I love my bed! I know some people feel that time spent asleep is wasteful and claim they can manage perfectly well on just 4 hours sleep a night but I have always felt that sleeping is one of the most pleasurable things that we do and that it makes my waking life worth living. And now my love of sleep has been totally vindicated in a new book by Matthew Walker called 'Why We Sleep: The New Science of Sleep and Dreams'. The book has quite a lot to say about sleep and ageing so I thought I'd pick out the most relevant parts of it to share with you. Hopefully it won't alarm you too much because throughout the book, Walker stresses the vital importance of good quality sleep for our physical and mental health - to quote him "Sleep is the single most effective thing we can do to reset our brain and body health each day - Mother Nature's best efforts yet at contra-death." Fortunately he gives lots of advice on how to improve the quality of the sleep we are having, which I know is a concern for lots of us as we age.
Why We Sleep: This was a mystery for a very long time. In evolutionary terms, sleep is a very bad idea because asleep we are clearly much more vulnerable to attack from predators and yet our need to be unconscious for around a third of the time in a 24 hour period has not changed over thousands of years. Walker makes the very strong case that sleep is essential for our survival because of what happens to our bodies and minds in terms of essential repair. Shakespeare summed it up brilliantly when he wrote in Macbeth:
"Sleep that knits up the ravelled sleeve of care,
The death of each day's life, sore labour's bath,
Balm of hurt minds, great nature's second course,
Chief nourisher in life's feast."
The Circadian Rhythm - Lark or Owl?
Our circadian rhythm is the twenty-four hour body clock which governs (among many other things) wakefulness, levels of alertness and how and why we become sleepy and ready for our beds. It's taken me 69 years to discover that my circadian rhythm is not only normal, but shared by 30% of the population! I am an 'Owl' which means that my body is very alert and wakeful until around 11.30 pm. I rarely go to bed before that time and then I read for half an hour, and sleep like a log from midnight until (preferably) at least 8 am. I tend to wake very slowly and feel groggy and thick headed until about 11.00 am. All my life, 'Larks' - the 40% of the population who snap awake at 6.00 am and are asleep by 10pm - have judged me as 'lazy' because I find it so hard to get going in the mornings. Having read a perfect description of my circadian rhythm in Walker's book I feel so relieved - there is nothing wrong with me! I am not lazy and, when I can go to bed and get up at a time that is best for my body, I sleep really soundly and feel full of beans from around 11am until midnight.
Melatonin and Adenosine.
It's our circadian rhythm which prepares us for bed with the release of the hormone melatonin. This is released as night approaches to regulate the timing of when sleep occurs, but it has no effect on the generation of sleep itself. Melatonin, contrary to popular belief, doesn't act as a sleeping pill, but as a starter gun for the the period of drowsiness to be triggered. From a high peak at midnight, melatonin levels gradually diminish to attain their lowest levels by midday. The second force that will determine when you feel sleepy is a chemical in the brain called adenosine. This gradually builds up with every waking minute until, at its peak, it creates such strong sleep pressure that slumber becomes an irresistible urge. Both melatonin and adenosine are affected by ageing.
Sleep and Ageing
Some people think we need less sleep the older we get. However the fact that we tend to sleep less well doesn't mean that we don't need the restorative benefits of a good night's sleep. Walker goes so far as to suggest that many of the health problems of ageing are both caused and greatly exacerbated by poor quality sleep. There are three main causes of this as we get older:
1. The first is that from our forties both the intensity and length of time we spend in the vital NREM (Non Rapid Eye Movement) period of sleep diminishes. The NREM phase is essential for memory and learning.
2. Our sleeping patterns become fragmented. Weaker bladders mean that we wake to go to the loo more frequently than we did when younger.
3. Our circadian timing changes as we age. Melatonin tends to be released earlier in the evening leading to a great desire to be in bed at an earlier time. Going out in the evening becomes a challenge, to stay awake for long enough to enjoy the film, theatre or restaurant outing. Falling asleep in the chair in front of the TV clears away the sleep pressure of adenosine, meaning that at bedtime there is not enough left to get you to sleep or to stay asleep for very long.
How to Get a Better Night's Sleep
Walker has a couple of age-related pieces of advice (1 and 2) and some general guidance for all adults (3-8):
1. Regular exercise will help you to sleep better. However, Walker suggests that you wear sunglasses for morning exercise but take them off for afternoon exercise as a way to combat the early to bed, early to rise sleep pattern with lessened exposure to bright light in the first half of the day. He also suggests that it's best not to exercise two to three hours before bedtime.
2. You may wish to consult your doctor about prescribing melatonin to be taken in the evening to combat the lower levels of melatonin that older bodies tend to release.
3. Get up and go to bed at the same time every day, including weekends to create regular habits around sleeping time and waking time. If you do none of the other things advised here, at least do this!
4. Caffeine and nicotine are stimulants which affect sleep. Best not to drink coffee (or tea or cola-type drinks) after mid-afternoon as their effects can last up to 8 hours. For smokers the stimulating effect of nicotine means that you sleep more lightly and may wake earlier than you'd like because of nicotine withdrawal.
5. Avoid alcohol and large meals before bedtime as both will interfere with the quality of rest. Heavy use of alcohol robs you of REM (Rapid Eye Movement) sleep, keeping your sleep light.
6. Don't nap after 3 pm. Naps may help you to make up for lost sleep, but will make it harder to fall asleep at night.
7. Check with your doctor that medications you may be prescribed for heart or blood pressure problems or asthma are not delaying or disrupting your sleep. Some over the counter remedies for coughs, colds or allergies, including herbal remedies might also affect the quality of your sleep. It might be possible to take such medication earlier in the day.
8. Keep your bedroom for sleeping only and make sure the room is very dark and cool - no warmer than 18º. Also avoid using electronic tablets like iPads in the bedroom and up to two hours before bedtime as studies show that because of their blue LED light, they block the rise in melatonin by 23%.
9. Take a hot bath and relax for at least a half an hour before bed to allow yourself to unwind.
10. Don't lie in bed awake. If you are feeling anxious get up and do something relaxing until you feel sleepy and then go back to bed.
I do hope you have found this blog helpful and not worrying. I can thoroughly recommend the book, however it does stress just how important sleep is to our well- being - which might cause you to lose sleep! I found it very helpful because it gave the perfect explanation for my terrible grogginess first thing. Now I know this is down to my Owl circadian rhythm, I can completely relax about it. Do share your experiences and anything that you have found works for you to get a better night's sleep by leaving a comment below.