Introduction
Nerio Defense, supported by Samsung, is actively exploring and developing advanced software solutions that leverage the sensor capabilities of cutting-edge personal health devices such as the Samsung Galaxy Ring and the Samsung Galaxy Watch Ultra 8. These technologies enable high-quality, continuous measurement of vital physiological parameters directly from the soldier, offering new possibilities for real-time readiness assessment and long-term health monitoring.
In modern military operations, physical fitness and psychological resilience are fundamental for operational success. Typically, readiness is evaluated through periodic medical inspections, fitness tests, and subjective assessments. However, these provide only a snapshot, often missing subtle physiological changes that accumulate over time — such as stress load, inadequate recovery, or early signs of fatigue or overtraining.
Long-term monitoring of vital parameters — such as heart rate variability (HRV), blood oxygen saturation, blood pressure calculations, body energy and stress metrics — provides an objective, continuous readout of a soldier’s physiological and psychological state. This approach enables a deeper understanding of readiness and resilience, supports better decision-making for deployment, and aids early intervention to prevent injury, illness or burnout.
Why Heart Rate Variability (HRV) Matters
Heart Rate Variability (HRV) quantifies the variation in time intervals between consecutive heartbeats. It reflects the balance between the sympathetic and parasympathetic nervous systems. A higher HRV indicates better recovery and adaptability, while lower HRV suggests accumulated stress, fatigue, or impaired recovery.
Scientific studies consistently highlight HRV as one of the most powerful indicators of overall health and resilience. For instance, a comprehensive review concluded that HRV is an effective performance and health indicator for tactical professionals, provided that measurement methods are standardised (Tomes et al., 2020). Longitudinal studies on military recruits show that nightly HRV correlates with physical activity load, sleep quality, cognitive demand and overall allostatic stress (Corrigan et al., 2022; Macartney et al., 2022).
Importantly, HRV is strongly linked to psychological resilience. The Marine Resiliency Study demonstrated that lower pre-deployment HRV was associated with a significantly higher risk of developing PTSD post-deployment (Minassian et al., 2015). This highlights HRV as a crucial biomarker for mental health monitoring in soldier populations.
Beyond HRV: The Role of Other Vital Parameters
While HRV is central, other physiological parameters further strengthen readiness assessment:
• Blood Oxygen Saturation (SpO₂) — Low or fluctuating oxygen saturation compromises cognitive function, endurance and recovery. Continuous SpO₂ monitoring helps identify early respiratory strain.
• Blood Pressure Calculations — Trends in blood pressure reflect cardiovascular load. Military personnel endure variable workloads that can stress the cardiovascular system; long-term tracking enables early detection of risk.
• Body Energy and Stress Metrics — Composite metrics derived from HRV, resting HR, sleep and activity provide a holistic view of accumulated fatigue, overtraining risk and readiness.
Integrating these parameters helps commanders and medics identify subtle physiological shifts long before they manifest as performance decline, injury or illness.
Why Long-Term Monitoring Matters
Periodic medical tests are limited because they capture only snapshots. Continuous or at least frequent monitoring provides dynamic insight into:
• Cumulative stress and fatigue trends
• Readiness fluctuations based on workload, sleep and environmental conditions
• Individual baselines and personalised thresholds
• Early warning signs of overtraining, burnout or cardiovascular strain
These factors are essential in combat environments where conditions fluctuate quickly and unpredictable stress loads accumulate. Long-term physiological monitoring moves soldier health management from reactive to proactive.
Implementing Long-Term Monitoring in Military Contexts
Based on scientific evidence, the following steps are recommended:
1. Establish Individual Baselines
Measurement under rested, standardised conditions is essential.
2. Continuous or Periodic Monitoring
Prefer nocturnal measurements for consistency. ECG-based HRV is ideal, but validated PPG sensors (such as Samsung Galaxy Ring and Galaxy Watch Ultra 8) offer strong real-world performance.
3. Integrated Data Analysis
Combine physiological data with training logs, sleep profiles, nutrition and subjective wellbeing.
4. Defined Intervention Protocols
Thresholds for HRV drops, elevated resting heart rate or low SpO₂ should trigger recovery interventions.
5. Post-Mission and Post-Deployment Assessments
Monitor recovery trajectory back to baseline.
6. Continuous Improvement
Use collected data to refine monitoring, prediction models and readiness classifications.
Conclusion
Long-term monitoring of HRV and other physiological parameters enables a comprehensive, personalised assessment of soldier readiness. In collaboration with partners such as Samsung, Nerio Defense aims to push the boundaries of real-time health insight for the dismounted soldier. By leveraging advanced biosensors and intelligent analytics, military units can make better-informed decisions, reduce health risks, and improve mission performance.
References
Tomes, C., et al. (2020). Heart Rate Variability and Its Application to Tactical Professionals: A Systematic Review.Frontiers in Public Health, https://www.frontiersin.org/articles/10.3389/fpubh.2020.00191
Corrigan, S., et al. (2022). Monitoring Responses to Basic Military Training with Heart Rate Variability.PubMed: https://pubmed.ncbi.nlm.nih.gov/35394465/
Macartney, M., et al. (2022). Overnight Sleeping Heart Rate Variability of Army Recruits During Basic Training.PubMed: https://pubmed.ncbi.nlm.nih.gov/35833968/
Minassian, A., et al. (2015). Association of Predeployment Heart Rate Variability With Risk of Postdeployment PTSD. JAMA Psychiatry. https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2436276
Gancitano, G., et al. (2021). Heart Rate Variability in Active-Duty Special Forces and Public Order Personnel Exposed to Different Daily Tasks. Sustainability. https://www.mdpi.com/2071-1050/13/7/3867
An, E., et al. (2020). Heart Rate Variability as an Index of Resilience. Military Medicine. https://academic.oup.com/milmed/article/185/3-4/363/5681698
Corrigan, S. L., et al. (2023). Overnight HRV Responses to Military Combat Engineer Training. https://www.sciencedirect.com/science/article/abs/pii/S0003687022002587
Blomberg, I. (2022). Jämförande studie av mättekniker för HRV (Comparative study of HRV measurement techniques). DIVA Portal. https://www.diva-portal.org/smash/get/diva2:1684122/FULLTEXT01.pdf
Minassian, A., Geyer, M. A., Baker, D. G., et al. (2014). Heart Rate Variability Characteristics in a Large Group of Active-Duty Marines. Psychosomatic Medicine. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4062545/
DataDrivenHälsa (2025). Stress och HRV – vad säger forskningen? (Popular science summary). https://datadrivenhalsa.se/stress-hrv-forskning
