Our circadian rhythm is our internal clock that helps our bodies regulate a pattern of sleep and wakefulness. It is in charge of the normal time frame that you get sleepy and wake up from your slumber. However, as we age, our circadian rhythm may change, and we may experience disrupted sleep. Keep reading to find out why, and what you can do to better manage your internal clock.
How your circadian rhythm is established.
Your circadian rhythm usually follows sunlight. During the day, when there is light outside, your body knows that it is time to be awake. When your core temperature is elevated, your body has internal and external stimuli signaling that it is time to be awake.
As the day transitions to night, and the sky darks, your core temperature drops and you start to get sleepy. Your brain signals to your body that it is time to go to sleep.
This process is heavily influenced by genetics, however, adjustments like shift work and irregularities in the lengths of day and night (longer day time periods in certain seasons, compared to others) can change your circadian rhythm.
How your circadian rhythm changes with age.
Another process that can impact or change circadian rhythms is aging. As we age, our circadian rhythm shifts earlier, about a half hour per decade starting at middle age. This means that those who are over 65 should go to bed around 7 or 8pm and wake up around 3 or 4am. However, this change is normally unwanted by most individuals so they fight it, and go to sleep later. The circadian rhythm is so run by genetics, that regardless what time you go to sleep, you may tend to still wake up at 3 or 4, leading to disrupted sleep.
There are several theories as to why this happens. One of them is that genes in the suprachiasmatic nucleus (the part of the brain responsible for regulating our circadian rhythm) start to change with age, and allow for less fluctuation in the normal circadian rhythm. This leads to a reduced amount of melatonin being produced and lighter sleep. This is why older individuals report decreased sleep quality, regardless of how long they spent in bed.
Another theory is that eyes change over time and let is less light. Without this light, the brain doesn't receive the proper stimulation for full wakefulness and signals for earlier bedtimes when the light decreases just the slightest. Those with cataracts actually report better sleep because their surgery allows more light to enter.
How to deal with changing rhythms.
It may be tempting to take naps in the middle of the day, but naps may disrupt your sleeping patterns even more. Going to sleep and waking up at the same time everyday may give you the regulation that you need to get more sound sleep. Also, going to bed earlier and waking up earlier may help.
Another way to deal with changing rhythms is to let more light in. If you keep your house bright and spend more time outside during the day, then you may sleep more soundly at night. It may also help to relocate somewhere where the sun is always shining (like Florida)! If you would like to push your bedtime even later, don't get too much light in the early morning, but wait until the evening to go for a walk or use a bright light for light exposure therapy. This can change the release of melatonin so your body can better fight the inclination to go to bed earlier.
The best way, however, to improve sleep habits is to improve your sleep hygiene. Sleep hygiene is your sleep routine that you use to signal to your brain and body that it is time to go to sleep. This means that around the same time everyday, you start the same, or similar, sequence of activities. It's like you're coaching your body to prepare for bed by giving it a recognizable signal. Sleep hygiene also involves your sleep environment. Keeping a dark, quiet, cool room will assist you with sleeping through the night and avoiding those disruptions.
Sources:
https://www.sleepfoundation.org/circadian-rhythm/how-age-affects-your-circadian-rhythm