Cardiorespiratory fitness in relation to cardiometabolic health in adult Mexican Rarámuri.

Objective: In indigenous people of Mexico, there is a scarcity of information on the relationship between cardiorespiratory fitness (CRF) and clinical cardiometabolic health. The objective was to study the relationship between CRF and cardiometabolic health in adult Mexican Rarámuri (also known as Tarahumara), and to study cardiac health and physiological adaptations to ultradistance running in a subgroup of Rarámuri. Methods: In rural Rarámuri (n = 66) living at moderate altitude (1150-2400 m above sea level), we carried out measurements of anthropometry, hemodynamics (sitting blood pressure and heart rate), plasma glucose, electrocardiogram and echocardiography, and estimated CRF using a sub-maximal steptest. Results: Mean age of the studied population was 36.1 (standard deviation 11.6) years. Two participants (3%) were underweight, and ~47% were overweight/obese. Hypertension was found in ~24% of the participants. Mean CRF was moderately high to moderately low at 49 and 34 mLO2/min/kg in men and women, respectively, and CRF was significantly and inversely associated with hemodynamic and biochemistry measures except for blood glucose (p < 0.05). In a sub-group of runners, three men had mildly increased relative ventricular mass (range 118-128 g/m2). Conclusion: We found a relatively high proportion of overweight/obesity as well as hypertension. The expected inverse relationship between CRF and cardiometabolic measurements was observed. Abnormal physiological myocardiac adaptation to ultradistance running was minimal.