Exercise Physiology
yasamin yarahmadi
Abstract
The pathophysiology of heat stress occurs when the body's environmental and physiological responses exceed its ability to maintain homeostasis. When internal heat signals or external factors raise body temperature beyond a certain limit that the cooling mechanisms can effectively manage, the resulting ...
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The pathophysiology of heat stress occurs when the body's environmental and physiological responses exceed its ability to maintain homeostasis. When internal heat signals or external factors raise body temperature beyond a certain limit that the cooling mechanisms can effectively manage, the resulting increase in core temperature triggers response pathways that themselves induce physiological stress. The primary response mechanisms to heat stress include sweating, peripheral vasodilation, and shivering as thermogenic responses—all of which are activated by elevated temperatures and may seem counterproductive to the body's requirements, yet they operate through a neuromuscular and hormonal feedback system. Genetic factors influence individual heat tolerance; for instance, certain populations have variations in heat shock proteins (HSP70) and ion channels (TRPV1, RYR1) that enhance their heat response and tolerance. Additionally, individuals with higher relative VO2 max levels demonstrate greater heat tolerance, as those who are physically trained exhibit more sudomotor activity and effective evaporative cooling compared to untrained individuals. Furthermore, individuals who acclimatize to heat over time develop improved thresholds for heat stress, enabling them to better regulate internal and cardiovascular temperature stresses during exposure. This knowledge is crucial for populations at risk and in situations where physical exertion is required in hot conditions.
Exercise Physiology
Mojtaba Ghorbani Asiabar; Morteza Ghorbani Asiabar; Alireza Ghorbani Asiabar
Abstract
Purpose: This study aimed to investigate the influence of genetic polymorphisms and metabolomic profiles on physiological adaptations to a 6-week High-Intensity Interval Training (HIIT) program in individuals with moderate fitness levels, addressing the variability in exercise response. Method: Thirty ...
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Purpose: This study aimed to investigate the influence of genetic polymorphisms and metabolomic profiles on physiological adaptations to a 6-week High-Intensity Interval Training (HIIT) program in individuals with moderate fitness levels, addressing the variability in exercise response. Method: Thirty moderately fit adults participated in a supervised 6-week HIIT intervention. Pre- and post-training assessments included VO2max, lactate threshold, genetic profiling of key polymorphisms (e.g., PPARGC1A rs8192678) using PCR and next-generation sequencing, and untargeted metabolomic analysis via liquid chromatography-mass spectrometry (LC-MS). Statistical analyses involved paired t-tests, multivariate regression, principal component analysis (PCA), and partial least squares discriminant analysis (PLS-DA). Results: Significant improvements were observed in VO2max (p < 0.001) and lactate threshold (p = 0.004). Carriers of the PPARGC1A G allele showed greater aerobic capacity gains, accompanied by upregulation of PGC-1α expression. Metabolomic profiling revealed significant shifts in glucose and lipid metabolism pathways post-HIIT. Multivariate models identified interactions between genetic variants and metabolomic changes that predicted individual training responsiveness. Conclusion: Integrating genetic and metabolomic data enhances understanding of individual variability in HIIT adaptations and supports the development of personalized exercise prescriptions to optimize health and performance outcomes.
