Sleep – or lack of it

As stress levels are building up, and sleep is becoming a luxury, it’s hard not to wonder what effect this is having on my body, and how my body manages to cope.

Firstly, sleep is a necessity for most vertebrates, without which physical fitness and immunological functions suffer significantly.  Although scientists don’t fully understand why we need sleep, it is thought that it is necessary to restore what is lost while we are awake. Muscle growth, tissue repair, protein synthesis and growth hormone release occur mostly, or in some cases solely, during sleep.

Not only is sleeping necessary, it also prefers to stick to a pretty tight schedule. The circadian rhythm is the daily cycle of activities observed in many living organisms, i.e. a body clock. The body regulates its own times for sleeping and waking, and is cued by a number of factors. These include the optic nerve sending signals to the brain and a bundle of nerves in the hypothalamus.

A chemical that effects our perception of tiredness is adenosine, which is a by-product of our neurons activities during the day that builds up in the brain. Caffeine works by blocking the actions of adenosine in the brain, thus counteracting the tiring feeling caused by adenosine.

A key hormone in initiating and maintaining sleep is melatonin, which is regulated by exposure to light. It is even known as the “hormone of darkness” because it is secreted when it is dark. Consequently, using a mobile phone just before bed is going to effect this regulation, and will make it much more difficult to fall asleep. Before the invention of the light bulb, people slept on average 3 hours longer.

Light isn’t the only issue we face nowadays when it comes to sleep. Clashes between what our bodies need, and what our lives demand, causes ‘social jet lag’. This includes having different amounts of sleep on weekends and weekdays, and spending less time outside (affecting the circadian rhythms). This is particularly significant for teenagers, as our wake-sleep cycles are set later. We tend to not feel sleepy till later, and then need to sleep later, yet we have to wake up early to fit into the normal working day of adults.

When we really don’t get enough sleep, our body has an impressive and quite surprising method for staying awake. If you’re deprived of sleep for longer than 40 hours, your body goes into brief and unpreventable microsleeps. These can last for a fraction of a second or up to thirty seconds.

It is clear that social demands of the modern age have caused our sleep to suffer, and given our complex sleep cycles it is not always as simple as just ‘going to bed earlier’ and then wondering why we’re still lying there wide awake at midnight. However there are some steps we can take to improve our sleep. Firstly, as mentioned earlier, caffeine opposes the effects of natural sleep-inducing chemicals produced by your body, so avoiding caffeine along with other chemicals that interfere with sleep is going to help. Secondly, creating a dark sleeping environment will help your body regulate the correct levels of melatonin needed for sleep. Getting into a regular routine will also help your body to maintain its circadian rhythm, especially maintaining that on weekends.