Research

Hormonal

A flatter diurnal slope in salivary cortisol (characterized by elevated evening levels rather than depressed morning levels) is associated with a significantly increased risk of cardiovascular mortality in middle-aged adults.

This research suggests that how your cortisol levels drop throughout the day is more important for heart health than how high they are in the morning. Specifically, a 'flat' slope—where evening cortisol remains elevated rather than declining—predicts higher cardiovascular risk. While you cannot directly 'dose' cortisol, this pattern is often linked to chronic stress, poor sleep, or fatigue. Prioritizing stress reduction techniques and ensuring adequate sleep duration may help normalize this diurnal rhythm, potentially lowering cardiovascular risk.

GoodSupportsHIGH confidence
Flatter slopes in cortisol decline across the day were associated with increased risk of all-cause mortality... This excess mortality risk was mainly driven by an increased risk of cardiovascular deaths... These findings demonstrate, for the first time, the relationship between a flatter slope in cortisol levels across the day and an increased risk of cardiovascular disease mortality in a nonclinical population.
Meena Kumari et al. · The Journal of Clinical Endocrinology & Metabolism · 2011

Why this rating

Prospective cohort study with large sample size (n=4047) and rigorous cortisol sampling protocol, but limited by relatively few mortality events (n=32 CVD) and potential residual confounding.

Source

Association of Diurnal Patterns in Salivary Cortisol with All-Cause and Cardiovascular Mortality: Findings from the Whitehall II Study

Meena Kumari et al. · The Journal of Clinical Endocrinology & Metabolism · 2011

DOI 10.1210/jc.2010-2137

cohort · n=4047Cited 338×
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DOI resolved against Crossref · corpus check 2026-06-10

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