Anemia defined as reduced hemoglobin levels of red blood cells may carry less oxygen to skeletal muscle and impair physical performance. Previous studies have shown that exercise intolerance was related to moderate or severe anemia, however, the relationship to mild anemia was unknown. We investigated the cross-sectional association of mild anemia defined as a hemoglobin level of 10.0–13.9 g/dL with physical fitness in 3,666 military young males in Taiwan in 2014. Aerobic fitness was evaluated by 3000-meter run test, and anaerobic fitness was evaluated by 2-minute sit-ups and 2-minute push-ups, respectively. Multiple logistic regressions for the best 10% and the worst 10% performers were used to determine the relationship. There were 343 mild anemic males in whom 47.8% were microcytic anemia and 3,323 non-anemic males for the analysis. The multiple logistic regression shows that as compared with non-anemic males, mild anemic males were more likely to be the worst 10% performers in the 3000-meter run test (odds ratios (OR) and 95% confidence intervals: 1.47, 1.01–2.14) after adjusting for age, service specialty, body mass index, waist size, mean blood pressure, unhealthy behaviors, lipid profiles, and exercise frequency. On the contrary, mild anemic males had higher possibility to be the best 10% performers in the 2-minute push-ups test (OR: 1.48, 1.08–2.04). However, there was no association between mild anemia and 2-minute sit-ups. Our findings suggest that unspecified mild anemia might be associated with lower cardiorespiratory fitness but not with anaerobic fitness in physically active military males.

Low-grade inflammation, which is related to obesity and toxic substance use in young adults, may be associated with poor physical fitness. We investigated the association between total leukocyte count and physical fitness in a military cohort of 3,453 healthy young Taiwanese males aged 20-50 years in a cross-sectional study in 2014. Low-grade inflammation was defined according to equally sized quartiles of total leukocyte counts within the suggested normal limits (4.00-9.99 × 10 3 /mm 3). Aerobic fitness was assessed by the time for a 3-kilometer run test, and anaerobic fitness was evaluated by the numbers of sit-ups and push-ups performed in 2 minutes. Automatic monitoring systems were used to verify the scores for all procedures. Multiple linear regression was utilized to identify the associations among variables. When compared with the lowest counts (4.00-5.49 × 10 3 /mm 3), the second highest (6.50-7.49 × 10 3 /mm 3) and highest normal leukocyte counts (7.50-9.99 × 10 3 /mm 3) were correlated with longer times for a 3-kilometer run (β and 95% confidence intervals =4.93 (1.61, 8.25) and 4.65 (2.20, 7.10), respectively) and fewer numbers of push-ups performed in 2 minutes (β = −0.59 (−1.15, −0.03) and −0.56 (−0.96, −0.17), respectively), after adjustments for age, service specialty, waist circumference, body mass index, alcohol consumption, tobacco smoking, and physical activity. However, the association with 2-minute sit-ups was null. Our study suggested an inverse association between total leukocyte count and not only aerobic fitness but also parts of anaerobic fitness in young males. The temporal association needs confirmation in longitudinal studies.

The metabolically healthy obese (MHO) characterized by the absence of metabolic syndrome have shown superior cardiorespiratory fitness (CRF) and similar muscular strength as compared with the metabolically unhealthy obese (MUO). However, this finding might be biased by the baseline sedentary behavior in the general population. This study utilized 3669 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 presence of at least two major components of the metabolic syndrome, according to the International Diabetes Federation criteria for Asian male adults. Four groups were accordingly classified as the metabolically healthy lean (MHL, n = 2510), metabolically unhealthy lean (MUL, n = 331), MHO (n = 181) and MUO (n = 647). CRF was evaluated by time for a 3-km run, and muscular strengths were separately assessed by numbers of push-up and sit-up within 2 min. 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 metabolic syndrome prevalence in MUL and MUO was 49.8% and 47.6%, respectively. The performance of CRF did not differ between MHO and MUO (892.3 ± 5.4 s and 892.6 ± 3.0 s, p = 0.97) which were both inferior to MUL and MHL (875.2 ± 4.0 s and 848.6 ± 1.3 s, all p values < 0.05). The performance of muscular strengths evaluated by 2-min push-ups did not differ between MUL and MUO (45.3 ± 0.6 and 45.2 ± 0.4, p = 0.78) which were both less than MHO and MHL (48.4 ± 0.8 and 50.6 ± 0.2, all p values < 0.05). However, the performance of 2-min sit-ups were only superior in MHL (48.1 ± 0.1) as compared with MUL, MHO and MUO (45.9 ± 0.4, 46.7 ± 0.5 and 46.1 ± 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.