The Effects of Smoking on the Diagnostic Characteristics of Metabolic Syndrome: A Review.

Metabolic syndrome is a growing epidemic that increases the risk for cardiovascular disease, diabetes, stroke, and mortality. It is diagnosed by the presence of three or more of the following risk factors: 1) obesity, with an emphasis on central adiposity, 2) high blood pressure, 3) hyperglycemia, 4) dyslipidemia, with regard to reduced high-density lipoprotein concentrations, and 5) dyslipidemia, with regard to elevated triglycerides. Smoking is one lifestyle factor that can increase the risk for metabolic syndrome as it has been shown to exert negative effects on abdominal obesity, blood pressure, blood glucose concentrations, and blood lipid profiles. Smoking may also negatively affect other factors that influence glucose and lipid metabolism including lipoprotein lipase, adiponectin, peroxisome proliferator-activated receptors, and tumor necrosis factor-alpha. Some of these smoking-related outcomes may be reversed with smoking cessation, thus reducing the risk for metabolic disease; however, metabolic syndrome risk may initially increase post cessation, possibly due to weight gain. Therefore, these findings warrant the need for more research on the development and efficacy of smoking prevention and cessation programs.

Higher-protein intake improves body composition index in female collegiate dancers.

Aesthetic athletes strive to attain an ideal body image and the physical demands placed on dancers make their body composition and fitness equally as important as their technique. Body composition has shown positive changes in response to increased protein intake and may improve aesthetics of dance performance. The purpose of this study was to determine the extent to which supplemental whey protein (PRO) would improve body composition in female collegiate dancers compared with an isocaloric placebo (PLA). Twenty-one (age, 19.6 ± 1.4 years) female collegiate dancers were randomly assigned to consume PRO or PLA (25 g, 3×/day) for 12 weeks. Laboratory testing at weeks 0, 6, and 12 included 24-h urine collection, body composition (dual-energy X-ray absorptiometry), resting metabolic rate, and performance. Data were reported as means ± SD. Significance was accepted at p < 0.05. Body weight, fat mass, and lean soft tissue did not change between groups or over time. Body composition index (BCI = [(LSTpost - LSTpre) + (FMpre - FMpost)]; where LST is lean soft tissue, FM is fat mass, pre is pre-intervention, and post is post-intervention) significantly improved over time in PRO (+0.6 ± 1.9) but not PLA (-1.8 ± 3.1; p = 0.048); however, neither group demonstrated changes in laboratory performance tests. Protein supplementation for 12 weeks significantly improved BCI and provided a simple way to improve the diet in female collegiate dancers. Novelty Twelve weeks of protein supplementation does not change body weight in female collegiate dancers. BCI improves following protein supplementation in female collegiate dancers.

Cigarette Smoking: An Accessory to the Development of Insulin Resistance.

Insulin resistance is a condition characterized by decreased sensitivity of a skeletal or adipose cell to insulin, resulting in decreased glucose uptake by the cell. This can lead to hyperinsulinemia and further reduce insulin sensitivity. Insulin resistance is one of the primary factors contributing to metabolic syndrome (MetS), causing elevated glucose and fatty acid concentrations in the blood. Smoking is associated with insulin resistance in a dose-dependent manner. It directly increases the risk for insulin resistance, mainly via hormone activation, and may indirectly cause insulin resistance due to its effects on abdominal obesity. Nicotine may be the factor underlying these potential mechanisms. With the prevalence of prediabetes and diabetes on the rise, and considering the role of smoking and its relationship to insulin resistance, smoking reduction or cessation may be a viable option for those who are at risk or already identified as insulin resistant. Therefore, smoking cessation or reduction would serve as a beneficial component in any diabetes prevention or treatment plan.

Effects of Resistance Training and Protein Supplementation in Breast Cancer Survivors.

PURPOSE: This study aimed to evaluate 12 wk of resistance training (RT; n = 16) and protein supplementation (RT + protein; n = 17) on muscular strength, body composition, and blood biomarkers of muscle (insulin-like growth factor 1 [IGF-1]), fat (adiponectin), and inflammation (human C-reactive protein [CRP]) in breast cancer survivors (BCS). METHODS: Thirty-three BCS (59 ± 8 yr) were measured pre- and posttraining for one-repetition maximum (1-RM) muscular strength (chest press and leg extension), body composition (lean mass [LM] and fat mass [FM]) via dual-energy x-ray absorptiometry, and serum concentrations of IGF-1, adiponectin, and CRP. RT consisted of 2 d·wk using 10 exercises for two sets of 10-12 repetitions and a third set to failure at ~65%-85% of 1-RM. RT + protein consumed 20 g of protein twice a day. ANOVA was used for analyses. Significance was set at P ≤ 0.05. RESULTS: Average RT intensity was 65%-81% of 1-RM and was not different between RT and RT + protein. There were no group-time interactions for strength, LM, FM, and biomarkers. Both groups significantly increased upper (+31 ± 18 kg) and lower (+19 ± 12 kg) body strength, LM (+0.9 ± 1.0 kg) and decreased FM (-0.5 ± 1.2 kg), and percent body fat (-1.0% ± 1.2%). Serum levels of IGF-1 significantly increased from baseline to 12 wk in both RT (102 ± 34 to 115 ± 33 ng·mL) and RT + protein (110 ± 40 to 119 ± 37 ng·mL); adiponectin and CRP did not change. CONCLUSIONS: Twelve weeks of RT at 65%-81% of 1-RM, 2 d·wk in BCS, was well tolerated and significantly improved strength, body composition, and IGF-1. Supplemental protein (40 g·d) did not induce a change in any variable. However, on the basis of food logs, reductions in total calories and dietary protein intake from whole foods resulted in only a net protein increase of 17 g·d for RT + protein, which may have influenced the results.

Effects of a 12-Month Pedometer-Based Walking Intervention in Women of Low Socioeconomic Status.

This study examined the effects of a 12-month walking intervention in overweight/obese, low socioeconomic women. Forty-six women (48.2 ± 8.0 years) entered the study. Outcomes included weight, waist and hip circumferences, body mass index (BMI), blood pressure, glycosylated hemoglobin, blood lipids, fibrinogen, and high-sensitivity C-reactive protein (hsCRP). Both intention-to-treat analyses in all participants and group analyses in study completers only (3K group = increased steps/day by ≥3,000; No Δ group = did not increase steps/day by ≥3,000) were conducted. Group × time ANOVA was used. In study completers, 3K significantly increased steps/day (6,903 ± 3,328 to 12,323 ± 5,736) compared to No Δ (4,926 ± 3,374 to 5,174 ± 3,095) from baseline to 12 months. There was a significant time effect for weight (P = 0.030), BMI (P = 0.029), and hsCRP (P = 0.044). Low socioeconomic women who adhere to a long-term, pedometer-based walking intervention significantly increased steps/day and may improve body weight, BMI, and hsCRP. This could help reduce health disparities in this population over time.

Impact of Four Weeks of a Multi-Ingredient Performance Supplement on Muscular Strength, Body Composition, and Anabolic Hormones in Resistance-Trained Young Men.

Although multi-ingredient performance supplements (MIPS) have increased in popularity because of their array of ergogenic ingredients, their efficacy and safety remain in question. The objective of this study was to determine the impact of supplementation with T+ (SUP; Onnit Labs, Austin, TX, USA), an MIPS containing long jack root, beta-alanine, and branched-chain amino acids, and other proprietary blends, on strength, body composition, and hormones in young resistance-trained men. Subjects were randomized to consume either T+ (SUP; n = 14; age, 21 ± 3 years; body fat, 18.3 ± 4.7%) or an isocaloric placebo (PL; n = 13; age, 21 ± 3 years; body fat, 21.5 ± 6.2%) for 4 weeks. Both groups underwent a progressive, 4-week high-intensity resistance training protocol. Before and after the training protocol, mood state, body composition, blood hormones (also collected at midpoint), and maximal strength were measured. SUP had significantly greater increases in bench press (SUP, 102 ± 16 kg to 108 ± 16 kg vs. PL, 96 ± 22 kg to 101 ± 22 kg; p < 0.001) and total weight lifted (SUP, 379 ± 59 kg to 413 ± 60 kg vs. PL, 376 ± 70 kg to 400 ± 75 kg; p < 0.001) compared with PL. Additionally, deadlift strength relative to total body mass (calculated as weight lifted/body mass; kg:kg) (2.08 ± 0.18 to 2.23 ± 0.16; p = 0.036) and lean mass (2.55 ± 0.19 to 2.72 ± 0.16; p = 0.021) increased significantly in SUP but not PL (2.02 ± 0.30 to 2.15 ± 0.36 and 2.56 ± 0.31 to 2.70 ± 0.36, respectively). No other significant differences were detected between groups for the remaining variables. Supplementing with SUP enhanced resistance training adaptations independent of hormonal status, and thus SUP use may warrant inclusion into peri-workout nutrition regimens. This study was registered with clinicaltrials.gov (identifier: NCT01971723).

EPOC Comparison Between Isocaloric Bouts of Steady-State Aerobic, Intermittent Aerobic, and Resistance Training.

PURPOSE: Excess postexercise oxygen consumption (EPOC) is dependent on intensity, duration, and mode of exercise. The purpose of this study was to compare the effect of both exercise mode and intensity on EPOC while controlling for caloric expenditure and duration. METHOD: Ten low to moderately physically active men (22 ± 2 yrs) performed 3 nonrandomized isocaloric bouts of exercise separated by 7 days. The 1st session was resistance training (RT), followed by moderate-intensity steady-state (SS) aerobic exercise, and concluding with a high-intensity intermittent (IT) aerobic session. RESULTS: Total energy expenditure, rate of energy expenditure, and duration did not differ among trials (p>.05). Respiratory exchange ratio was greater during the RT trial than the SS trial (p < .05). At 12 hr postexercise, resting metabolic rate (RMR) was higher after the RT trial (4.7 ± 0.67 mL/kg/min) and IT trial (4.6 ± 0.62 mL/kg/min) compared with their respective baseline measurements (p < .008) and the SS trial (4.3 ± 0.58 mL/kg/min; p < .008). At 21 hr postexercise, RMR was higher after the RT trial (3.7 ± 0.51 mL/kg/min) and IT trial (3.5 ± 0.39 mL/kg/min) compared with the SS trial (3.2 ± 0.38 mL/kg/min; p < .008). The SS trial did not influence RMR at either 12 hr or 21 hr postexercise. CONCLUSION: Both RT and IT aerobic work increased EPOC to a greater degree than did SS work, indicating that either mode may be more effective at increasing total daily caloric expenditure than SS aerobic exercise.

Continuous and intermittent walking alters HDL(2)-C and LCATa.

PURPOSE: The purpose of this study was to determine if exercise, whether continuous (CE: completed all in one session) or intermittent (completed in either two (IE 2) or three (IE 3) exercise sessions) expending the same number of calories alters reverse cholesterol transport or low density lipoprotein (LDL) particle size. METHODS: Sixteen healthy (22±2.1 year old) men (VO(2) max=37.0±3.3mL/kg/min) randomly completed three exercise trials, CE, IE 2 and IE 3, expending 450 calories. Blood samples were drawn immediately post-exercise (IPE) and 24 and 48h following exercise and analyzed for total cholesterol (TC), triglycerides (TG), low density lipoprotein (LDL-C), high density lipoprotein (HDL-C) and subfractions (HDL(2)-C, HDL(3)-C). Samples were also analyzed to determine LDL-C particle size, lecithin cholesterol acyl transferase activity (LCATa) and cholesterol ester transfer protein activity (CETPa). RESULTS: HDL(2)-C increased significantly 48h post-exercise in the CE and IE 2 groups. Additionally, the IE 3 group had significant increases in HDL(2)-C at 24 (39%) and 48h post-exercise by 66%. This change in HDL(2)-C was significantly and positively correlated (r=0.62; p<0.05) to the changes in LCATa which increased compared to baseline at 48h post-exercise in the CE and IE 3 groups. No significant changes in LDL particle size or alterations in CETPa were seen. CONCLUSIONS: The results of this study indicate that whether the exercise is continuous or intermittent, keeping calorie expenditure the same, causes significant changes in the HDL(2)-C subfraction, which was augmented by an increase in LCATa.

The effect of fat intake and antihypertensive drug therapy on serum lipid profile: a cross-sectional survey of serum lipids in male and female hypertensives.

The present study aimed to investigate the effect of betablocker with diuretics therapy on serum cholesterol and high density lipoprotein (HDL-C) lipids in cross-sectional data (age, sex, weight, and body mass index (BMI), smoking/alcoholic consumption) and supplemented vegetarian low-fat diet with daily low fat energy intake, salt intake, duration of drug therapy, and serum protein as effective measures of lowering blood pressure among hypertensives in both males and females. Hypertensive patients on betablocker and/or thiazide therapy were compared in cross-section study with their age, blood pressure, fat intake, serum lipid profile, BMI, and serum albumin in males and females. Dietary fat intake and serum lipid profile were income related. Betablocker and diuretics therapy in combination with dietary fat intervention was beneficial for prolonged dyslipidemia control. Serum cholesterol level was main contributing factor dependent on BMI, duration of drug, and socio-economic factors. Fat intake contributed in hypertension and serum cholesterol levels. A cross-sectional data analysis showed beneficial effects of "low fat-salt-smoking-alcohol consumption and combined polyunsaturated fatty acid with antihypertensive therapy approach" to keep normal dyslipidemia and hypertension. Low fat intake, low salt, smoking, alcohol consumption, and combination of dietary oil supplements with lipid betablockers and diuretic modulators were associated with low hypertension and controlled dyslipidemia in Asian sedentary population.

[Methods to identify the anaerobic threshold for type-2 diabetic and non-diabetic subjects]. / Métodos para identificar o limiar anaeróbio em indivíduos com diabete tipo 2 e em indivíduos não-diabéticos.

BACKGROUND: In spite of Anaerobic Threshold (AT) to be widely used on exercise evaluation for different populations, there are few studies comparing methods to identify AT for individuals with type-2 diabetes. OBJECTIVE: To compare methods of AT determination on type-2 diabetics (T2D) and non-diabetic (ND) subjects and verify the acid-base balance as related to AT intensity. METHODS: T2D (n=10; 54.5+/-9.5 yr; 30.1+/-5.0 kg/m(2)) and younger ND (n=10; 36.6+/-12.8 yr; 23.9+/-5.0 kg/m(2)) performed an incremental test (IT) on a cycle ergometer. The over-proportional increase in VE/VO2 and blood lactate ([lac]) identified the ventilatory (VT) and lactate thresholds (LT) respectively. The workload corresponding to the lower blood glucose ([gluc]) during test identified the individual glucose threshold (IGT). The AT was also determined by polynomial adjustment of the VE/Workload and [lac]/Workload responses to identify exercise intensities above which an over-proportional increase in VE and [lac] did occur and were named VT VE/W and LT[lac]/W. RESULTS: The workload (Watts-W) corresponding to LT, VT, IGT, LT Lac/W and VT VE/W of diabetics (85.0+/-32.1; 88.0+/-31.7; 86.0+/-33.8; 82.0+/-20.9 and 90.2+/-22.2W) and non-diabetics (139.0+/-39.0; 133.0+/-42.7; 140.8+/-36.4; 122.7+/-44.3 and 133.0+/-39.1W) differed between groups (p<0.001), but not within groups. Thus it was evidenced an agreement among the studied methods. The pH and pCO2 were significantly decreased in parallel to the increase in [lac], pO2 and VE at supra AT intensities. CONCLUSION: The AT intensities, as determined by different methods both for diabetics and non-diabetic individuals, were in agreement to each other and identified exercise intensities above which the acid-basic balance is disrupted.

Métodos para identificar o limiar anaeróbio em indivíduos com diabete tipo 2 e em indivíduos não-diabéticos / Methods to identify the anaerobic threshold for type-2 diabetic and non-diabetic subjects / Métodos para identificar el umbral anaeróbico en individuos con diabetes tipo 2 y en individuos no diabéticos

Fundamento: Apesar de o limiar anaeróbio (LAn) ser utilizado na avaliação funcional de diferentes populações, estudos comparando métodos para sua identificação em diabéticos tipo-2 tem sido pouco realizados. Objetivo: Comparar protocolos de identificação do LAn em indivíduos diabéticos tipo 2 e em não-diabéticos, e analisar respostas relacionadas ao equilíbrio ácido-básico em intensidades relativas ao LAn. MÉTODOS: Diabéticos tipo 2 (n=10; 54,5±9,5 anos; 30,1±5,0 kg/m²) e jovens não-diabéticos (n=10; 36,6±12,8 anos; 23,9±5,0 kg/m²) realizaram teste incremental (TI) em ciclo ergômetro. O aumento desproporcional no equivalente ventilatório de oxigênio (VE/VO2) e lactatemia ([lac]) identificaram intensidades (Watts-W) correspondentes aos limiares ventilatório (LV) e de lactato (LL), respectivamente. A intensidade correspondente à menor glicemia ([glic]) foi considerada limiar glicêmico individual (LGI). O LAn também foi determinado por ajuste polinomial das razões VE/Watts (LV VE/W) e [lac]/Watts (LL[lac]/W), as quais identificaram intensidades acima das quais um aumento desproporcional na VE e [lac] ocorreram. Resultados: Não foram observadas diferenças entre LL, LV, LG, LL[lac]/W e LV VE/W em diabéticos (85,0±32,1; 88,0±31,7; 86,0±33,8; 82,0±20,9 e 90,2±22,2W) e não-diabéticos (139,0±39,0; 133,0±42,7; 140,8±36,4; 122,7±44,3 e 133,0±39,1W). Contudo os valores de LAn diferiram significativamente entre grupos (p<0.001). A técnica de Bland-Altman confirmou concordância entre os protocolos. Reduções significativas no pH e pCO2 em paralelo a um aumento na [lac], pO2 e VE foram observadas em intensidades supra limiares. Conclusão: Os protocolos apresentaram, para ambos os grupos estudados, concordância na identificação do LAn, que se mostrou como uma intensidade de exercício acima da qual ocorre perda de equilíbrio ácido-básico.

Background: In spite of Anaerobic Threshold (AT) to be widely used on exercise evaluation for different populations, there are few studies comparing methods to identify AT for individuals with type-2 diabetes. Objective: To compare methods of AT determination on type-2 diabetics (T2D) and non-diabetic (ND) subjects and verify the acid-base balance as related to AT intensity. METHODS: T2D (n=10; 54.5±9.5 yr; 30.1±5.0 kg/m²) and younger ND (n=10; 36.6±12.8 yr; 23.9±5.0 kg/m²) performed an incremental test (IT) on a cycle ergometer. The over-proportional increase in VE/VO2 and blood lactate ([lac]) identified the ventilatory (VT) and lactate thresholds (LT) respectively. The workload corresponding to the lower blood glucose ([gluc]) during test identified the individual glucose threshold (IGT). The AT was also determined by polynomial adjustment of the VE/Workload and [lac]/Workload responses to identify exercise intensities above which an over-proportional increase in VE and [lac] did occur and were named VT VE/W and LT[lac]/W. Results: The workload (Watts-W) corresponding to LT, VT, IGT, LT Lac/W and VT VE/W of diabetics (85.0±32.1; 88.0±31.7; 86.0±33.8; 82.0±20.9 and 90.2±22.2W) and non-diabetics (139.0±39.0; 133.0±42.7; 140.8±36.4; 122.7±44.3 and 133.0±39.1W) differed between groups (p<0.001), but not within groups. Thus it was evidenced an agreement among the studied methods. The pH and pCO2 were significantly decreased in parallel to the increase in [lac], pO2 and VE at supra AT intensities. Conclusion: The AT intensities, as determined by different methods both for diabetics and non-diabetic individuals, were in agreement to each other and identified exercise intensities above which the acid-basic balance is disrupted.

Fundamento: A pesar de que el umbral anaeróbico (UAn) se utiliza en la evaluación funcional de diferentes poblaciones, pocos estudios que comparen métodos para su identificación en diabéticos tipo 2 están siendo realizados. Objetivo: Comparar protocolos de identificación del UAn en individuos diabéticos tipo 2 y en no diabéticos, y analizar respuestas relacionadas al equilibrio ácido-base en intensidades relativas al UAn. MÉTODOS: Diabéticos tipo 2 (n=10; 54,5±9,5 años; 30,1±5,0 kg/m²) y jóvenes no diabéticos (n=10; 36,6±12,8 años; 23,9±5,0 kg/m²) realizaron un test incremental (TI) en ciclo ergómetro. El aumento desproporcionado en el equivalente ventilatorio de oxígeno (VE/VO2) y lactatemia ([lac]) identificó intensidades (Watts-W) correspondientes a los umbrales ventilatorio (UV) y de lactato (UL), respectivamente. La intensidad correspondiente a la menor glucemia ([gluc]) se consideró umbral glucémico individual (UGI). El UAn también fue determinado por ajuste polinomial de las razones VE/Watts (UV VE/W) y [lac]/Watts (UL[lac]/W), las que identificaron intensidades por encima de las cuales ocurriera un aumento desproporcionado en la VE y [lac]. Resultados: No se observaron diferencias entre UL, UV, UG, UL[lac]/W y UV VE/W en diabéticos (85,0±32,1; 88,0±31,7; 86,0±33,8; 82,0±20,9 y 90,2±22,2W) y no diabéticos (139,0±39,0; 133,0±42,7; 140,8±36,4; 122,7±44,3 y 133,0±39,1W). Sin embargo, los valores de UAn difirieron significativamente entre los grupos (p<0.001). La técnica de Bland-Altman confirmó una concordancia entre los protocolos. En las intensidades sobre los umbrales se observaron reducciones significativas en el pH y pCO2 paralelamente a un aumento en la [lac], pO2 y VE. Conclusión: Los protocolos presentaron, para ambos grupos estudiados, concordancia en la identificación del UAn, que se mostró como una intensidad de ejercicio, por encima de la cual ocurre pérdida de equilibrio ácido-base.

Smoking and smoking cessation -- the relationship between cardiovascular disease and lipoprotein metabolism: a review.

Cigarette smoking is generally accepted as the most preventable cause of death in the United States today. Individuals who smoke experience a wide range of physiologic side effects that increase the risk of cardiovascular disease (CVD), including insulin resistance, elevated catecholamine levels which contribute to an elevated heart rate and blood pressure, and hypercholesterolemia. The link between hypercholesterolemia and cardiovascular disease has been extensively researched and is undeniable. What is more, this link is strengthened in smokers as cigarette smoking is known to increase total cholesterol (TC), triglycerides (TG), and low-density lipoprotein (LDL), while acting to decrease the cardio-protective high-density lipoprotein (HDL). Alterations in the enzymes that control lipid transport may be a key underlying mechanism contributing to these health destroying effects. This review examines the current literature related to: (1) smoking, lipoproteins, and lipid-related enzymes; (2) the impact of nicotine, carbon monoxide and free radicals on physiologic parameters related to health; and (3) metabolic issues involving smoking cessation and nicotine replacement therapy.

Pedometer measurement of physical activity and chronic disease risk factors of obese lower socioeconomic status African American women.

BACKGROUND: To evaluate physical activity with pedometers and health markers of chronic disease in obese, lower socioeconomic African American women. METHODS: Thirty-five women (48 +/- 8 years) wore pedometers for 2 weeks. One-way analyses of variances were used to compare age, weight, body mass indices (BMI), and health markers of chronic disease (including blood pressure, cholesterol, triglycerides, glycosylated hemoglobin, fibrinogen, C-reactive protein) between women who were classified by steps per day as sedentary (SED < 5000; 2941 +/- 1161 steps/d) or active (ACT > or = 5000; 7181 +/- 2398 steps/d). RESULTS: ACT had significantly lower BMI (ACT: 37.2 +/- 5.6; SED: 44.4 +/- 7.2 kg/m2) and hip circumferences (ACT: 37.2 +/- 5.6; SED: 44.4 +/- 37.2 cm) and higher total cholesterol (ACT: 230 +/- 53; SED: 191 +/- 32 mg/dL) than SED. There were no differences in health markers of chronic disease between SED and ACT. Pearson product moment correlations showed significant negative correlations between steps/d and weight (r = -.42), BMI (r = -.46), and hip circumference (r = -.47). CONCLUSIONS: Increased levels of physical activity were associated with reduced BMI and hip circumferences but were not associated with lower health markers for chronic disease in obese, lower socioeconomic African American women.

Running performance differences between men and women:an update.

More than a decade ago it was reported in the journal Nature that the slope of improvement in the men's and women's running records, extrapolated from mean running velocity plotted against historical time, would eventually result in a performance intersection of the sexes across a variety of running distances. The first of these intersections was to occur for 42 000 m before the 21st century. Most of the error in this prediction is probably explained by the linear mathematical treatment and extrapolation of limited performance data, since including world record-setting running performances for women before and after 1985 results in a non-linear data fit. The reality of early, disproportionate improvements in women's running that gave the appearance of an impending convergence with men is best explained by an historical social sports bias. Women's times have now reached a plateau similar to that observed for men at comparative performance milestones in the marathon. Sex differences at distances from 100 to 10 000 m show similar trends. The remaining sex gaps in performance appear biological in origin. Success in distance running and sprinting is determined largely by aerobic capacity and muscular strength, respectively. Because men possess a larger aerobic capacity and greater muscular strength, the gap in running performances between men and women is unlikely to narrow naturally.

Reliability of heart rate responses at given ratings of perceived exertion in cycling and walking.

Eleven healthy men (M age = 27 years, SD = 4) completed three cycling and three walking trials in an alternating order. During each trial, participants were allowed, within 3 min, to adjust the work rate to correspond to given rating of perceived exertion (RPE) values according to the following order: RPE 11, 13, and 15. For cycling as well as walking, at each RPE there were no significant differences between mean heart rate responses across the three trials (p > .05). Mode-specific estimates for heart rate intraclass correlation coefficient and coefficient of variation ranged between .80 and .91, and 5.6% and 8.3%, respectively. This study provides absolute reliability estimates for heart rate responses when using RPE in a production format and suggests there may be RPE- (and mode) specific practice requirements for achieving a reliable heart rate response at a given RPE.

Acute exposure to environmental tobacco smoke reduces HDL-C and HDL2-C.

BACKGROUND: Chronic environmental tobacco smoke (ETS) exposure increases individuals risk of coronary artery disease by reducing high-density lipoprotein cholesterol (HDL-C). Currently, there is limited research on the acute effects of ETS on HDL-C. This study examined the acute influence of ETS on HDL-C and its subfractions. METHODS: Twelve male subjects (25.7 +/- 3.0 years) were examined to determine the influence of an acute 6-h exposure to ETS on lipid and lipoprotein levels. Baseline blood samples were drawn before ETS exposure from an antecubital vein at 6 am, 2 pm, and 10 pm. The following day, subjects were exposed to 6 h of ETS, approximately 4-10 pm. Blood was again collected at 8, 16 and 24 h following ETS exposure. Blood was assayed for total cholesterol (TC), HDL-C and its subfractions HDL(2)-C and HDL(3)-C. RESULTS: As a result of ETS exposure, HDL-C and HDL(2)-C levels were significantly reduced by 18% and 37%, respectively. This effect was sustained, with a decrease in HDL-C of 13% and HDL2-C of 28% still evident at 24-h post-exposure. TC was unchanged (pre- 187.3 +/- 41.6 and post- 187.0 +/- 46.3); however, there were significant decreases in the TC/HDL-C and HDL2-C/HDL3-C ratios by 16% and 29%, respectively, which were sustained for 24 h. CONCLUSIONS: The findings of this study demonstrate that a 6-h exposure has a negative impact on lipid and lipoprotein profiles and that these levels remained depressed for at least 24 h.

Acute effects of premeal versus postmeal exercise on postprandial hypertriglyceridemia.

OBJECTIVE: The objective of this study was to examine the effects of the timing of exercise relative to the consumption of a fat-rich meal (81% fat) on postprandial hypertriglyceridemia. DESIGN: A single bout of exercise was either completed 30 minutes before the fat meal (EM trial) or initiated 90 minutes after the fat meal (ME trial). A third trial, fat meal only, served as a control (CON trial). The trials performed in a random order, and venous blood samples were drawn before and 1.5, 3.5, 5.5, and 7.5 hours after the meal for the determination of triglycerides, glycerol, insulin, glucose, and free fatty acids. PARTICIPANTS: Ten untrained healthy males 25.2 +/- 0.9 years old (mean +/- SE) with maximal oxygen uptake (VO2max) of 46.6 +/- 3.0 mL.kg(-1).min(-1). INTERVENTION: Walking exercise performed at 50% VO2max for 90 minutes. MAIN OUTCOME MEASURE: Postprandial hypertriglyceridemia, which was quantified by calculating the area under the triglycerides curve over the 7.5-hour postprandial period. RESULTS: The mean incremental area under the curve (total area adjusted to baseline) describing postprandial hypertriglyceridemia was lower both in the EM trial (3.16 +/- 0.99 mmol.L(-1).8 h) and in the ME trial (2.96 +/- 0.69 mmol.L(-1).8 h) compared with CON trial (6.18 +/- 1.10 mmol.L(-1).8 h; P<0.05). The corresponding areas under the curve describing the postprandial insulinemia were not different between trials (ME: 38.56 +/- 8.36 uIU.mL(-1).8 h; EM: 21.65 +/- 3.80 uIU.mL(-1).8 h; CON: 25.06 +/- 5.15 uIU.mL(-1).8 h; P>0.05). CONCLUSION: A single bout of moderate intensity exercise decreases postprandial hypertriglyceridemia irrespective of the timing of the exercise relative to a high-fat meal.

Effects of low and moderate exercise intensity on postprandial lipemia and postheparin plasma lipoprotein lipase activity in physically active men.

This study was designed to assess differences in the intensity of exercise to attenuate postprandial lipemia (PPL). Thirteen healthy men (age 23.8 +/- 0.9 yr) participated in three random-ordered trials: in low-(25% peak oxygen consumption; Low) and moderate-intensity (65% peak oxygen consumption; Mod) exercise trials, which were completed 1 h before a high-fat meal (1.3 g fat/kg body mass), and a control (Con), fat meal only, trial. Venous blood samples were obtained before the fat meal, and at 2, 4, 6, 8, and 20 h after the fat meal. PPL in the Mod trial (267 +/- 50 mg.dl-1.8 h) was lower compared with that in either Con (439 +/- 81 mg.dl-1.8 h) or Low (403 +/- 91 mg.dl-1.8 h) trials (P < 0.05), whereas there was no difference in PPL between Con and Low trials (P > 0.05). High-density lipoprotein cholesterol (HDL-C) and HDL subtype 2 cholesterol were not different between or within trials (P > 0.05). Postprandial insulinemia was lower in the Mod trial (20.5 +/- 5.7 microIU.ml-1.8 h; P < 0.05), but not in the Low trial (31.4 +/- 4.7 microIU.ml-1.8 h), compared with that in the Con trial (34.9 +/- 5.0 microIU.ml-1.8 h). Postheparin lipoprotein lipase activity at 8 h was higher in the Low trial compared with that in either Con or Mod trials, whereas there were no differences between trials at 20 h. These results suggest that, when exercise is performed 1 h before a fat meal, only exercise of moderate but not of low intensity attenuates PPL and that this effect is not associated with changes in postheparin lipoprotein lipase activity.

Blood glucose threshold and the metabolic responses to incremental exercise tests with and without prior lactic acidosis induction.

This study compared the metabolic-ventilatory responses and the glycemic threshold identified during lactate minimum (LM) and individual anaerobic threshold (IAT) tests. In addition, the ability to determine the anaerobic power, aerobic-anaerobic transition (Trans) (e.g. ventilatory threshold; VT) and the maximal oxygen consumption (VO(2max)) all within a single incremental treadmill test (IT) was investigated. Fifteen physically fit men [25.9 (5.5) years; 77.4 (6.5) kg] performed the following: test 1, IT for IAT; and test 2, LM: 30-s Wingate test followed by 8 min rest and then an IT that was the same as test 1. Blood lactate concentration [lac], glucose concentration [gluc], pH, PO(2), PCO(2), base excess (BE) and ventilatory variables were measured. At the beginning of the IT for LM, the ventilation, PO(2) and VO(2) were higher and the pH, BE and PCO(2) were lower in relation to IAT ( P<0.05), while no differences were observed after reaching LM intensity during IT. Moreover, the Trans could be identified by [lac] (IAT, LM), minute ventilation [V(E;) VT identified during IAT protocol (VT-IAT) and VT identified during LM protocol (VT-LM)], and [gluc] (IGT, GM) during the IT for IAT and LM. The velocities (kilometers per hour) corresponding to IAT (12.6+/-1.6), VT-IAT (12.5+/-1.7), IGT (12.6+/-1.6), LM (12.5+/-1.5), VT-LM (12.3+/-1.5), and GM (12.6+/-1.9) were not different from each other and the LM and IAT protocols resulted in the similar VO(2max). We concluded that: (1) after reaching the LM the metabolic responses during IT are similar to IAT; (2) performing a Wingate test prior to an IT does not interfere with the Trans and VO(2max) attainment; (3) and the IGT and GM can predict the Trans.