Urbanization, Physical Capacity, and Body Composition in Rarámuri and Mestizo Populations From Northern Mexico.

Urbanized Rarámuri and Mestizo participants exhibited higher body weight, BMI, and body fat percentage compared to non-urbanized rural Rarámuri participants.

• Cross-sectional study conducted in Chihuahua, Mexico with n=171 participants (84 men, 87 women).
• Three groups were compared: non-urbanized rural Rarámuri (NURR), urbanized Rarámuri (UR), and urban Mestizo (MEST).
• Differences in body weight, BMI, and body fat percentage were statistically significant (p < 0.05).
• Anthropometric assessments followed ISAK and YMCA protocols; classifications were based on WHO and YMCA reference standards.
• Statistical differences were analyzed using the Kruskal-Wallis test.

Non-urbanized rural Rarámuri maintained a leaner and metabolically efficient phenotype compared to urbanized groups.

• The NURR group showed lower adiposity indicators relative to both UR and MEST groups.
• Waist circumference revealed a greater distribution of metabolic risk among UR and MEST participants compared to NURR.
• The NURR group's phenotype was described as 'leaner and metabolically efficient.'
• Differences were statistically significant at p < 0.05 using the Kruskal-Wallis test.

Urbanized Rarámuri and Mestizo participants demonstrated lower VO2max and functional endurance compared to non-urbanized rural Rarámuri.

• Aerobic capacity (VO2max) was assessed following YMCA protocols.
• Both UR and MEST groups exhibited lower VO2max than the NURR group (p < 0.05).
• Functional endurance was also lower in UR and MEST groups.
• Physical fitness assessments included push-ups, sit-ups, flexibility, and aerobic capacity.

Urbanization was associated with a progressive increase in adiposity and a decline in aerobic capacity across the three population groups.

• The pattern followed a gradient from NURR (least urbanized) to UR to MEST (most urbanized).
• The authors describe this as a 'biocultural transition' in which 'traditional physical activity patterns erode' and 'physiological efficiency and cardiometabolic health deteriorate.'
• The study characterized urbanization's effect as inducing 'functional regression rather than adaptation.'
• The study design was cross-sectional, so causal directionality cannot be established.

The Rarámuri case was identified as an example of how erosion of indigenous physical activity patterns is linked to deterioration in physiological efficiency and cardiometabolic health.

• The authors note the importance of 'preserving indigenous mobility and physical culture as key components of public health and cultural identity.'
• The findings highlight a 'clear biocultural transition' associated with urbanization.
• The Rarámuri are an indigenous population from northern Mexico (Chihuahua) known historically for endurance physical activity.