This Week In HRV - Episode 12

Studies & Resources Discussed

Insomnia and HRV in Medical Students
Publication: Cureus
Title: “Insomnia and Its Impact on Psychomotor Reactivity, Autonomic Function, and Psychological Well-Being Among Medical Students: A Cross-Sectional Analytical Study”
Authors: Dhanusri, Rajalakshmi, Prakash, Bharadwaj, and Harichandrakumar
Key Finding: The severity of insomnia among medical students was associated with slower reaction times and higher psychological distress, while short-term resting HRV remained largely unchanged. Early cognitive and mood changes appear before resting HRV declines, underscoring that subjective fatigue and attention lapses can be earlier indicators than RMSSD or SDNN.
Link: https://www.cureus.com/articles/427559-insomnia-and-its-impact-on-psychomotor-reactivity-autonomic-function-and-psychological-well-being-among-medical-students-a-cross-sectional-analytical-study#!/

Meta-Analysis: HRV in Insomnia Disorder
Publication: Sleep and Breathing
Title: “Heart rate variability in patients with insomnia disorder: a systematic review and meta-analysis”
Authors: Zhao and Jiang
Key Finding: Across 17 studies and 921 participants, insomnia showed only mild, non-significant reductions in HRV measures such as SDNN and HF-norm. The review emphasizes methodological variability and suggests that chronic insomnia’s autonomic signature is subtle and context-dependent.
Link: https://link.springer.com/article/10.1007/s11325-022-02720-0

Sleep Deprivation and HRV
Publication: Frontiers in Neurology
Title: “Effects of Sleep Deprivation on Heart Rate Variability: A Systematic Review and Meta-Analysis”
Authors: Zhang, Niu, Ma, Wei, Zhang, and Du
Key Finding: Eleven trials revealed consistent sympathetic dominance after sleep deprivation, as evidenced by decreased RMSSD, increased LF and LF/HF, and stable SDNN. These findings reinforce that RMSSD is the most sensitive marker of HRV for acute sleep loss and stress load.
Link: https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2025.1556784/full

COMISA: Insomnia and Sleep Apnea Combined
Publication: Scientific Reports
Title: “Heart Rate Variability Analysis in Comorbid Insomnia and Sleep Apnea (COMISA)”
Authors: Martín-Montero, Vaquerizo-Villar, García-Vicente, Gutiérrez-Tobal, Penzel, and Hornero
Key Finding: Using over 5,000 overnight ECGs, COMISA patients showed reduced parasympathetic tone while awake and increased sympathetic drive during sleep. This dual imbalance likely explains elevated cardiovascular risk when both disorders coexist.
Link: https://www.nature.com/articles/s41598-025-02541-7

Depression and HRV in Students
Publication: Kompasiana
Title: “Diagnosis of Depressio...