The Science of Biological Clocks: How Circadian Rhythms Impact Aging

We really do have an internal alarm clock. It’s called circadian rhythm. Circadian rhythm determines when we awaken and when we slumber. It’s one reason some of us are night owls and others are morning doves. It even subtly shifts our sleep patterns as we get older –– causing many of us to get less sleep than we need and to sleep less soundly when we do. 

So how do you work with your circadian rhythm and not against it? How does it change as we age and how does it affect life expectancy? And are there recognized conditions that make it extremely difficult for some people to conform to normal, daytime work hours? Read on to learn more about the science of biological clocks and how circadian rhythms affect aging.

What is Circadian Rhythm?

The sleep-wake cycle is overseen by your brain and regulated by hormones like melatonin and cortisol. This central circadian clock works in conjunction with other circadian clocks throughout the body. They are triggered by changes in light — both natural sunlight and artificial lights such as from televisions, computers, and smartphones. They can also be disrupted by caffeine and other stimulants. 

The reason most teens are night owls and most older adults morning doves is partly due to hormonal shifts and partly because few circadian clocks are actually on a 24-hour a day schedule. However, there are some people with natural inclinations toward being awake at night. While most people fall asleep a few hours past sunset, those with delayed sleep phase disorder or delayed sleep wake phase disorder remain up long past midnight. They have no problem getting seven hours of sleep per night – so long as they are allowed to sleep in until the late morning. Those with delayed sleep wake phase disorder usually experience secretion of the sleep-inducing hormone melatonin hours after people without the disorder. 

Treatment for conditions like delayed sleep phase disorder or delayed sleep wake phase disorder include light therapy and melatonin supplements. Although these disorders are more common in teenagers, they affect around four percent of the adult population. When there are no other underlying sleep disorders or mental health concerns, having delayed sleep phase disorder or delayed sleep wake phase disorder only presents health risks for those who are forced to adhere to traditional daytime work schedules. That’s because those with the disorder who are forced to awaken early despite their body’s natural inclination often spend their waking hours exhausted. That’s why so many people with these disorders work non-traditional hours either as remote workers or working later shifts. 

Still, most people wake up after sunrise, as it gets lighter and warmer. The energizing hormone cortisol is released as we arise. After sunset, our core body temperature begins to decrease while the hormone melatonin makes us sleepy. This cycle of waking up and going to sleep is called the circadian rhythm. 

The human body is constantly striving toward homeostasis. This is the steady-state when hormonal and blood sugar levels are even. It’s when our energy needs have been met. Getting a bad night’s sleep interferes with homeostasis. If you’ve ever had a sleepless night and awakened starving and craving carbs, it’s partly because you have fallen out of sync with circadian rhythm. As a result, the body releases an appetite-triggering hormone called ghrelin. Produced from the cells of an empty stomach, it is instrumental in the storage of fat. To further complicate matters, the body suppresses the release of leptin – a hormone that usually tells us when we are full. So, persistent sleep problems like insomnia can lead to weight gain and significant health issues.  

If you’re having trouble sleeping, it might be hormones. If your cortisol levels are elevated from stress or other factors, it can inhibit your ability to sleep soundly. Getting tested is the best way to find out. Although most companies charge hundreds of dollars to test hormone levels, the good news is that Kyla offers a comprehensive test for just $99. It may even be covered through your insurance. The test examines not only hormonal levels, but blood sugar levels, heart health, and so much more. 

Begin by downloading the Kyla app. You’ll be prompted to answer a series of questions that will reveal what lifestyle adjustments you can make to improve longevity and consistently achieve homeostasis. Or you can fill out an online survey. Whether online or from the app, you’ll easily learn the best test for you. Ordering is easy. Soon you’ll receive a test kit along with simple directions for sample collection. Collect a few drops of blood and mail the sample back to Kyla labs postage-free. 

Soon after, you’ll learn not only about your present health but the best steps to avoid future problems. Elevated hormonal or blood sugar levels are often a sign that you’re out of sync with your body’s circadian rhythms. Along with learning if your blood sugar and hormonal levels are optimal, you’ll discover if you are at risk for diabetes, cognitive decline, cardiovascular disease, or cancer. You’ll learn about heart, lung, and liver health along with if you are deficient in vitamins B and D. 

The Kyla app will also help you track your nutrition intake, set goals, and even have a consultation with a Kyla doctor. By making adjustments you can lengthen your longevity while improving cognitive function. You can even discover how your lifestyle affects your body by tracking vital health indicators like primary care and hormone levels while conveniently monitoring your data. The Kyla app lets you visualize your progress through graphs for better insights. Using the Kyla’s app health assessment, you can also identify health risks depending on your lifestyle and create a tailored plan.

How Does Circadian Rhythm Change as We Get Older?

Aging is the progressive deterioration of cells also known as senescence. During senescence our cells get older but instead of dying they stop dividing. These old cells accumulate. Besides harming healthy, dividing cells these senescent cells can contribute to chronic inflammation in the body which elevates the risk of cancer. Senescence affects both our bodies and our minds –– including circadian rhythm. This is partly because neurons focused on sleep begin to disappear as we get older. This neuron loss in the brain affects our ability to sleep. It’s also accelerated with dementia. 

We also will get fewer hours of sound slumber if we are physically inactive and aren’t exposed to sustained sunlight outdoors on a daily basis. Studies have shown that as our circadian clock grows weaker, it accelerates aging. So if we want healthy aging, understanding how to preserve the circadian clock’s normal function is a vital step. It may even be possible to reverse aging by in essence improving the circadian clock’s timekeeping ability. When the circadian clock weakens it raises the risk of both sleep issues and diseases like Alzheimer’s.

Our circadian clock changes as we age. This can affect everything from behavior to hormones. Researchers are still determining which changes to our circadian rhythms are inevitable and which can be altered. That’s because, as an article in The Journal of Clinical Investigations points out, there is “…mounting evidence that disrupted circadian rhythms are an early warning sign of developing neurodegenerative diseases, such as Alzheimer’s, Parkinson’s, and Huntington’s and that the circadian clock is heavily implicated in the etiology of metabolic diseases, chronic inflammation, and cancers.”

The circadian clock begins to shift at around age 60. Called phase advance, it’s why many of us are more adept at mental challenges before noon. It’s also why we get sleepy as the afternoon progresses. Many older adults have a physical need to be asleep by eight p.m. and awaken naturally seven hours later. So, by delaying sleep they may still awaken at three a.m. but spend the rest of the night tossing and turning. No matter your age, if you are consistently awakening in the middle of the night and unable to return to sleep, keeping an earlier bedtime could be the single most significant way to improve your health. 

How Does Your Circadian Rhythm  Affect Healthy Aging?

Healthy aging means reducing senescence and metabolic deterioration. It’s precursor, metabolic syndrome has been linked to everything from cancer to cardiovascular disease. Its hallmarks include high blood pressure along with elevated levels of blood sugar and triglycerides in the blood along with low levels of HDL. People with risk factors for metabolic syndrome are often apple-shaped with waists measuring over 40 inches for men or 35 inches for women. 

As explained in the Translational Medicine of Aging, data “…indicates that the circadian clock governs daily fluctuation of metabolic activity…This suggests that the activation of the circadian clock defends organisms from metabolic aging, eventually resulting in systemic healthy aging. This notion is strongly supported by mounting evidence indicating that dietary interventions robustly affect the circadian clock machinery and subsequent clock-controlled metabolic pathways.”

In a nutshell, we can reverse metabolic deterioration and avoid the hallmarks of metabolic syndrome through some very simple lifestyle adjustments. This includes moderate, daily physical activity and eating a nutritious, healthy diet. In fact, recent research suggests that dietary interventions — eating less at more optimal times — can alter the progressive deterioration of circadian rhythm. As an article in Nature Communications notes. “A major challenge is to understand, mechanistically, the progressive deregulation of metabolic function and to design interventions to delay the onset of age-related diseases… Dietary restriction widely improves lifespan and healthspan and some of its benefits could be mediated by the circadian system.”

In fact, one circadian protein, Bmal1, regulates how our bodies transform food into fuel through the body’s uptake of glucose or blood sugar. This interaction is altered when we eat late at night or eat calorie-dense, low-nutrient food. Circadian proteins like Bmal1 can affect circadian rhythm and this in turn impacts how we age.  Bmal1 and other core circadian proteins have non-redundant jobs when it comes to maintaining homeostasis. If they are compromised or reduced, it can negatively affect healthy aging. These circadian proteins are intimately involved with metabolism, which is why both diet and exercise are key components toward maintaining a healthy circadian rhythm. 

Living longer doesn’t necessarily mean living better. Analyzing data from the Healthy Life Expectancy (HALE) indicator, the World Health Organization determined that across the planet people today spend more than ten percent of their lifespans battling diseases related to age. That means an 80-year old would spend more than eight years suffering needlessly. Adjustments to circadian rhythms can have a profound influence on not just life expectancy but health spans – those valuable, disease free years.

Kyla’s anti-aging focus includes examining how your circadian clock is connected to everything from mental health to your risk for conditions including cardiovascular disease and type 2 diabetes. By downloading the Kyla app and enrolling in the Kyla Anti-Aging program, you will gain insights into your health through AI analytics and advanced testing. In the anti-aging program you can enhance your well-being and proactively manage chronic conditions. So download the app today and see how to not only lengthen your lifespan but your health span as well. 

Sources:

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