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The Importance Of Sleep: Why Less Than 6 Hours Of Sleep May Raise Your Risk Of Dementia

October 24, 2024

Sleep is one of the most important functions for human survival. Without it, we cannot function properly let alone perform efficiently. 

When we sleep, the glymphatic system is engaged. Think of this as a type of ‘plumbing’ system for the brain that works by detoxifying – it removes the buildup of waste products and plaque, allowing you to have a clean, fresh start when you wake up in the morning. This is why we so often feel revitalised after a good night’s sleep. At the same time as eliminating these toxins, sleep filters out unnecessary connections while enforcing new neural pathways to solidify memory, experience and emotions, all the while preserving your brain health. 

Our brains contain approximately 86 billion neurons, each sending and receiving chemical and electrical signals to one other – this is their way of communicating. When we are sleep deprived, neurons can become ‘fuzzy’ and they end up failing to communicate with one another. ‘Our ability to recall, consider and concentrate depends on millions of cells working smoothly together’, writes Professor James Goodwin in his book Supercharge Your Brain. Without the right amount of sleep each night, you will find it difficult to process properly. Your decision making will be hopeless and you won’t be able to think straight. This, on an ongoing basis, not only contributes to cognitive decline, but also dementia in later life. 

So what is the ideal amount of sleep we should be getting each night? The answer is 7-9 hours, not necessarily per night, but 7-9 hours per 24 hour period.  This is because our sleep patterns change as we age, so if we are sleeping less hours per night, short napping during the day will help.  Any less, or more, is linked to cognitive problems in later life. Professor James Goodwin states that it’s “not what we do occasionally that matters; it’s our long-term, persistent sleep behaviour”, so we needn’t be worried about the occasional bad night sleep or weekend lie-in. 

This weekend the clocks will go back one hour, allowing us all to have that extra hour of sleep. Here are our top five tips on how to get help get a good night’s sleep:

  1. Set a time limit with your screen: avoid phones, Ipads and laptops two hours before bed. The blue light from the screen tells the brain that we have oncoming daylight, waking you up rather than sending you to sleep. 
  2. Limit alcohol before bed: alcohol has a soporific effect, making you feel drowsy to start with, but waking you up in the early hours of the morning. 
  3. Meditate: set aside 1-3 minutes before you go to sleep each night for some quiet meditation. This can as simple as taking six deep breaths or practising gratitude to calm the body and relax the mind. 
  4. Scent before sleep: smelling a relaxing scent can calm the nervous system. Lavender is a safe, yet effective alternative to prescribed medication, helping to reduce any anxiety experienced before bed. 
  5. Create a dark environment: dark stimulates the pineal gland located deep in the brain. When stimulated, the pineal gland produces melatonin which is the hormone that encourages that feeling of tiredness. 

In general, changing the clock back in the autumn and forwards in the spring is an ill-advised move for our health, regardless of any practical benefits. Every cell, organ and system, and most certainly our brains, are finely tuned to the time of day (daylight hours or photoperiod).  The statistics bear this out: on the day of the change there is an increase in cardiovascular incidents including heart attacks and strokes, hospital admissions increase, as do inflammatory stress markers in the blood, mood disturbances and even the number of road traffic accidents.

For more information, visit our Sleep pillar here and have a read of how a good night’s sleep could be the dream prescription for a healthier body and brain.