Chronic stress, allostatic load and multisystem disease: mapping mechanisms and evidence for lifestyle interventions – a narrative review

Chronic psychological stress is linked to cardiovascular, metabolic, immune-mediated, gastrointestinal, and depressive disorders. Allostatic load (AL), defined as the cumulative physiological cost of repeated or sustained adaptation, serves as the primary framework for explaining these associations. Lifestyle interventions, including yoga, meditation, physical activity, sleep improvement, dietary modification, and social support, are widely recommended for stress-related health issues. It remains uncertain whether these interventions influence multisystem AL or only affect individual biomarkers and symptoms. This narrative review is based on a structured, though non-systematic, PubMed/MEDLINE search that prioritised systematic reviews, meta-analyses, randomised trials, and large cohort studies. The review summarises neural, neuroendocrine, autonomic, inflammatory, metabolic, gut-brain, cellular, and epigenetic pathways through which stress becomes biologically embedded, distinguishing mechanisms established in humans from those inferred primarily from animal or cross-sectional studies. Intervention evidence is then mapped against the five biomarkers of a recently proposed consensus AL index (C-reactive protein [CRP], resting heart rate, high-density lipoprotein cholesterol, waist-to-height ratio, and glycated haemoglobin) as well as clinical endpoints. Physical activity and a Mediterranean-style diet have the strongest support across these domains and clinical outcomes. Meditation, yoga, and slow breathing yield small-to-moderate improvements in distress and in certain cardiometabolic and autonomic markers, while cognitive behavioural therapy demonstrates clinical-endpoint evidence in insomnia and coronary heart disease. Few randomised trials have assessed composite AL, and their findings are inconsistent. No intervention has yet demonstrated disease prevention through reduction of AL. Standardised AL measurement in adequately powered trials represents the most important next step.