Aging Alters Circadian Rhythms

How do circadian rhythms affect sleep patterns? Find out here.

Reviewed and approved by el médico Diego Pereira.

Written by Josberth Johan Benitez Colmenares

Last update: 25 January, 2023

One of the characteristics of aging is more trouble sleeping and having to get up more often during the night. Indeed, as people age, they’re exposed to episodes of insomnia and other sleep disorders. All this combined with a series of changes in the body, which alters what’s known as the biological clock. We’ll show you the relationship between aging and circadian rhythms.

Circadian rhythms help regulate the sleep process (with the help of the homeostatic sleep-wake system). Although it’s a very precise mechanism, the truth is that it can easily be altered. Let’s see how aging alters circadian rhythms and what the consequences are.

How aging affects circadian rhythms

For most people, their sleep cycles are regulated by the periods of the day. That is, they wake up when the sun rises over the horizon and become drowsy when it sets. This evolutionary mechanism is present in animals and plants and is regulated by hormones such as melatonin. Roughly speaking, this is what we call circadian rhythms.

The circadian rhythms in human beings have an average duration of 24 hours (between 23.5 to 24.5 hours in sighted adults). It’s synchronized every day through interaction with the environment. As with animals and plants, this process occurs mainly in sunlight and the darkness of night. The most important timings occur at the beginning and end of the day.

As the evidence indicates, this complex process changes in older adults. In almost all of them there’s a phase delay. As we have already explained, circadian rhythms are regulated by different interactions with the environment. In light of this, researchers point to several catalysts as drivers of this mismatch:

• Ingestion of medications (which cause drowsiness or prolonged wakefulness)
• Less exposure to sun health (compared to younger adults)
• Diet changes
• Less physical activity throughout the day
• Ambient temperature
• Rest patterns throughout the day
• Presence of certain medical conditions (such as diabetes or insulin resistance)
• Hormonal changes due to age

Regarding the latter, there’s evidence that the secretion of melatonin and cortisol changes with age. Both have a direct impact on the deregulation of circadian rhythms. In general, the changes begin around the age of 60 and worsen in the following decades. At first, the changes are slight, but when the person reaches 80 years of age it is much more consolidated.

Consequences of circadian rhythm disturbance in older adults

The Sleep Foundation estimates that most older adults go to bed around 7 or 8 pm and wake up around 3 or 4 am. m. This is the main consequence of the relationship between aging and the circadian rhythm. Other consequences that specialists point out are the following:

• Increased activity during the morning: The changes in the circadian phases motivate older adults to be more active in the morning. They manage their activities early in the morning, while in the afternoon they are sleepier and more apathetic.
• More awakenings during the night: In contrast to younger adults, older adults tend to wake up more frequently during the night. Awakenings are so frequent that it creates the feeling that you have spent much of the night awake.
• Less time in phases 3 and 4 sleep and in the REM phase: That is, the deepest stages of sleep. As a consequence, older adults show a reduction in what is known as restful sleep.
• Greater irritability: The absence of rest translates into greater irritability during wakefulness. They also increase the chances of developing stress, depression, and anxiety. All of these decrease personal and family well-being.

The impact is much greater than indicated. The main function of circadian rhythms is to regulate metabolic processes, so all of these are changed. The chances of developing inflammation increase, the production of hormones becomes unbalanced, some diseases can develop, cognitive deterioration accelerates, and so on.

How to deal with these episodes?

There’s nothing you can do to stop the disruption of your circadian rhythms that comes with aging. This occurs naturally, and affects all people to varying degrees as they get older. Still, some lifestyle habits can keep it in check to a certain degree. Let’s have a look at some useful daily habits:

• Exercise regularly
• Keep the bedroom dark and quiet at bedtime.
• Reduce the consumption of coffee, alcohol and nicotine.
• Reduce naps that are taken throughout the day to just 30 minutes.
• Use the bed only to sleep or have sex (not to watch television or similar activities that could keep you awake).
• Reduce exposure to screens at least an hour before going to sleep.
• Maintain a healthy diet with an emphasis on fruit and vegetables.
• Avoid eating food or drinking lots of fluids immediately before going to sleep.
• Expose yourself to sunlight at the beginning and end of the day.
• Keep possible underlying diseases (diabetes, heart conditions and so on) in check.

If you have any difficulty sleeping, don’t hesitate to consult a specialist. There are many ways to deal with the problem, so you don’t have to just live with the consequences. As you have seen, a healthy life is positively related to a lower impact on the circadian rhythms due to aging. Try to include all these habits in your daily routine.