George Ziogas

Physiological and Perceived Exertion Responses to Six Modes of Submaximal Exercise

In order to compare the cardiovascular and perceived exertion responses to 6 modes of exercise, 10 male recreational exercisers were habituated to treadmill jogging, stationary skiing, shuffle skiing, stepping, stationary cycling, and stationary rowing. After following a specific dietary preparation, each participant performed a 20-min exercise bout at a constant 14-rating of perceived exertion (RPE) followed by a second exercise bout at 60% of mode-specific peak oxygen consumption (VO2peak). On the 14-RPE trial, oxygen consumption (VO2) and oxygen pulse were significantly higher during jogging than during other exercise modes, and oxygen pulse was higher during skiing than during shuffle skiing. On the 60% VO2peak bout, oxygen pulse was significantly higher during jogging than during shuffle skiing, cycling and rowing. Ratings of perceived exertion were significantly higher during cycling than during jogging. These results indicated that a variety of exercise modes can be used to develop fitness, but jogging may induce a slightly more favorable VO2-to-RPE relationship.

%VO2max versus %HRmax regressions for six modes of exercise

The purpose of the study was to compare the %VO2max versus %HRmax regression equations developed from data collected during incremental work on six exercise modes: treadmill (T), cycle (C), skier (S), shuffle skier (SS), stepper (ST), and rower (R). Ten active males were habituated to all modes and then performed an incremental test to maximum on each mode. Mode order was assigned by Latin square sequences and the tests were separated by at least 72 h. VO2 and HR were recorded at each increment. Regression analyses were performed using SAS-GLM. Regressions for T, S, SS, and ST were not significantly different. C had a lower intercept and higher slope, while R had a higher intercept and lower slope than the other exercise modes. These results suggest that weight bearing exercise modes have similar %VO2max-%HRmax regressions. However, weight supported and arm exercise modes appear to have different regressions.

Influence of Fitness Status on Very-Low-Density Lipoprotein Subfractions and Lipoprotein(a) in Men and Women

The purpose of this study was to examine the influence of the physical activity level of men and women on the very-low-density lipoprotein (VLDL) subfractions and lipoprotein(a) [Lp(a)]. Fifty-four men (n = 30) and women (n = 24) aged 30 to 53 years were recruited based on their level of activity over the past 2 years, and formed three groups: sedentary (S), no routine activity; recreational exercise (R), routine moderate exercise three to five times per week; and trained (T), competition-based, high-volume aerobic training five to seven times per week. Each subject underwent a maximal oxygen consumption (VO2max) test and was measured for body composition (skinfolds) and waist to hip ratio (WHR). Following a prescribed 24-hour diet and abstinence from activity, a blood sample was obtained from each subject and the plasma was analyzed for cholesterol and triglycerides (TGs) in VLDL1, VLDL2, and VLDL3 subfractions. High-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C) and Lp(a) also were analyzed. Total VLDL-C was higher in men than in women, but no gender differences were observed in VLDL subfractions. VLDL1-TG and VLDL2-TG were elevated in the S group compared with groups R and T, even though total VLDL-TG, LDL-C, and HDL-C values were not different among the groups. Values for Lp(a) were not significantly different between men and women or among the groups. The two exercising groups were not different on any lipoprotein variable or WHR. VLDL1-TG was inversely correlated with VO2max and HDL-C. These results suggest that life-style activity is associated with a favorable VLDL subfraction pattern and WHR, but not Lp(a). In addition, long-term recreational activity is associated with a lipoprotein profile and WHR similar to those obtained with higher-volume exercise training.

Predicting Postprandial Lipemia in Healthy Adults and in At‐Risk Individuals With Components of the Cardiometabolic Syndrome

To determine whether a single‐point triglyceride (TG) concentration could estimate the 8‐hour postprandial lipemic (PPL) response, men and women performed baseline PPL (n=188) and postexercise PPL (n=92) trials. Correlations were generated between TG concentrations at baseline and at various time points after a high‐fat meal vs 8‐hour area under the TG curve (TG‐AUC) and peak TG level. Stepwise multiple regression and bootstrap simulations using TG level and additional predictor variables of sex, age, percentage of body fat, training status, and maximal oxygen consumption indicated that the 4‐hour TG concentrations accounted for >90% of the variance in TG‐AUC and peak TG responses during the PPL trials. Equations were confirmed by cross‐validation in healthy as well as at‐risk individuals with components of the cardiometabolic syndrome. Our data suggest that the 4‐hour TG value is highly related to the total 8‐hour PPL response and can be used for accurate estimation of PPL in a clinical or research setting.

Dietary Preparation Before Rest and Exercise Testing

To compare the effectiveness of four dietary preparations for stabilizing resting and exercise measurements, seven male recreational exercisers (27 +/- 4 y) participated in four dietary preparations, each repeated in successive weeks: (1) 24-h random diet including an overnight fast (RAN); (2) 24-h random diet, including fast, followed by a standard meal 3 h before testing (RANM); (3) 24-h prescribed diet including an overnight fast (PRES); and (4) 24-h prescribed diet, including fast, followed by a standard meal (PRESM). After each preparation, metabolic rate (VO2) and respiratory exchange ratio (RER) were measured at rest and in association with moderate treadmill exercise. Plasma was analyzed for glucose, cholesterol, and high-density lipoprotein (HDL)-cholesterol. Repeated measures analyses of variance (ANOVAs) followed by Tukey posthoc tests indicated that resting VO2, RER, and blood parameters were not different between the two trials on the same diet. Exercise RER, however, was slightly different in trial 1 than in trial 2 for all preparations except PRESM. Combining both trials, resting VO2 and exercise RER were higher when a pretesting meal was administered. Plasma values were not different for the four dietary preparations. These results suggest that a standard overnight fast appears to be adequate for establishing representative and reproducible rest and exercise values for the parameters measured, except possibly for exercise RER reliability.

Influence of activity level on vitamin E status in healthy men and women and cardiac patients.

BACKGROUND Plasma Vitamin E status may indicate protection against cholesterol oxidation. The purpose of this study was to determine if the plasma vitamin E status is influenced by exercise training status or a single session of submaximal exercise. METHODS The 41 participants were categorized as sedentary, recreational endurance trained, competitive endurance trained, or cardiac rehabilitation patients. Subjects completed a 3-day dietary record. After a 24-hour diet and exercise control period, including a 12-hour fast, venous blood was collected. Plasma was analyzed for total cholesterol, high-density lipoprotein cholesterol (HDL-C), total lipid, vitamin E, and low-density lipoprotein (LDL) vitamin E concentrations. Each subject then exercised on a treadmill at 60% of measured maximal oxygen consumption for 30 minutes. Postexercise samples were collected 5 minutes after the activity. RESULTS Multivariate analysis of variance and follow-up Tukey post hoc tests indicated that the cardiac rehabilitation group had lower total fat and monounsaturated fat intake in the diet than the other groups, and the competitive-endurance trained group had higher HDL-C levels. Plasma vitamin E was higher in the cardiac rehabilitation group, but the statistical differences disappeared when expressed per unit of plasma total lipid. The vitamin E content of LDL was not different among the groups. A single exercise session did not alter the plasma lipoprotein or vitamin E status. CONCLUSIONS These results suggest that habitual activity level of healthy individuals or a single session of exercise does not influence the plasma vitamin E or LDL vitamin E concentrations. However, patients in an endurance cardiac rehabilitation program tend to show normal to elevated plasma vitamin E status.