article 2025 Modified Stress Score and Sympathetic–Parasympathetic Ratio Using Ultra-Short-Term HRV in Athletes: A Novel Approach to Autonomic Monitoring Andrew D. Fields, Matthew A. Mohammadnabi, Michael V. Fedewa, Michael R. Esco JournalJ. Funct. Morphol. Kinesiol.DOI10.3390/jfmk10030310Publication typeOriginal ResearchPopulationcompetitive male athletes View on DOI ↗