Summary Accurate measures of body composition (BC) are essential for performance and health. In addition to accuracy, BC measures should be practical and be minimally invasive to maximize their utility. The purpose of the present study was to compare the day‐to‐day variability and validity of four common laboratory‐based body composition assessments to a criterion four‐compartment model. Dual x‐ray absorptiometry (DXA), air displacement plethysmography (BP), multi‐frequency bioelectrical impedance (MF‐BIA) and underwater weighing (UWW) were performed twice in a sample of 32 young men and women. Participants were assessed in a fasted, euhydrated state 2–7 days apart. All methods were compared to a criterion four‐compartment model using BP‐derived body volume, DXA‐derived bone mineral content and MF‐BIA‐derived total body water (4CBP). Additional four‐compartment models using UWW‐ and DXA‐derived body volume were also examined (4CUWW) and (4CDXA). Validity results were conducted with paired t‐tests and Bland–Altman analysis. Reliability was determined using intraclass correlations (ICC), coefficients of variation (CV) and standard error of the measurement (SEM). Validity analysis revealed that all methods overestimated per cent body fat and fat mass, and underestimated fat‐free mass when compared with 4CBP, but only DXA and BP were significantly different (P<0·008). All measures were highly reliable across days (ICCs > 0·9, CVs < 12%). Results of the present study indicate that typical laboratory‐based methods of body composition are valid and reliable. However, we caution that results should not be translated between methods and assessments should be performed with the same instrument when the goal is to monitor changes in body composition over time.

These findings indicate that 500 kcal of continuous aerobic exercise before a meal attenuates PPL in men with MetS. This outcome can be achieved through low- or moderate-intensity exercise performed in a single session. Accumulating moderate-intensity exercise does not appear to effectively modulate PPL in men with MetS.

Aerobic exercise lowers the postprandial triglyceride response to a high-fat meal. Niacin lowers fasting but not postprandial triglycerides and appears to influence the triglyceride-lowering effect of aerobic exercise when combined. However, exercise decreases postprandial insulin concentrations after niacin administration, which illustrates the potential metabolic benefits of exercise in persons taking niacin.

Serum adiponectin concentrations are higher in women than men. The sexual dimorphism for adiponectin has been attributed to the direct effects of testosterone on adipose tissue adiponectin secretion. However, serum testosterone and adiponectin concentrations are generally lower in obese men than lean men, suggesting that sex steroids may not be the only factor that contributes to sex differences in serum adiponectin. The primary objective of this study was to examine the influence of sex, body composition, and nonesterified fatty acids (NEFAs) on serum adiponectin concentrations. Women and men between the ages of 18 and 35 years were consecutively accrued into the study. Sixty-one participants were partitioned into normal-weight (15 female and 16 male) or obese (14 female and 16 male) groups. Blood samples were obtained after a 12-hour fast. Differences between groups were determined by analysis of variance with Tukey-Kramer post hoc testing. Serum adiponectin was 26% higher in women compared with men. Body mass index was associated with total serum adiponectin in men (r = -0.63, P < .05) but not women. Adiponectin was correlated with the homeostasis model assessment index in women (r = -0.56, P < .05) and men (r = -0.58, P < .05) and with NEFAs (r = -0.68, P < .05) in men only. After partitioning men and women into normal-weight and obese groups, serum adiponectin was lower and NEFAs were higher in obese men only. Homeostasis model assessment was similar between obese women and men despite higher NEFAs in the obese men. Leptin and plasminogen activator inhibitor-1 were higher in obese participants but were not associated with serum NEFAs. These results suggest that serum NEFAs may reduce adiponectin concentrations independent of their effects on insulin sensitivity in obese young men.

The purpose of this study was to compare blood lipid responses to continuous versus accumulated exercise. Nine participants completed the following conditions on separate occasions by treadmill walking/jogging at 70% of VO2max: 1) one 500-kcal session and 2) three 167 kcal sessions. Total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG) concentrations were measured from serum samples obtained 24 h prior to and 24 and 48 h after exercise. All blood lipid responses were analyzed in 2 (condition) x 3 (time) repeated measures ANOVAs. HDL-C increased by 7 mg/dL over baseline at 48 h post-exercise with three accumulated sessions versus 2 mg/dL with continuous exercise (P < 0.05). Triglyceride concentrations were unchanged in both conditions. These findings suggest that three smaller bouts accumulated on the same day may have a modestly greater effect for achieving transient increases in HDL-C compared to a continuous bout of similar caloric expenditure.

The aim of this study was to compare postexercise autonomic nervous system (ANS) recovery between a high-intensity training protocol (HITP) and high-intensity treadmill running (TM) in 10 physically fit males. For each trial, ANS activity was measured through the heart rate variability markers of log-transformed square root of the successive R-R differences (lnRMSSD) and high frequency power (lnHF). These markers were analyzed in 5-minute segments at 5-10 minutes of the pre-exercise period (PRE) and during the postexercise period at 15-20 minutes (POST15-20min), 20-25 minutes (POST20-25min), 25-30 minutes (POST25-30min), and 1 hour (POST60min). Plasma epinephrine (E) and norepinephrine (NE) were also examined at PRE, immediately post exercise (IPE), 1-hour post (1HP), and 2-hour post (2HP). The results of this study demonstrate a significant overall time-dependent decreases in lnRMSSD and lnHF (p = 0.003 and 0.001, respectively) in both trials. Trial-dependent differences were also observed in postexercise lnRMSSD and lnHF measures, HITP being significantly lower than TM (p = 0.002 and 0.000, respectively). lnRMSSD at POST60min-HITP remained significantly lower compared to PRE (p ≤ 0.05). lnHF returned to baseline in HIPT and TM (p = 0.081 and 0.065, respectively). A time-dependent increase in E and NE was observed in both trials at time point IPE when compared to PRE (p ≤ 0.05). E at 1HP and 2HP returned to near resting levels (p = 0.62, p = 0.26), whereas NE remained slightly elevated in both groups (p = 0.003, p = 0.021). A trial-dependent increase was observed with the HITP eliciting a greater E response (p = 0.025) and NE response (p = 0.03). The HITP causes a greater disruption of the ANS than intensity-matched TM exercise.

Inflammatory markers such as C-reactive protein (CRP), fibrinogen, and white-blood-cell (WBC) count are strongly associated with cardiovascular disease. The authors' purpose was to compare the inflammatory response to a single aerobic-exercise session between individuals of high and moderate fitness. Ten apparently healthy highly fit and 11 moderately fit men expended 500 kcal at 70% of VO2peak. Fasting blood samples were obtained on 2 consecutive days before and again at 24, 72, and 120 h postexercise. Blood samples were analyzed for CRP, fibrinogen, and WBC count. CRP was 76% lower at baseline in the highly fit group than in the moderately fit group (P = 0.03). CRP, fibrinogen, and WBC count remained unaltered, however, in the days after exercise (P > 0.05 for all). These findings suggest that markers of inflammation are stable in the days after a single session of moderate-intensity aerobic exercise in apparently healthy men of at least average fitness.

An observational study was conducted to evaluate hygiene habits of students with fields of study, gender, and understanding of hygiene at a university in Alabama. One hundred students were randomly observed in ten restrooms on campus to determine whether or not students washed their hands. The study was divided into an observational stage, a quiz to ascertain student's knowledge of hygiene and the spread of pathogens, and a survey of self-reported illness rates. Females had a tendency to wash their hands more often than males while visiting the bathroom (p = 0.02, X 2 = 11.6). Science majors were more likely to wash their hands than non-science majors (p ≤ 0.001, X 2 = 5.2). Females (p ≤ 0.0001, df = 98, F = 21.5) and science majors (p ≤ 0.0001, df = 98, F = 81.4) scored significantly higher on the survey than males and nonscience majors, and that those observed not washing their hands reported being sick more often than those observed washing their hands (X 2 = 155.0, df = 3, p < 0.001, Fisher's exact p< 0.001). Clin Lab Sci 2010;23(2):89