Mitochondrial Biosensorics Check-Up Is Crucial for Physical Fitness and Exercise Intervention Quality—Facts and Practical Recommendations

A constantly increasing incidence of chronic diseases is a challenge for healthcare worldwide, being directly associated with physical inactivity, which is considered an important cause of most chronic diseases. In contrast, physical exercise has been proven as a powerful instrument of healthcare to protect individuals against health-to-disease transition and against disease progression. Nonetheless, a number of studies warn against inappropriate high-intensity and/or unaccustomed exercise that exceeds an individual’s physical capacity. Indeed, extensive cardiac activity during prolonged exercise leads to significantly increased cardiac dimensions, triggering cardiac complications that may result in arrhythmogenic sudden cardiac death. The remarkable plasticity of mitochondria allows these organelles to sense and adapt to a variety of stressors and respond to stimuli by molecular signalling, regulating bioenergetics and cellular homeostasis, decisive for repair processes, proliferation, apoptosis, and tissue regeneration to combat degeneration, with whole body outcomes. Mitochondria act as biosensors in the human body; they are reactive to stimuli and protective against health-to-disease transition. To perform this life-important function throughout life, mitochondria need supportive measures, including physical activity, considered an essential pillar of mitochondrial medicine. This article highlights reciprocity between the quality of mitochondrial health and homeostasis on one hand and physical fitness and exercise intervention on the other hand. The proposed novelty relates to the monitoring of mitochondrial homeostasis, which is strongly recommended for creating individualised training programmes, and monitoring exercise efficacy during and after the programme is completed. To this end, a patient-friendly non-invasive approach is already established, utilising tear fluid multi-omics, mitochondria as the vital biosensors, and AI-based multi-professional data interpretation.