Low heart rate variability is associated with increased risk of hospitalized heart failure and heart failure with preserved ejection fraction in post-menopausal women.

Heart rate variability and the risk of heart failure and its subtypes in post-menopausal women: The Women’s Health Initiative study

Reduced heart rate variability (HRV) is a common finding in individuals with posttraumatic stress disorder (PTSD) and may serve as an endophenotype in PTSD research.

Posttraumatic Stress Disorder and Alterations in Resting Heart Rate Variability: A Systematic Review and Meta-Analysis

Low heart rate variability is associated with increased risk of coronary heart disease and death from various causes, suggesting it is a marker of less favorable health.

Low Heart Rate Variability in a 2-Minute Rhythm Strip Predicts Risk of Coronary Heart Disease and Mortality From Several Causes: The ARIC Study

Lower vagal activity is found in individuals with schizophrenia compared to healthy controls, suggesting reduced vagal tone may be an endophenotype for the development of psychotic symptoms.

Resting vagal activity in schizophrenia: Meta-analysis of heart rate variability as a potential endophenotype

Low heart rate variability is associated with increased cardiac disease risk, with genetic variants (GNG11, RGS6) playing a key role in vagal heart rhythm regulation.

Genetic loci associated with heart rate variability and their effects on cardiac disease risk

Adding heart rate variability biofeedback to psychotherapy improves heart rate variability and reduces depressive symptoms in major depressive disorder treatment.

Adding HRV biofeedback to psychotherapy increases heart rate variability and improves the treatment of major depressive disorder.

Exercise therapy may improve heart rate variability in patients with myocardial infarction, chronic heart failure, and revascularization by increasing vagal tone and decreasing sympathetic activity.

Improvements in heart rate variability with exercise therapy.

Heart rate variability (HRV) is impacted by stress and supports its use as an objective assessment of psychological health and stress.

Stress and Heart Rate Variability: A Meta-Analysis and Review of the Literature

Chronic alcohol use leads to decreased heart rate variability, with low dose use (1-2 drinks per day) increasing it in nondependent users, and abstinence improving it in dependent subjects.

Characteristics of heart rate variability in alcohol-dependent subjects and nondependent chronic alcohol users.

Short-term exposure to PM 2.5 is associated with decreased heart rate variability, potentially increasing the risk of cardiovascular disease through disturbance of autonomic nervous function.

Acute effect of ambient fine particulate matter on heart rate variability: an updated systematic review and meta-analysis of panel studies

Higher training intensities and frequencies are more likely to improve heart rate variability and cardiovascular health in young and middle-aged, healthy adults.

Effects of Different Training Interventions on Heart Rate Variability and Cardiovascular Health and Risk Factors in Young and Middle-Aged Adults: A Systematic Review

Depression without cardiovascular disease is associated with reduced heart rate variability, but various antidepressant treatments do not resolve these decreases, highlighting the need to identify individuals at risk in remission.

Impact of Depression and Antidepressant Treatment on Heart Rate Variability: A Review and Meta-Analysis

Short-term heart rate variability testing can enhance risk assessment in low to intermediate-risk individuals without known coronary artery disease by detecting subclinical or early ischemia.

Heart Rate Variability for Risk Assessment of Myocardial Ischemia in Patients Without Known Coronary Artery Disease: The HRV‐DETECT (Heart Rate Variability for the Detection of Myocardial Ischemia) Study†

Women exhibit lower heart rate variability during stress compared to men, indicating sex differences in stress-induced hyperarousal.

Quantitative meta-analysis of heart rate variability finds reduced parasympathetic cardiac tone in women compared to men during laboratory-based social stress

Aerobic exercise for 12 weeks did not significantly change heart rate variability parameters in women with systemic lupus erythematosus.

Heart Rate Variability in Women with Systemic Lupus Erythematosus: Association with Health-Related Parameters and Effects of Aerobic Exercise

Aging leads to a decline in heart rate variability, which may indicate increased mortality risk, and gender influences heart rate.

Twenty-four hour time domain heart rate variability and heart rate: relations to age and gender over nine decades.

HRV-B training improves heart rate variability coherence, restores autonomic health, and reduces symptoms in cancer survivors.

Heart rate variability (HRV) training for symptom control in cancer survivors.

Short-term heart rate variability may be a marker of ill health or a mediator of the effect of selected biomedical risk factors on cardiovascular disease.

Cardiovascular diseases, risk factors and short-term heart rate variability in an elderly general population: the CARLA study 2002–2006

A moderate negative correlation was found between fast food consumption and heart rate variability, indicating an increased risk for adverse cardiac outcomes.

The Correlation between Heart Rate Variability and Diet

HRV analysis is an appropriate tool to examine the physiological effects of the menstrual cycle in young healthy women and postmenopause in old women, affecting health management and overall quality of life.

Analysis of HRV during the Menstrual Cycle and Postmenopause

What are the health effects of a low HRV?

These studies suggest that low heart rate variability is associated with increased risks of heart failure, coronary heart disease, PTSD, schizophrenia, and negative impacts from stress, alcohol use, and air pollution.