Sleep is food for the brain and is as vital as the air we breathe and the food we eat. Healthy sleep keeps us happy, healthy and alert. Too many of us forget that the lack of adequate, restful slumber has serious consequences – at home, in the workplace and on the highway. Getting enough continuous, quality sleep contributes to how we perform and feel the next day, but also has a huge impact on our overall quality of life. Not only does good quality sleep make us function well during the day but it allows our bodies to rest and recuperate.
Adequacy of sleep is a function of its duration, quality and timing. We need consolidated, restorative sleep for many functions including:
Adequacy of sleep is a function of its duration, quality and timing. We need consolidated, restorative sleep for many functions including:
- Cognitive, social and physical performance
- Functioning in a safe, efficient and effective way
- Emotional enhancement and relating well with others
- Healthy immune function
- Learning and memory consolidation
- Prevention of health problems and optimal health
Duration – the amount of sleep we need differs from person to person, although research suggests that adults need 7-9 hours each night for optimal health and wellbeing. Sleeping more than 9 hours or less than 6 hours per night on a long term basis is associated with a higher death rate. Contrary to common myth, older adults need as much sleep as younger adults, but they often do not have as efficient or good quality sleep.
Quality - the quality of sleep is also imperative to health and functioning. It is important to have adequate amounts of each stage of sleep, and that sleep is uninterrupted and consolidated.
During sleep we experience two alternating states of sleep – NREM sleep and REM sleep.
- Stage 1 – this is called light sleep and is our initial entry into sleep.
- Stage 2 – occurs with sleep onset when you become disengaged from the environment, breathing and heart rate are regular and body temperature is decreasing.
- Stages 3 and 4 – also known as deep sleep, and are the deepest stages of sleep when we experience the most restorative sleep. Muscles are completely relaxed, blood pressure drops and breathing slows. During these stages of sleep, blood supply to the muscles is increased, energy is restored, tissue is repaired and growth hormone production takes place.
Rapid-eye movement or REM sleep occurs increasingly over the latter part of the night and is necessary for providing energy to our brain and our body. During REM our brains are active and dreaming occurs. REM sleep contributes to learning and memory consolidation.
- NREM sleep accounts for 75% of sleep time.
- REM sleep accounts for 25% of sleep time.
Timing – sleep quality is improved if we sleep in synch with our body clock. This means that the best time to sleep is during the night when our biological rhythm is set to sleep. Sleep is regulated by two body systems – the sleep/wake restorative process, and the circadian biological clock.
- Sleep/wake restorative processoccurs naturally in response to how long we are awake; the longer we are awake, the stronger the drive to sleep.
- Circadian body clock – this clock controls the timing of sleep and wakefulness during the day-night cycle. Timing is regulated by the circadian (biological) clock that is located in our brain. This part of the brain is influenced by light so that we naturally tend to get sleepy during the night when it is dark, and are active during the day when it is light. This clock runs on a 24-hour cycle.
Summary:
We all need sleep of optimal duration, quality and timing if we hope to be at our best the next day as well as greater overall health and wellness. There are a huge number of factors that can negatively impact the duration, quality and timing of sleep. Therefore it is important to take action to ensure we get the best, most natural sleep possible.
