From babies that sleep most of the day, toddlers that need an afternoon nap, teenagers that sleep like the dead and adults that rarely sleep at all, most of us are aware that the length, depth and quality of our sleep changes dramatically throughout our lives. This blog post is the last in a series aimed at giving you a deeper understanding into what is going on at each age and why, and is about how we sleep in old age.
Both anecdotal and research evidence supports the fact that we are far more likely to experience sleep-related problems later in life, but why is this the case and can we do anything to improve our sleep past the age of retirement?
Sleep issues tend to be more prevalent in older adults for a number of reasons, some directly related to the process of sleeping and the structure of that sleep and others related to influential factors that are more related to ageing than to sleep itself.
In order to gain all of the positive health benefits and feel refreshed after sleep, all humans need to spend at least some of their time asleep in the stage termed deep non-REM. Entry into this level of sleep is determined by the production of powerful brainwaves generated by a specific section of the brain. However, our ability to produce these brainwaves and therefore to enter into and, more importantly, to maintain deep NREM sleep reduces year on year after the age of 25, so that an older adult spends 80-90% less time in deep sleep than a teenager.
This means that older people experience their sleep as being more fragmented than before; they wake up more often overnight and are disturbed more easily by noise, mental activity (intrusive thoughts) or physical sensations such as pain, temperature changes, bladder urgency etc. It also means that older adults spend more time in lighter levels of sleep and may report feeling unrested even if their sleep has been consistent.
Interestingly, this decline in satisfaction with sleep is usually an unconscious effect - we have a tendency to attribute our low mood, physical ailments and decreased energy levels on other health conditions and fail to associate them with poor sleep quality.
It is a common misconception that older adults do not need as much sleep as their younger relatives. In reality, the longer and better quality your sleep is at this age determines not only your longevity but also your quality of life. It is not that sleep is needed less, but that it is just less able to be achieved. As at any other stage in life, not getting enough good quality sleep often results in daytime fatigue and it is not uncommon for older adults to make up for what they have lost overnight with a nap during the day.
In addition, as we progress through life, our internal body clock (circadian rhythm) that signals to us when we should be awake and asleep, shifts slightly earlier, so that we have a tendency to struggle to stay awake earlier and earlier in the evening and then find ourselves awake (but possibly not rested) earlier and earlier in the morning. This shift and the return to biphasic sleeping (sleeping in two phases) is completely natural and is a globally recognised phenomena. It also marks a return to how we sleep as young children, which is interesting to note if you believe that life is a circle.
Add into all of this the other age-related factors that influence sleep, for example, medical conditions and the medications taken for them, stress, hormonal fluctuations, and lifestyle factors such as diet, exercise, smoking and alcohol use, and it is not difficult to understand why sleep issues are more prevalent in older adults.
The last possible influential factor on the inability of older adults to sleep is related to the amount of sleep pressure they build up during the day. I will explain more about sleep pressure in another blog post, but simply put, it works in very much the same way as hunger - steadily increases over time from the last time that you ate/slept and is increased by both physical and mental activity.
There is an argument (albeit a contentious one) that older adults, particularly those in their retirement, are not as physically or mentally active as their younger relatives and are therefore not as “hungry” for sleep. Now I can imagine a few people currently shouting at the screen that they or their retired relatives are just as or even far more active now than they were in earlier life, but these individuals are more likely to be the exception rather than the rule. You may also find that these individuals do not have any issues with their sleep but do let me know if you disagree.
Unfortunately, the instinctive reactions to experiencing increasingly fragmented, un-refreshing sleep can often make the situation worse. Daytime napping (including falling asleep in front of the TV!) may enable us to supplement shorter overnight sleep, but may also cause the body’s natural drive for sleep at night (sleep pressure) to decrease, exacerbating the problem in the long run. Going to bed earlier in an attempt to sleep more will only cause you to spend more time awake in bed, creating a negative mental association between your bed and the stress and worry of not being able to sleep.
Probably the biggest block to sleep that we develop with age is related to the automatic nature of sleep. The transition into sleep is a completely natural process that becomes more difficult the more we think about it (in a similar way to driving a car or dancing). Once we have experienced an issue with our sleep, we can then begin to try too hard and the effort of doing so may well then prevent us from sleeping. In the long-term, if we continue to try and fail to sleep well our self-confidence in our ability to sleep is then also undermined setting up a negative loop in which it is too easy to get caught.
So what can we do to improve our sleep in later life. My first recommendation is to come to terms with the fact that you will never sleep in the same way that you did as a teenager or young adult and to accept that this is not your fault. No one, regardless of age, sleeps well every single night and there will always be some nights that are better than others, but worrying about your sleep will only make matters worse. Try to stick to a routine as much as possible, practice good sleep hygiene and if you must nap during the day, take your nap as early as possible. Lastly, if you are ever in bed and you are not asleep, get up and do something else. Never try to force yourself to sleep.