T-cell counts in response to acute cardiorespiratory or resistance exercise in physically active or physically inactive older adults: a randomized crossover study.

T cells often undergo age-related changes, which may be offset by regular exercise training. However, the majority of literature is derived from cardiorespiratory exercise studies. The purpose of this study was to examine the effects of acute cardiorespiratory exercise and acute resistance exercise on the T-cell response among physically active (PA) older adults compared with physically inactive (PI) older adults. Twenty-four healthy older adults [PA n = 12; PI n = 12; means ± SD; age (years) PA 62 ± 5, PI 64 ± 5; body mass index (BMI; kg/m2) PA 23.9 ± 3.0, PI 25.6 ± 3.5] completed one bout each of matched intensity cardiorespiratory exercise and resistance exercise in a randomized order. Blood samples drawn preexercise, postexercise, and 1 h postexercise (recovery) were analyzed by flow cytometry for T cells and T-cell subsets. Resistance exercise mobilized more T-cell subsets in PI (10 of the measured types, including total T cells; CD45RA+ CD62L+, CD45RA- CD62L+, CD45RA- CD62L-, and CD45RA+ CD62L- T cells), whereas cardiorespiratory exercise mobilized more subsets in PA (CD45RA+ CD62L- and CD57+ CD45RA+ CD62L- CD4+ T cells). Both cardiorespiratory exercise and resistance exercise elicited a significant (P < 0.05) mobilization of highly differentiated (CD45RA+ CD62L-; CD57+ CD45RA+ CD62L-) CD8+ T cells into the circulation postexercise in both PA and PI groups. Furthermore, cardiorespiratory exercise resulted in a decrease in the number of circulating Th17 cells postexercise, whereas resistance exercise increased Th17 cell mobilization compared with the cardiorespiratory exercise response. There are differences between cardiorespiratory exercise and resistance exercise on the immune responses of T cells, particularly in PI individuals. This research study was registered at clinicaltrials.gov NCT03794050. NEW & NOTEWORTHY A bout of resistance exercise did not elicit the same T-cell responses as a bout of walking on a treadmill, and the response was also not the same for people who participate in regular exercise compared with those who do not. Although there were several similarities, these potential differences underscore the importance of careful selection of exercise protocol based on the population studied and the desired T-cell response to exercise outcome.

A Short-Term Paleolithic Dietary Intervention Does Not Alter Adipokines Linked to Adiposity.

The Paleolithic diet, characterized by an emphasis on hunter-gatherer type foods accompanied by an exclusion of grains, dairy products, and highly processed food items, is often promoted for weight loss and a reduction in cardiometabolic disease risk factors. Specific adipokines, such as adiponectin, omentin, nesfatin, and vaspin are reported to be dysregulated with obesity and may respond favorably to diet-induced fat loss. We aimed to evaluate the effects of an eight-week Paleolithic dietary intervention on circulating adiponectin, omentin, nesfatin, and vaspin in a cohort of physically inactive, but otherwise healthy adults. METHODS: Seven inactive adults participated in eight weeks of adherence to the Paleolithic Diet. Fasting blood samples, anthropometric, and body composition data were collected from each participant pre-and post-intervention. Serum adiponectin, omentin, nesfatin, and vaspin were measured. RESULTS: After eight weeks of following the Paleolithic diet, there were reductions (p<0.05) in relative body fat (-4.4%), waist circumference (- 5.9 cm), and sum of skinfolds (-36.8 mm). No changes were observed in waist to hip ratio (WHR), or in adiponectin, omentin, and nesfatin (p>0.05), while serum vaspin levels for all participants were undetectable. CONCLUSIONS: It is possible that although eight weeks resulted in modest body composition changes, short-term fat loss will not induce changes in adiponectin, omentin, and nesfatin in apparently healthy adults. Larger, long-term intervention studies that examine Paleolithic diet-induced changes across sex, body composition, and in populations with metabolic dysregulation are warranted.

ß2-Adrenergic receptor signaling mediates the preferential mobilization of differentiated subsets of CD8+ T-cells, NK-cells and non-classical monocytes in response to acute exercise in humans.

Acute exercise preferentially mobilizes cytotoxic T-cells, NK-cells and non-classical monocytes to the bloodstream under the influence of hemodynamic forces and/or ß2-adrenergic receptor (ß2-AR) signaling. However, the relative contribution of these mechanisms to the redeployment of the most exercise-responsive cell types is largely unknown. We determined the lymphocyte and monocyte subtypes mobilized to blood during exercise via ß2-AR signaling whilst controlling for ß1-AR mediated reductions in hemodynamic forces. In a randomized, double blind, complete cross-over design, 14 healthy cyclists exercised for 30-minutes at +10% of blood lactate threshold after ingesting: (1) a placebo, (2) a ß1-preferential antagonist (10 mg bisoprolol), or (2) a non-preferential ß1 + ß2-antagonist (80 mg nadolol) across three trials separated by >7-days. Bisoprolol was administered to reduce hemodynamic forces (heart rate and blood pressure) during exercise to levels comparable with nadolol but without blocking ß2-ARs. The mobilization of total NK-cells, terminally differentiated (CD57+) NK-cells, central memory, effector memory and CD45RA+ effector memory CD8+ T-cells; non-classical monocytes; and γδ T-cells were significantly blunted or abrogated under nadolol compared to both bisoprolol and placebo, indicating that the exercise-induced mobilization of these cell types to the blood is largely influenced by ß2-AR signaling. Nadolol failed to inhibit the mobilization of classical monocytes, CD4+ T-cells (and their subsets) or naïve CD8+ T-cells, indicating that these cell types are mobilized with exercise independently of the ß2-AR. We conclude that the preferential mobilization of NK-cells, non-classical monocytes and differentiated subsets of CD8+ T-cells with exercise is largely dependent on catecholamine signaling through the ß2-AR. These findings provide mechanistic insights by which distinct lymphocyte and monocyte subtypes are preferentially mobilized to protect the host from anticipated injury or infection in response to an acute stress response.

Body composition assessment in overweight women: validation of air displacement plethysmography.

PURPOSE: The purpose of this study was to evaluate the validity and reliability of air displacement plethysmography (ADP) compared to a dual energy x-ray absorptiometry (DXA) criterion for body composition measurement in overweight and obese women (BMI ≥ 25·0 kg m(2) ). SUBJECTS/METHODS: Twenty-four overweight and obese women (Mean ± SD; Age: 36·6 ± 12·0 years; Height: 166·4 ± 5·8 cm; Weight: 86·5 ± 14·2 kg; Body Fat: 38·5 ± 3·7%; BMI: 31·3 ± 5·5 kg m(2) ) were tested after an 8-h fast. Fat mass (FM), fat-free mass (FFM) and percent body fat (%BF) were measured by ADP and compared to values determined by the DXA criterion. FFM from DXA was calculated as lean mass plus bone mineral content. A paired samples t-test was used to test for significant differences in the body composition variables between methods. A one-way ANOVA along with intraclass correlation coefficient (ICC), SEM,%SEM and MD was used to represent reliability. RESULTS: Validity data comparing ADP and DXA demonstrated no significant difference in FM (ADP-DXA FM = 0·99 kg; P = 0·113), FFM (0·98 kg; P = 0·115) and %BF (1·56%; P = 0·540). Reliability data for ADP between the first and second trials showed no significant difference in FM (P = 0·168; ICC = 0·994; SEM = 0·668), FFM (P = 0·058; ICC = 0·973; SEM = 0·892) or %BF (P = 0·121; ICC = 0·971; SEM = 0·813). CONCLUSIONS: For overweight and obese women, ADP was found to be a valid measure of FM, FFM and %BF when compared with DXA. The reliability of ADP was supported for all body composition variables.