Every day we devote about one third of our time on sleep and many of us understand sleep mainly as a time of doing nothing, kind of like being switched off. However while we are asleep our brain is working hard to build new pathways which are vital for learning, memory and new ideas. Furthermore our immune and hormone system switches from day shift tasks to night shift tasks. A good night sleep will therefore improve your ability to fight infection, as a rested body fights pathogens more efficiently.

Throughout the last decades medical researchers have gained insights into the importance of sleep and dreaming for human health. Many population studies today aim to assess not only how much and when certain parts of the population sleep but also whether our sleep patterns have changed over time and in how far chronic diseases could be associated with this.

Although there is quite a wide variation of sleep patterns between individuals current evidence suggests at least 7 to 8 hours continuous sleep per night is healthy for most people, below and above that the risk of physical and mental health problems, injury and mortality increases whereas productivity decreases. Population studies suggest a higher risk for the metabolic syndrome, diabetes type 2 and obesity in people who usually sleep shorter or longer than 7 to 8 hours per night. It appears however that sleep duration has declined in the USA and Europe by about 2 hours over the last 50 years.

According to a recent study in the USA up to 29% adults report to sleep less then 7 hours per night and up to 70 million U.S. adults state to have chronic sleep disorders. These numbers might be just as high for the UK and in particular in groups of people which are under a lot of time pressures, work related or personal stress.

Based on this study, women and people below the age of 45 years are more likely to report insufficient sleep in the preceding 30 days and the 25-34 years old usually report the highest number of nights of insufficient sleep. People above 65 years of age commonly report insomnia, however if their health status is taken into consideration healthy elderly appear to gain enough sleep whereas the ones who suffer of chronic diseases have often reduced hours of sleep.

A further aspect of healthy sleep is when someone is asleep or awake. Studies on shift workers support that working through nights has negative effects on quality of sleep and health which is believed to be caused by varying hormonal levels within the body at day and at night or our inner ‘clock’. The human body is adapted to be awake at day hence certain hormones are excreted at specific times of the day. Cortisol for example has high the circulating levels in the morning which decrease progressively throughout the day. Cortisol is vital for the energy metabolism and is as such involved in weight gain or weight loss, this may in part explain why shift workers tend to be more likely to be overweight as low circulating cortisol in the night could support weight gain.

Another important hormone influenced by our biological ’clock’ is melatonin which is released in larger amounts when the night falls and makes you feel drowsy and sleepy. This hormone is also believe to be the causal factor for the sleepiness in the afternoon dip as there is an increased production of melatonin between 1pm and 4pm.

So, how to get a good night's sleep?

• Avoid caffeine it can take up to 8 hours to wear of the effects of caffeine hence a coffee in the late afternoon could prevent you from falling asleep.

• Avoid other stimulants such as certain pain killers, alcohol (prevents deep sleep) or nicotine.

• Avoid large heavy meals before going to sleep.

• Avoid exercise before bed time as exercise increases your metabolism and blocks sleep hormones hence you may find it difficult to fall asleep. However exercising during the day is beneficial for a good night sleep.

• Having a hot bath before going to bed as well as creating a calm and relaxed environment improves your chances of a good night sleep.

• Try to reduce any noise and light in your sleeping room and have a comfortable bed/mattress.

• Aim to go to bed always around the same time this will help you body to adjust and get prepared to sleep.

• Don’t lie awake in bed, if you are unable to find sleep within 20 min, get up and try to do something relaxing rather than rolling back and forth in your bed and getting more and more anxious about not falling asleep.

Andrea Zick, Esteem Fitness Nutritionist London

Esteem Fitness – Personal Training London and the South East