Doctors used heart rate variability (HRV) to monitor the diver’s autonomic nervous system.
Decompression Sickness Linked to Diving Incident
A recent case report highlights a rare heart condition linked to decompression sickness (DCS) in a recreational diver. The study, published in Frontiers in Physiology (Schmitz, 2025), describes a 35-year-old male diver who experienced neurological symptoms and persistent bradycardia after multiple dives.
The diver completed six consecutive days of diving, with two to four dives daily. Shortly after surfacing from his final dive, he experienced lightheadedness, vertigo, and numbness in his left leg. Despite initial treatment with hyperbaric oxygen therapy (HBOT), his heart rate remained abnormally low, prompting further investigation.
Heart Rate Variability (HRV) Analysis
Doctors used heart rate variability (HRV) to monitor the diver’s autonomic nervous system. HRV measures how the body regulates heart rate through the balance of sympathetic (stress-related) and parasympathetic (relaxation-related) activity. Advanced techniques, such as Principal Dynamic Mode (PDM) analysis, revealed a biphasic autonomic response.
During HBOT, the diver’s heart showed high parasympathetic activity, which helps the body relax. However, after treatment, his HRV data indicated a shift toward sympathetic dominance, suggesting autonomic imbalance. This imbalance persisted for several days, even as his symptoms improved.
Key Findings
The study revealed:
- Bradycardia (low heart rate) persisted during and after HBOT.
- HRV metrics showed reduced vagal tone (parasympathetic activity) post-treatment.
- Advanced analysis detected impaired long-term autonomic regulation.
These findings suggest that DCS can cause lasting disruptions in the body’s autonomic control, even after standard treatment.
Implications for Divers
The report emphasizes the importance of monitoring heart function in divers with DCS. Traditional methods may miss subtle changes in autonomic regulation. Advanced HRV analysis could help identify hidden risks and guide safe return-to-dive decisions.The diver’s case also highlights the need for awareness of DCS symptoms. Early recognition and treatment are critical to prevent long-term complications.This study provides valuable insights into the complex effects of DCS on the heart and nervous system. It underscores the potential of HRV analysis as a tool for improving diving safety and post-dive care.
References
Schmitz, G. (2025). Case report: Biphasic autonomic response in decompression sickness: HRV and sinoatrial findings. Frontiers in Physiology, 16. https://doi.org/10.3389/fphys.2025.1605779
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Until 2023, Dr. Charudatta S Pathak held multiple academic positions, including lecturer, assistant professor, professor, dean, principal, director, and vice chancellor at public and private universities across India. From 2008 to 2010, he held the position of project lead in the CAE department at a European multinational corporation. Throughout his 28-year professional experience, he observed a requirement for reliable publications aimed at youngsters in grades 8 to 12, specifically for early-stage career planning. He initiated the establishment of ENTECH Digital Magazine, a complimentary periodical released on a monthly basis, accessible via stemconference.in and magzter.com. Teenagers with a keen interest in Science, Technology, Engineering, and Mathematics (STEM) and aspiring to pursue professional paths in these domains can consider reading ENTECH Digital Magazine.
