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.

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.

Accuracy of Physical Self-Description Among Chronic Exercisers and Non-Exercisers.

This study addressed the role of chronic exercise to enhance physical self-description as measured by self-estimated percent body fat. Accuracy of physical self-description was determined in normal-weight, regularly exercising and non-exercising males with similar body mass index (BMI)'s and females with similar BMI's (n=42 males and 45 females of which 23 males and 23 females met criteria to be considered chronic exercisers). Statistical analyses were conducted to determine the degree of agreement between self-estimated percent body fat and actual laboratory measurements (hydrostatic weighing). Three statistical techniques were employed: Pearson correlation coefficients, Bland and Altman plots, and regression analysis. Agreement between measured and self-estimated percent body fat was superior for males and females who exercised chronically, compared to non-exercisers. The clinical implications are as follows. Satisfaction with one's body can be influenced by several factors, including self-perceived body composition. Dissatisfaction can contribute to maladaptive and destructive weight management behaviors. The present study suggests that regular exercise provides a basis for more positive weight management behaviors by enhancing the accuracy of self-assessed body composition.

Effect of functional isometric squats on vertical jump in trained and untrained men.

Functional isometrics (FIs) combine dynamic and isometric muscle actions and may hyperstimulate the nervous system leading to an enhanced postactivation potentiation (PAP) and improved subsequent performance. The purpose of this study was to investigate the impact of an FI squat on the countermovement vertical jump (CMVJ) in resistance trained and untrained men. Thirteen trained men (age: 22.8 +/- 3.2 years, mass: 90.0 +/- 16.3 kg, and height: 178.9 +/- 7.1 cm) and 8 untrained men (age: 28.5 +/- 5.9 years, mass: 101.5 +/- 23.0 kg, and height: 177.0 +/- 4.8 cm) participated. On separate days, subjects performed CMVJs after 2 different warm-up conditions. The warm-up conditions consisted of either 5 minutes of low-intensity cycling or 5 minutes of low-intensity cycling plus a 3-second FI squat with 150% of their 1 repetition maximum (1RM). A 2 x 3 repeated-measures analysis of variance with Bonferroni post hoc revealed that when comparing the 2 warm-up conditions in the trained subjects, a significant increase (p < 0.05) in CMVJ occurred at 4 minutes (2.4 cm, +5.1%) post-FI squat. This increase was maintained when subjects were retested at 5 minutes post (2.6 cm, + 5.5%). No significant difference in CMVJ was detected in the untrained group (p = 0.49). Results support the addition of an FI squat performed at 150% of 1RM to a low-intensity cycling warm-up to enhance PAP in resistance trained but not in untrained men as measured by CMVJ. Practically, adding functional isometrics to a warm-up scheme may significantly enhance acute, short-term power output in resistance trained men.

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.

Anabolic androgenic steroids: use and perceived use in nonathlete college students.

OBJECTIVE: The authors investigated the use and perceived use of anabolic androgenic steroids (AAS) among nonathlete college students. PARTICIPANTS: The authors surveyed a sample of 485 nonathlete college students at a major metropolitan university. METHODS: They administered a survey on use and perceived use of AAS to the students. RESULTS: Forty-two participants (9%) reported using AAS (37 men, 5 women). Seniors were the most likely to use AAS (36%), and freshman the least likely (7%). Thirty-four percent of nonusers and 41% of users indicated they knew between 1 and 5 AAS users. Of the total sample, 36% perceived that 5% to 10% of nonathlete college students used AAS. Reasons for AAS use were because friends were using (7%), a desire to enhance physical appearance (45%), and a desire to increase physical performance (48%). CONCLUSIONS: These findings may have significant implications in planning strategic preventive educational programs, and health educators should target incoming college freshmen with the intent of dissuading AAS use.

Metabolic demands of "junkyard" training: pushing and pulling a motor vehicle.

Junkyard training involves heavy, cumbersome implements and nontraditional movement patterns for unique training of athletes. This study assessed the metabolic demands of pushing and pulling a 1,960-kg motor vehicle (MV) 400 m in an all-out maximal effort. Six male, strength-trained athletes (29 +/- 5 years; 89 +/- 12 kg) completed 3 sessions. Sessions 1 and 2 were randomly assigned and entailed either pushing or pulling the MV. Oxygen consumption (VO(2)) and heart rate (HR) were measured continuously. Blood lactate was sampled immediately prior to and 5 minutes after sessions 1 and 2. Vertical jump was assessed immediately prior to and after sessions 1 and 2. During session 3 a treadmill VO(2)max test was conducted. No significant differences (p < 0.05) in VO(2), HR, or blood lactate occurred between pushing and pulling efforts. VO(2) and HR peaked in the first 100 m, and from 100 m on, VO(2) and HR averaged 65% and 96% of treadmill maximum values (VO(2)max = 50.3 ml x kg(-1) x min(-1); HRmax = 194 b x min(-1)). Blood lactate response from the push and pull averaged 15.6 mmol.L(-1), representing 131% of the maximal treadmill running value. Vertical jump decreased significantly pre to post in both conditions (mean = -10.1 cm, 17%). All subjects experienced dizziness and nausea. In conclusion, a 400-m MV push or pull is an exhausting training technique that requires a very high anaerobic energy output and should be considered an advanced form of training. Strength coaches must be aware of the ultra-high metabolic and neuromuscular stresses that can be imposed by this type of training and take these factors into consideration when plotting individualized training and recovery strategies.

Cold exposure and exercise metabolism.

Research regarding the effect of cold exposure on metabolism and substrate utilisation during exercise has produced inconsistent results. Intensity of exercise and training status of subjects are known to impact metabolism and substrate utilisation regardless of environmental conditions. Duration and intensity of cold exposure during exercise also may exert impact. Thus, systematic manipulation of these variables (fitness, intensity of exercise, cold conditions) should provide a means to determine metabolic and substrate utilisation patterns when exercising in the cold. However, a number of variables have been introduced into research methodologies that may confound results. Duration and intensity of cold exposure prior to exercise, and acclimation and clothing status of subjects may confound or override the influence of other variables. Future research addressing the impact of cold exposure on metabolism and substrate utilisation during exercise must attempt to isolate and control each influential factor (prior to and during exercise), and must be alert to the interactive effects that can occur.

Anabolic steroid usage in athletics: facts, fiction, and public relations.

Anecdotal evidence suggests the widespread usage of anabolic steroids among athletes (20-90%), particularly at the professional and elite amateur levels. In contrast, scientific studies indicate that usage is rare and no higher than 6%. Conclusions from scientific studies suggest that anabolic steroid usage declines progressively from high school to college and beyond; however, anecdotal evidence claims the opposite trend. In this clash between "hard" scientific data vs. "soft" anecdotal information, it is natural that professionals would gravitate toward scientifically based conclusions. However, in the case of anabolic steroids (a stigmatized and illegal substance), should word-of-mouth testimony from individuals closest to the issues--those who have participated in and coached sports, those who have served as drug-testing overseers, and journalists who relentlessly track leads and verify sources--be set aside as irrelevant? Not if a complete picture is to emerge. In this review, hard scientific evidence is placed on the table side-by-side with soft anecdotal evidence, without weighting or bias. The purpose is to allow the opportunity for each to illuminate the other and, in so doing, potentially bring us a step closer to determining the true extent of anabolic steroid usage in athletics.

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.