Anabolic steroid- and exercise-induced cardiac stress protein (HSP72) in the rat

The present study investigated the effects of exercise and anabolic-androgenic steroids on cardiac HSP72 expression. Male Wistar rats were divided into experimental groups: nandrolone exercise (NE, N = 6), control exercise (CE, N = 6), nandrolone sedentary (NS, N = 6), and control sedentary (CS, N = 6). Animals in the NE and NS groups received a weekly intramuscular injection (6.5 mg/kg of body weight) of nandrolone decanoate, while those in the CS and CE groups received mineral oil as vehicle. Animals in the NE and CE groups were submitted to a progressive running program on a treadmill, for 8 weeks. Fragments of the left ventricle were collected at sacrifice and the relative immunoblot contents of HSP72 were determined. Heart weight to body weight ratio was higher in exercised than in sedentary animals (P < 0.05, 4.65 ± 0.38 vs 4.20 ± 0.47 mg/g, respectively), independently of nandrolone, and in nandrolone-treated than untreated animals (P < 0.05, 4.68 ± 0.47 vs 4.18 ± 0.32 mg/g, respectively), independently of exercise. Cardiac HSP72 accumulation was higher in exercised than in sedentary animals (P < 0.05, 677.16 ± 129.14 vs 246.24 ± 46.30 relative unit, respectively), independently of nandrolone, but not different between nandrolone-treated and untreated animals (P > 0.05, 560.88 ± 127.53 vs 362.52 ± 95.97 relative unit, respectively) independently of exercise. Exercise-induced HSP72 expression was not affected by nandrolone. These levels of HSP72 expression in response to nandrolone administration suggest either a low intracellular stress or a possible less protection to the myocardium.

Treadmill exercise testing of asymptomatic men and women without evidence of heart disease

The aim of this study was to test the hypothesis of differences in performance including differences in ST-T wave changes between healthy men and women submitted to an exercise stress test. Two hundred (45.4%) men and 241 (54.6%) women (mean age: 38.7 ± 11.0 years) were submitted to an exercise stress test. Physiologic and electrocardiographic variables were compared by the Student t-test and the chi-square test. To test the hypothesis of differences in ST-segment changes, data were ranked with functional models based on weighted least squares. To evaluate the influence of gender and age on the diagnosis of ST-segment abnormality, a logistic model was adjusted; P < 0.05 was considered to be significant. Rate-pressure product, duration of exercise and estimated functional capacity were higher in men (P < 0.05). Sixteen (6.7%) women and 9 (4.5%) men demonstrated ST-segment upslope ≥0.15 mV or downslope ≥0.10 mV; the difference was not statistically significant. Age increase of one year added 4% to the chance of upsloping of segment ST ≥0.15 mV or downsloping of segment ST ≥0.1 mV (P = 0.03; risk ratio = 1.040, 95% confidence interval (CI) = 1.002-1.080). Heart rate recovery was higher in women (P < 0.05). The chance of women showing an increase of systolic blood pressure ≤30 mmHg was 85% higher (P = 0.01; risk ratio = 1.85, 95%CI = 1.1-3.05). No significant difference in the frequency of ST-T wave changes was observed between men and women. Other differences may be related to different physical conditioning.

Exercise training and detraining modify the morphological and mechanical properties of single cardiac myocytes obtained from spontaneously hypertensive rats

We determined the effects of exercise training and detraining on the morphological and mechanical properties of left ventricular myocytes in 4-month-old spontaneously hypertensive rats (SHR) randomly divided into the following groups: sedentary for 8 weeks (SED-8), sedentary for 12 weeks (SED-12), treadmill-running trained for 8 weeks (TRA, 16 m/min, 60 min/day, 5 days/week), and treadmill-running trained for 8 weeks followed by 4 weeks of detraining (DET). At sacrifice, left ventricular myocytes were isolated enzymatically, and resting cell length, width, and cell shortening after stimulation at a frequency of 1 Hz (~25°C) were measured. Cell length was greater in TRA than in SED-8 (161.30 ± 1.01 vs 156.10 ± 1.02 μm, P < 0.05, 667 vs 618 cells, respectively) and remained larger after detraining. Cell width and volume were unaffected by either exercise training or detraining. Cell length to width ratio was higher in TRA than in SED-8 (8.50 ± 0.08 vs 8.22 ± 0.10, P < 0.05) and was maintained after detraining. Exercise training did not affect cell shortening, which was unchanged with detraining. TRA cells exhibited higher maximum velocity of shortening than SED-8 (102.01 ± 4.50 vs 82.01 ± 5.30 μm/s, P < 0.05, 70 cells per group), with almost complete regression after detraining. The maximum velocity of relengthening was higher in TRA cells than in SED-8 (88.20 ± 4.01 vs70.01 ± 4.80 μm/s, P < 0.05), returning to sedentary values with detraining. Therefore, exercise training affected left ventricle remodeling in SHR towards eccentric hypertrophy, which remained after detraining. It also improved single left ventricular myocyte contractile function, which was reversed by detraining.

Cardiovascular and autonomic modulation by the central nervous system after aerobic exercise training

The autonomic nervous system plays a key role in maintaining homeostasis under normal and pathological conditions. The sympathetic tone, particularly for the cardiovascular system, is generated by sympathetic discharges originating in specific areas of the brainstem. Aerobic exercise training promotes several cardiovascular adjustments that are influenced by the central areas involved in the output of the autonomic nervous system. In this review, we emphasize the studies that investigate aerobic exercise training protocols to identify the cardiovascular adaptations that may be the result of central nervous system plasticity due to chronic exercise. The focus of our study is on some groups of neurons involved in sympathetic regulation. They include the nucleus tractus solitarii, caudal ventrolateral medulla and the rostral ventrolateral medulla that maintain and regulate the cardiac and vascular autonomic tonus. We also discuss studies that demonstrate the involvement of supramedullary areas in exercise training modulation, with emphasis on the paraventricular nucleus of the hypothalamus, an important area of integration for autonomic and neuroendocrine responses. The results of these studies suggest that the beneficial effects of physical activity may be due, at least in part, to reductions in sympathetic nervous system activity. Conversely, with the recent association of physical inactivity with chronic disease, these data may also suggest that increases in sympathetic nervous system activity contribute to the increased incidence of cardiovascular diseases associated with a sedentary lifestyle.

Influence of eNOS gene polymorphism on cardiometabolic parameters in response to physical training in postmenopausal women

The health-promoting effects of exercise training (ET) are related to nitric oxide (NO) production and/or its bioavailability. The objective of this study was to determine whether single nucleotide polymorphism of the endothelial NO synthase (eNOS) gene at positions -786T>C, G894T (Glu298Asp) and at the variable number of tandem repeat (VNTR) Intron 4b/a would interfere with the cardiometabolic responses of postmenopausal women submitted to physical training. Forty-nine postmenopausal women were trained in sessions of 30-40 min, 3 days a week for 8 weeks. Genotypes, oxidative stress status and cardiometabolic parameters were then evaluated in a double-blind design. Both systolic and diastolic blood pressure values were significantly reduced after ET, which was genotype-independent. However, women without eNOS gene polymorphism at position -786T>C (TT genotype) and Intron 4b/a (bb genotype) presented a better reduction of total cholesterol levels (-786T>C: before = 213 ± 12.1, after = 159.8 ± 14.4, Δ = -24.9% and Intron 4b/a: before = 211.8 ± 7.4, after = 180.12 ± 6.4 mg/dL, Δ = -15%), and LDL cholesterol (-786T>C: before = 146.1 ± 13.3, after = 82.8 ± 9.2, Δ = -43.3% and Intron 4b/a: before = 143.2 ± 8, after = 102.7 ± 5.8 mg/dL, Δ = -28.3%) in response to ET compared to those who carried the mutant allele. Superoxide dismutase activity was significantly increased in trained women whereas no changes were observed in malondialdehyde levels. Women without eNOS gene polymorphism at position -786T>C and Intron 4b/a showed a greater reduction of plasma cholesterol levels in response to ET. Furthermore, no genotype influence was observed on arterial blood pressure or oxidative stress status in this population.

Strength and power training did not modify cardiovascular responses to aerobic exercise in elderly subjects

Resistance training increases muscle strength in older adults, decreasing the effort necessary for executing physical tasks, and reducing cardiovascular load during exercise. This hypothesis has been confirmed during strength-based activities, but not during aerobic-based activities. This study determined whether different resistance training regimens, strength training (ST, constant movement velocity) or power training (PT, concentric phase performed as fast as possible) can blunt the increase in cardiovascular load during an aerobic stimulus. Older adults (63.9 ± 0.7 years) were randomly allocated to: control (N = 11), ST (N = 13, twice a week, 70-90% 1-RM) and PT (N = 15, twice a week, 30-50% 1-RM) groups. Before and after 16 weeks, oxygen uptake (VO2), systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) were measured during a maximal treadmill test. Resting SBP and RPP were similarly reduced in all groups (combined data = -5.7 ± 1.2 and -5.0 ± 1.7%, respectively, P < 0.05). Maximal SBP, HR and RPP did not change. The increase in measured VO2, HR and RPP for the increment in estimated VO2 (absolute load) decreased similarly in all groups (combined data = -9.1 ± 2.6, -14.1 ± 3.9, -14.2 ± 3.0%, respectively, P < 0.05), while the increments in the cardiovascular variables for the increase in measured VO2 did not change. In elderly subjects, ST and PT did not blunt submaximal or maximal HR, SBP and RPP increases during the maximal exercise test, showing that they did not reduce cardiovascular stress during aerobic tasks.

Acute effects of resistance exercise and intermittent intense aerobic exercise on blood cell count and oxidative stress in trained middle-aged women

The aim of this study was to compare the effect of an intermittent intense aerobic exercise session and a resistance exercise session on blood cell counts and oxidative stress parameters in middle-aged women. Thirty-four women were selected and divided into three groups: RE group (performing 60 min of resistance exercises, N = 12), spinning group (performing 60 min of spinning, N = 12), and control group (not exercising regularly, N = 10). In both exercise groups, lymphocytes and monocytes decreased after 1-h recuperation (post-exercise) compared to immediately after exercise (P < 0.05). Immediately after exercise, in both exercised groups, a significant increase in TBARS (from 16.5 ± 2 to 25 ± 2 for the spinning group and from 18.6 ± 1 to 28.2 ± 3 nmol MDA/mL serum for the RE group) and protein carbonyl (from 1.0 ± 0.3 to 1.6 ± 0.2 for the spinning group and from 0.9 ± 0.2 to 1.5 ± 0.2 nmol/mg protein for the RE group) was observed (P < 0.05). A decrease in antioxidant activities (non-protein sulfhydryl, superoxide dismutase, catalase) was also demonstrated with a negative correlation between damage markers and antioxidant body defenses (P < 0.05). These results indicate that an acute bout of intermittent or anaerobic exercise induces immune suppression and increases the production of reactive oxygen species, causing oxidative stress in middle-aged and trained women. Furthermore, we demonstrated that trained women show improved antioxidant capacity and lower oxidative damage than sedentary ones, demonstrating the benefits of chronic regular physical activity.

Genetic and environmental influences on blood pressure and physical activity: a study of nuclear families from Muzambinho, Brazil

Blood pressure (BP) and physical activity (PA) levels are inversely associated. Since genetic factors account for the observed variation in each of these traits, it is possible that part of their association may be related to common genetic and/or environmental influences. Thus, this study was designed to estimate the genetic and environmental correlations of BP and PA phenotypes in nuclear families from Muzambinho, Brazil. Families including 236 offspring (6 to 24 years) and their 82 fathers and 122 mothers (24 to 65 years) were evaluated. BP was measured, and total PA (TPA) was assessed by an interview (commuting, occupational, leisure time, and school time PA). Quantitative genetic modeling was used to estimate maximal heritability (h²), and genetic and environmental correlations. Heritability was significant for all phenotypes (systolic BP: h² = 0.37 ± 0.10, P < 0.05; diastolic BP: h² = 0.39 ± 0.09, P < 0.05; TPA: h² = 0.24 ± 0.09, P < 0.05). Significant genetic (r g) and environmental (r e) correlations were detected between systolic and diastolic BP (r g = 0.67 ± 0.12 and r e = 0.48 ± 0.08, P < 0.05). Genetic correlations between BP and TPA were not significant, while a tendency to an environmental cross-trait correlation was found between diastolic BP and TPA (r e = -0.18 ± 0.09, P = 0.057). In conclusion, BP and PA are under genetic influences. Systolic and diastolic BP share common genes and environmental influences. Diastolic BP and TPA are probably under similar environmental influences.

Diastolic function is associated with quality of life and exercise capacity in stable heart failure patients with reduced ejection fraction

Exercise capacity and quality of life (QOL) are important outcome predictors in patients with systolic heart failure (HF), independent of left ventricular (LV) ejection fraction (LVEF). LV diastolic function has been shown to be a better predictor of aerobic exercise capacity in patients with systolic dysfunction and a New York Heart Association (NYHA) classification ≥II. We hypothesized that the currently used index of diastolic function E/e' is associated with exercise capacity and QOL, even in optimally treated HF patients with reduced LVEF. This prospective study included 44 consecutive patients aged 55±11 years (27 men and 17 women), with LVEF<0.50 and NYHA functional class I-III, receiving optimal pharmacological treatment and in a stable clinical condition, as shown by the absence of dyspnea exacerbation for at least 3 months. All patients had conventional transthoracic echocardiography and answered the Minnesota Living with HF Questionnaire, followed by the 6-min walk test (6MWT). In a multivariable model with 6MWT as the dependent variable, age and E/e' explained 27% of the walked distance in 6MWT (P=0.002; multivariate regression analysis). No association was found between walk distance and LVEF or mitral annulus systolic velocity. Only normalized left atrium volume, a sensitive index of diastolic function, was associated with decreased QOL. Despite the small number of patients included, this study offers evidence that diastolic function is associated with physical capacity and QOL and should be considered along with ejection fraction in patients with compensated systolic HF.

Effect of physical training on liver expression of activin A and follistatin in a nonalcoholic fatty liver disease model in rats

Nonalcoholic fatty liver disease (NAFLD) is characterized by fat accumulation in the liver and is associated with obesity and insulin resistance. Activin A is a member of the transforming growth factor beta (TGF)-β superfamily and inhibits hepatocyte growth. Follistatin antagonizes the biological actions of activin. Exercise is an important therapeutic strategy to reduce the metabolic effects of obesity. We evaluated the pattern of activin A and follistatin liver expression in obese rats subjected to swimming exercise. Control rats (C) and high-fat (HF) diet-fed rats were randomly assigned to a swimming training group (C-Swim and HF-Swim) or a sedentary group (C-Sed and HF-Sed). Activin βA subunit mRNA expression was significantly higher in HF-Swim than in HF-Sed rats. Follistatin mRNA expression was significantly lower in C-Swim and HF-Swim than in either C-Sed or HF-Sed animals. There was no evidence of steatosis or inflammation in C rats. In contrast, in HF animals the severity of steatosis ranged from grade 1 to grade 3. The extent of liver parenchyma damage was less in HF-Swim animals, with the severity of steatosis ranging from grade 0 to grade 1. These data showed that exercise may reduce the deleterious effects of a high-fat diet on the liver, suggesting that the local expression of activin-follistatin may be involved.

Effect of exercise training on Ca2+ release units of left ventricular myocytes of spontaneously hypertensive rats

In cardiomyocytes, calcium (Ca2+) release units comprise clusters of intracellular Ca2+ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca2+ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca2+ sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F0), full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms). These changes were partially reversed in HT rats (frequency of Ca2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F0, full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of left ventricular myocytes.

Short-term follow-up of exercise training program and beta-blocker treatment on quality of life in dogs with naturally acquired chronic mitral valve disease

This study aimed to evaluate the effects of carvedilol treatment and a regimen of supervised aerobic exercise training on quality of life and other clinical, echocardiographic, and biochemical variables in a group of client-owned dogs with chronic mitral valve disease (CMVD). Ten healthy dogs (control) and 36 CMVD dogs were studied, with the latter group divided into 3 subgroups. In addition to conventional treatment (benazepril, 0.3-0.5 mg/kg once a day, and digoxin, 0.0055 mg/kg twice daily), 13 dogs received exercise training (subgroup I; 10.3±2.1 years), 10 dogs received carvedilol (0.3 mg/kg twice daily) and exercise training (subgroup II; 10.8±1.7 years), and 13 dogs received only carvedilol (subgroup III; 10.9±2.1 years). All drugs were administered orally. Clinical, laboratory, and Doppler echocardiographic variables were evaluated at baseline and after 3 and 6 months. Exercise training was conducted from months 3-6. The mean speed rate during training increased for both subgroups I and II (ANOVA, P>0.001), indicating improvement in physical conditioning at the end of the exercise period. Quality of life and functional class was improved for all subgroups at the end of the study. The N-terminal pro-brain natriuretic peptide (NT-proBNP) level increased in subgroup I from baseline to 3 months, but remained stable after training introduction (from 3 to 6 months). For subgroups II and III, NT-proBNP levels remained stable during the entire study. No difference was observed for the other variables between the three evaluation periods. The combination of carvedilol or exercise training with conventional treatment in CMVD dogs led to improvements in quality of life and functional class. Therefore, light walking in CMVD dogs must be encouraged.

Exploring the experiences of youth in a development program with integrated physical activity in Costa Rica

National governments, the United Nations, and other organizations have deemed sport and other means of physical activity such as recreation, games and play for development a useful means for addressing a wide range of problems in communities and more specifically, providing youth with an opportunity to experience the benefits of physical activity. There is a need for research that furthers our understanding of how participants experience these programs. Specifically, the purpose of this study, was to better understand the lived experiences of the participants in a YMCA camp program that integrated physical activity and play for the specific development of poor youth street workers. A phenomenological approach infonned by a critical perspective (Creswell, 2003; Rossman & Rallis, 2003) was used. The study took place through the Asociaci6n Cristiana de J6venes de Costa Rica (ACJ) in Central America. The focus was on a camp program and the lived experiences of six purposefully chosen, youth street workers between the ages of 13-17. Their experiences were explored through semi-structured interviews. Other data that fonn the study include: field notes, observations, a reflexive journal and document analysis. The findings that emerged from the data include main themes of relationships, poverty, personal change and empowennent. For many youth, the ACJ is a relatively safe place to play, to "detach," their minds, to "distract" and "disorient" themselves from their dysfunctional families, violent neighbourhood, the poverty they live in, and from the necessity of having to work in the street to supplement the family income. Although many studies have shown that programs that include physical activity, play and/or sport have a positive impact on youth with regard to healthy development and improvements in well-being, there has been little work done to address the voices and experiences of the youth that participate in these programs. Using an interpretive-critical approach, this study focused on the participants' personal backgrounds, their experiences within the program and their critical reflections on the program. This study draws from a phenomenological philosophy and method to report findings from participants in an ACJ program in Costa Rica. This research shows how these youth were given the opportunity to use the program and the ACJ property as a relatively safe place to play, to behave like the youth they are, to establish and maintain their friendship networks, and develop empathy and conflict resolution skills. The fmdings from this study reveal how by participating in the ACJ program they each described a personal change, wherein they felt empowered to learn they could positivel y control themselves and as a result positively affect their own futures. These fmdings contribute knowledge surrounding the lived experiences of youth in developmental programs that use physical activity.

A physical activity intervention in a workplace setting

Physical inactivity poses a huge burden on Canada's health care system and is detrimental to the health of Canadians (Katzmarzyk & Janssen, 2004). Walking is a viable option for individuals to become physically active on a daily basis and is in fact the most commonly reported leisure time physical activity. It has been associated with many health benefits including weight loss/weight control, reduced risk of coronary artery disease and diabetes, lowered blood pressure, and improved psychological wellbeing (Brisson & Tudor-Locke, 2004). Specifically, individuals' stage of change, selfefficacy and health related quality of life (HRQL) are three psychological constructs that can be greatly improved with increased physical activity (Dishman, 1991; Penedo & Dahn, 2005; Poag & McAuley, 1992). Public health physical activity recommendations exist but many individuals find these difficult to meet due to overly busy lifestyles (Public Health Agency of Canada, 2003). Pedometers are inexpensive devices that can monitor individual bouts of walking so that the incorporation of physical activity into one's daily life is more plausible. They are also excellent tools for motivation, goalsetting, and immediate feedback (Brisson & Tudor-Locke, 2004). Since many people spend a large proportion of their time at their places of employment, workplaces have begun to be a common site for the development of physical activity interventions. These programs have been growing in popUlarity and have shown numerous benefits for both employees and employers (Voit, 2001). The purpose of the current study was to implement and evaluate the use of a pedometer-based physical activity intervention incorporating goal-setting and physical activity logs in a workplace setting, and to examine the relationship between different types of self-efficacy (task, barrier, and scheduling) and different phases of the intervention. Twenty male participants from a local steel manufacturing plant who exhibited health risk factors (e.g. hypertension, diabetes, etc.) were assigned to one of two groups (group A or group B). All participants were asked to wear pedometers on their waists, record their daily steps, set goals that were outlined on a step-tracking sheet (detennined by their baseline number of steps), and keep track of their work days, wakelbed time, sedentary time, and time spent doing other physical activity. Group A began the intervention immediately following the baseline measures, whereas group B continued with their regular routine for 4 weeks before beginning. Physiological measures (height, weight, blood pressure, relative body fat, waist and hip circumference, and body mass index) were taken and a battery of questionnaires that assessed barrier, task and scheduling self-efficacy, HRQL, and stage of change administered at baseline, week 5 (end of intervention for group A), week 9 (end of intervention for group B; follow-up for group A) and week 13 (follow-up for both groups). Results showed that this workplace physical activity intervention was successful at increasing the participants' daily steps, that task self-efficacy is a significant predictor of participants' exercise adherence during the initial stages of participation (intervention phase), and that the participants felt that this intervention was effective. Finally, further exploratory analyses showed that this intervention was effective for all participants, but most valuable for participants most in need of improvement - that is, those who were most sedentary prior to the intervention. This intervention is an inexpensive use of simple and effective tools (e.g. pedometers), has the potential to attract a wide variety of participants and become a pennanent part of any health promotion initiative.

The exercise leader's gender and physique salience : effects on self-presentational concerns in an exercise context

Self-presentation is the process by which individuals attempt to monitor and control how others perceive and evaluate them (Leary, 1992; Leary & Kowalski, 1990). Self-presentational concerns have been shown to influence a number of exercise-related behaviours, cognitions, and affective responses to exercise (e.g., social anxiety). Social anxiety occurs when an individual wants to create a specific impression on others, but is unsure (s)he will be successful (Leary & Kowalski, 1995). Social physique anxiety (SPA) is a specific form of social anxiety related the evaluation of one's body (Hart, Leary, & Rejeski, 1989). Both social anxiety and SPA may act as deterrents to exercise (Lantz, Hardy, & Ainsworth, 1997; Leary, 1992), so it is important to examine factors that may influence social anxiety and SPA; one such factor is self-presentational efficacy (SPE). SPE is one's confidence in successfully making desired impressions on others (Leary & Atherton, 1986) and has been associated with social anxiety and SPA (Leary & Kowalski, 1995; Gammage, Martin Ginis, & Hall, 2004). Several aspects of the exercise environment, such as the presence of mirrors, clothing, and the exercise leader or other participant characteristics, may be manipulated to influence self-presentational concerns (e.g., Gammage, Martin Ginis et aI., 2004; Martin & Fox, 2001; Martin Ginis, Prapavessis, & Haase, 2005). Given that the exercise leader has been recognized as one of the most important influences in the group exercise context (Franklin, 1988), it is important to further examine how the leader may impact self-presentational concerns. The present study examined the impact of the exercise leader's gender and physique salience (i.e., the extent to which the body was emphasized) on SPE, state social anxiety (SSA), and state social physique anxiety (SPA-S) of women in a live exercise class. Eighty-seven college-aged female non- or infrequent exercisers (i.e., exercised 2 or fewer times per week) participated in a group exercise class led by one of four leaders: a female whose physique was salient; a female whose physique was non-salient; a male whose physique was salient; or a male whose physique was non-salient. Participants completed measures of SPE, SSA, and SPA-S prior to and following completion of a 30- minute group exercise class. In addition, a measure of social comparison to the exercise leader and other participants with respect to attractiveness, skill, and fitness was completed by participants following the exercise class. A MANOV A was conducted to examine differences between groups on postexercise variables. Results indicated that there were no significant differences between groups on measures ofSPE, SSA, or SPA-S (allp's > .05). However, when all participants were collapsed into one group, a MANOV A showed a significant time effect (F(3, 81) = 19.45,p < .05, 1')2= .419). Follow-up ANOVAs indicated that post-exercise SPE increased significantly, while SSA and SPA-S decreased significantly (SPE: F(I, 83) = 30.87,p < .001,1')2 = .27; SSA: F(I,83) = 11.09,p < .001, 1')2 = .12; SPA-S: F (1,83) = 42.79,p < .001, 1')2 = .34). Further, results of a MANOVA revealed that participants who believed they were less fit than other group members (i.e., made negative social comparisons) reported significantly more post-exercise SSA and SP A-S than those who believed they were more fit than the other participants (i.e., made positive comparisons; SSA: F(2, 84) = 3.46, p < .05, 1')2 = .08; SPA-S: F(2, 84) = 5.69, p < .05, 1')2 = .12). These results may indicate that successfully completing an exercise class may serve as a source of SPE and lead to reduced social anxiety and SPA-S in this population. Alternatively, characteristics of the exercise leader may be less important than characteristics of the other participants. These results also suggest that the types of social comparisons made may influence self-presentational concerns in this sample. Future research should examine how the type of social comparison (i.e., negative or positive) made to the other group members may either generate or reduce anxiety. Also, factors that contribute to the types of social comparisons made with other exercisers should be examined. Implications for practice and research are discussed.