Ten-year cardiovascular risk assessment in university students.

Cardiovascular disease (CVD) is responsible for more than half of all deaths in the European region. The aim of the study was to compare body composition, blood pressure, total cholesterol (TC) and high density lipoprotein cholesterol (HDL-C), family history, activity behaviors, and the 10-year risk of having a heart attack between 166 university students (21.62 ± 2.59 yrs) from Utah (USA) and 198 students (22.11 ± 2.51 yrs) from Hungary. Ninety-two percent of the Hungarian students and 100% of the Utah students had an estimated 10-year Framingham risk score of 1% or less. The high prevalence of low risk was primarily due to the young age of study participants, healthy body composition and non-smoking behavior. Hungarians who had higher 10-year risk of heart attack had significantly higher waist hip ratio (WHR), TC, diastolic blood pressure (DBP) and were smokers compared to those Hungarians with lower risk. The self-reported physical activity levels between the two groups of students were not different. In conclusion the young men and women who participated in this study were, for the most part healthy; however the smoking habits and the lower physical activity of the Hungarian students likely elevated their risk of CVD.

Reliability and concurrent validity of Futrex and bioelectrical impedance.

Thirty Caucasian males (aged 19-32yr) participated in this study designed to investigate the reliability of multiple bioelectrical impedance analysis (BIA) and near-infrared spectroscopy (Futrex, FTX) measurements and the validity of BIA and FTX estimations of hydrostatically (UW) determined percent body fat (%BF). Two BIA and two FTX instruments were used to make 6 measurements each of resistance (R) and optical density (OD) respectively over a 30 min period on two consecutive days. Repeated measures ANOVA indicated that FTX and BIA, using manufacturer's equations, significantly (p<0.01) under predicted UW by 2.4 and 3.8%BF respectively. Standard error of estimate (SEE) and total error (TE) terms provided by regression analysis for FTX (4.6 and 5.31%BF respectively) and BIA (5.65 and 6.95%BF, respectively) were high. Dependent t-tests revealed no significant differences in either FTX or BIA predictions of %BF using two machines. Intraclass reliabilities for BIA and FTX estimates of UW %BF across trials, days, and machines all exceeded 0.97. A significant random error term associated with FTX and a significant subject-by-day interaction associated with BIA was revealed using the generalizability model. Although FTX and BIA estimates of UW %BF were reliable, due to the significant underestimation of UW %BF and high SEE and TE, neither FTX nor BIA were considered valid estimates of hydrostatically determined %BF.

Development of a submaximal treadmill jogging test for fit college-aged individuals.

The purpose of this study was to develop a single-stage submaximal treadmill jogging test for the estimation of maximal oxygen uptake (VO2max). VO2max was measured in 129 relatively fit individuals (males = 84, females = 45), 18-29 yr, using a maximal treadmill protocol (mean +/- SD; VO2max = 48.3 +/- 6.2 ml.kg-1 x min-1, range = 35.6 to 62.3 ml.kg-1 x min-1). The treadmill test required subjects to sustain a comfortable, submaximal jogging pace (4.3-7.5 mph; level grade) until a steady-state heart rate was achieved (approximately 3 min). To help ensure that a submaximal level of exertion was realized for the treadmill jogging test, treadmill speed and exercise HR criteria were established that restricted treadmill speed to < or = 7.5 mph for males and < or = 6.5 mph for females and steady-state exercise HR < or = 180 bpm. Multiple regression analysis (N = 66) to estimate VO2max from the treadmill jogging test yielded the following validation (V) model (r(adj) = 0.84, SEE = 3.2 ml.kg-1 x min-1): VO2max = 54.07 + 7.062 * GENDER (0 = female; 1 = male) - 0.1938 * WEIGHT (kg) + 4.47* SPEED (miles.h-1) - 0.1453 * HEART RATE (bpm). Cross-validation (CV) of the treadmill jogging test comparing observed and estimated VO2max (N = 63) resulted in r(adj) = 0.88, SEE = 3.1 ml.kg-1 x min-1. The results indicate that this submaximal single-stage treadmill jogging test based on multiple linear regression provides a valid and convenient method for estimating VO2max.

VO2max estimation from a submaximal 1-mile track jog for fit college-age individuals.

The primary purpose of this study was to develop a submaximal field test for the estimation of maximal oxygen uptake (VO2max) using a 1-mile track jog. A second purpose was to determine the accuracy of the 1.5-mile run in estimating VO2max for both male and female subjects. VO2max was measured in 149 relatively fit college students (males = 88, females = 61) 18-29 yr using a treadmill protocol (mean +/- SD; VO2max = 47.7 +/- 6.3 ml.kg-1 x min-1). Multiple regression analysis (N = 54) to estimate VO2max from the submaximal, steady-state 1-mile track jog yielded the following validation (V) model (r(adi) = 0.87, SEE = 3.0 ml.kg-1 x min-1): VO2max = 100.5 + 8.344* GENDER (0 = female; 1 = male) - 0.1636* BODY MASS (kg) - 1.438* JOG TIME (min.mile-1) - 0.1928* HEART RATE (bpm). To help ensure that a submaximal level of exertion was realized for the 1-mile track jog, elapsed jog time was restricted to > or = 8.0 min for males and > or = 9.0 min for females and exercise HR to < or = 180 bpm. Cross-validation (CV) of the 1-mile track jog comparing observed and estimated VO2max (N = 52) resulted in radj = 0.84, SEE = 3.1 ml.kg-1 x min-1. Multiple regression analysis (N = 50) to estimate VO2max from the 1.5-mile run (V:N = 49, radj = 0.90, SEE = 2.8 ml.kg-1 x min-1; CV: N = 47, radj = 0.82, SEE = 3.9 ml.kg-1 x min-1), used elapsed run time, body mass, and gender as independent variables.(ABSTRACT TRUNCATED AT 250 WORDS)

Muscle malonyl-CoA decreases during exercise.

Malonyl-CoA, the inhibitor of carnitine acyltransferase I, is an important regulator of fatty acid oxidation and ketogenesis in the liver. Muscle carnitine acyltransferase I has previously been reported to be more sensitive to malonyl-CoA inhibition than is liver carnitine acyltransferase I. Fluctuations in malonyl-CoA concentration may therefore be important in regulating the rate of fatty acid oxidation in muscle during exercise. Male rats were anesthetized (pentobarbital via venous catheters) at rest or after 30 min of treadmill exercise (21 m/min, 15% grade). The gastrocnemius/plantaris muscles were frozen at liquid N2 temperature. Muscle malonyl-CoA decreased from 1.66 +/- 0.17 to 0.60 +/- 0.05 nmol/g during the exercise. This change was accompanied by a 31% increase in cAMP in the muscle. The decline in malonyl-CoA occurred before muscle glycogen depletion and before onset of hypoglycemia. Plasma catecholamines, corticosterone, and free fatty acids were all significantly increased during the exercise. This exercise-induced decrease in malonyl-CoA may be important for allowing the increase in muscle fatty acid oxidation during exercise.

Exercise during gravity inversion: acute and chronic effects.

The purpose of this study was to determine whether gravity inversion could correctly be called an exercise, and whether inversion and inverted exercise produced safe blood pressure responses. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and oxygen consumption (VO2) were measured in 19 healthy young men (means = 20.31 years) in seven positions: (1) standing passive (STD), (2) inverted passive (INV), (3) standing recovery postpassive inversion (SRPI), (4) standing exercise (SDE), (5) standing recovery poststanding exercise (SRPSE), (6) inverted exercise (INVE), and (7) inverted recovery postinverted exercise (IRPIE). Ten of the subjects participated in a five-week inversion training program, after which all 19 subjects were retested. Compared to STD, INV elicited significant increases in SBP/DBP and a significant decrease in HR. The average INV blood pressure was 146/97 mmHg, which was further increased during INVE to 158/101 mmHg. These responses increase the workload of the heart and may be dangerous to some populations. No physiologic adaptations occurred in any of the inverted positions as a result of inversion training. Gravity inversion should not be compared to or classified as an exercise. Some previously suggested inverted exercises are not recommended. Because of the nature of the responses, medical screening before the use of inversion devices is critical.