Human limits in next-generation fighter aviation: psychophysiological stressors, readiness, health, performance, and...

The transition to fifth- and sixth-generation fighter aircraft is increasing the psychophysiological demands placed on military aircrew. Next-generation fast-jet operations combine sustained and repetitive high-G loading; intermittent hypoxia, hyperoxia, and hypobaria associated with unexplained physiological episodes; prolonged single-seat missions; advanced helmet-mounted displays; acoustic and thermal stress; and high cognitive load from sensor fusion, automation, and manned-unmanned teaming. These exposures challenge autonomic regulation, cerebral and respiratory physiology, neurocognitive performance, sensory integration, and central nervous system resilience. This narrative review synthesizes evidence across cardiovascular-autonomic and hemodynamic function; respiratory physiology and unexplained physiological episodes in the on-board oxygen generating system era; cognitive workload, fatigue, and pilot experience; visual-oculomotor, vestibular, auditory, thermal, and musculoskeletal stress; biological markers of neural strain; and aircrew surveillance and countermeasures. The organizing construct is psychophysiological readiness: the integrated capacity to meet mission demands without disproportionate physiological cost or degraded decision quality. Evidence from direct fifth-generation studies, other fast-jet operations, simulators, and controlled aerospace analogues shows measurable changes in heart rate variability, cerebral oxygenation and perfusion, cortical activity, sensory function, and neurostructural biomarkers, but direct fifth-generation evidence remains limited and responses are strongly individualized and context dependent. Current surveillance remains largely episodic and domain-siloed. We therefore propose a staged monitoring framework combining validated cardiovascular-autonomic and hemodynamic measures with neurocognitive, sensory, wearable, and biomarker data, while treating AI/ML as an experimental analytic layer requiring prospective validation. Longitudinal, career-spanning monitoring could ultimately support earlier identification of vulnerability and evidence-based optimization of training, recovery, and countermeasures while preserving human aeromedical oversight.