Metabolically Healthy Obesity and Physical Fitness in Military Males in the CHIEF Study

Abstract The metabolically healthy obese (MHO) characterized by the absence of abdominal obesity have been reported to have superior cardiorespiratory fitness (CRF) than the metabolically unhealthy obese (MUO). However, this finding might be biased by the baseline sedentary behavior in the general population.This study utilized 3,669 physically active military males aged 18-50 years in Taiwan. Obesity and metabolically unhealthy were respectively defined as body mass index ≥27.5 kg/m2 and waist circumference ≥90 cm, specifically for Asian male adults. Four groups were accordingly classified as the metabolically healthy lean (MHL, n=2,607), metabolically unhealthy lean (MUL, n=234), MHO (n=208) and MUO (n=620). CRF was evaluated by time for a 3-kilometer run, and muscular strengths were separately assessed by numbers of push-up and sit-up within 2 minutes. Analysis of covariance was utilized to compare the difference in each exercise performance between groups adjusting for age, service specialty, smoking, alcohol intake, and physical activity.The prevalence of metabolic syndrome in MUO, MHO, MUL and MHL was 45.3% 13.0%, 29.1% and 3.7%, respectively. The performance of CRF did not differ between MHO and MUO (895.3±5.1 sec and 891.5±3.1 sec, p=0.68) which were both inferior to MUL and MHL (877.5±4.8 sec and 849.5±1.4 sec, all p-values <0.05). The performance of muscular strengths evaluated by 2-minute push-ups did not differ between MUL and MUO (44.8±0.2 and 45.2±0.5, p=0.40) which were both less than MHO and MHL (48.1±0.8 and 50.5±0.2, all p-values <0.05). However, the performance of 2-minute sit- ups were only superior in MHL (48.0±0.2) as compared with MUL, MHO and MUO (46.0±0.5, 46.7±0.5 and 46.2±0.3, respectively, all p-values <0.05).Our findings suggested that in a physically active male cohort, the MHO might have greater muscle strengths, but have similar CRF level compared with the MUO.