What does the stress hormone cortisol do to my ageing?
Chronically elevated cortisol accelerates muscle loss and disrupts your metabolism, and that effect is real. Good sleep and limiting chronic stress are the most concrete tools for keeping it in check.
Cortisol is the body's primary 'breaking-down' hormone. It works in direct opposition to anabolic hormones such as testosterone and growth hormone. When your cortisol level is chronically elevated, it inhibits the building of muscle tissue and promotes its breakdown. Review literature describes that counteracting influence on muscle building as substantial, which makes it relevant to the muscle loss that normally accompanies ageing.
Sleep plays a concrete role. Too little or poor-quality sleep raises cortisol levels in the afternoon while simultaneously lowering testosterone. That combination tips the balance between anabolism and catabolism against your muscles and metabolism, and has been linked to faster ageing and greater insulin resistance. The exact magnitude differs from person to person and from study to study, but the pattern is measurable.
Your internal clock drives the cortisol rhythm throughout the day. Good news: that clock ticks just as precisely in healthy older adults as in young people, averaging around 24 hours and 11 minutes. But when the rhythm is disrupted from the outside, by night shifts, jet lag, chronic stress, or a lot of artificial light at night, cortisol patterns become irregular. That has been associated with a higher risk of mood disorders such as depression.
What can you do to lower cortisol? Massage therapy shows an average decline of around 31% in saliva and urine measurements across multiple studies, combined with a rise in serotonin and dopamine. That is one of the better-supported non-pharmacological approaches. Physical exercise reliably raises anabolic hormones such as testosterone and DHEA in older adults, but its effect on cortisol itself is inconsistent and inconclusive across studies. The supplement ashwagandha showed no demonstrable effect on cortisol in a small but well-designed study in men aged 40-70, although DHEA-S did rise by 18%. On the basis of that one small study, little can be said with certainty about ashwagandha and cortisol.
Based on a mix of systematic reviews, a meta-analysis (massage), a small RCT (ashwagandha), and observational/laboratory studies. The evidence for the catabolic action of cortisol and the sleep effect is moderately strong; the evidence for the effect of exercise on cortisol and for ashwagandha is limited.