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Association of red blood cell size and physical fitness in a military male cohort: The CHIEF study
Author(s) -
Lai ShiueWei,
Tsai KunZhe,
Lin YenPo,
Liu PangYen,
Lin YuKai,
Chang PingYing,
Dai MingShen,
Chao TsuYi,
Han ChihLu,
Lin GenMin
Publication year - 2021
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.13836
Subject(s) - microcytosis , mean corpuscular volume , medicine , physical fitness , anaerobic exercise , odds ratio , mean corpuscular hemoglobin concentration , logistic regression , hemoglobin , demography , anemia , physiology , physical therapy , iron deficiency , sociology
Summary Anemia manifested as reduced red blood cell (RBC) amounts or hemoglobin levels has been associated with lower cardiorespiratory fitness. However, the relationship of smaller RBC with physical fitness was unknown. We included 2933 non‐anemic military males (hemoglobin levels: 11.1‐15.9 g/dL and mean corpuscular volume (MCV) <100 fL) in Taiwan during 2014. Aerobic fitness was assessed by time for a 3000‐meter run, and anaerobic fitness was evaluated by numbers of sit‐ups and push‐ups, each performed within 2 minutes. Multiple linear and logistic regression models adjusting for age, service specialty, lipid profiles, and hemoglobin levels were used to determine the associations. Microcytosis and normocytosis were defined as MCV ≤ 70 fL (n = 190) and MCV > 70 fL (n = 2743), respectively. The linear regression shows that as compared with microcytosis, normocytosis was associated with more numbers of sit‐ups performed within 2 minutes ( β = 1.51, P ‐value = 0.02). The logistic regression also reveals that those males with microcytosis had higher probability as the worst 10% performers in the 2‐minute push‐up test (odds ratio: 1.91, 95% confidence intervals: 1.18‐3.12). By contrast, there was no association of microcytosis with 3000‐meter running time. Our study suggests that non‐anemic microcytosis was associated with lower anaerobic fitness but not with aerobic fitness. Whether the causative factors for microcytosis such as iron deficiency status and thalassemia trait unavailable in the study might account for the relationship needs further investigations.