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.

Lipoprotein subfraction changes after continuous or intermittent exercise training.

PURPOSE: This study compared total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) and their respective subfractions after completing 4 wk of either intermittent (INT-EX) or continuous (CON-EX) aerobic exercise training (TRAIN). METHODS: Untrained males (N = 7) and females (N = 11) completed 4 wk of TRAIN of supervised treadmill jogging occurring 5 d.wk(-1) for 30 min per session at 60% VO2max (75% HRmax). CON-EX was a single 30-min bout. INT-EX consisted of three 10-min bouts separated by 20 min of seated rest. Pre- and post-TRAIN fasting plasma samples were collected after subjects had followed 48 h of activity restriction and a 24-h repeated diet including a 12-h dietary fast. Postprandial lipemia was measured for 8 h following a standardized high-fat meal. RESULTS: Fasting triglycerides and very LDL-C were not affected by TRAIN, and TRAIN did not change postprandial area under the curve or peak in either group. With groups combined, TRAIN significantly decreased TC, total LDL-C, and the TC:HDL ratio, and increased HDL-C subfraction 2 and LDL mean particle size. Total intermediate-density lipoprotein cholesterol remained unchanged at post-TRAIN, and was not different between groups. CONCLUSIONS: To prevent dyslipidemia, our findings suggest that persons who are normolipidemic can improve the lipoprotein profile equally with CON-EX and INT-EX by lowered TC through the sum of changes in LDL-C subfractions, increased mean LDL particle size, and increased HDL-C subfraction 2 concentration.

Single sessions of intermittent and continuous exercise and postprandial lipemia.

PURPOSE: This study compared the effects of continuous (CON-EX) and intermittent (INT-EX) exercise on postprandial lipemia (PPL). METHODS: Subjects were 18 inactive males (N = 7) and females (N = 11), aged 25 +/- 1.8 yr (mean +/- SE), VO2max 38.4 +/- 1.5 (mL x kg(-1)x min(-1)), and BMI 23.2 +/- 0.8 (kg x m(-2)). After 48-h activity and 24-h dietary control periods, subjects consumed a high-fat meal (HFM) containing 1.5 g fat (88% of calories), 0.05 g protein, and 0.4 g carbohydrate per kilogram body weight for three trials: no exercise (NOEX), CON-EX, and INT-EX. Both exercise trials consisted of 30 min of treadmill running at 60% VO2max. INT-EX was conducted in a single session of three bouts, each lasting 10 min and separated by a 20-min rest period. Blood was collected before the HFM (0 h) and at 2, 4, 6, and 8 h post-HFM. Exercise trials were completed 12 h before the HFM. Trials were separated by 7-10 d and were performed in random order. RESULTS: Plasma analysis indicated TG incremental area under the curve (AUCI) and TG incremental peak (PeakI) were significantly lower in INT-EX compared with NOEX, but CON-EX was not different from INT-EX or NOEX. Compared with females, males had significantly higher AUCI and PeakI in both exercise trials, but genders were not different in the NOEX trial. No difference was discovered among trials in high density lipoprotein (HDL)Total-C, HDL2-C, and HDL3-C, or fasting total cholesterol (TC) or fasting TC:HDL ratio. Females had higher fasting HDLTotal-C, HDL2-C, and HDL3-C compared with males. No gender or trial difference was found for fasting TC or TC:HDL ratio. CONCLUSIONS: Our data suggest that a single bout of INT-EX is more effective than CON-EX for lowering PPL as compared with NOEX in inactive, normolipidemic individuals.

Comparison of the Bod Pod and dual energy x-ray absorptiometry in men.

The majority of studies investigating the accuracy of the Bod Pod have compared it to hydrostatic weighing (HW), the long held, and perhaps outdated 'gold standard' method of body composition analysis. Much less research has compared the Bod Pod to dual energy x-ray absorptiometry (DXA), a technique that is becoming popular as an alternative reference method. The purpose of this study was to compare per cent fat estimates by the Bod Pod to those of DXA in a large number of men. Participants were 160 men (32 +/- 11 years). Per cent body fat was estimated to be 19.4 +/- 6.8 and 21.6 +/- 8.4 for DXA and the Bod Pod, respectively. Although the two methods were highly correlated (0.94), the mean difference of 2.2% was significant (p < 0.01). The amount of difference increased as body fatness increased (p < 0.0001). The results of this study indicate that a difference between methods existed for our sample of men. It is uncertain exactly where the difference lies. Practitioners should be aware that even with the use of technologically sophisticated methods (i.e., Bod Pod, DXA), differences between methods exist and the determination of body composition is at best, an estimation.

Effects of omega-3 fatty acid supplementation and exercise on low-density lipoprotein and high-density lipoprotein subfractions.

The purpose of this study was to examine the effect of combining exercise with omega-3 fatty acids (n-3fa) supplementation on lipoprotein subfractions and associated enzymes. Subjects were 10 recreationally active males, aged 25 +/- 1.5 years (mean +/- SE), who supplemented n-3fa (60% eicosapentaenoic acid [EPA] and 40% docosahexaenoic [DHA]) at 4 g/d for 4 weeks. Before and after supplementation, subjects completed a 60-minute session of treadmill exercise at 60% Vo(2)max. Following a 24-hour diet and activity control period, blood was collected immediately before and after the exercise session to assess lipid variables: high-density lipoprotein cholesterol (HDL-C) and subfractions, low-density lipoprotein cholesterol (LDL-C) and subfractions and particle size, lecithin:cholesterol acyltransferase (LCAT) activity, and cholesterol ester transfer protein (CETP) activity. Supplementation with n-3fa alone increased total HDL-C and HDL(2)-C, while exercise alone increased total HDL-C, HDL(3)-C, and total LDL-C. LDL subfractions, particle size, and LCAT and CETP activities were not affected by supplementation. Combination treatment resulted in an additive effect for HDL(3)-C only and also increased LDL(1)-C versus baseline. LCAT and CETP activities were not affected by treatments. These results suggest that n-3fa supplementation or an exercise session each affect total HDL-C and subfractions but not LDL-C or subfractions. In addition, the combination of n-3fa and exercise may have additional effects on total HDL-C and LDL-C subfractions as compared to either treatment alone in active young men.

Effect of n-3 fatty acids on free tryptophan and exercise fatigue.

Free tryptophan (Trp), which is augmented by liberated free fatty acids (FFA) from adipose tissue, can induce mental fatigue via serotonin during exercise. Since an attenuation in FFA has been observed with omega-3 fatty acid (n-3fa) use, our purpose was to examine the effect of n-3fa supplementation on free Trp availability and exercise fatigue. Ten recreationally trained men ( n=5) and women ( n=5), with maximal oxygen consumption (VO(2max))of 51.6 (3.0) and 44.3 (1.4) ml kg(-1) min(-1), respectively, were studied on two occasions following an overnight fast, before and after n-3fa supplementation (4 g day(-1) for 4 weeks). The exercise trials consisted of a 75-min treadmill run at 60% VO(2max) followed immediately by a high-intensity incremental bout to fatigue. Measurements included exercise monitors, plasma volume (PV), triglycerides (TG), FFA, glycerol, lactate, and glucose. Free Trp and branched-chain amino acids (BCAA) were measured and correlated with time to fatigue; all blood variables were corrected for PV. Free Trp, lactate, glucose, FFA, and glycerol were not significantly different between trials, but TG ( P<0.001) and the free Trp/BCAA ratio were significantly lower after n-3fa use [1.76 (0.18)x10(-2) microg ml(-1)] versus before supplementation [2.17 (0.22), P=0.033]. There was a non-significant increase in time to fatigue after supplementation [10.2 (0.3) min] versus before n-3fa use [9.7 (0.2), P=0.068], and a tendency for higher BCAA levels after supplementation, P=0.068. However, neither free Trp nor the free Trp/BCAA ratio significantly predicted time to fatigue. In conclusion, n-3fa supplementation did not diminish free Trp concentrations or significantly improve endurance performance during a maximal bout of exercise.

Effectiveness of a selected bedding system on quality of sleep, low back pain, shoulder pain, and spine stiffness.

OBJECTIVE: To determine whether clinical and statistically significant changes in back pain, shoulder pain, spine stiffness, and quality of sleep may be documented after use of a prescribed bedding system. DESIGN: Quasi-experimental field study of single group pretest-posttest design with subjects serving as their own controls. SETTING: Two chiropractic clinics and the Oklahoma State University Program of Health and Human Performance. SUBJECTS: Convenience sample of 22 subjects (women, n = 13; men, n = 9) between the ages of 25 and 75 years with documented disturbed sleep, shoulder pain, low back pain, and spine stiffness of a chronic nature. OUTCOME MEASURES: Pretest and posttest 28-day Visual Analog Scales for pain, spine stiffness, and quality of sleep. MAIN RESULTS: The experimental bedding system reduced back pain by 57.21% (P =.000001), reduced shoulder pain by 60.83% (P =.000005), reduced back stiffness by 59.12% (P =.000004), and improved quality of sleep by 60.73% (P =.000001). CONCLUSIONS: Results suggest that subjects obtain significant improvement in shoulder and back pain, back stiffness, and quality of sleep after 28 days of prescribed bedding system use as compared with 28 days of personal bedding use. Female subjects and those with lower body weight were more likely to significantly improve than heavier and more obese subjects.