Cardiorespiratory fitness, physical activity, sedentary behavior, and circulating white blood cells in US youth

Abstract

The white blood cell (WBC) count indicates the number of white blood cells (ie, neutrophils, lymphocytes, monocytes, basophils, and eosinophils) in a sample of blood. High or extremely low total WBC counts in circulation at resting conditions could be related to the presence of illness. White blood cells are made in the bone marrow and protect the body against infection and aid in the immune response. 1 Importantly, the WBC count is considered a clinical marker that reflects inflammatory processes related to cardiometabolic disorders involved in the development of cardiovascular diseases (CVD). 1 Existing research recognizes the critical role physical activity (PA) plays on the immune system of children 2 by inducing both a short-term pro-inflammatory effect and a long-term anti-inflammatory effect, a dual response that is mediated by the coordinated activation of numerous cytokines and chemokines. 3 Previous research has established that moderate-to-vigorous PA (MVPA) 4,5 and cardiorespiratory

Handgrip Strength and Its Relationship with White Blood Cell Count in U.S. Adolescents

“…For this reason, these findings could be relevant since increased BMI in childhood and adolescence might be linked to faster ageing and could have a harmful impact on future health later in life [ 29 ]. Conversely, another study using the present sample showed an inverse relationship between WBC count, cardiorespiratory fitness and habitual physical activity levels [ 10 ]. People who were physically active or had high aerobic fitness potentially participated in activities that benefited their muscular fitness levels [ 30 ], which could explain (at least partially) our results.…”

“…According to the relationship between the immune system and muscular fitness, a recent systematic review and meta-analysis performed by Tuttle et al [ 7 ] indicated that higher systemic inflammation is linked to lower muscle strength and muscle mass in humans. Conversely, only a few studies [ 8 , 9 , 10 ] have examined the relationships between WBC counts and cardiorespiratory fitness, physical activity and sedentary behavior among children and adolescents. Nevertheless, the role of muscular fitness (as a protecting factor for an optimal immune system) and WBC remains unclear.…”

Associations between leisure-time physical activity level and peripheral immune cell populations in the US general population, analysis of the National Health and Nutrition Examination Survey data, 1999-2018

“…We observed an inverse association between leisure-time physical activity level and WBC count. Large observational studies consistently reported that individuals performing more frequent or more intense physical activity, regardless of leisure-time or total physical activity, had a lower WBC count (17,20,22,23,28,30,31). A higher objectively measured moderate-to-vigorous physical activity level was associated with a lower WBC count in the US adult population, healthy US male population, and US youth population in previous NHANES studies (17,20,30).…”

“…Leisure time physical activity is any physical activity outside of work and may include both intensive and non-intensive activities. Previous reports have observed an association between physical activity level and speci c peripheral immune cell populations in various populations (17)(18)(19)(20). Of total physical activity, higher levels of moderate-to-vigorous physical activity, measured objectively, was associated with a lower WBC count (20).…”

“…Differences by sex have been observed such that associations between tness level, WBCs, and mortality are less consistent in women compared to men (21). Second, while previous studies have observed lower WBC count with higher physical activity levels, their reports are largely limited to assessment of linear trend (17,20). Assessing the association between leisure-time physical activity level and metrics of WBC count and NLR which predict mortality in the US general population may provide clinical meaningfulness.…”