Physiological Responses to High-Intensity Exercise
Summary
High-intensity exercise imposes rapid and substantial demands on cardiovascular, respiratory, metabolic and neuromuscular systems. Cardiac output rises steeply to augment oxygen delivery, while ventilation increases disproportionately to maintain blood gas homeostasis. Metabolically, there is a swift shift from oxidative phosphorylation towards anaerobic glycolysis, leading to lactate accumulation and acid–base disturbances. Neuromuscular activation intensifies to sustain force output, yet progressive metabolite build-up and impaired excitation–contraction coupling drive the onset of fatigue. Concurrent hormonal and cellular signalling pathways, including catecholamine release and mitochondrial adaptations, modulate substrate utilisation and endurance capacity. Understanding these integrated responses underpins training strategies, rehabilitation protocols and performance optimisation across health and athletic populations.
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Physiological Responses to High-Intensity Exercise publication trend
The graph below shows the total number of articles in physiological responses to high-intensity exercise across all publications each year (not limited to Nature Index journals).
Technical terms
VO2max: Maximum rate of oxygen uptake during incremental exercise, reflecting aerobic capacity.
Ventilatory threshold: Exercise intensity at which ventilation increases disproportionately to oxygen uptake, marking a shift towards greater anaerobic metabolism.
Rating of perceived exertion (RPE): Subjective numerical scale used by individuals to gauge exercise intensity based on perceived effort and strain.
Near-infrared spectroscopy (NIRS): Optical technique for non-invasive measurement of local tissue oxygenation by detecting haemoglobin and myoglobin chromophore signals.
Critical power (CP): The highest sustainable power output that separates steady-state metabolic responses from progressive exhaustion in severe-intensity exercise.
References
- Estimation of ventilatory thresholds during exercise using respiratory wearable sensors. npj Digital Medicine (2024).
- Rating of Perceived Exertion: A Large Cross-Sectional Study Defining Intensity Levels for Individual Physical Activity Recommendations. Sports Medicine - Open (2024).
- Monitoring Changes in Oxygen Muscle during Exercise with High-Flow Nasal Cannula Using Wearable NIRS Biosensors. Biosensors (2023).
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