Why does sleep change when we age?

As we age it’s very typical to notice a shift in our sleeping patterns and for many this change is not positive, but one that is likely to cause sleep problems. It’s easy to notice the physical changes our body is undergoing as we age; like wrinkled skin, gray hair, less muscle mass, but there are multiple changes going on at the molecular level that we can’t see. Many of these body function changes are driven by our hormones and the fluctuations in their balance. We are well aware of the hormonal surge that occurs during the teenage years, but we also experience dramatic changes later in life, as the level of some hormones drop, as others may increase. One such hormone that has been shown to significantly change is melatonin. 

Melatonin is the hormone needed for healthy sleep, both quality and duration. It provides a host of other benefits to our bodies, including incredible anti-aging properties, but it’s most well known as the hormone that is released at night-time, sending us into a tired and sleepy state. 

Does melatonin production change as we age?

Melatonin is produced by the pineal gland, in the hypothalamus of the brain. There are numerous steps involved in the production and synthesis process, following this high-level biological pathway - tryptophan (an amino acid from the protein we eat), is converted to serotonin, which then converts to melatonin. The pathway is well explained here.

The synthesis and release of melatonin are governed by the amount of light in our environment - stimulated by darkness, and inhibited by light. Even though it is commonly called the sleep hormone, a better description would in fact be the darkness hormone, due to activation being entirely dependent on the lack of light. This lack of light, naturally occurring after the sunset, is registered by photoreceptors in the eye, called Intrinsically Photosensitive Retinal Ganglia Cells, or IPRGC for short. Their responsibility is not vision related, but purely to detect the level of light in our environment. Think of it like a switch - when light stimulates these cells, the switch is turned on, a message via chemicals is sent to our master clock (the Suprachiasmatic Nucleus or SCN) which in turn sends signals all over the body, triggering a cascade of hormone releases and body functions. But not only do they detect light, they also detect the diminishing light, with the end result being the activation of the release of melatonin. 

The typical cycle for an adult is a feeling of sleepiness, two hours after the onset of melatonin production. Many things can affect this cycle, and especially detrimental is our modern lifestyle of staring at and surrounded by artificial lights, coupled with a lack of natural sunlight exposure during the daytime. As mentioned above, the light in our environment is directly related to melatonin, with the lack of it being equally important. Turning on light bulbs and electronic devices at night-time is causing our brain to think it’s still day-time and as a result, it maintains the sensation of alertness. Switching off this artificial light source, and allowing the natural process of melatonin release to occur, would be the ideal but probably impossible for most of us to do. The alternative is to block this artificial light, especially the highly energetic blue light, with eyewear that is designed to be effective at absorbing the most harmful range, up to 550nm. 

Another key factor is our age. In the later stages of our lives the hormonal shifts we experience are more likely to be major declines, and in some cases, a complete lack of hormone production. Studies have found melatonin is one of these hormones, declining dramatically as we age. 

As you can see in this chart, research shows that our melatonin starts at negligible levels as a newborn, peaks in our early childhood, declines once reaching puberty, rapidly decreasing through our 20-30’s, leveling off at approximately the 50 year old mark, hitting a low point around 60, to stay at this level from this point onwards. 

Melatonin changes as we age

 

There are other factors at play on aging that are yet to be fully understood. These include the interactivity of medications with melatonin levels and also the general deterioration in our body functions and organs, such as the Suprachiasmatic Nucleus and the pineal gland, that play starring roles in our sleep/wake cycle 

In addition, health conditions are likely to contribute to poor quality and duration of sleep. Depression, anxiety, heart disease, diabetes, and ailments causing pain such as arthritis are all likely to cause issues getting to and staying asleep. 

What is the typical sleep schedule of an older adult?

As we age, the big change likely to take place, from approximately 50 years onwards, is our sleeping phase advances forward, with a move towards a feeling of sleepiness earlier in the evening and a corresponding earlier wake up time. This is not the body’s way of saying we need less sleep, in fact, the recommended sleep for older adults is the same for all adults - 7-8 hours per night. It’s a reflection of many changes our body is experiencing at this time of its life, and are a combination of external and internal factors.

How can I protect my sleep as I age?

The first step is realizing your body now functions to the beat of a different rhythm. Understanding that the production of your melatonin will be naturally lower, makes it even more important to protect yourself from artificial blue light at night that is disrupting its release when most needed. With lower amounts available, you need as much as possible to be secreted into your bloodstream for the desired sleepiness effect. And as discussed earlier in the article, if your Intrinsically Photosensitive Retinal Ganglia Cells, or IPRGC, are still being stimulated by light at night, they won’t send the correct signals for melatonin secretion to happen. Only when the environment is dark enough is the switch to release melatonin activated.

Yes the ideal would be to keep artificial LED lights or devices off at night-time, but that’s pretty much impossible. We need to find alternative solutions to deal with our modern lit-up lifestyles and this is where we can help, with expertly developed, tinted eyewear. 

Only tinted lenses effectively block the full range of melatonin-destroying, artificial blue light that we expose ourselves to nightly. The red tinted lenses (Nights) are designed to absorb this artificial blue light, before it reaches the IPRGCs. Instead this allows for the darkness signal to be registered, in turn activating the release of melatonin so we experience a feeling of sleepiness at the appropriate time.

Conclusion

There are many factors that contribute to a change in circadian rhythms and a corresponding change in sleep patterns as we age. Much lower levels of melatonin is the chemical factor that plays a major role in disrupting our sleep. Whilst taking medication may be required, we highly recommend you first address the problem through natural mechanisms, the easiest being - change your environment to allow your body to function as it’s designed to. Blocking the artificial blue light that is not allowing your eyes to register darkness will not only help your quality and duration of sleep, but there is also evidence to support melatonin provides many anti-aging benefits beyond its primary role as a sleep-aide. 

For more on this read our article - What else is melatonin good for?

And for tips on how to increase your levels naturally - Can melatonin levels be increased with food?

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