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THE CENTER WITHIN · EVIDENCE LIBRARY

How common chronic stress, pain and anxiety are, and why they matter for how we age

Why This Matters: The Case for Nervous System Care

Background10 verified peer-reviewed articles

WHAT THE RESEARCH SHOWS

Chronic stress is not only a feeling. Large bodies of research link it to measurable changes in the body: how the heart is regulated, how cells age and how long people live. At the same time, the conditions that keep the nervous system stuck in "fight-or-flight" (anxiety, chronic pain and the two together) are extremely common. This page summarizes the peer-reviewed evidence behind The Center Within's focus on nervous system health.

the studies,

READ THE EVIDENCE

10 of 10 studies

A – StrongGlobal burden of mental disorders, 1990–2023 (Global Burden of Disease)Systematic analysis (Global Burden of Disease) · Need

IN PLAIN LANGUAGE

There were an estimated 1.17 billion cases of mental health conditions worldwide in 2023, and rates have risen since 1990. Anxiety is now one of the top causes of health loss of any disease.

Study type
Systematic analysis (Global Burden of Disease)
Who was studied
204 countries and territories
Outcome area
Need
Key finding
An estimated 1.17 billion prevalent cases of mental disorders in 2023, a 24.2% increase in age-standardized prevalence since 1990. Mental disorders were the leading cause of years lived with disability. Anxiety disorders ranked 11th among all diseases and injuries.
Evidence grade
A – Strong
Limitations
Modeled estimates; data gaps in lower-income regions. An erratum was published (PMID 42624153).
Citation
GBD 2023 Mental Disorder Collaborators. Updated trends in the global prevalence and burden of mental disorders, 1990-2023: a systematic analysis for the Global Burden of Disease Study 2023. Lancet. 2026;407(10543):2040-2064.
PubMed 42167272DOI 10.1016/S0140-6736(26)00519-2
A – StrongChronic pain and anxiety/depression co-occur in 12 million US adultsNational survey analysis (NHIS 2019) · Need

IN PLAIN LANGUAGE

More than half of US adults with ongoing anxiety or depression also live with chronic pain, and people facing both have the hardest time with work and daily life.

Study type
National survey analysis (NHIS 2019)
Who was studied
31,997 US adults
Outcome area
Need
Key finding
About 12 million US adults (4.9%) have both chronic pain and anxiety/depression symptoms. Chronic pain co-occurred in 55.6% of adults with unremitted anxiety/depression. This group had the greatest limits on work and social life.
Evidence grade
A – Strong
Limitations
Cross-sectional; self-report.
Citation
De La Rosa JS, Brady BR, Ibrahim MM, et al. Co-occurrence of chronic pain and anxiety/depression symptoms in U.S. adults: prevalence, functional impacts, and opportunities. Pain. 2024;165(3):666-673.
PubMed 37733475DOI 10.1097/j.pain.0000000000003056
A – StrongAbout 40% of adults with chronic pain have depression or anxietySystematic review & meta-analysis · Need

IN PLAIN LANGUAGE

Chronic pain and emotional distress travel together: roughly 4 in 10 people with chronic pain also have significant anxiety or depression.

Study type
Systematic review & meta-analysis
Who was studied
376 studies, 347,468 adults with chronic pain, 50 countries
Outcome area
Need
Key finding
Clinically significant depression was present in 39.3% and anxiety in 40.2% of adults with chronic pain. Rates were highest in fibromyalgia, women and younger people.
Evidence grade
A – Strong
Limitations
High heterogeneity between studies.
Citation
Aaron RV, Ravyts SG, Carnahan ND, et al. Prevalence of Depression and Anxiety Among Adults With Chronic Pain: A Systematic Review and Meta-Analysis. JAMA Netw Open. 2025;8(3):e250268.
PubMed 40053352DOI 10.1001/jamanetworkopen.2025.0268
A – StrongChronic pain affects 1 in 5 US adultsNational survey analysis (NHIS 2019) · Need

IN PLAIN LANGUAGE

About one in five American adults lives with chronic pain, and massage is one of the most common ways people manage it.

Study type
National survey analysis (NHIS 2019)
Who was studied
Nationally representative US adults
Outcome area
Need
Key finding
50.2 million US adults (20.5%) reported pain on most days or every day. Physical therapy and massage were the most commonly used management strategies.
Evidence grade
A – Strong
Limitations
Self-reported data.
Citation
Yong RJ, Mullins PM, Bhattacharyya N. Prevalence of chronic pain among adults in the United States. Pain. 2022;163(2):e328-e332.
PubMed 33990113DOI 10.1097/j.pain.0000000000002291
B – ModerateChronic stress accelerates telomere shortening (landmark study)Cross-sectional study (landmark) · Need / longevity

IN PLAIN LANGUAGE

This landmark study, co-authored by Nobel laureate Elizabeth Blackburn, found that women under the most chronic stress had cells that appeared about ten years "older" at the level of their telomeres.

Study type
Cross-sectional study (landmark)
Who was studied
Healthy premenopausal women
Outcome area
Need / longevity
Key finding
Perceived and chronic stress were associated with higher oxidative stress, lower telomerase and shorter telomeres. Women with the highest stress had telomeres shorter by the equivalent of at least one decade of aging.
Evidence grade
B – Moderate
Limitations
Cross-sectional; women only; association, not causation. Included as a foundational (pre- 2010) study.
Citation
Epel ES, Blackburn EH, Lin J, et al. Accelerated telomere shortening in response to life stress. Proc Natl Acad Sci U S A. 2004;101(49):17312-5.
PubMed 15574496DOI 10.1073/pnas.0407162101
B – ModeratePerceived stress linked to faster biological aging (Dunedin Study)Longitudinal cohort (Dunedin Study) · Need / longevity

IN PLAIN LANGUAGE

In a decades-long study, people with high perceived stress aged biologically about 2.4 months faster each year, an effect similar in size to smoking. The authors suggest treating stress could slow aging.

Study type
Longitudinal cohort (Dunedin Study)
Who was studied
955 adults followed from ages 32 to 45
Outcome area
Need / longevity
Key finding
All four types of stress were associated with faster biological aging. High perceived stress was linked to about 2.4 extra months of aging per year, comparable to smoking and low education.
Evidence grade
B – Moderate
Limitations
Observational; single birth cohort.
Citation
Bourassa KJ, Caspi A, Brennan GM, et al. Which Types of Stress Are Associated With Accelerated Biological Aging? Comparing Perceived Stress, Stressful Life Events, Childhood Adversity, and Posttraumatic Stress Disorder. Psychosom Med. 2023;85(5):389-396.
PubMed 37053097DOI 10.1097/PSY.0000000000001197
B – ModerateAllostatic load (stress "wear and tear") predicts mortalitySystematic review & meta-analysis · Need / longevity

IN PLAIN LANGUAGE

Allostatic load measures the cumulative toll of chronic stress on the body. People with the highest levels had a 22% higher risk of dying from any cause and a 31% higher risk of dying from heart disease.

Study type
Systematic review & meta-analysis
Who was studied
17 studies
Outcome area
Need / longevity
Key finding
High allostatic load was associated with 22% higher all-cause mortality (HR 1.22) and 31% higher cardiovascular mortality (HR 1.31). The authors call it a modifiable risk factor.
Evidence grade
B – Moderate
Limitations
High heterogeneity (I² > 90%); varied definitions of allostatic load.
Citation
Parker HW, Abreu AM, Sullivan MC, Vadiveloo MK. Allostatic Load and Mortality: A Systematic Review and Meta-Analysis. Am J Prev Med. 2022;63(1):131-140.
PubMed 35393143DOI 10.1016/j.amepre.2022.02.003
B – ModerateHigh perceived stress raises coronary heart disease risk (meta-analysis)Meta-analysis of prospective cohorts · Need / longevity

IN PLAIN LANGUAGE

Across nearly 120,000 people, those who felt highly stressed had about a 27% greater risk of developing heart disease.

Study type
Meta-analysis of prospective cohorts
Who was studied
6 studies, 118,696 participants
Outcome area
Need / longevity
Key finding
High perceived stress was associated with a 27% higher risk of incident coronary heart disease (RR 1.27).
Evidence grade
B – Moderate
Limitations
Small number of studies; stress measures varied.
Citation
Richardson S, Shaffer JA, Falzon L, Krupka D, Davidson KW, Edmondson D. Meta-analysis of perceived stress and its association with incident coronary heart disease. Am J Cardiol. 2012;110(12):1711-6.
PubMed 22975465DOI 10.1016/j.amjcard.2012.08.004
A – StrongLow heart rate variability predicts mortality (38,008 participants)Systematic review & meta-analysis · Need / longevity

IN PLAIN LANGUAGE

Heart rate variability, a marker of the calming branch of the nervous system, is one of the most consistent predictors of longevity. People with the lowest HRV had a 56% higher risk of death.

Study type
Systematic review & meta-analysis
Who was studied
32 studies + 2 individual-participant datasets; 38,008 participants
Outcome area
Need / longevity
Key finding
Lower HRV predicted higher mortality across ages, sexes and populations. The lowest quartile of RMSSD had a 56% higher mortality risk (HR 1.56).
Evidence grade
A – Strong
Limitations
Observational association; does not prove raising HRV extends life.
Citation
Jarczok MN, Weimer K, Braun C, et al. Heart rate variability in the prediction of mortality: A systematic review and meta-analysis of healthy and patient populations. Neurosci Biobehav Rev. 2022;143:104907.
PubMed 36243195DOI 10.1016/j.neubiorev.2022.104907
B – ModerateLow HRV predicts first cardiovascular event in healthy populationsMeta-analysis & dose-response meta-regression · Need / longevity

IN PLAIN LANGUAGE

In people without heart disease, lower heart rate variability was linked to a 32–45% higher risk of a first heart attack or stroke.

Study type
Meta-analysis & dose-response meta-regression
Who was studied
8 studies, 21,988 participants without known CVD
Outcome area
Need / longevity
Key finding
Low HRV was associated with a 32–45% increased risk of a first cardiovascular event. Each 1% increase in SDNN corresponded to roughly 1% lower risk.
Evidence grade
B – Moderate
Limitations
Observational; limited number of studies.
Citation
Hillebrand S, Gast KB, de Mutsert R, et al. Heart rate variability and first cardiovascular event in populations without known cardiovascular disease: meta-analysis and dose- response meta-regression. Europace. 2013;15(5):742-9.
PubMed 23370966DOI 10.1093/europace/eus341

EDUCATIONAL DISCLAIMER

This library is for educational purposes and is not medical advice. Individual results vary. Consult a qualified provider before starting any new therapy. Citations were verified against PubMed on September 25, 2026.

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