The effects of ageing on sleep

Have you noticed that you are waking up earlier in the morning when it used to be impossible for you as a teenager to wake before 11am? You�re not alone. Sleeping habits change naturally as we age, especially in our older years. Hence, it is important that we become aware of such changes and manage it for our well-being.

Changes in sleeping patterns

Here are some changes in sleeping patterns that you may have experienced over the years:

1. Increased sleep fragmentation
   You are stirred awake from sleep multiple times in the middle of the night.
2. More fragile sleep
   You may have become more sensitive to external stimuli, such as light or sound, which causes you to wake more easily from these disturbances. You feel like a lighter sleeper as compared to your younger days.
3. Advanced sleep timing
   You feel excessive sleepiness earlier in the evening and go to bed early, which results in earlier waking time.
4. Longer sleep-onset latency
   You are taking a longer time to fall asleep than before.

Needless to say, these changes greatly affect your quality of sleep and can be disruptive to your lifestyle. You will feel more tired than usual in the day and may need to adjust your daily schedule in order to go to bed earlier.

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Potential causes of sleep disturbances in older adults

There are a few reasons why sleep disturbances occur in older adults:

• Changes in circadian rhythm

The circadian rhythm also known as the sleep/wake cycle, is a natural internal �schedule� that your body follows every 24 hours. It tells your body the right time to sleep, wake up and eat. The body will follow the circadian rhythm�s cue to initiate the right biological processes, such as secreting the right hormones, to execute the instructed action.

As you grow older, your circadian rhythm will be altered, which in turn causes sleep disturbances. Research has shown that ageing is associated with a weaker circadian arousal signal, which causes the person to feel drowsy during the day instead of being alert as the circadian rhythm is not regulating the body properly. The body is not instructed to carry out the right processes, such as secreting less sleep-inducing hormones, melatonin, during the day in order to keep awake. As a result, the person tends to sleep early and wake up earlier as well (for example, sleeping at 8pm and waking at 4am), cumulating into a sleep disorder known as advanced sleep-wake phase disorder.

Similarly, during the night, an altered circadian rhythm can result in an increase of cortisol hormone levels in older adults, when it should usually fall. Research showed that the increase of this hormone is significantly correlated to increased sleep fragmentation and reduced Rapid Eye Movement (REM) sleep.

2. Medical conditions

Experiencing sleep disturbances can also be caused by health issues. A study done on Parisian older adults found that those sleeping too little tend to be suffering from obesity, insomnia, cognitive impairment and general poor health. Those sleeping too much tend to be those who were anxious, unhealthy, insomniac or apneic.

Negative changes in the respiratory system due to ageing can also cause the occurrence of sleep apneas, hypopneas, and arousals from sleep, resulting in sleep disturbances. People suffering from Alzheimer�s disease, where there is dramatic cell loss in the brain, have also been found to experience severe sleep fragmentation. Other factors such as medication use, nocturnal urinary frequency and chronic pain can also affect sleep.

• Poor sleep hygiene

Poor sleep hygiene can cause sleep disturbances in everyone, not just older adults.

Irregular bedtimes disrupt the circadian rhythm and make it harder to achieve quality sleep. Exposing yourself to too much light at night, such as light emitted from television or handphones, influences your circadian rhythm to think that it is still daytime. It confuses your body into staying awake, which makes it harder for you to fall asleep.

Caffeinated drinks can keep you awake beyond bedtime and even if you do fall asleep, it may decrease the time you spend in deep sleep, causing sleep fragmentation and increasing the likelihood of waking up at the slightest external disturbance.

Poor sleep means poor memory

One of the most significant impacts of poor sleep on older adults is impaired memory function, specifically sleep-dependent memory consolidation. Countless research has shown that sleep is important for learning, because it is during sleep that memories from what we have learnt in the day is consolidated, or in other words, stored in our brains. The storing of these memories allows us to recall what we have learnt later on.

As mentioned above, ageing alters the circadian rhythm, which in turn changes the time spent in REM sleep and the levels of melatonin secretion. Changes in REM sleep and high levels of melatonin inhibits memory consolidation during sleep. An increase in evening cortisol levels also affects memory consolidation since low levels of this hormone is needed during early sleep in order for memory to be stored. One other change in sleep through the night is the decrease in deep sleep (slow-wave sleep) which is also key in allowing the brain to store and retain new information. With all these factors affecting long-term memory storage, it is no wonder that older adults have a hard time recalling new information they have learnt.

Tips to achieve better sleep for older adults

Now that you have understood the changes and causes of sleep disturbances, you can better identify steps to manage these changes. Here are some tips that you can follow to get better sleep:

• Regulate sleeping and waking time
  Adhering closely to a regular sleeping schedule can regulate your circadian rhythm and maximise the amount of deep sleep you get. Avoid sleeping longer and hitting the snooze button on your alarm as this throws your circadian rhythm off.

5. Avoid late naps
   It is important to not nap late in the day as this can impair your ability to fall asleep at night. Do remember to keep your naps short (around 20 minutes).
6. Improve your sleeping environment
   Make sure your bedroom is quiet, dark and comfortable. Place your phone on airplane mode if it is near you when you sleep so that there will be no sounds or lights emitted from it. Earplugs and sleeping masks can help prevent you from waking due to external stimuli.
7. Avoid supper
   Eating a big meal before sleep increases your metabolism and makes it difficult to fall into a deep sleep. Avoid drinking caffeine 6 hours before bed as well.
8. Reduce screen time
   Avoid using digital devices at least 1-2 hours before bedtime so that your body understands that it is time to wind down and prepare for sleep.

It is also important to remember that the optimal amount of sleep differs amongst every individual, but the recommended amount is 7-9 hours in adults of ages 18-64 years old, and 7-8 hours in older adults 65 years and above.

�Quality of sleep does not have to be compromised because of ageing. Take small and simple steps to achieve better sleep each night.� - Active Health Coach Mason Tan

With better understanding, you can make changes to age healthily through a good night�s rest.

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