Exercise In Men Research Articles

Endocrine Response Patterns to Acute Unilateral and Bilateral Resistance Exercise in Men

Rehabilitation programs and research experiments use single-arm protocols in which the contralateral arm is not functional or used as a control limb. This study was interested in determining the hormonal signal impacts of such one- versus two-arm exercise responses that might have an impact on adaptational changes with training. The purpose was to examine the acute hormonal responses to a unilateral and a bilateral upper-body resistance exercise (RE) protocol. A balanced randomized treatment intervention with series time frame for blood collections before and after exercise was used as the basic experimental design. Ten recreationally resistance trained men (18-25 years, 20.4 +/- 1.2 years, 175.6 +/- 4.5 cm, 81.7 +/- 9.3 kg) gave informed consent to participate in the investigation. Each subject performed unilateral (dominant arm only) and bilateral upper-body RE protocol separated by 1 week in a balanced randomized fashion. The RE protocol consisted of 3 sets of 10 repetitions of 5 different dumbbell upper-body exercises at 80% of 1-repetition maximum, and blood samples were obtained before and 5, 15, and 30 minutes immediately postexercise (IP). Blood was obtained and analyzed for lactate, immunoreactive growth hormone (iGH), cortisol (C), total testosterone (T), and insulin concentrations. Total volume of work also was determined for the 2 exercise sessions. Total volume of work performed during the unilateral protocol was 52.1% of that for the bilateral protocol. Both RE protocols elicited a significant (p < or = 0.05) increase in lactate and iGH, but the increase for the bilateral condition was significantly greater. Cortisol decreased significantly during recovery for the unilateral condition. Testosterone was not affected by either protocol. Insulin was significantly increased at IP and 5 minutes postexercise for both conditions.These results indicate that the hormonal responses to dominant-arm unilateral RE is blunted compared to that for bilateral RE. This differential endocrine response is likely a result of the difference in volume between the protocols. It is important to pay attention to the amount of muscle mass utilized in a resistance exercise protocol to optimize endocrine signaling.

Psychological Responses to Acute Resistance Exercise in Men and Women Who Are Obese

The purpose of the study was to investigate the psychological response to the very first session of resistance exercise on positive well-being (PWB), psychological distress (PD), and perception of fatigue in untrained men and women who are obese. Forty-five (male = 22, female = 23) untrained, middle-aged volunteers (mean +/- SEM, 51.0 +/- 1.0; range, 40-69 years) participated in the study. Participants were divided into 4 groups according to sex and obesity level (i.e., men who are obese, men who are nonobese, women who are obese, women who are nonobese). The threshold for obesity was defined as waist circumference >or=94 cm for men and 80 cm for women. Measures included body composition, aerobic power, muscle strength, and quality of life (Short Form 36, SF-36). Before and after resistance exercise, participants completed the Subjective Exercise Experience Scale (SEES). Paired sample t-tests were used to assess changes in SEES scores within group pre- and post-exercise and repeated-measures analysis of variance were used to assess changes in SEES scores between groups. Exercise increased the perception of PWB in both women who are obese and nonobese, without changes in PD or fatigue. In women, the change in PWB after exercise was negatively correlated with most scales of the SF-36, particularly with the mental health dimension (r = -0.55, p < 0.01). No significant changes in PWB, PD, or fatigue were found in men who are obese. Acute resistance exercise improved PWB in women who are obese and nonobese and those with lower self-perceived quality of life scores at the start improved the most. In addition, resistance exercise did not increase feelings of distress in either women or men who are obese.

A Comparison Of Directly Measured Versus Predicted Energy Cost Of Upper Body Exercise In Men

A Comparison Of Directly Measured Versus Predicted Energy Cost Of Upper Body Exercise In Men

A Forty-Year Follow-Up of the Dallas Bed Rest and Training Study: The Effect of Age on the Cardiovascular Response to Exercise in Men

In 1966, five 20-year-old men underwent a comprehensive physiological evaluation of the capacity for adaptation of the cardiovascular system in response to 3 weeks of bed rest and 8 weeks of heavy endurance training; these same participants were reevaluated before and after training at the age of 50. The aim of the present study was to reexamine these same men 40 years following the original assessments. In all three studies, minute ventilation and expired gases were analyzed during exercise testing with Douglas bag collection. Cardiac output (CO) was determined using the acetylene rebreathing technique. Compared with the original 30-year interval, the decline in maximal oxygen uptake (VO(2max)) (-11% vs -25%), maximal CO (+6% vs -11%), and maximal stroke volume (+10% vs -10%) were greater between 50 and 60 years of age. The annualized decline in VO(2max) (55 mL/min/y) between ages 50 and 60 was approximately fourfold higher than the decline between 20 and 50 years (12 mL/min/y). In the original five participants of the Dallas Bed Rest and Training Study, VO(2max) declined after 40 years of living due to a balanced decrease in central and peripheral determinants of oxygen uptake. The rate of decline in VO(2max) and its components accelerated after the age of 50 years secondary to age and clinical comorbidities. The net proportional decline in VO(2max) for a period of 40 years of life was comparable with that experienced after 3 weeks of strict bed rest at the age of 20 (27% vs 26%, respectively).

Mechanics of Breathing during Exercise in Men and Women

Women have smaller airways and lung volumes and lower resting maximal expiratory flow rates relative to men. Female athletes develop expiratory flow limitation more frequently than male athletes, and they have greater increases in end-expiratory and end-inspiratory lung volume at maximal exercise. Women use a greater fraction of their ventilatory reserve and have a higher metabolic cost of breathing.

No Reduction in C-Reactive Protein following a 12-Month Randomized Controlled Trial of Exercise in Men and Women

Low-grade systemic inflammation is suggested to play a role in the development of several chronic diseases including cancer. Higher levels of physical activity and lower adiposity have been associated with reduced levels of markers of systemic inflammation, such as C-reactive protein (CRP); however, reductions in CRP have not been consistently observed in randomized controlled trials of exercise. To examine the effect of a 12-month aerobic exercise intervention on CRP levels in men and women. One hundred two men and 100 women, sedentary and of ages 40 to 75 years, with mean body mass index (BMI) of 29.9 and 28.7 kg/m(2), respectively, were randomly assigned to a 12-month moderate-to-vigorous aerobic exercise intervention (6 d/wk, 60 min/d, 60-85% maximum heart rate) or control group. Fasting blood samples were collected at baseline and at 12 months. CRP levels were measured by high-sensitivity latex-enhanced nephelometry. At baseline, CRP was 1.16 and 2.11 mg/L for men and women, respectively, and CRP was correlated with percent body fat (r = 0.48, P < or =0.001), BMI (r = 0.37, P < or = 0.001), and aerobic fitness (r = -0.49, P < or = 0.001). No intervention effects were observed for CRP in men or women, or when stratified by baseline BMI (<30 versus > or =30 kg/m(2)), baseline CRP (<3 versus > or =3 mg/L), or change in body weight, body composition, or aerobic fitness. A 12-month moderate-to-vigorous aerobic exercise intervention did not affect CRP levels in previously sedentary men or women with average-risk CRP values at baseline.

The Effects of Systolic Hypertension on Arterial-Ventricular Coupling at Rest and During Exercise In Men and Women

The Effects of Systolic Hypertension on Arterial-Ventricular Coupling at Rest and During Exercise In Men and Women

Asymmetric Weight Gain and Loss from Increasing and Decreasing Exercise

Although increases and decreases in physical activity are known to cause weight loss and weight gain, respectively, it is not known whether the magnitudes of these changes in weight are equal. Unequal (asymmetric) weight changes could contribute to overall weight gain or loss among individuals with seasonal or irregular activity. Changes in adiposity were compared with the running distances at baseline and follow-up in men and women whose reported exercise increased (N = 4632 and 1953, respectively) or decreased (17,280 and 5970, respectively) during 7.7 yr of follow-up. Per km.wk(-1) decreases in running distance caused more than four times greater weight gain between 0 and 8 km.wk(-1) (slope +/- SE, males: -0.068 +/- 0.005 kg.m(-2); females: -0.080 +/- 0.01 kg.m(-2)) than between 32 and 48 km.wk(-1) (-0.017 +/- 0.002 and -0.010 +/- 0.005 kg.m(-2), respectively). In contrast, increases in running distance produced the smallest weight losses between 0 and 8 km.wk(-1) and statistically significant weight loss only above 16 km.wk(-1). Above 32 km.wk(-1) (30 kcal.kg(-1)) in men and 16 km.wk(-1) (15 kcal.kg(-1)) in women, weight loss from increasing exercise was equal to or greater than weight gained from decreasing exercise; otherwise, weight gain exceeded weight loss. Weight gained because of reductions in weekly exercise below 30 kcal.kg(-1) in men and 15 kcal.kg(-1) in women may not be reversed by resuming prior activity. Current IOM guidelines (i.e., maintain total energy expenditure at 160% of basal) agree with the men's exercise threshold for symmetric weight change with changing exercise levels. Asymmetric weight changes below this threshold may contribute to weight gain among less-active subjects.

The Influence of Calcium Consumption on Weight and Fat Following 9 Months of Exercise in Men and Women

Background: There is some evidence that calcium consumption improves weight loss during energy restriction but the effects of calcium consumption in conjunction with chronic exercise are unknown.Objective: The purpose of the study was to determine the degree to which calcium consumption influences weight and fat weight change as a result of 9 months of verified supervised exercise in the absence of energy restriction.Methods: Participants were 50 previously sedentary, overweight and moderately obese men (n=20) and women (n=30). Exercise of moderate intensity was performed for 45 min/d, 5 d/wk, under supervision. Diet intake was ad libitum and was measured for energy, macronutrient and micronutrient composition at baseline, 4 and 9 months by use of observer recorded weighed plate waste and multiple-pass 24-h dietary recall procedures.Results: Average calcium consumption was 987 ± 389 mg/day for men and 786 ± 276 mg/day for women. Weight change over the 9 months was −4.6 ± 4.6 kg for men and 0.2 ± 3.3 kg for women. Calcium consumption was associated with weight change (r =−0.47, p<0.05) in men. The calcium to protein ratio was associated with weight change (r=0.56) and fat weight change (r=−0.53) in men. There was no observed association between calcium and weight or fat weight change in women.Conclusion: Weight and fat weight loss as a result of nine months of moderate intensity exercise may be improved by increased calcium consumption in men but was not observed in women.

The effects of exposure to muscular male models among men: Exploring the moderating role of gym use and exercise motivation

This study examines the effects of exposure to the muscular male body ideal on body-focused negative affect among male gym users and non-exercisers. As hypothesized, the impact of media exposure depended on men's exercise status. Non-exercisers ( n = 58) reported greater body-focused negative affect after exposure to images of muscular male models than after neutral images (no model controls), whereas gym users ( n = 58) showed a tendency for less body-focused negative affect after the model images than after the control images. Furthermore, the extent to which gym users were motivated to increase strength and muscularity moderated these exposure effects; men who reported stronger strength and muscularity exercise motivation reported a greater degree of self-enhancement after exposure to the muscular ideal. The findings are interpreted with respect to likely differences in motives for social comparisons.

Transactional sex with casual and main partners among young South African men in the rural Eastern Cape: Prevalence, predictors, and associations with gender-based violence

We explored the prevalence and predictors of transactional sex with casual partners and main girlfriends among 1288 men aged 15–26 from 70 villages in the rural Eastern Cape province of South Africa. Data were collected through face-to-face interviews with young men enroling in the Stepping Stones HIV prevention trial. A total of 17.7% of participants reported giving material resources or money to casual sex partners and 6.6% received resources from a casual partner. Transactionally motivated relationships with main girlfriends were more balanced between giving (14.9%) and getting (14.3%). We constructed multivariable models to identify the predictors for giving and for getting material resources in casual and in main relationships. Each model resulted in remarkably similar predictors. All four types of exchange were associated with higher socio-economic status, more adverse childhood experiences, more lifetime sexual partners, and alcohol use. Men who were more resistant to peer pressure to have sex were less likely to report transactional sex with casual partners, and men who reported more equitable gender attitudes were less likely to report main partnerships underpinned by exchange. The most consistent predictors of all four types of transaction were perpetration of intimate partner violence and rape against women other than a main partner. The strong and consistent association between perpetration of gender-based violence and both giving and getting material goods from female partners suggests that transactional sex in both main and casual relationships should be viewed within a broader continuum of men's exercise of gendered power and control. HIV prevention interventions need to explicitly address transactional sex in the context of ideas about masculinity, which place a high emphasis on heterosexual success with, and control of, women.

Exogenous Oxidation of Isomaltulose Is Lower than That of Sucrose during Exercise in Men

Isomaltulose (ISO) is a disaccharide that is slowly digested, resulting in a slow availability for absorption. The aim of this study was to compare the blood substrate responses and exogenous carbohydrate (CHO) oxidation rates from orally ingested sucrose (SUC) and ISO during moderate intensity exercise. We hypothesized that the oxidation of ISO is lower compared with SUC, resulting in lower plasma glucose and insulin concentrations and subsequent lower CHO and higher fat oxidation rates. Ten trained men [maximal oxygen uptake (VO2max), 64 ± 1 mL/(kg body mass·min)] cycled on 3 occasions for 150 min at 59 ± 2% VO2max and consumed either water (WAT) or 1 of 2 CHO solutions providing 1.1 g/min of CHO in the form of either SUC or ISO. Peak exogenous CHO oxidation rates were higher (P < 0.05) during the SUC trial (0.92 ± 0.03 g/min) than during the ISO trial (0.54 ± 0.05 g/min). Total endogenous CHO oxidation over the final 90 min of exercise was lower (P < 0.05) in the SUC trial (107 ± 10 g) than in the WAT (137 ± 7 g) and ISO (127 ± 9 g) trials. Fat oxidation was higher during the WAT trial than during the SUC and ISO trials. ISO resulted in a lower plasma insulin response at 30 min compared with SUC, whereas the glucose response did not differ between the 2 CHO. Oxidation of ingested ISO was significantly less than that of SUC, most likely due to the lower rate of digestion of ISO. A lower CHO delivery and a small difference in plasma insulin may have resulted in higher endogenous CHO use and higher fat oxidation during the ISO trial than during the SUC trial.

Comparison of the Symptoms of Exercise-induced Muscle Damage After an Initial and Repeated Bout of Plyometric Exercise in Men and Boys

Comparison of the Symptoms of Exercise-induced Muscle Damage After an Initial and Repeated Bout of Plyometric Exercise in Men and Boys

17β-Estradiol Supplementation Decreases Glucose Rate of Appearance and Disappearance with No Effect on Glycogen Utilization during Moderate Intensity Exercise in Men

Women use less carbohydrate during endurance exercise, as compared with men. In rodents, 17beta-estradiol (E2) supplementation robustly increases lipid use and lowers muscle and liver glycogen use during exercise. E2 supplementation has been found to influence substrate selection by decreasing glucose rate of appearance (Ra), disappearance (Rd), and metabolic clearance rate during exercise in humans; however, neither a change in total carbohydrate use nor a sparing of muscle glycogen was demonstrated. We investigated the effect of 8 d of E2 (2 mg/d) supplementation on glucose turnover and net muscle glycogen use in 11 men using a randomized, double-blind, placebo-controlled, crossover design. Subjects underwent primed constant infusion of [6,6-(2)H]glucose, and muscle biopsies were taken before and after 90 min of cycling at 65% maximal oxygen uptake. E2 supplementation decreased the respiratory exchange ratio (P = 0.03) and glucose Ra and Rd (both P = 0.04) during exercise, as compared with placebo. E2 supplementation lowered proglycogen (P < 0.05) and total glycogen (P = 0.04) concentration, as compared with placebo; however, there was no effect of E2 on net muscle glycogen use during exercise. These findings show that E2 supplementation alters fuel selection in exercising men by increasing lipid use and reducing carbohydrate use, glucose Ra (primarily liver glucose production), and Rd (primarily muscle glucose uptake). Furthermore, E2 reduces the basal level of total muscle glycogen, particularly the proglycogen form.

The Effect of the Glycemic Index of an Evening Meal on the Metabolic Responses to a Standard High Glycemic Index Breakfast and Subsequent Exercise in Men

The present study investigated the effect of the glycemic index of an evening meal on responses to a standard high glycemic index (HGI) breakfast the following morning. The metabolic responses to exercise 3 h after breakfast were also investigated. Seven active males completed 2 trials. In each trial, participants were provided with an evening meal on day 1, which was composed of either HGI or LGI (high or low glycemic index) carbohydrates. On day 2, participants were provided with a standard HGI breakfast and then performed a 60 min run at 65% VO(2max) 3 h later. Plasma glucose and serum insulin concentrations following breakfast were higher in the HGI trial compared to the LGI trial (P < 0.05). During exercise, there were no differences in substrate utilization. The results suggest that consuming a single LGI evening meal can improve glucose tolerance at breakfast but the metabolic responses to subsequent exercise were not affected.

Fibrinolytic Potential And Vasodilatory Capacity Following Acute Exercise In Men

Fibrinolytic Potential And Vasodilatory Capacity Following Acute Exercise In Men

Fibrinolytic Potential And Vasodilatory Capacity Following Acute Exercise In Men

Fibrinolytic Potential And Vasodilatory Capacity Following Acute Exercise In Men

Acute Hormonal Responses to Submaximal and Maximal Heavy Resistance and Explosive Exercises in Men and Women

The purpose of this study was to examine acute hormonal and neuromuscular responses in men and women to 3 heavy resistance but clearly different exercise protocols: (a) submaximal heavy resistance exercise (SME), (b) maximal heavy resistance exercise (HRE), and (c) maximal explosive resistance exercise (EE). HRE included 5 sets of 10 repetition maximum (10RM) sit-ups, bench press, and bilateral leg extensions (David 210 machine) with a 2-minute recovery between the sets. In SME, the load was 70%, and in EE, the load was 40% from that used in HRE. A significant increase (p < 0.05) in serum growth hormone (GH) was observed after HRE both in men and women, but the increase was greater (p < 0.05) in men than in women. Serum testosterone (T) increased significantly (p < 0.05) only during HRE in men. Since GH and T are anabolic hormones, the acute exercise-induced response during HRE may play an important role in the long-term anabolic adaptation processes related to muscle hypertrophy and maximal strength development.

Compulsive Exercise in Men Poses Challenge

Compulsive Exercise in Men Poses Challenge

Rate and Amplitude of Adaptation to Two Intensities of Exercise in Men Aged 65–75 yr

To test the hypothesis that in males aged 65-75 yr when the total amount of work completed is similar in endurance training three times per week for 12 wk at either 50% or 70% peak oxygen uptake (VO2(peak)), there will be no significant difference in time course and amplitude of selected responses. Subjects were randomly assigned to three groups: 70% VO2(peak), N = 19; 50% VO2(peak), N = 16; or control group, N = 19. Subjects underwent a maximal cycle exercise test and blood volume (Evans Blue) determination at 0, 4, 8, and 12 wk. A submaximal exercise test (50 W) was conducted at weeks 0 and 12 where cardiac output was determined. The exercise groups maintained the same exercise relative intensity throughout the 12 wk and completed a similar total amount of work. There were significant and similar increases in peak VO2, power and heart rate (HR) for both exercise groups. Linear models best described the time course for peak power and HR in both exercise groups. In the 70% VO2(peak) group, a quadratic model for VO2 and a linear model for VE were the best fit. There were no significant changes in blood or plasma volume for any groups over the 12 wk. Significant increases in stroke volume and significant decreases in HR at 50 W were found in both exercise groups after training. Moderate-intensity cycle exercise (50% VO2(peak)) to achieve 180-200 kJ per session, three times a week for 12 wk is a safe and effective stimulus for healthy asymptomatic men aged 65-75 yr to improve functional capacity in a primarily linear manner.