes out the trivial details, emphasises what is important, drafts as coherent, thumbnail stories and integrates it all into the database of associated memories in the brain. If we don't get sufficient downtime for this work, our minds become overloaded with unnecessary detail and too disorganised to work well.
The brain organ that consolidates new memories is called the hippocampus. Most brain cells can't regenerate themselves but the hippocampus is the exception. It can generate new cells in response to new memory tasks, but this makes it particularly vulnerable to cortisol. Just as it does in the digestive and immune systems, cortisol damages the genesis of new cells. It also inhibits the growth of connections between cells that embed memory. With sustained stresss, the hippocampus can actually shrink in mass. This explains why poor sleep, stress and depression typically cause memory failures and a tendency to behave thoughtlessly.
We also solve problems while asleep. Musicians learning a piece of music will rehearse the most difficult passages in their sleep. Rats will repeatedly revisit the parts of the maze where they got lost. In sleep, the brain seeks out the hidden connections between memories in ways that the conscious mind can't. This lateral, associative way of thinking helps resolve the cognitive failures, big and small, of the previous day. It also enhances our ability to solve problems when we wake up. All this takes time. It takes sufficient sleep of the right quality for optimal results.
WHY IT IS HARD TO IMPROVE OUR SLEEP
It doesn't hurt to have a bad night or two. We can catch up on the sleep we've missed the next night or lie in bed longer than usual on the weekend. With chronic sleep deprivation however we gradually lose that ability to pay off the sleep debt.
Anxiety trains the body to have higher levels of cortisol regardless of the time of day. This means that although your cortisol will be at its lowest levels at 3 am, it will still be higher than it should. When this happens, lying in bed for a few extra hours no longer works. Even if you are dozing, you will be too close to the surface of sleep to benefit. Once our sleep becomes ragged it is not easy to restore it. Insomnia, stress, ill-health and fatigue form a feedback cycle that can be quite difficult to break.
So why don't we take sleep more seriously? In medical terms, poor sleep is like the elephant in the room. It contributes to so many ailments but we ignore it. Sleep can be improved – there is no mystery about how to do it – but it does take more effort than we are inclined to give it. It would involve changing some habits and taking time from other activities we would prefer to do, such as watching TV. It is not surprising that we find it all too hard to contemplate.
Expensive as it seems to be, good sleep is worth the price. Better sleep can help if you suffer from indigestion or pain; if you feel perpetually tired or off-colour ,or are prone to infections; if you are more anxious, depressed or fat than you would like to be; if you feel unable to think clearly or see things in perspective; if you are so irritable or mentally absent that your relationships suffer; if your memory is shot, and if you feel older than you should.
Better sleep can help all of the above. It is quite possible that many of our common ailments would decline in severity, and some would vanish, if we just got enough sleep. We feel tired and run-down and unable to cope not because of some mysterious ailment. We are tired because we are tired. We are not getting enough sleep. If we slept more and improved the quality, we would feel a lot better.
HOW MEDITATION HELPS
Meditation helps insomniacs in several ways. It calms them down before going to bed. It defuses the thinking that tends to keep them awake. It initiates the sleep response as soon as they lie down. It helps them go back to sleep if they wake in the small hours. And if they do remain awake for whatever reason, it enables them to be calm and relaxed in that state instead of fretting.
Many insomniacs come to my meditation courses. Within a few weeks, about half are
sleeping better and some are vastly improved. Often the results are immediate. People
often tell me they they sleep their best on the night after the meditation class.
As meditators become more self observant, they notice how certain activities help or hinder their sleep. We can't expect to fall asleep quickly after TV, computer activity, emotional excitement or any mentally demanding work. Reading a book seems to be fine. A big evening meal doesn't help or coffee in the preceding hours.
Lying in bed talking to a partner or thinking over the day will counteract sleep. It is much better to intend to go to sleep, or to meditate the moment your head hits the pillow. Similarly, if you wake in the night or if you have to go to the toilet. Any time you spend processing your thoughts in bed is likely to wake you up even further.
If you are stressed, you are unlikely to sleep well unless you can also relax occasionally during the day. Most of us have automatic strategies to help us do this. We have teabreaks; we sit and read the paper mindlessly; we zone out at meetings or we potter round the house.
These are times when you slow down and collect your energy. You take a few steps in the direction of sleep without going the whole way. I train people to do short spot meditations' for a similar effect. If you can deliberately relax a little many times a day, you are likely to sleep better at night. You can release the daily tensions as you go rather than hoping to defuse them all when you you hit the pillow.
When you are in bed, you can't count on the momentum of fatigue pulling you down towards sleep as it does in a sitting meditation. After a few minutes in bed, your body is relaxed anyway and that dynamic is no longer happening. This is why trying to blank out or daydream, or waffle your way into sleep, is unlikely to work. It will be your mind that is keeping you awake.
Paradoxically, the best way to fall asleep is to make your mind as sharp and focused as it
can be. In other words, to meditate well with no indulgent wandering. This is the only
way to reliably cut free from the thoughts that keep you awake. Any meditation
practice will do, but I often use music. If I switch on my bedside CD player and listen
as intently as I can, I am usually asleep within a minute. Meditation is useful even if you
don't fall asleep. Many people are so scared of not sleeping that the fear keeps them
awake. If you lie there worrying, you will burn a lot of energy and get up in the
morning exhausted. If you meditate, however, your body can still rest, your mind can
be calm and you are more likely to dip in and out of sleep.
If you are wide awake because of physical pain or emotional turmoil or a partner's snoring, it can be invaluable to meditate. You may not fall asleep, but your mind becomes more detached and dispassionate. You may not like the situation but you don't have to over-react. While not perfect, this can be vastly preferable to rising in the morning irritated and exhausted.
