In 2004, Elissa Epel and Elizabeth Blackburn published a study in the Proceedings of the National Academy of Sciences that would change the way stress researchers thought about biological ageing. They measured telomere length in two groups of women: those caring for a chronically ill child, and those without caregiving stress. Women under the highest levels of caregiving stress had telomeres equivalent in length to women 9 to 17 years older. The more years of caregiving, the shorter the telomeres. Blackburn would go on to receive the Nobel Prize in Medicine for her work on telomeres. This study placed chronic psychological stress directly in the pathway of biological ageing.
The Mechanisms by Which Stress Ages the Body
Chronic stress activates the HPA axis, producing sustained elevation of cortisol. Elevated cortisol promotes cellular oxidative stress, damages mitochondrial DNA, accelerates telomere shortening, impairs DNA repair mechanisms, and suppresses anti-ageing proteins including sirtuins. It also sustains pro-inflammatory signalling via NF-kappaB activation, contributing to the chronic low-grade inflammation that drives most age-related disease. These are not speculative mechanisms. They are documented, measurable biological changes occurring in real time in chronically stressed individuals.
Perceived Stress vs Actual Stress
Research by Kelly McGonigal and others has found that it is not the stressful events themselves but the perception of those events as harmful that drives the worst biological outcomes. Adults who experience high stress but do not perceive it as harmful show better health outcomes than those with lower stress who perceive their stress as very damaging. This does not diminish the importance of reducing chronic stress where possible, but it does point to the additional value of developing a more resilient cognitive relationship with stressful experience.
Sources
- Epel, E.S., et al. (2004). Accelerated telomere shortening in response to life stress. Proceedings of the National Academy of Sciences, 101(49), 17312-17315.
- McEwen, B.S. (2007). Physiology and neurobiology of stress and adaptation: central role of the brain. Physiological Reviews, 87(3), 873-904.
- Kiecolt-Glaser, J.K., et al. (2002). Psychoneuroimmunology and psychosomatic medicine: back to the future. Psychosomatic Medicine, 64(1), 15-28.