Chronic Stress, Cortisol, and Aging: The Longevity Cost of Always Being On
Short-term stress responses help the body meet a challenge. When stress systems are overstimulated or fail to switch off, the wear and tear has been called allostatic load, and over long periods it can lead to disease.1 This article covers what research shows about chronic stress, cortisol and aging, and what has been shown to lower measurable stress markers.
- Stress responses are adaptive in the short term, but chronic overactivation carries a cost, called allostatic load, that can lead to disease over long periods.1
- Chronic exposure to stress hormones affects brain structures involved in thinking and mental health, with effects that depend on when and for how long it happens.2
- In a study of mothers, the most stressed women had telomeres shorter by the equivalent of at least a decade of additional aging.3
- In a meta-analysis, meditation reduced cortisol, C-reactive protein, blood pressure and heart rate.5
- One proposed link between chronic stress and disease is that immune cells stop responding to cortisol, letting inflammation run unchecked; in virus-challenge studies, this resistance predicted more inflammation and more colds.6
Stress activates the hypothalamic-pituitary-adrenal (HPA) axis, which releases cortisol, and the sympathetic nervous system, which releases adrenaline and noradrenaline. This activation of neural, hormonal and immune mechanisms, called allostasis, helps the body adapt; when the systems are overstimulated or do not switch off, the price of adaptation is called allostatic load.1
Cortisol's Longevity Effects: The Biological Mechanisms
The brain: Chronic exposure to stress hormones affects brain structures involved in cognition and mental health at every stage of life, from before birth to old age, and the effects depend on the timing and duration of exposure.2
Immune dysregulation: Researchers have proposed that chronic stress makes immune cells resistant to cortisol's signal, so inflammation is not turned down. In two studies in which volunteers were exposed to a cold virus, this glucocorticoid receptor resistance predicted more inflammatory cytokines and a higher risk of developing a cold.6
Telomeres: In a study of mothers, both how stressed they felt and how long they had been under stress were linked to higher oxidative stress, lower telomerase activity and shorter telomeres; the most stressed women had telomeres shorter by the equivalent of at least a decade of additional aging.3 The study was observational, so it shows an association rather than proof that stress shortened them.
What Chronic Stress Is Linked To
Heart attacks. INTERHEART compared 11,119 people who had a first heart attack with 13,648 matched controls in 52 countries; the people who had heart attacks more often reported stress at work and at home, financial stress and stressful life events.8 After adjusting for age, sex, region and smoking, permanent stress at work went with about twice the odds of a heart attack (odds ratio 2.14), as did permanent stress at home (2.12), while periods of general stress carried a smaller increase (1.45). Depression was also more common among people with heart attacks, at 24.0% against 17.6%.8 As a case-control study, it shows an association rather than proof that stress caused the heart attacks.
Caregiving strain. Among 392 caregivers and 427 non-caregivers aged 66 to 96 who lived with their spouses, caregivers who reported mental or emotional strain had a 63% higher risk of death over four years than non-caregivers, after adjusting for existing disease.9 Caregivers who were helping without feeling strained had no increase in risk, and the authors concluded that strain itself is an independent risk factor for death among older spousal caregivers.9
Lost sleep. In young men, a night of partial or total sleep deprivation raised cortisol the following evening by 37% and 45% and delayed its usual evening fall.10 The researchers concluded that even partial sleep loss slows the stress system's recovery from its morning peak, which could weaken the resilience of the stress response and speed the metabolic and cognitive effects of excess cortisol.10
Measuring Stress Load: Heart Rate Variability
Heart rate variability (HRV) reflects the balance between sympathetic and parasympathetic input to the heart.4 Our HRV article covers what it predicts and how to read wearable data.
What Actually Reduces Chronic Stress Biology
What has been measured: In a meta-analysis of trials, meditation lowered cortisol, C-reactive protein, blood pressure, heart rate, triglycerides and tumour necrosis factor-alpha.5 Relationships matter too: across 148 studies, stronger social relationships were linked to a 50% higher likelihood of survival.7 For sleep, see our sleep course.
A Head-to-Head Treatment Trial
Mind-body training has been tested directly against medication. In a randomized trial of 276 adults with anxiety disorders, an 8-week mindfulness-based stress reduction course was compared with the antidepressant escitalopram.11 Anxiety severity fell by 1.35 points with the course and 1.43 with the drug on a clinician-rated scale, a difference small enough to show that the course was not worse than the medication.11 The 208 people in the main analysis had a mean age of 33, so the results apply most directly to younger adults.
Putting It Together
Across these studies, persistent stress carries more risk than occasional pressure: permanent stress at work or home, not periods of stress, went with about double the odds of a heart attack,8 and strained caregivers, not all caregivers, had higher mortality.9 The levers with measured effects are protecting sleep,10 keeping strong relationships7 and building a regular practice such as mindfulness training.5,11
References
- 1McEwen BS. "Stress, adaptation, and disease. Allostasis and allostatic load." Ann N Y Acad Sci. 1998;840:33-44. PubMed · DOI
- 2Lupien SJ, et al. "Effects of stress throughout the lifespan on the brain, behaviour and cognition." Nat Rev Neurosci. 2009;10(6):434-45. PubMed · DOI
- 3Epel ES, et al. "Accelerated telomere shortening in response to life stress." Proc Natl Acad Sci U S A. 2004;101(49):17312-5. PubMed · DOI
- 4 "Heart rate variability: standards of measurement, physiological interpretation and clinical use. Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology." Circulation. 1996;93(5):1043-65. PubMed
- 5Pascoe MC, et al. "Mindfulness mediates the physiological markers of stress: Systematic review and meta-analysis." J Psychiatr Res. 2017;95:156-178. PubMed · DOI
- 6Cohen S, et al. "Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk." Proc Natl Acad Sci U S A. 2012;109(16):5995-9. PubMed · DOI
- 7Holt-Lunstad J, et al. "Social relationships and mortality risk: a meta-analytic review." PLoS Med. 2010;7(7):e1000316. PubMed · DOI
- 8Rosengren A, et al. "Association of psychosocial risk factors with risk of acute myocardial infarction in 11119 cases and 13648 controls from 52 countries (the INTERHEART study): case-control study." Lancet. 2004;364(9438):953-62. PubMed · DOI
- 9Schulz R, Beach SR. "Caregiving as a risk factor for mortality: the Caregiver Health Effects Study." JAMA. 1999;282(23):2215-9. PubMed · DOI
- 10Leproult R, et al. "Sleep loss results in an elevation of cortisol levels the next evening." Sleep. 1997;20(10):865-70. PubMed
- 11Hoge EA, et al. "Mindfulness-Based Stress Reduction vs Escitalopram for the Treatment of Adults With Anxiety Disorders: A Randomized Clinical Trial." JAMA Psychiatry. 2023;80(1):13-21. PubMed · DOI
