Metabolic and Cardiovascular Responses on a Novel, Whole Body Exercise Device Compared to a Cycle Ergometer

International Journal of Exercise Science 12(2): 1206-1215, 2019. The purpose of this study was to compare the metabolic effects during a similar bout of exercise on a novel, whole body exercise device (Fish and Kangaroo Machine; FKM) and a cycle ergometer. Recreationally active men and women (n =13) completed two exercise sessions. The exercise protocol included intervals alternating between exercise (3-min) and rest (3-min) for a total duration of 39-min. The exercise intensity between the two modes was matched based on heart rate response. Heart rate, cardiac output, and stroke volume were measured using a wireless telemetry technique (Physioflow Enduro). Oxygen consumption (VO2) was measured via breath-by-breath automated analysis of expired respiratory gas (MGC Diagnostics Ultima). Capillary blood lactate was measured using a handheld meter (LactatePlus). While maintaining the heartrate response, stroke volume presented at a higher-level during rest periods, although not significant. There was also higher cardiac output at the end of the exercise bout with the FKM. VO2 was lower at the same heart rate and peak lactate was higher during FKM exercise. Cardiovascular recovery was improved following FKM exercise compared to cycling. The observed responses demonstrated that for a similar heart rate response, the FKM has an enhanced anaerobic metabolic component compared to cycling. These findings demonstrate the FKM may represent a novel exercise device comparable to cycling with unique anaerobic training potential

A Rapid, Flow Cytometry-Based Assay for the Determination of Natural Killer Cell Activity in Isolated Periphery Blood Mononuclear Cells

Natural killer cell activity (NKCA) is an important assessment of innate immunity in humans. Natural killer (NK) cells are known to be affected by exercise; therefore it is of interest to have an efficient method for measuring NKCA in pre- and post-exercise blood samples. Assays for NKCA include incubating human NK cells (effector cells) with stained target cells. The target cells are typically from the human leukemia cell line K562. The number of K562 target cells killed can be determined using a dead cell dye. Control target cells incubated alone provide a measure of spontaneous cell death. PURPOSE: The purpose of this study was to optimize a flow cytometry protocol for testing natural killer cell activity in human blood. METHODS: In a series of experiments, different variables were altered or held constant to find a method that yielded consistent, easily-distinguishable results. Variables tested included using freshly-stained target cells (K562 cells), or previously-stained K562 cells that had been stored in liquid nitrogen; number of cell washes; ratios and concentrations of target and effector cells; co-incubation time of target and effector cells; concentration and incubation time with dead cell dye (7AAD); and source of effectors cells (whole blood or isolated periphery blood mononuclear cells (PBMC)). RESULTS: We have found that consistent results are obtained with the following protocol: K562 cells are stained with 0.15 μM CFSE in 1 ml for 15-min, then incubated with 1ml complete-media containing 10% FCS for 30-min. The stained cells are washed three times with 15 ml PBS, resuspended in DMSO-containing complete media, aliquoted, and stored in liquid nitrogen. When needed, the target cells are thawed and washed three times with 50 ml PBS. The target cells are co-incubated with isolated PBMCs at concentration ratios of 1:20, 1:40, and 1:80 (target: effector) for 2 h, using 5000 target cells in a final volume of 100 µl. Following incubation, 30 μl 7 AAD-dye is added for 20-min, and then acquired on a flow cytometer. Representative results are shown above. Live target cells are shown in the upper left quadrant (CFSE+7AAD-), while dead target cells are found in the upper right quadrant (CFSE+7AAD+). Effectors cells have been gated out based on CFSE expression (CFSE-). Note the increase in dead target cells from incubation with PBS only (left figure), to incubation with effector cells (right figure). CONCLUSIONS: We have optimized a method of measuring NKCA in human PBMCs using flow cytometry

Consequences of Weight Cycling: An Increase in Disease Risk?

Research indicates that weight cycling, or “yo-yo dieting” is a common occurrence in obese populations. The long term negative health consequences of weight cycling are debated and it is unclear whether or not this weight change pattern poses a greater disease risk compared to obesity maintenance. This review discusses the prevalence of weight cycling and physiological alterations occurring during weight loss that promotes weight regain. We also discuss the effect weight regain has upon adipose tissue in terms of rate and type of accumulation. Also within this review are discussions surrounding the previously published literature based upon human and rodent research. We focus on previous limitations and difference in experimental design that have perhaps resulted in mixed findings concerning independent effects of weight cycling on health parameters. The final purpose of this review is to discuss future directions in evaluating the pro-inflammatory response to weight cycling in order to compare the disease risk compared to obesity maintenance

Mixed High-Fat and Stock Diet Caused a Greater Increase in Body Mass than High-Fat Diet Alone

Increased dietary palatability may lead to excess food consumption which in turn causes an excess of caloric intake and weight gain. Although most obesity studies in rodents utilize a high-fat diet, food variation, a combination of different diets for example, may actually increase body weight and fat mass beyond that of solely high-fat feeding. Purpose: To examine the changes in weight gain and body composition in mice that consume either a high-fat diet or a combination of high-fat and stock diet. Methods: 10 CD-1 male mice were randomly assigned to one of two groups based on dietary composition (N=5/group). HF mice consumed a high-fat diet (60% kcal from fat) and HF+Stock mice consumed a 50:50 combination of high-fat and stock diet (13.5% kcal from fat) for 24-weeks. Bi-weekly measurements were made on body composition (lean and fat mass) using an EchoMRI scanner and body weight using a digital scale. Food intake was recorded weekly. Results: HF and HF+Stock gained significant body weight, 41% and 66% respectively, from baseline to week 24 (P\u3c0.001, F12,84=45.483). On average, HF gained 23% lean mass (P\u3c0.001, F10,70=42.276) and 170% fat mass (P\u3c0.001, F10,70=31.873), while HF+Stock gained 27% lean mass and 260% fat mass from baseline. There were no differences between groups for body weight, lean mass, or fat mass. Conclusions: Although not significant, there was a greater increase in body weight, lean and fat mass in mice that consumed a combination of high-fat and stock diets. The results suggest diet variation has a positive effect in inducing obesity in mice. This study is limited in that only five animals were used in each group, thus leading us to believe that increasing the N per group will result in significant differences between groups. Expansion of this pilot study is warranted in the future

Cell-Surface Receptor Expression on Monocytes of Young and Old Mice

Background. Monocyte assessment is used in aging research. In humans, reduced expression of toll-like receptors, T-lymphocyte priming receptors and increases in intracellular adhesion molecules on monocytes have been associated with functional decrements, resulting in increased disease risk. While use of mouse models is extensive in aging research, mouse monocyte assessment is rare. We aimed to evaluate differences in cell-surface protein expression in classic (CD115+/Gr-1high) and non-classic (CD115+/Gr-1low) monocyte subsets of old and young mice. Methods. Venous blood was drawn from 18 old (80-wks) and 18 young CD-1 mice (15-20-wks). Flow cytometry was used to assess subpopulations of CD115+ monocytes for TLR2, TLR4, CD80, CD86, MHC II, CD54 and CD25. Data were analyzed with 2 (age groups) x 2 (monocyte populations) repeated measures ANOVA; significance was set at P\u3c0.05. Results. Old mice had greater proportions of classic monocytes (P\u3c0.05). TLR4 and CD80 was 27% and 37% lower in classic monocytes of old mice (P\u3c0.05). Body weight was not a significant covariate in the analysis. Conclusions. We found that old mice had elevated classic monocyte proportions and with lower expression of TLR4 and CD80. Because similar findings in older adults have been associated with increased risk of cardiovascular disease and infection, we surmise that old mice were also had increased disease risk compared to young mice. These findings support the use of monocyte subset phenotyping in murine models of aging

The International Journal of Exercise Science: 2010 Year in Review

The International Journal of Exercise Science: 2010 Year in Revie