Summary: Ciara Burns’ solo experience rowing across the Atlantic served not only as an extreme athletic challenge but also as a controlled opportunity to study how mind and body interact under prolonged stress. Continuous monitoring of heart rate variability, paired with self-reported wellbeing and sleep notes, revealed measurable connections between psychological states and physiological responses during this 42-day ocean crossing.
Heart rate variability (HRV) provided insight into overall fitness, sleep quality and the body’s ability to regenerate during short sleep periods. The collected data highlight how sleep and recovery patterns changed across distinct psychological phases of the voyage and suggest practical strategies for future expeditions that disrupt normal circadian rhythms.
Key Facts:
- Heart Rate Variability: HRV was analyzed to assess fitness, sleep quality and nighttime regeneration. Results show clear links between psychological stressors and autonomic nervous system responses.
- Disrupted Sleep Rhythm: The team followed a three-hour shift pattern—three hours rowing, three hours resting. This unusual schedule correlated with declines in sleep quality during psychologically demanding moments and with a progressive reduction in regenerative capacity.
- Protective Physiological Adjustment: As the voyage progressed, average heart rate tended to slow and parasympathetic (vagal) activity increased, suggesting the body adopted a protective mode to limit cardiac strain under extended stress.
Source: Vienna University of Technology
Background: In 2021 Ciara Burns took part in a 42-day Atlantic crossing as one of twelve rowers. Such endurance challenges push participants to extreme physical and mental limits, making them valuable case studies for both sports science and physiology. Burns, a student at TU Wien (Vienna University of Technology), collected continuous heart rate data with wearable sensors and kept detailed logs of sleep and subjective wellbeing throughout the journey.
The subsequent analysis, now published, identifies patterns in psychological state, sleep quality and autonomic regulation that emerged while operating on an inverted day-night schedule. Researchers emphasize practical lessons for future long-duration, sleep-disrupting expeditions.
Interpreting heartbeat variability
“Heart rate recordings yield many useful indicators,” explains Prof. Eugenijus Kaniusas, head of the Biomedical Sensing and Therapy group at TU Wien, who provided scientific oversight. HRV is particularly informative: it reflects the body’s readiness, sleep recovery and autonomic balance. Normally HRV increases during sleep and is lower during wakefulness; a pronounced difference is a sign of healthy regeneration. When HRV during sleep and wake becomes similar, it signals an impaired ability to switch into restorative states.
The three-hour shift system and its effects
During the crossing the crew maintained a strict rhythm: three hours rowing followed by three hours off, around the clock. While this approach has practical advantages for small ocean teams, the study examined how such a schedule affects circadian regulation and recovery. Burns identified three particularly challenging periods: an initial adaptation phase, a midpoint realization of the voyage’s scale, and a late stage when the destination felt near but was not yet reached. In each of these phases, subjective sleep quality dropped, and objective HRV measures confirmed disrupted recovery.
In addition to these discrete dips, the data show a gradual decline in the body’s ability to regenerate during the short sleep windows as the trip progressed. Simultaneously, markers of parasympathetic (vagal) activity increased while sympathovagal balance shifted toward vagal dominance—consistent with a compensatory, protective physiological response that slows average heart rate to limit cardiac strain.
Practical recommendations
Studies like this are rare because most endurance athletes are reluctant to add the burden of continuous data collection to an already harsh environment. “Ciara’s meticulous monitoring under challenging conditions provided uniquely precise data,” notes Prof. Kaniusas. The project received ethical approval and institutional support at TU Wien.
Based on these findings, organizers of similar expeditions might consider gradual transitions into shift schedules rather than an abrupt switch from a normal day-night pattern to three-hour shifts. A planned adaptation phase could reduce the initial drop in wellbeing. For the midpoint challenge—when realization of the remaining distance can undermine morale—the researchers recommend deliberate morale-boosting interventions, such as a small celebration or rewarding activity to acknowledge progress and lift spirits.
About this research
Author: Florian Aigner
Source: Vienna University of Technology
Contact: Florian Aigner – Vienna University of Technology
Image credit: Neuroscience News
Original Research: Open access. “Mental and physiological wellbeing while rowing across the North Atlantic: a single-case study of subjective versus objective data” by Eugenijus Kaniusas et al., Frontiers in Psychology.
Abstract
Mental and physiological wellbeing while rowing across the North Atlantic: a single-case study of subjective versus objective data
Introduction: Unassisted Atlantic rowing is an extreme test of human endurance. In this case, a 42-day crossing involved 12 rowers each alternating in three-hour shifts, a schedule that disrupts circadian timing and autonomic balance. Continuous empirical quantification of subjective wellbeing, sleep quality and autonomic function during such voyages has been limited.
Methods: Using self-reported questionnaires and HRV measurements taken every other day in a single female participant, researchers tracked changes in perceived sleep quality, mental wellbeing and autonomic control, testing whether subjective and objective measures deteriorate in parallel and whether three-hour shifts attenuate circadian HRV patterns.
Results: Perceived sleep quality was most affected by awakenings during sleep, while mental wellbeing correlated primarily with physical exhaustion. Subjective wellbeing and sleep fell after 2–3 days at voyage start, around mid-journey, and again several days before completion. Objective HRV trajectories diverged from subjective reports: autonomic recovery during brief sleep windows progressively declined, even as vagal activity increased and sympathovagal balance shifted toward vagal tone. The three-hour shifts weakened the circadian rhythm of HRV.
Discussion: These findings illustrate how the human body meets prolonged mental and physical strain at sea and provide evidence-based guidance for preparing and supporting participants in future extreme endurance events that disrupt normal sleep and autonomic rhythms.