Some people cannot sleep because they have insomnia. Me? I cannot sleep because I have an Internet connection.

Sleep is a sadly neglected part of human life. If we are short of time, if we have too much to do, or are under pressure at work, or with our homework, we tend to scrimp on our sleep. Working an all nighter is a badge of honour in some companies. This sounds like a good idea, freeing up more time for us to deal with the stressful goings on in our lives. However we may just be storing up more trouble for ourselves than we avoid.

Many of the old wives tales and nursery rhymes contain a large element of truth.

Early to bed, early to rise, makes a boy healthy, wealthy and wise.

You need your beauty sleep.

Missing a night of sleep has the same effects on our brains as having a blood alcohol level that is above the legal driving limit.

On occasion I like to watch the programme “Air Crash Investigations”. This is not because of the rather naff animations of planes crashing, but instead I like the careful root cause analysis that is undertaken to find the real causes of any accident. Quite often a major contributing factor is described as “subtle incapacitation”.  More often than not this means the pilots had not had enough sleep.

In the UK a few years ago there was a crash involving a train and a car, caused by the driver falling asleep at the wheel and driving onto the tracks.

The Three Mile Island and Chernobyl nuclear disasters were also contributed to by a lack of adequate sleep for key staff.

In the US it is estimated that tiredness contributes to 100,000 car accidents every year with around 1500 fatalities. The ubiquitous signs we see on motorways around the world are not just for show.

So, how much sleep should we all be getting?  This is variable and changes with age, on average the young need more sleep than the old. We all know of people, such as Margaret Thatcher, a former UK Prime Minister, who seemed to get by on fewer than six hours a night, however this is not common and only about 3% of people have a genetic make up that lets them function properly on this little sleep. For us mere mortals the following table provides a reasonable guide. The majority of us need to sleep for at least the average number of hours.

• Newborn to 2 months        12 – 18 hours (although to all new parents this does not seem possible)
• 3 months to 1 year            14 – 15 hours
• 1 to 3 years old                  12 – 14 hours
• 3 to 5 years old                  11 – 13 hours
• 5 to 12  years old               10 – 11 hours
• 12 – 18 years old                8.5 – 10 hours
• 18+ years old                     7.5 – 9 hours

A recent survey of teenagers found that as a group they required 9.25 hours of sleep per night, but were only actually getting 7.25 hours. This is a sleep deficit of some 14 hours a week, some of this can be reclaimed by sleeping later at the weekends but results in a chronic state of sleep deprivation. Sleep deprivation is highly likely for most of us if we get are getting fewer than eight hours of sleep each night. This sleep debt comes at a high price.

The cartoons and movies usually show sleep deprivation as people falling asleep into their food or propping their eyelids open with matchsticks. This is amusing, but the symptoms of sleep deprivation are much more subtle and insidious. Many of us probably cannot remember what it is like to be properly refreshed and fully awake. Some of the things that we would regard as normal are in fact signs of sleep deprivation.

• Struggle to wake up in the mornings, reliant on alarm clocks and overly reliant on the snooze button.
• Afternoon tiredness and a slump in concentration and effectiveness.
• Tendency to fall asleep or get drowsy in meetings or warm rooms.
• Get sleepy when driving or after a large meal.
• Need a daytime nap.
• Feel the need to sleep too much at weekends “to catch up”.
• Fall asleep in front of the television or while relaxing.
• Fall asleep within five minutes of going to bed.

Lack of sleep affects us much more than we would think. It impairs judgement, reduces coordination and delays reaction times. In fact it has remarkably similar effects to being drunk.

So what effects does lack of sleep have on the average person?

• Tiredness, fatigue, lack of motivation and general lethargy.
• Impaired problem solving skills.
• Poor concentration and memory difficulties.
• Weight gain.
• Decision making problems.
• Impaired immunity and increased susceptibility to colds and other health problems.
• Problems coping with stress.
• Increased risks of developing diabetes, heart disease, other health problems.
• Moodiness, low mood, irritability.

Chronic sleep deficits have a link to weight gain and obesity.

There are two main hormones that are involved in hunger and satiety control.

1. Ghrelin stimulates the appetite, when we do not get enough sleep the body makes more ghrelin leading to stimulation of our appetite.
2. Leptin sends signals to the brain to signal that we are full. When we do not sleep enough leptin secretion is reduced. The combination of the two means that we feel hungrier without the usual indication that we are full.  This means that we crave more food and do not know when to stop eating. Hence there can be significant weight gain.

It is not only the number of hours that we sleep, but also the quality of that sleep that matters. There are in effect four phases to sleep and we cycle through them several times a night. This cycling seems to be vital for health.

1. Stage 1. Transition to sleep. Usually this lasts about 5 to 10  minutes. Our eyes move slowly under the lids, our muscle activity slows down and although drowsy, we are easy to rouse.
2. Stage 2. Light sleep. This is the first stage of what can be called true sleep. It usually lasts from 10 to 25  minutes and is characterised by the eyes stopping moving, a slowing in our heart rate and a decrease in body temperature. This phase accounts for about 50% of the sleep we get.
3. Stage3. Deep sleep. We are difficult to wake up and once woken, we feel groggy and struggle to adjust to being awake, and can be disorientated for several minutes. Brain activity is very slow and our blood is directed towards the muscles allowing physical recovery. Roughly 30% of the sleep cycle is spent in deep sleep.
4. REM sleep. Rapid eye movement sleep.  Roughly 70 to 90 minutes after falling asleep we enter REM sleep, where the eyes can be seen to move rapidly around under the eyelids, breathing becomes shallow, arm and leg muscles become paralysed. About 20%.

More of our deep sleep occurs in the early half of the night while there is usually more REM sleep in the second half of the night. Over the course of the night we cycle through the various sleep phases several times. The most important phases appear to be deep sleep and REM sleep.

Deep sleep helps to maintain health, stimulates growth and development, allows muscles and other organs to repair, and boosts the immune system. REM sleep is the phase in which most dreaming occurs, and dreaming seems to play a key role in keeping our mind working well. Learning and memory are enhanced by this part of the sleep cycle and impaired when we do not sleep enough.

To repay our sleep debt it is not enough just to have a lie in at the weekends. From the figures above about teenagers’ sleep patterns, we can see that on average a teen is 14 hours in sleep debt each week. this means that the equivalent of nearly two nights sleep are missed in just one week. On an annual basis this is nearly three months a year. Sleeping in at the weekend can make up for some of this deficit, but not enough for healthy functioning, concentration and academic success.

What can we do about our chronic sleep deficit?

1. While an adult needs at least seven and a half hours, nine and a half hours is the right amount of sleep for an average teenager.  This should be the target for every night. Consistent sleep is the best way to get out of sleep debt and to stay out of it.
2. Start with an extra hour or two of sleep every night. If you have a sleep debt of 20 hours an extra hour for three weeks would be one way to do this.
3. Use an App or other sleep monitoring device (even a pencil and paper) to record our sleep pattern, total hours slept each night, how we feel during the day etc.
4. Use holiday time to pay off a longer term sleep deficit. For a couple of weeks we can try going to bed at the usual time and sleeping right through until we wake up naturally, no clocks or alarms. This method also helps us to work out a sleep pattern that works for us.
5. Make sleep a priority and schedule enough in your day.  Getting more sleep will increase our productivity and enable us to do more.

Sleep also leads to improved grades at school, better relationships and a greater sense of well being.

My grandmother was a great believer in the restorative and health benefits of sleep and would often say

I could go away for  a fortnight with the bags under your eyes. You need more sleep laddie.

Perhaps we should all do ourselves a favour and follow her advice.

I will post more on sleep later.
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