Key Takeaways
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Cortisol, often called the "stress hormone", influences multiple dimensions of ageing, from DNA damage to memory decline.
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Disrupted cortisol rhythms and chronic stress can accelerate biological, cognitive, and metabolic ageing.
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Positive self-perceptions and strong social ties can buffer cortisol’s negative effects, supporting healthier ageing.
While cortisol is essential for life, without it, you would not wake up in the morning, yet too much of it over time can age you faster. This dual role makes cortisol one of the most intriguing hormones in understanding longevity.
The adrenal glands release cortisol in response to stress and follow a natural 24-hour cycle. In balanced amounts, it regulates metabolism, blood pressure, and the immune system. But when levels remain elevated for too long, research indicates it may accelerate ageing across biological, cognitive, metabolic, and psychological domains.
Let’s explore how this single hormone weaves through every layer of the ageing process.
Biological Ageing and Cortisol Rhythms
One of cortisol’s most crucial roles lies in its daily rhythm. Normally, cortisol peaks in the morning, helping you feel alert, and dips at night to allow restorative sleep. When this circadian rhythm is disrupted, cortisol can remain consistently elevated throughout the day — a phenomenon linked to accelerated biological ageing in men (R).
Researchers have found that men with flattened cortisol patterns had a higher biological age based on vascular and physiological markers (R). Essentially, when cortisol loses its natural ebb and flow, it places the body in a state of continuous “stress mode”, which can speed up the physical ageing process.
This discovery highlights the importance of protecting your daily rhythms, such as maintaining regular sleep patterns and exposure to natural light.
Cognitive Ageing and Memory
Cortisol also plays a profound role in brain health and memory. High, chronic cortisol levels have been consistently linked with impaired cognition, particularly in older adults.
One large-scale study measuring cortisol in hair samples, a method reflecting long-term exposure, found that older adults with higher cortisol performed significantly worse on memory recall and cognitive screening tests (R). Another study showed that elevated cortisol before learning reduced memory formation in older adults, highlighting how the ageing brain is more vulnerable to stress (R).
These findings suggest that managing stress levels over the lifespan may support sharper memory and sustained cognitive performance into later years.
Degenerative Conditions and Metabolic Stress
Cortisol doesn’t just act on the brain, it affects nearly every organ system. Over time, chronically elevated cortisol contributes to degenerative diseases.
Research shows that cortisol promotes muscle breakdown, atherosclerosis, and immune dysfunction, which are hallmark conditions of ageing (R). The effects become worse in older adults who develop insulin resistance. In these cases, there is less hormonal opposition to cortisol’s breakdown effects, leaving muscles, blood vessels, and immune cells more vulnerable.
This means that the interplay between cortisol and metabolic health is critical. By supporting insulin sensitivity through nutrition, physical activity, and balanced lifestyle choices, you may help reduce cortisol’s degenerative effects on the body.
Cortisol at the Cellular Level: DNA and Mitochondria
Perhaps the most striking evidence of cortisol’s role in ageing lies at the molecular level. High cortisol is associated with oxidative stress, a process where reactive oxygen species damage DNA, RNA, and proteins. Studies show that 24-hour cortisol levels correlate with increased biomarkers of DNA and RNA oxidative damage (R). Laboratory findings further reveal that cortisol impairs mitochondrial function, reducing the cell’s ability to produce energy and survive (R).
This cellular damage is considered a hallmark of ageing, linking stress exposure directly to the body’s fundamental biological clock.
Rising Cortisol Levels With Age
Interestingly, cortisol itself tends to rise as we grow older. Longitudinal studies have shown that older adults secrete more cortisol over time (R). This increase is especially pronounced in individuals with chronic conditions such as cardiovascular disease, diabetes, or reduced kidney function (R).
This trend supports the idea that cortisol is both a marker and driver of ageing, increasing with accumulated stress exposure while also fuelling further physical decline.
Cortisol and Brain Ageing
When it comes to the brain, cortisol can be neurotoxic in excess. The hippocampus, a brain region essential for memory and stress regulation, is particularly sensitive to cortisol.
Research links high cortisol to longer latencies in brain processing speeds and higher metabolic demands in neural tissue, both indicators of brain ageing (R). Over time, this means that chronic stress may not only erode memory but also alter how efficiently the brain processes information.
Social and Psychological Buffers Against Cortisol
Here’s the encouraging part: while cortisol can accelerate ageing, research also shows there are powerful buffers.
Older adults who hold positive self-perceptions of ageing show lower cortisol increases across decades (R). Similarly, cultivating strong social ties has been linked to healthier cortisol rhythms and even longer telomeres, the protective caps on DNA strands associated with longevity (R).
This suggests that the way you think about ageing and the strength of your social connections can have tangible, biological effects on how your body manages stress.
Living Well With Cortisol
Cortisol may be the body’s built-in stress alarm, but over time, unchecked levels can accelerate ageing in profound ways. From disrupting circadian rhythms and damaging DNA to impairing memory and fuelling degenerative disease, its effects are far-reaching.
The good news is that your lifestyle choices and mindset matter. By supporting circadian balance, maintaining social connections, and nurturing positive beliefs about ageing, you can help buffer cortisol’s impact.
Curious about more ways to support healthy cortisol through lifestyle choices? Read our next blog on How to Manage Stress for Healthy Ageing.
