We spend around one third of our life sleeping. In terms of time, that’s a staggering 25 years. So it obviously must be important to our health and wellbeing. What is it and why do we need it?
So what is sleep?
We often think sleep is just the opposite of awake. That it is a time when the body and mind slow down or even shut down. In fact it is not a total shut down, during our sleep cycle several important stages have been documented. Science is just beginning to discover the some of the functions that are critical for our optimal sleep and by extension our optimal health.
Modern brain scanning techniques have enabled researchers to understand more about what happens to our mind and body during our sleep cycles.
- Stage One. The transition phase. Muscle activity slows. Body twitching is often observed.
- Stage Two. Heart rate and breathing slows. Breathing becomes even and regular. The majority of our sleep is in this state
- Stage Three. Delta waves are produced by the brain. Heart rate and breathing are at their lowest levels.
- Stage Four. Rhythmic breathing and very limited muscle activity.
REM (Rapid Eye Movement) sleep takes place during the sleep cycle. During this phase the brain is very active. This is when we dream. Our closed eyes dart about and our breathing rate and blood pressure rise.
The frequency of our brain waves change throughout our sleep cycle. The deeper we sleep the lower the frequency.
Why do we need to sleep?
Well if you think about it from an evolutionary point of view sleep doesn’t make a lot of sense. The time of sleep for our ancestors was a time of helplessness and danger. Sleep must be an absolute imperative to us or evolution would have discarded it early on.
Although there is not complete agreement between researchers they all tend to believe
- That sleep is a time to process the information that we have picked up during the day. A time to consolidate short-term memory into long-term.
- That the body re-energizes, restores tissue and recovers from the days activities
- That sleep is also a time to synthesize hormones.
How much sleep do we need?
We all know that healthy sleep is critical to everybody. During each phase of our lives different amounts of sleep are required. Probably it is obvious that young children need much more sleep that an elderly person due to the amount of energy they are using during their daytime activities. What might not be so obvious is because childhood is the time when huge amounts of information and learning is being processed that the child needs more time to consolidate short-term memory into long-term memories. Typically children might need between 10-14 hours of sleep a night to maintain optimal alertness and development.
Of course this does not explain why your teenage son spends 16 hours sleeping through a complete Sunday!! That is probably being researched some where though.
Unfortunately we cannot accumulate sleep to pay back what could be termed a sleep debt. The best sleep routines are consistent regardless of our age or daily challenges.
How does the body recover during sleep?
During our daily activities various daytime hormones are released in order to meet the bodies activity requirements. Stress hormones are released to enhance our energy levels, as well as serotonin to maintain our mood balance. We can be described as being in a catabolic state.
When sleeping our body drastically reduces the release of daytime hormones and starts to produce the hormones required for sleep and recuperation. Melatonin is released to induce sleep and growth hormones are secreted to stimulate the bodies repair processes. The growth hormones are released when we are in our deepest sleep cycle known as sleep phase four, as noted above.
7 reason to get more sleep
- Better health. Good sleep patterns and quality don’t grant immunity from illness. But studies have found links between lack of sleep and heart disease, obesity and diabetes.
- Pain management. Getting enough sleep may actually hurt less. Studies have shown a link between sleep loss and lower pain thresholds.
- Better mood. When we don’t get enough sleep we all can recognize that we can be more emotional and cranky.
- Clearer thoughts. A bad or short night sleep leaves us feeling confused and fuzzy. Many studies have found a clear connection between lack of sleep and inability to solve simple logic and math problems.
- Stronger immune system. Some studies have shown that subjects that slept for less than seven hours per night were three times more likely to get sick.
- Better muscle building. Regular exercise normally will result in better sleep. For weekend or serious athletes more sleep better recovery.
- Job performance. Showing up at work drowsy will turn into poor job performance.