VO2max In Men Research Articles

Prediction of Maximal Oxygen Consumption in Cycle Ergometry in Competitive Cyclists.

Models for predicting maximal oxygen consumption (VO2max) in average adults might not be suitable for athletes, especially for competitive cyclists who can have significantly higher VO2max than normally active people. The aim of this study was to develop a clinically applicable equation for predicting VO2max during cycle ergometry in competitive cyclists and to compare its accuracy to the traditional American College of Sports Medicine (ACSM) equation. Maximal cycle ergometry tests were performed in 496 male and 84 female competitive cyclists. Six predictors were initially used to model the prediction equation (power output, body weight, body height, fat mass, fat-free mass and age). Power output and body weight were the most important parameters in the model predicting VO2max. Three new equations were derived: for male (VO2max = 0.10 × PO - 0.60 × BW + 64.21), female cyclists (0.13 × PO - 0.83 × BW + 64.02) and the non-gender-specific formula (0.12 × PO - 0.65 × BW + 59.78). The ACSM underestimated VO2max in men by 7.32 mL/min/kg (11.54%), in women by 8.24 mL/min/kg (15.04%) and in all participants by 7.45 mL/min/kg (11.99%), compared to the new equation that underestimated VO2max in men by 0.12 mL/min/kg (0.19%) and in all participants by 0.65 mL/min/kg (1.04%). In female cyclists, the new equation had no relative bias. We recommend that medicine and sports practitioners adapt our proposed equations when working with competitive cyclists. Our findings demonstrate the need to evaluate prediction models for other athletes with a special focus on disciplines that demand high aerobic capacity.

The Effects of Moderate Intensity Treadmill Exercise with Gradual Increase of Speed and Inclination on VO2max in Men with Type 2 Diabetes Mellitus

Background: The American College of Sport Medicine (ACSM) recommends cardiorespiratory fitness training in people with diabetes mellitus (DM) for 3-7 days a week, total duration 150 minutes a week with moderate intensity using large muscle groups. Treadmill training is the best cardiorespiratory fitness training because it involves large muscle group compared to static cycle and arm crank.Aim: To determine the effect of moderate intensity treadmill exercise with gradual increase of speed and inclination on VO2max in men with T2DM.Material and Methods: Randomized group design in 22 men with T2DM, suitable with inclusion criteria was divided into 2 groups, the experimental and control group. The experimental group received moderate intensity treadmill exercise, 3 times a week with gradual increase of speed and inclination for 4 weeks. The control group underwent standard therapy. Measurement of VO2max was performed before and after program in both groups.Results: A significant increase of VO2max in the experimental group (p = 0.003). Compared to the control group, alteration of VO2max also significant among the experimental group (p = 0.000).Conclusion: Moderate intensity treadmill exercise with gradual increase on speed and inclination for 4 weeks increase VO2max in men with T2DM.

Handgrip Strength-Related Factors Affecting Health Outcomes in Young Adults: Association with Cardiorespiratory Fitness.

Objectives Handgrip strength (HS) is a risk factor of all-cause mortality and cardiovascular diseases. However, the influencing factors and mechanisms contributing to this correlation remain unclear. Therefore, we aimed to explore factors related to HS and investigated the mechanism underlying its risk predictive value. Methods This was a prospective, cross-sectional study. One hundred forty-five participants were recruited from December 2019 to November 2020. HS was measured using a hydraulic hand dynamometer and adjusted for body mass index (HSBMI) and body surface area (HSBSA). Body composition was assessed via bioimpedance spectroscopy. Physical fitness was measured using a cardiopulmonary exercise test system. Univariate, multiple linear regression analyses and receiver operator characteristic curve (ROC) were conducted to evaluate the associations between various participant characteristics and HS. Results The average participant age was 21.68 ± 2.61 years (42.8% were male). We found positive correlations between HSBMI/HSBSA and VO2max, VEmax, Loadmax, and METmax in both sexes (p < 0.05). Lean-tissue, protein, total water, and inorganic salt percentages were positively correlated, and fat percentage was negatively correlated with HSBMI in men and with HSBMI and HSBSA in women (p < 0.05). Multiple regression revealed that VO2max was independently associated with HSBSA in both sexes (β = 0.215, 0.173; 95%confidence interval [CI] = 0.032 − 0.398, 0.026-0.321; p = 0.022, 0.022, respectively) and independently associated with HSBMI in women (β = 0.016, 95%CI = 0.004 − 0.029, p = 0.011). ROC analysis showed that HSBMI and HSBSA can moderately identify normal VO2max in men (area under curve [AUC] = 0.754, 0.769; p = 0.002, 0.001, respectively) and marginally identify normal VO2max in women (AUC = 0.643, 0.635; p = 0.029, 0.042, respectively). Conclusions BMI- and BSA-adjusted HS could serve as indicators of physical health, and HSBSA may moderately reflect cardiorespiratory fitness levels in healthy young adults, particularly in males. Clinical trials registry site and number: China Clinical Trial Center (ChiCTR1900028228).

Relationship between anthropometric characteristics and aerobic fitness among Malaysian men and women.

This cross-sectional study evaluated the relationships between anthropometric and aerobic fitness (rate of perceived exertion [RPE] and predicted maximal oxygen uptake [VO2max]) among 228 participants (age: 23.78±4.42 years). RPE and predicted VO2max were determined during the cycle ergometer exercise test. Data were also obtained for height, weight, body mass index (BMI), hip and waist (WC) circumferences. Data analysis revealed VO2max is correlated with WC (r=−0.571), weight (r=−0.521), waist-to-height ratio (WHtR) (r=−0.516), waist-to-hip ratio (WHR) (r=−0.487), and BMI (r=−0.47) in men, while, in women with WC (r=−0.581), weight (r=−0.571), WHtR (r=−0.545), BMI (r=−0.545), WHR (r=−0.473), and height (r=−0.287) (all P<0.05). Regression analysis showed WC was a significant predictor for VO2max in men and women (r 2=32.6% vs. 33.7%). The receiver operating characteristic curve of WC showed 0.786 and 0.831 for men and women, respectively. WC or abdominal obesity is the strongest predictor for VO2max, which is an indicator of aerobic fitness in Malaysian adults.

Agreement between ACSM’s equation and cardiopulmonary exercise test in determine maximal oxygen uptake in individuals with metabolic syndrome

PurposeLow functional capacity is associated with cardiovascular risk factors. Cardiopulmonary exercise test (CPET) is the gold standard evaluation to determine functional capacity through maximal oxygen uptake (VO2max) measurement. However, the high financial cost, the material and the time spent on this method difficult its use in a large number of clinicals. In this sense, it is possible to determine VO2max via the equivalence formulas. The aim of this study was to verify the agreement between indirect calculation of VO2max using American College of Sports Medicine (ACSM) equation and the directly measure of maximal oxygen uptake in metabolic syndrome (MetS) patients.MethodsSixty non‐diabetic and without medication patients with MetS (ATP‐III) were divided in 2 groups, according to gender: Male (n=32; 46±9 y; 31.2±3.0 kg/m2); and Female (n=28; 49±9 y; 32.7±3.1 kg/m2). VO2max was measured during CPET in a cycle ergometer with ramp protocol and estimated by ACSM’s equation [VO2= 7.0+ (1.8 x work rate)/body mass].ResultsAll patients included achieved respiratory exchange rate (RER=VCO2/VO2) &gt;1.10 at maximal exercise. In Male group, despite correlation between methods (R=0.78; P=0.0001), VO2max estimated by ACSM’s equation was higher than the VO2max of the direct measurement (28.7±3.1 vs. 26.9±6.0 ml/kg/min; P=0.049). Similarly, in Female group there was correlation (R=0.79; P=0.0001), however VO2max estimated by ACSM’s equation was higher than direct measured VO2max (20.3±3.3 vs. 18.8±3.3 ml/kg/min; P=0.0008). In both genders, Bland‐Altman plot analysis suggested a lack of agreement between predicted and direct VO2max.ConclusionIn bout groups, Male and Female, the ACSM’s equation overestimates the VO2max. It seems that ACSM’s equation is not capable of accurately predicting VO2max in men and women with MetS.

Development of Global Reference Standards for Directly Measured Cardiorespiratory Fitness: A Report From the Fitness Registry and Importance of Exercise National Database (FRIEND)

ObjectiveTo begin the process of developing global reference standards for adults from directly measured cardiorespiratory fitness (CRF). MethodsPercentiles of maximal oxygen consumption (VO2max) for men and women were determined for each decade from 20 through 79 years of age using International data from the Fitness Registry and Importance of Exercise: A National Database (FRIEND-I) along with previously published data from seven studies. FRIEND-I data from January 1, 2014, through January 1, 2019, included 11,678 maximal treadmill tests from three countries, whereas the previously published reports included 32,329 maximal treadmill tests from six countries. ResultsFRIEND-I data revealed significant differences between sex and age groups for VO2max (P<0.01). For the 20- to 29-years of age group, the 50th percentile VO2max in men and women were 49.5 mLO2⋅kg-1⋅min-1 and 40.6 mLO2⋅kg-1⋅min-1, respectively. VO2max declined an average of 9% per decade with the 50th percentile for the 70- to 79-years of age group having a VO2max of 30.8 mLO2⋅kg-1⋅min-1 in men and 25.0 mLO2⋅kg-1⋅min-1 in women. These results were similar in magnitude and direction to the previously published literature. Within both the FRIEND-I and previously published data there were CRF differences between countries. ConclusionThis report begins to establish global reference standards for CRF. Continued development of FRIEND-I will increase global representation providing an improved ability to identify and stratify CRF risk categories.

Criterion validity of the Ekblom-Bak and the \xc5strand submaximal test in an elderly population

PurposeThe aim of this study was to validate the submaximal Ekblom-Bak test (EB-test) and the Åstrand test (Å-test) for an elderly population.MethodsParticipants (n = 104), aged 65–75 years, completed a submaximal aerobic test on a cycle ergometer followed by an individually adjusted indirect calorimetry VO2max test on a treadmill. The HR from the submaximal test was used to estimate VO2max using both the EB-test and Å-test equations.ResultsThe correlation between measured and estimated VO2max using the EB method and Å method in women was r = 0.64 and r = 0.58, respectively and in men r = 0.44 and r = 0.44, respectively. In women, the mean difference between estimated and measured VO2max was − 0.02 L min−1 (95% CI − 0.08 to 0.04) for the EB method and − 0.12 L min−1 (95% CI − 0.22 to − 0.02) for the Å method. Corresponding values for men were 0.05 L min−1 (95% CI − 0.04 to 0.14) and − 0.28 L min−1 (95% CI − 0.42 to − 0.14), respectively. However, the EB method was found to overestimate VO2max in men with low fitness and the Å method was found to underestimate VO2max in both women and men. For women, the coefficient of variance was 11.1%, when using the EB method and 19.8% when using the Å method. Corresponding values for men were 11.6% and 18.9%, respectively.ConclusionThe submaximal EB-test is valid for estimating VO2max in elderly women, but not in all elderly men. The Å-test is not valid for estimating VO2max in the elderly.

Sex Dimorphism of VO2max Trainability: A Systematic Review and Meta-analysis.

Increases in maximal oxygen uptake (VO2max) are strongly associated with improved cardiovascular health. The aim was to perform a systematic review and meta-analysis to determine whether VO2max responses to endurance training (ET), the most effective intervention to improve VO2max, are influenced by sex. We conducted a systematic search of MEDLINE and Web of Science since their inceptions until February 2019 for articles assessing the VO2max response to a given sex-matched dose of ET in healthy age-matched men and women. Meta-analyses were performed to determine the mean difference between VO2max responses in men versus women. Subgroup and meta-regression analyses were used to assess potential moderating factors. After systematic review, eight studies met the inclusion criteria. All studies implemented common modalities of ET in healthy untrained individuals, comprising a total of 175 men and women (90♂, 85 ♀). ET duration and intensity were sex-matched in all studies. After data pooling, ET induced substantially larger increases in absolute VO2max in men compared with women (mean difference =+191ml·min-1, 95% CI 99, 283; P < 0.001). A greater effect of ET on relative VO2max was also observed in men versus women (mean difference =+1.95ml·min-1·kg-1, 95% CI 0.76, 3.15; P = 0.001). No heterogeneity was detected among studies (I2 = 0%, P ≥ 0.59); the meta-analytical results were robust to potential moderating factors. Pooled evidence demonstrates greater improvements in VO2max in healthy men compared with women in response to a given dose of ET, suggesting the presence of sexual dimorphism in the trainability of aerobic capacity.

Aerobic exercise training at maximal fat oxidation intensity improves body composition, glycemic control, and physical capacity in older people with type 2 diabetes

BackgroundAerobic training has been used as one of the common treatments for type 2 diabetes; however, further research on the individualized exercise program with the optimal intensity is still necessary. The purpose of this study was to investigate the effects of supervised exercise training at the maximal fat oxidation (FATmax) intensity on body composition, glycemic control, lipid profile, and physical capacity in older people with type 2 diabetes. MethodsTwenty-four women and 25 men with type 2 diabetes, aged 60–69 years. The exercise groups trained at the individualized FATmax intensity for 1 h/day for 3 days/week over 16 weeks. No dietary intervention was introduced during the experimental period. Whole body fat, abdominal fat, oral glucose tolerance test, lipid profile, and physical capacity were measured before and after the interventions. ResultsFATmax intensity was at 41.3 ± 3.2% VO2max for women and 46.1 ± 10.3% VO2max for men. Exercise groups obtained significant improvements in body composition, with a special decrease in abdominal obesity; decreased resting blood glucose concentration and HbA1c; and increased VO2max, walking ability, and lower body strength, compared to the non-exercising controls. Daily energy intake and medication remained unchanged for all participants during the experimental period. ConclusionBeside the improvements in the laboratory variables, the individualized FATmax training can also benefit daily physical capacity of older people with type 2 diabetes.

Maximal oxygen uptake is associated with allele -202 A of insulin-like growth factor binding protein-3 (IGFBP3) promoter polymorphism and (CA)n tandem repeats of insulin-like growth factor IGF1 in Caucasians from Poland.

Physical fitness is a trait determined by multiple genes, and its genetic basis is modified by numerous environmental factors. The present study examines the effects of the (CA)n tandem repeats polymorphism in IGFI gene and SNP Alw21I restriction site -202 A>C polymorphism in IGF1BP3 on VO2max--a physiological index of aerobic capacity of high heritability. The study sample consisted of 239 (154 male and 85 female) students of the University School of Physical Education in Poznań and athletes practicing various sports, including members of the Polish national team. An association was found between -202 A/C polymorphism of IGFBP3 gene with VO2max in men. Higher VO2max values were attained by men with CC genotype, especially male athletes practicing endurance sports and sports featuring energy metabolism of aerobic/anaerobic character. A statistically significant influence of allele 188 and genotype 188/188 of tandem repeats (CA)n polymorphism of IGF1 gene on VO2max was found in women. Also, lower values of maximal oxygen uptake were noted in individuals with allele 186 or genotype 186/186, and higher VO2max values in athletes with allele 194.

Crossfit-Based High-Intensity Power Training Improves Maximal Aerobic Fitness and Body Composition [RETRACTED

The purpose of this study was to examine the effects of a crossfit-based high-intensity power training (HIPT) program on aerobic fitness and body composition. Healthy subjects of both genders (23 men, 20 women) spanning all levels of aerobic fitness and body composition completed 10 weeks of HIPT consisting of lifts such as the squat, deadlift, clean, snatch, and overhead press performed as quickly as possible. Additionally, this crossfit-based HIPT program included skill work for the improvement of traditional Olympic lifts and selected gymnastic exercises. Body fat percentage was estimated using whole-body plethysmography, and maximal aerobic capacity (VO2max) was measured by analyzing expired gasses during a Bruce protocol maximal graded treadmill test. These variables were measured again after 10 weeks of training and compared for significant changes using a paired t-test. Results showed significant (p < 0.05) improvements of VO2max in men (43.10 ± 1.40 to 48.96 ± 1.42 ml · kg · min) and women (35.98 ± 1.60 to 40.22 ± 1.62 ml · kg · min) and decreased body fat percentage in men (22.2 ± 1.3 to 18.0 ± 1.3) and women (26.6 ± 2.0 to 23.2 ± 2.0). These improvements were significant across all levels of initial fitness. Significant correlations between absolute oxygen consumption and oxygen consumption relative to body weight was found in both men (r = 0.83, p < 0.001) and women (r = 0.94, p < 0.001), indicating that HIPT improved VO2max scaled to body weight independent of changes to body composition. Our data show that HIPT significantly improves VO2max and body composition in subjects of both genders across all levels of fitness.

Maximal Aerobic Power Characteristics of Male Professional Soccer Players, 1989–2012

The purpose of this investigation was to quantify maximal aerobic power (VO2max) in soccer as a function of performance level, position, age, and time of season. In addition, the authors examined the evolution of VO2max among professional players over a 23-y period. 1545 male soccer players (22 ± 4 y, 76 ± 8 kg, 181 ± 6 cm) were tested for VO2max at the Norwegian Olympic Training Center between 1989 and 2012. No differences in VO2max were observed among national-team players, 1st- and 2nd-division players, and juniors. Midfielders had higher VO2max than defenders, forwards, and goalkeepers (P < .05). Players <18 y of age had ~3% higher VO2max than 23- to 26-y-old players (P = .016). The players had 1.6% and 2.1% lower VO2max during off-season than preseason (P = .046) and in season (P = .021), respectively. Relative to body mass, VO2max among the professional players in this study has not improved over time. Professional players tested during 2006-2012 actually had 3.2% lower VO2max than those tested from 2000 to 2006 (P = .001). This study provides effect-magnitude estimates for the influence of performance level, player position, age, and season time on VO2max in men's elite soccer. The findings from a robust data set indicate that VO2max values ~62-64 mL · kg-1 · min-1 fulfill the demands for aerobic capacity in men's professional soccer and that VO2max is not a clearly distinguishing variable separating players of different standards.

Development Of A Valid Rowing-Specific VO2max Field Test

Currently, there are no feasible methods for testing aerobic capacity in the field among rowers. PURPOSE: To produce a valid, field-based VO2 test for rowers using minimal equipment. METHODS: Thirty rowers (15 men and 15 women) between the ages of 18 and 26 years were recruited from rowing clubs within the District of Columbia metropolitan area. The test protocol consisted of a maximum of seven 2-min stages on a rowing ergometer, separated by 30 second breaks during which blood lactic acid concentrations were determined. Intensity level started at 200 W for men and 150 W for women, and increased by 50 W with each additional stage. VO2 was determined by sampling expired gas fractions of CO2 and O2 from a mixing chamber (ParvoMedics 2400; Sandy, UT) and athletes were instructed to row to volitional exhaustion. To predict VO2max from the submaximal data, VO2 was regressed on peak heart rate for stages 1-5 in men and stages 1-4 in women. RESULTS: Approximately 80% of the men and 87% of the women achieved a respiratory exchange ratio (RER) of 1.10 or greater and lactic acid concentrations of 8.87±3.8 and 8.40±4.2 mmol·L-1 were achieved for men and women respectively confirming that athletes performed close to maximal effort. Submaximal heart rate was a significant correlate of VO2, but this relation was stronger in men (r=0.73; p<0.0001) than in women (r=0.57; p<0.001). Further, the VO2max values predicted from heart rate data were approximately 23% and 25% lower than what was actually achieved for men and women, respectively, and the correlation between predicted and actual VO2max was only modest in men (r=0.55; p<0.05) and quite negligible in women (r = -0.05; p=0.85). CONCLUSION: Although this field test was adequate in predicting VO2max in men, it performed poorly in women. The 30-sec rests at the end of each stage may have attenuated the strong linear relation often observed between heart rate and VO2. Moreover, women had greater relative increases in intensity with increasing stage compared with men, which may have prematurely shortened their test. Modifications to the testing protocol should produce stronger correlations and a more accurate prediction of VO2max.

Impact Of Gender On Substrate Utilization During Treadmill Walking At A Self-selected Pace

PURPOSE: To determine the impact of gender on substrate utilization during exercise at a self-selected pace. METHODS: Healthy male (n = 17) and female (n = 17) subjects performed a maximal exercise grade test and a 20-min bout of treadmill walking at a preferred pace in order to determine fat and carbohydrate (CHO) oxidation rates. Gas exchange measurements were performed throughout the tests and stoichiometric equations were used to calculate substrate oxidation rates. For each individual, a best-fit polynomial curve was constructed of fat oxidation rate (g·min-1) vs exercise intensity (%VO2max) and used to obtain the following variables: (a) the maximal rate of fat oxidation (MFO) measured over the entire range of exercise intensities; (b) the exercise intensity at which the MFO was observed (Fatmax); and (c) Fatmax zone, a range of exercise intensities with fat oxidation rates equal to ± 10% of Fatmax. Independent t-tests were used to examine gender differences in substrate oxidation rates during the maximal exercise test and 20-min bout of walking at a preferred pace. RESULTS: The MFO was similar between men (0.41 ± 0.22 g·min-1) and women (0.39 ± 0.14 g·min-1). However, the Fatmax was lower (P < 0.01) in men (36.7 ± 6.5%VO2max) than in women (44.5 ± 5.4%VO2max). Similarly, the "low" (28.4 ± 5.2 and 33.3 ± 3.6%VO2max) and "high" (45.1 ± 8.2 and 56.0 ± 7.5%VO2max for men and women, respectively) borders of the Fatmax zone were lower (P < 0.05) in men than in women. During treadmill walking at a preferred pace, the CHO oxidation rates were greater (P < 0.01) in men (1.40 ± 0.65 g·min-1) than in women (0.87 ± 0.51 g·min-1), but there were no gender differences in the fat oxidation rates (0.24 ± 0.13 and 0.24 ± 0.08 g·min-1 for men and women, respectively). However, the contribution of fat oxidation to total energy expenditure (EE) was greater (P < 0.05) in women (45.5 ± 12.6%) than in men (32.7 ± 16.4%), despite no differences in the relative exercise intensity between the men (37.5 ± 10.7%VO2max) and women (and 40.3 ± 7.2%VO2max). CONCLUSION: Although men and women self-selected similar relative exercise intensity, the contribution of fat oxidation to total EE is significantly greater in women than in men. Interestingly, both genders self-selected an exercise intensity that falls within the Fatmax zone.

Endurance Exercise Training and High-Molecular Weight Adiponectin: the HERITAGE Family Study

Adiponectin, an insulin-sensitizing and anti-atherosclerotic adipocytokine, exists in different isoforms. The high-molecular weight (HMW) isoform may be more biologically active. PURPOSE: To examine the effect of a vigorous-intensity endurance exercise training program on serum HMW adiponectin concentration in a sample of black and white men and women aged 17 to 65 years (n=515). METHODS: Serum HMW adiponectin concentrations from before and after a 20-week exercise program were analyzed via ELISA. RESULTS: When controlling for age, HMW adiponectin concentration before training was not related to VO2max in men or women (r=−0.028 and −0.031, respectively, p>0.05). As we have previously found with total serum adiponectin, the HMW isoform decreased slightly as a result of exercise training (before vs. after: 3.01±0.10 vs. 2.53±0.09, mean±SE, p<0.001). This decrease was significant within each of the four race/sex groups (p=0.04). Baseline HMW adiponectin was related to intra-abdominal and subcutaneous abdominal fat areas and overall body fat mass (r=−0.287, −0.185, and −0.154, respectively, p=0.001). Training-related change in HMW adiponectin was not related to changes in these fat variables (r=−0.058, −0.089, and −0.014, p>0.05). However, significant change relationships were present in black women (r=−0.253, −0.338, and −0.367, p=0.02). HMW adiponectin and insulin sensitivity (derived from minimal modeling after intravenous glucose tolerance testing) were related at baseline (r=0.224, p<0.001), but training−induced changes were not related (r=0.006, p>0.05). At baseline, HMW adiponectin was related to HDL-cholesterol and triglyceride concentrations (r=0.405 and −0.210, p<0.001). A modest change relationship was present for HDL-cholesterol (r=0.162, p<0.001), but not triglyceride (r=0.027, p>0.05). CONCLUSIONS: Serum HMW adiponectin concentration did not increase in response to 20 weeks of vigorous-intensity exercise training. Overall, exercise-induced change in HMW adiponectin was not strongly related with changes in other factors associated with cardiometabolic risk. These results largely mirror those of total serum adiponectin previously found in the HERITAGE sample. Funded by the American Heart Association (Mid-Atlantic Affiliate) and multiple grants from NIH-NHLBI.

Physical activity, coronary artery calcium, and bone mineral density in elderly men and women: a preliminary investigation

The aim of this study was to examine the relationship between cardiorespiratory fitness, coronary artery calcification (CAC), and bone mineral density (BMD) in older adults. Thirteen highly active, endurance-trained “master athletes” (7 male and 6 female) and 12 sedentary (6 male and 6 female) older adults (age 60-78 years) were recruited for this study. All subjects had CAC measured by electron beam computed tomography; BMD assessed by dual-energy X-ray absorptiometry; and plasma mineral regulatory proteins, including matrix Gla protein, fetuin-A, osteocalcin, osteopontin, and osteoprotegerin, measured by enzyme-linked immunosorbent assay. Furthermore, maximal oxygen consumption (VO 2max) was measured in each subject to provide an objective measure of cardiorespiratory fitness. As expected, whole-body BMD was elevated in master athletes compared with sedentary adults (1.17 ± 0.02 vs 1.09 ± 0.02 g/cm 2, P < .05). CAC score did not differ between activity groups, but was 8-fold lower in women compared with men ( P < .05). The CAC score was not correlated with BMD, and there was no correlation between CAC and VO 2max when both sexes were included in the analysis. When the sexes were analyzed separately, several relationships were evident in men only. There was a significant inverse correlation between VO 2max and the number of calcified coronary artery lesions ( r = −0.596, P < .05), and the correlation between VO 2max and logCAC score approached significance ( r = −.493, P = .08). Furthermore, fetuin-A, a systemic inhibitor of vascular calcification, was positively correlated with VO 2max in men ( r = 0.679, P < .05). These data provide preliminary evidence that chronic exercise may simultaneously inhibit CAC and increase BMD. The positive correlation between VO 2max and plasma fetuin-A levels in men indicates a potential mechanism by which exercise may correlate negatively with CAC. Additional studies with larger sample sizes will be needed to determine if the protective effects of chronic exercise on CAC and BMD are sex specific or mediated through common mechanisms such as changes in circulating levels of mineral regulatory proteins.

Effect Of Caffeine On Metabolic And Cardiovascular Responses To Submaximal Exercise

Few studies have investigated the effect of caffeine on exercise responses in children. No study has compared the effects of caffeine on exercise responses between children versus adults. PURPOSE Compare the effects of caffeine on physiological responses to exercise between young boys versus college age men. METHODS Twenty-six 7–9 year old boys and eighteen 18–25 year old men participated in a double-blind, double-crossover placebo study. Subjects received in random order twice each, either a placebo drink (cherry flavored Sprite®-PL) or drink plus anhydrous caffeine (5 mg/kg body mass, CAF). Following a 60-minute absorption period children rode at 25 W and then 50 W while men rode at 50 W and then 60% VO2 max for 8 minutes each on an electronically braked ergometer while heart rate (HR), oxygen consumption (VO2), and respiratory exchange ratio (RER) were monitored continuously, and blood pressure (BP) was measured every two minutes. RESULTS HR was significantly lower (p < 0.05) at 25 W (119±10 vs 126±9 bpm) and 50 W in boys (150±15 vs 157±13 bpm) in CAF vs. PL, respectively. In men HR was the same at both 50 W (107±17 vs. 106±16 bpm) and 60% VO2 max (146±8 vs. 146±10 bpm) in CAF vs. PL, respectively. Systolic BP(SBP) was higher at 25 W (132±12 vs 128±12 mmHg, p < 0.05) and 50 W in boys (147±14 vs 144±14 mmHg, p = 0.067) in CAF vs. PL, respectively. Diastolic BP (DBP) was higher at 25 W (71±8 vs 68±8 mmHg, p < 0.05) and 50 W in boys (73±9 vs 70±9 mmHg, p < 0.05) in CAF vs PL, respectively. Blood pressure in men was always higher in CAF vs. PL but never reached statistical significance. Specifically, SBP was similar at 50 W (161±16 vs 159±15 mmHg, p = 0.685) and 60% VO2 max (200±20 vs 198±21 mmHg, p = 0.245) in CAF vs. PL, respectively. Diastolic BP was similar at 50 W (79±11 vs 76±8 mmHg, p = 0.058) and 60% VO2 max (84±12 vs 83±8 mmHg, p = 0.559) in CAF vs. PL, respectively. Both VO2 and RER were the same at both 25 W and 50 W in boys, and 50 W and 60% VO2 max in men in CAF vs PL. CONCLUSIONS Caffeine (5 mg/kg) has a similar effect on metabolic responses to exercise in boys and men. The same dose causes a significant elevation in exercise BP and decrease in HR in boys while in men there was only a trend for a similar change in BP (although not significant) with no change in HR.

Growth Hormone and Sex Corticosteroid Administration in Healthy Aged Women and Men: A Randomized Controlled Trial

Background: Hormone administration to elderly individuals can increase lean body mass (LBM) and decrease fat, but interactive effects of growth hormone (GH) and sex corticosteroids and their influence on strength and endurance are unknown. Objective: The purpose of this study was to evaluate the effects of recombinant human GH or sex corticosteroids on body composition, strength, endurance, and adverse outcomes in aged persons. Design, setting, and participants: This was a 26‐week randomized, double‐blind, placebo‐controlled parallelgroup trial in healthy, ambulatory, community‐dwelling US women (n = 57) and men (n = 74) aged 65 to 88 years recruited between June 1992 and July 1998. Interventions: Participants were randomized to receive GH (starting dose, 30 μg/kg, reduced to 20 μg/kg, subcutaneously 3 times/wk) + sex corticosteroids (women: transdermal estradiol, 100 μg/day, plus oral medroxyprogesterone acetate, 10 mg/day, during the last 10 days of each 28‐day cycle [HRT]; men: testosterone enanthate, biweekly intramuscular injections of 100 mg) (n = 35); GH + placebo sex corticosteroid (n = 30); sex corticosteroid + placebo GH (n = 35); or placebo GH + placebo sex corticosteroid (n = 31) in a 2 × 2 factorial design. Main outcome measures: Lean body mass, fat mass, muscle strength, maximum oxygen uptake (VO2 max) during treadmill test, and adverse effects. Results: In women, LBM increased by 0.4 kg with placebo, 1.2 kg with HRT (p = .09), 1.0 kg with GH (p = .001), and 2.1 kg with GH + HRT (p &lt; .001). Fat mass decreased significantly in the GH and GH + HRT groups. In men, LBM increased by 0.1 kg with placebo, 1.4 kg with testosterone (p = .06), 3.1 kg with GH (p &lt; .001), and 4.3 kg with GH + testosterone (p &lt; .001). Fat mass decreased significantly with GH and GH + testosterone. Women's strength decreased in the placebo group and increased nonsignificantly with HRT (p = .09), GH (p = .29), and GH + HRT (p = .14). Men's strength also did not increase significantly, except for a marginally significant increase of 13.5 kg with GH + testosterone (p = .05). Women's VO2 max declined by 0.4 mL/min/kg in the placebo and HRT groups but increased with GH (p = .07) and GH + HRT (p = .06). Men's VO2 max declined by 1.2 mL/min/kg with placebo and by 0.4 mL/min/kg with testosterone (p = .49) but increased with GH (p = .11) and with GH + testosterone (p &lt; .001). Changes in strength (r = .355; p &lt; .001) and in VO2 max (r = .320; p = .002) were directly related to changes in LBM. Edema was significantly more common in women taking GH (39% versus 0%) and GH + HRT (38% versus 0%). Carpal tunnel symptoms were more common in men taking GH + testosterone (32% versus 0%) and arthralgias were more common in men taking GH (41% versus 0%). Diabetes or glucose intolerance occurred in 18 GH‐treated men versus 7 not receiving GH (p = .006). Conclusions: In this study, GH with or without sex corticosteroids in healthy, aged women and men increased LBM and decreased fat mass. Sex corticosteroid + GH increased muscle strength marginally and VO2 max in men, but women had no significant change in strength or cardiovascular endurance. Because adverse effects were frequent (importantly, diabetes and glucose intolerance), GH interventions in the elderly should be confined to controlled studies.

Quadriceps Muscle Function in Relation to Habitual Physical Activity and VO2max in Men and Women Aged More Than 65 Years

The relationship of quadriceps maximal muscle power (Pmax), corresponding optimal shortening velocity (v(opt)), and relative fatigability (Pmax%D) to maximal oxygen uptake (VO2max) and habitual physical activity (PA) was examined in healthy community-dwelling subjects (29 women and 25 men) aged more than 65 years old. PA was evaluated by a questionnaire and expressed using two activity indices: mean habitual daily energy expenditure (MHDEE) and the daily energy expenditure corresponding to leisure time sports activities (Sports Activity). In women, Pmax correlated positively with VO2max (r = .56) and with Sports Activity (rho = .41). Both Sports Activity and Pmax were significant independent predictors of VO2max and accounted for 62% of variance in VO2max. In men, v(opt) was significantly negatively related to MHDEE (r = -.59) and to Sports Activity (rho = -.40). Neither in women nor in men was Pmax%D correlated with VO2max or PA indices. The different relationship of Pmax and v(opt) with VO2max and PA indices suggests that habitual PA may be sufficient in active older women, but not in men, to positively influence quadriceps muscle function. These gender differences may suggest different approaches in exercise programming for elderly women and men.

Relative exercise intensity of long-distance marching (120 km in 4 days) in 153 subjects aged 69-87 years.

The aim of this study was to determine the relative exercise intensity (oxygen uptake during the march/maximal oxygen uptake, VO2march/VO2max) during a long-distance march in subjects or over 70 years of age. Secondly, the effect of hypertension, cardiovascular and pulmonary diseases on the relative exercise intensity was evaluated. One hundred and fifty-three subjects, 97 men aged 76.7 (4.6) years and 56 women aged 72.8 (3.6) years who completed the 1993 Nijmegen day long-distance march (30 km x day(-1) on 4 consecutive days) participated in the study. Oxygen uptake (VO2) during walking at different velocities (v) was measured in a subgroup of nine men and nine women, selected randomly from the population under study. With these data, regression equations describing the relationship between VO2 and v were made. VO2march was estimated with the obtained regression equations from an average of the v(march) measured in all participants. VO2max was determined using incremental cycle ergometry in all subjects. VO2march was 13.7 (1.8) ml x kg(-1) x min(-1) in men and 15.2 (1.3) ml x kg x min(-1) in women at a mean v of 5 km x h(-1) in both sexes. This corresponded to 52% of VO2max in men and 63% in women. In both sexes subjects with cardiovascular and/or pulmonary diseases walked at a slower v and thus lower VO2march compared to subjects without these diseases. Due to the lower VO2max in subjects with these diseases there was no difference in the relative exercise intensity between the groups. A multiple linear regression analysis showed that and not age on the prevalence of hypertension, cardiovascular and/or pulmonary that VO2max was the most important predictor of the variance in self-selected v(march). This study demonstrates that these active people aged over 70 years could maintain a high relative exercise intensity during endurance walking on 4 subsequent days. Furthermore, it shows that the relative exercise intensity of marching is within the range recommended for improving fitness and reducing the risk of cardiovascular diseases. Finally, these results demonstrate that VO2max has a more important influence on performance than does age or chronic diseases in active elderly people.