The aim of the study was to examine the direction of the secular changes in the waist and hips circumferences, as well as selected associated body proportions, among children and adolescents from Kraków, Poland. The study group included 8–18-year-olds examined in three cross-sectional studies (1983, 2010, and 2020). The analyzed characteristics included body height, circumferences of the waist and hips, which were used to calculate Waist-to-Hip Ratio (WHR), and Waist-to-Height Ratio (WHtR). There was a secular increase regarding the majority of the analyzed features, particularly for the younger children (i.e., prepubertal/early pubertal age). The trends were also especially evident when comparing the results of the 1983 series to the results of their peers examined in 2020. An opposite trend was noted in adolescent girls. The observed changes reflect the secular trend resulting from changes in body composition and fat distribution happening due to alterations in the lifestyle and socio-economic environment of the population over the years. It should also be stressed that the increase in the studied characteristics occurred mainly in younger children. This suggests that the observed changes may have resulted from a shift in the age of maturation and also from the personal and social motivators characteristic for late adolescence.

This study provides a comprehensive evaluation of the effects of environmental stressors and physical exertion on human nociceptive processing across multiple ecologically relevant conditions. Using a repeated-measures design, participants (N = 45) completed up to five controlled laboratory (thermoclimatic chamber) sessions (baseline, simulated altitude at 4200 m asl, heat at +42 °C, cold at −10 °C, and exertion). Participants were tested by using electrical stimuli. Linear mixed-effects models with participant-level random intercepts, alongside estimated marginal means and bootstrap derived effect sizes, enabled robust characterization of within-subject differences. Thermal stress emerged as the strongest modulator of nociception. Heat exposure significantly elevated sensory and pain thresholds compared with all other conditions, whereas tolerance thresholds peaked during cold exposure, yielding the largest observed effects. Altitude consistently produced the lowest thresholds across all modalities. These contrasts were confirmed statistically in the mixed-effects models, and effect-size analyses indicated substantial within-subject differences between the thermal extremes. By integrating three distinct nociceptive modalities and extreme environment simulations, this work offers novel and informative insights into how environmental stressors shape pain processing. The discovery of opposing thermal effects on sensory/pain versus tolerance thresholds—within the same cohort and design—reveals modality-specific patterns not previously documented and suggests that hypoxia may further modulate these responses.