Capacity Maximal Oxygen Research Articles

A phase III clinical trial of exercise modalities on treatment side-effects in men receiving therapy for prostate cancer

BackgroundAndrogen deprivation therapy (ADT) is accompanied by a number of adverse side effects including reduced bone mass and increased risk for fracture, reduced lean mass and muscle strength, mood disturbance and increased fat mass compromising physical functioning, independence, and quality of life. The purpose of this investigation is to examine the effects of long term exercise on reversing musculoskeletal-related side effects, and cardiovascular and diabetes risk factors in men receiving androgen deprivation for their prostate cancer. Specifically, we aim to investigate the effects of a 12-month exercise program designed to load the musculoskeletal system and reduce cardiovascular and diabetes disease progression on the following primary endpoints: 1) bone mineral density; 2) cardiorespiratory function and maximal oxygen capacity; 3) body composition (lean mass and fat mass); 4) blood pressure and cardiovascular function; 5) lipids and glycemic control; and 6) quality of life and psychological distress.Methods/DesignMulti-site randomized controlled trial of 195 men (65 subjects per arm) undergoing treatment for prostate cancer involving ADT in the cities of Perth and Brisbane in Australia. Participants will be randomized to (1) resistance/impact loading exercise, (2) resistance/cardiovascular exercise groups and (3) usual care/delayed exercise. Participants will then undergo progressive training for 12 months. Measurements for primary and secondary endpoints will take place at baseline, 6 and 12 months (end of the intervention).DiscussionThe principal outcome of this project will be the determination of the strength of effect of exercise on the well established musculoskeletal, cardiovascular and insulin metabolism side effects of androgen deprivation in prostate cancer patients. As this project is much longer term than previous investigations in the area of exercise and cancer, we will gain knowledge as to the continuing effects of exercise in this patient population specifically targeting bone density, cardiovascular function, lean and fat mass, physical function and falls risk as primary study endpoints. In terms of advancement of prostate cancer care, we expect dissemination of the knowledge gained from this project to reduce fracture risk, improve physical and functional ability, quality of life and ultimately survival rate in this population.Clinical Trial RegistryA Phase III clinical trial of exercise modalities on treatment side-effects in men receiving therapy for prostate cancer; ACTRN12609000200280

Effects of Gradient Variations on Physiological Responses to a 30-minute Run

This study investigated whether variations in gradient would affect the magnitude of physiological responses during a 30-minute run at an intensity of 70% of maximal oxygen capacity ( O 2max ). Forty untrained collegiate men were randomly assigned into 0%, −5%, −11% and −16% groups ( n = 10 per group), and then performed a 30-minute run at gradients of 0%, −5%, −11%and −16%, respectively, at the intensity of 70%of their predetermined O 2max . Oxygen consumption ( O 2 ), minute ventilation ( E ), respiratory exchange ratio (RER), heart rate (HR), and rating of perceived exertion (RPE) were measured at 5, 10, 15, 20, 25 and 30 minutes, respectively, during each run. Blood lactate (LA) concentration was assessed by fingertip blood sample at 3 minutes after each run. The results showed that elevations in O 2 , E , RER and HR during running for the −11% and −16% groups were greater ( p < 0.05) than for the −5% and 0% groups. For the −11% group, elevations of these measures were greater ( p < 0.05) than those of these measures for the −5% group. However, the changes in these measures showed no significant difference ( p > 0.05) between the 0% and −5% groups, or between the −11% and −16% groups. As for RPE and LA, no significant differences ( p > 0.05) among the groups were observed. It is concluded that the steeper the gradient, the greater the increases in O 2 , E , RER and HR. This may be due to the fact that at a steeper downhill gradient (−16%), the quadriceps femoris muscle lengthens to a greater extent than at lower (−5%, −11%) and level gradients.

The Effects of Growth Hormone and/or Testosterone on Whole Body Protein Kinetics and Skeletal Muscle Gene Expression in Healthy Elderly Men: A Randomized Controlled Trial

Alterations of protein turnover may contribute to the progressive decline of muscle mass with aging. Our objective was to examine the effects of near-physiological recombinant human GH and/or testosterone (T) administration to older men on whole body protein kinetics and muscle gene expression. A 6-month randomized, double-blind, placebo-controlled trial in 21 healthy elderly men aged 65-75 yr, was performed. Participants were randomized to receive placebo GH and placebo T, rhGH and placebo T (GH), T and placebo GH (T), or rhGH and T (GHT). The leucine rate of appearance (index of proteolysis), nonoxidative leucine disposal rate (an index of protein synthesis), and leucine oxidation rate were measured with an infusion of l-[1-(13)C] leucine. Muscle biopsies for the measurement of gene expression were performed. Body composition and aerobic capacity (maximal oxygen capacity) were measured. Serum IGF-I levels increased significantly with GH and GHT (P < 0.001) compared with placebo. T increased significantly only in the T group (P = 0.028). Leucine rate of appearance and nonoxidative leucine disposal rate increased with GH (P = 0.015, P = 0.019) and GHT (P = 0.017, P = 0.02), but leucine oxidation did not change significantly in any treatment group. Midthigh muscle mass and maximal oxygen capacity increased (P < 0.04) with GHT only. Expression of muscle function genes did not change significantly, but the within-group comparisons revealed a significant increase of androgen receptor expression in the GHT group (P = 0.001). This study showed that 6-month treatment with low-dose GH alone or with T in healthy elderly men produces comparable increments in whole body protein turnover and protein synthesis.

Aerobic Capacity of Elderly People after a Short 6-week Intermittent Exercise Programme

Background: One of the most debilitating effects of advancing age is the progressive decline in aerobic exercise capacity. To prevent this decrease, exercise prescription has been proved to be effective in compensating for the age-associated decline in maximal oxygen capacity.&#x0D; &#x0D; Methods: 27 healthy sedentary elderly men (10) and women (17) aged 67±7 yr, were involved in a tailored 6-week intermittent exercise programme, with 30 min cycling per session, 3 times a week. One session alternated 4 min at a workload corresponding to the ventilatory threshold (called “bases”) and 1 min to a charge corresponding to 90% of the maximum tolerated power of the subjects (called “peaks”). This was repeated 6 times during one session. To determine these charges, all subjects underwent a 1-minute-step maximal incremental exercise test to find out their maximal tolerated power, peak oxygen consumption (VO2peak), maximal heart rate, and maximal lactate. A second maximal incremental exercise test was performed after the programme, to compare the different parameters.&#x0D; &#x0D; Results: For the whole group, maximal tolerated power increased from 113±8 watts to 13±9 watts (P &lt; 0.001), VO2 peak increased from 19.8±0.9 ml·kg-1·min-1 to 22.2 ±0.9 ml·kg-1·min-1 (P=0.002), maximal heart rate (143±4 vs 144±4 beats·min-1) and maximal lactate (5.4±0.3 vs 5.7±0.3 mmol·L-1) did not change. VO2 at ventilatory threshold increased from 950±57 ml·min-1 to 1095±69 ml·min-1 (P=0.007), and the corresponding power increased from 65±5 watts to 82±6 watts (P &lt; 0.001).&#x0D; &#x0D; Conclusions: Even after a short time training programme (6 weeks), we observed a significant improvement in aerobic capacity, and especially in sub-maximal workloads, which represented, for these subjects, their daily-life capacity.

Influences of Intermittent Anaerobic Exercise Program on Physical Fitness and Plasma Lactate, Oxidant and Anti-oxidant Status in Smokers and Non-smokers Judo Players.

Background: There is evidence of smoking’s negative impact and physical activity’s positive impact on long-term health. However, evidences regarding the association between smoking and exercise activity and the independent effects of these factors on antioxidant defense are lacking. The aim of this study is to investigate the association between smoking and the intermittent anaerobic exercise on the physical fitness, oxidant and antioxidant status in Judo player. Methods: Twenty male Judo player student from Department of Physical Education Al- Azhar University were enrolled in the study. They were of 2 groups, Non-smokers (NS) and smokers (SM). Both groups were subjected to regular Judo training program (2 hours/day, 3 sessions/week for 12 weeks). Also, both groups were subjected to an effort test (running of submaximal intensity until exhaustion ) and record of the maximum oxygen capacity (VO2max) using an ergometric bicycle. Heart rate (HR), mean arterial blood pressure (MBP) were recorded and blood samples were taken pre and post-effort test for determination of malondialdehyde (MDA),total antioxidant capacity (TAC), uric acid (Ua) and lactate (La) in the plasma. Also the time to exhaustion was recorded during the effort test. These measures were performed pre and post the training program. Results: At rest the pre-program data of SM showed significantly higher H.R., and plasma MDA ,and significantly lower TAC with tendency to increase in MBP and La levels, and decrease in VO2max, and Ua levels compared to NS. Before program and in response to acute exercise SM showed significantly higher H.R, MDA and La levels with significantly lower TAC, Ua and time to exhaustion compared to NS. On the other hand, after the program and in response to acute exercise, SM showed more pronounced significantly higher HR, MBP, MDA and La with significantly lower VO2max, time to exhaustion and TAC with insignificant changes in the Ua compared to the NS that showed significant increase in the Ua levels with insignificant changes in the MDA, TAC and the La levels in response to acute exercise. In response to the training program, SM showed significantly higher HR, MBP, MDA and La levels, with significantly lower VO2max, time to exhaustion, and TAC, and insignificant changes in the Ua levels compared to NS. Conclusion: We conclude that cigarette smoking has a significant detrimental effects on cardiovascular fitness, physical endurance, TAC and lipid peroxidation that all worsened by the intermittent anaerobic exercise. On the contrary , this type of training is beneficial in nonsmokers. Also we demonstrated that smoking prevent the beneficial effects of exercise , so smoking should be avoided in Judo players. Smokers should be given strong encouragement to stop smoking and to improve physical fitness.

Influences of Intermittent Anaerobic Exercise Program on Physical Fitness and Plasma Lactate, Oxidant and Anti-oxidant Status in Smokers and Non-smokers Judo Players.

Background: There is evidence of smoking’s negative impact and physical activity’s positive impact on long-term health. However, evidences regarding the association between smoking and exercise activity and the independent effects of these factors on antioxidant defense are lacking. The aim of this study is to investigate the association between smoking and the intermittent anaerobic exercise on the physical fitness, oxidant and antioxidant status in Judo player. Methods: Twenty male Judo player student from Department of Physical Education Al- Azhar University were enrolled in the study. They were of 2 groups, Non-smokers (NS) and smokers (SM). Both groups were subjected to regular Judo training program (2 hours/day, 3 sessions/week for 12 weeks). Also, both groups were subjected to an effort test (running of submaximal intensity until exhaustion ) and record of the maximum oxygen capacity (VO2max) using an ergometric bicycle. Heart rate (HR), mean arterial blood pressure (MBP) were recorded and blood samples were taken pre and post-effort test for determination of malondialdehyde (MDA),total antioxidant capacity (TAC), uric acid (Ua) and lactate (La) in the plasma. Also the time to exhaustion was recorded during the effort test. These measures were performed pre and post the training program. Results: At rest the pre-program data of SM showed significantly higher H.R., and plasma MDA ,and significantly lower TAC with tendency to increase in MBP and La levels, and decrease in VO2max, and Ua levels compared to NS. Before program and in response to acute exercise SM showed significantly higher H.R, MDA and La levels with significantly lower TAC, Ua and time to exhaustion compared to NS. On the other hand, after the program and in response to acute exercise, SM showed more pronounced significantly higher HR, MBP, MDA and La with significantly lower VO2max, time to exhaustion and TAC with insignificant changes in the Ua compared to the NS that showed significant increase in the Ua levels with insignificant changes in the MDA, TAC and the La levels in response to acute exercise. In response to the training program, SM showed significantly higher HR, MBP, MDA and La levels, with significantly lower VO2max, time to exhaustion, and TAC, and insignificant changes in the Ua levels compared to NS. Conclusion: We conclude that cigarette smoking has a significant detrimental effects on cardiovascular fitness, physical endurance, TAC and lipid peroxidation that all worsened by the intermittent anaerobic exercise. On the contrary , this type of training is beneficial in nonsmokers. Also we demonstrated that smoking prevent the beneficial effects of exercise , so smoking should be avoided in Judo players. Smokers should be given strong encouragement to stop smoking and to improve physical fitness.

Highlights from the Literature

Highlights from the Literature

Improving physical fitness and emotional well-being in adolescents of low socioeconomic status in Chile: results of a school-based controlled trial

Regular physical activity is associated with a reduced risk of all-cause mortality, and mortality due to cardiovascular disease and cancer. Among adolescents, physical activity is associated with benefits in the prevention and control of emotional distress, and improvement of self-esteem. Countries in transitional epidemiological scenarios, such as Chile, need to develop effective strategies to improve physical activity as a way to face the epidemic of chronic diseases. The objective of this study was to evaluate the effects of a school-based physical activity program on physical fitness and mental health status of adolescents living in a low socioeconomic status area in Santiago, Chile. A quasi-experimental design was used to evaluate the effects of the program over one academic year. The study included 198 students aged 15 years old. Two ninth grade classes were randomly selected as the intervention group, with two classes of the same grade as controls. A social planning approach was used to develop the intervention. The program was designed and implemented based on student preferences, teachers' expertise and local resources. Changes in physiological and mental health status were assessed. After the intervention, maximum oxygen capacity achieved a significant increase of 8.5% in the intervention versus 1.8% in the control group (p < 0.0001). Speed and jump performance scores improved significantly more in the intervention versus the control group (p > 0.01). Anxiety score decreased 13.7% in the intervention group versus 2.8% in the control group (p < 0.01), and self-esteem score increased 2.3% in the intervention group and decreased 0.1% in the control group after the end of the program (p < 0.0001). No significant change was observed in the depressive score. Student participation and compliance with the program was > 80%. To conclude, a school-based program to improve physical activity in adolescents of low socioeconomic status, obtained a high level of participation and achieved significant benefits in terms of physical fitness and mental health status.

Prevailing hyperglycemia is critical in the regulation of glucose metabolism during exercise in poorly controlled alloxan-diabetic dogs

The separate impacts of the chronic diabetic state and the prevailing hyperglycemia on plasma substrates and hormones, in vivo glucose turnover, and ex vivo skeletal muscle (SkM) during exercise were examined in the same six dogs before alloxan-induced diabetes (prealloxan) and after 4-5 wk of poorly controlled hyperglycemic diabetes (HGD) in the absence and presence of approximately 300-min phlorizin-induced (glycosuria mediated) normoglycemia (NGD). For each treatment state, the approximately 15-h-fasted dog underwent a primed continuous 150-min infusion of [3-(3)H]glucose, followed by a 30-min treadmill exercise test (approximately 65% maximal oxygen capacity), with SkM biopsies taken from the thigh (vastus lateralis) before and after exercise. In the HGD and NGD states, preexercise hepatic glucose production rose by 130 and 160%, and the metabolic clearance rate of glucose (MCRg) fell by 70 and 37%, respectively, compared with the corresponding prealloxan state, but the rates of glucose uptake into peripheral tissues (Rd(tissue)) and total glycolysis (GF) were unchanged, despite an increased availability of plasma free fatty acid in the NGD state. Exercise-induced increments in hepatic glucose production, Rd(tissue), and plasma-derived GF were severely blunted by approximately 30-50% in the NGD state, but increments in MCRg remained markedly reduced by approximately 70-75% in both diabetic states. SkM intracellular glucose concentrations were significantly elevated only in the HGD state. Although Rd(tissue) during exercise in the diabetic states correlated positively with preexercise plasma glucose and insulin and GF and negatively with preexercise plasma free fatty acid, stepwise regression analysis revealed that an individual's preexercise glucose and GF accounted for 88% of Rd(tissue) during exercise. In conclusion, the prevailing hyperglycemia in poorly controlled diabetes is critical in maintaining a sufficient supply of plasma glucose for SkM glucose uptake during exercise. During phlorizin-induced NGD, increments in both Rd(tissue) and GF are impaired due to a diminished fuel supply from plasma glucose and a sustained reduction in increments of MCRg.

Skeletal muscle basal AMP-activated protein kinase activity is chronically elevated in alloxan-diabetic dogs: impact of exercise.

The effect of diabetes and exercise on skeletal muscle (SkM) AMP-activated protein kinase (AMPK)alpha1 and -alpha2 activities and site-specific phosphorylation of acetyl-CoA carboxylase was examined in the same six dogs before alloxan (35 mg/kg)-induced diabetes (C) and after 4-5 wk of suboptimally controlled hyperglycemic and hypoinsulinemic diabetes (DHG) in the presence and absence of 300-min phlorizin (50 microg.kg-1.min-1)-induced "normoglycemia" (DNG). In each study, the dog underwent a 150-min [3-3H]glucose infusion period, followed by a 30-min treadmill exercise test (60-70% maximal oxygen capacity) to measure the rate of glucose disposal into peripheral tissues (Rdtissue). SkM biopsies were taken from the thigh (vastus lateralis) before and immediately after exercise. In the C and DHG states, the rise in plasma free fatty acids (FFA) with exercise ( approximately 40%) was similar. In the DNG group, preexercise FFA were significantly higher, but the absolute rise in FFA with exercise was similar. However, the exercise-induced increment in Rdtissue was significantly blunted (by approximately 40-50%) in the DNG group compared with the other states. In SkM, preexercise AMPKalpha1 and -alpha2 activities were significantly elevated (by approximately 60-125%) in both diabetic states, but unlike the C group these activities did not rise further with exercise. Additionally, preexercise acetyl-CoA carboxylase phosphorylation in both diabetic states was elevated by approximately 70-80%, but the increases with exercise were similar to the C group. Preexercise AMPKalpha1 and -alpha2 activities were negatively correlated with Rdtissue during exercise for the combined groups (both P < 0.02). In conclusion, the elevated preexercise SkM AMPKalpha1 and -alpha2 activities contribute to the ongoing basal supply of glucose and fatty acid metabolism in suboptimally controlled hypoinsulinemic diabetic dogs; but whether they also play a permissive role in the metabolic stress response to exercise remains uncertain.

Association between obesity and a polymorphism in the beta(1)-adrenoceptor gene (Gly389Arg ADRB1) in Caucasian women.

Genetic variants affecting adrenoceptors have been suggested to influence body fatness. A putative gain-of-function polymorphism in the beta(1)-adrenoceptor was recently discovered (Gly389Arg ADRB1). We examined the association between Gly389Arg ADRB1 and obesity status in a large cohort of well-characterized individuals. First, a large cohort of 931 Caucasian women (55.0+/-12.2 y) were genotyped for Gly389Arg ADRBbeta1 and we examined the association of the Arg allele with body weight and BMI (Gly/Gly, n=54; Gly/Arg, n=360; Arg/Arg, n=517). To further examine phenotypes regulating energy balance and body fatness, we examined the contribution of the Arg allele to body composition (DEXA), fat distribution (CT scan), resting energy expenditure, energy and macronutrient intake, maximal oxygen capacity, and physical activity in a subsample of 214 women from the main cohort that had been carefully characterized (Gly/Gly, n=19; Gly/Arg, n=82; Arg/Arg, n=113). In the entire cohort (n=931), allele frequencies were 0.25 and 0.75 for the Gly and Arg alleles, respectively. In this cohort, we found that each Arg allele was associated with greater body weight of 2.91 kg (P=0.01) and BMI of 0.86 kg/m(2) (P=0.05). Accordingly, in the subsample of women, each Arg allele was associated with greater fat mass (3.71 kg; P=0.008). Other phenotypes were not significantly associated with the presence of the Arg allele. This is the first study to investigate the relationship between the Gly389Arg ADRB1 variant and obesity. We found that the Arg allele is associated with greater body weight and BMI in Caucasian women due to a greater fat mass.

Physiological Profile of an Elite Freestyle Wrestler Preparing for Competition

The purpose of the present investigation was to describe the physiological changes of a nationally ranked older elite freestyle wrestler during a 7-month observation period as he prepared for the 2000 Olympic freestyle wrestling trials. A 33-year-old male wrestler was evaluated 3 times during the study for measurements of body composition, resting energy expenditure, maximal oxygen consumption, isometric strength, anaerobic power and capacity, nutritional intake, and various serum plasma constituents. Body weight decreased by 1 kg, which consisted of fat-free mass (FFM), whereas body fat remained stable at 5.8%. Muscular strength and aerobic power were maintained throughout the study. Measures of anaerobic work capacity tended to be higher and blood lactate lower as the subject progressed throughout the investigation. All serum plasma constituents were within clinically normal ranges and remained relatively stable. Despite a small loss of FFM, the subject was able to maintain muscular strength and aerobic fitness while concomitantly enhancing anaerobic capacity and power capabilities throughout the study period as he prepared for the 2000 Olympic freestyle wrestling trials.

Physiological Profile of an Elite Freestyle Wrestler Preparing for Competition

The purpose of the present investigation was to describe the physiological changes of a nationally ranked older elite freestyle wrestler during a 7-month observation period as he prepared for the 2000 Olympic freestyle wrestling trials. A 33-year-old male wrestler was evaluated 3 times during the study for measurements of body composition, resting energy expenditure, maximal oxygen consumption, isometric strength, anaerobic power and capacity, nutritional intake, and various serum plasma constituents. Body weight decreased by 1 kg, which consisted of fat-free mass (FFM), whereas body fat remained stable at 5.8%. Muscular strength and aerobic power were maintained throughout the study. Measures of anaerobic work capacity tended to be higher and blood lactate lower as the subject progressed throughout the investigation. All serum plasma constituents were within clinically normal ranges and remained relatively stable. Despite a small loss of FFM, the subject was able to maintain muscular strength and aerobic fitness while concomitantly enhancing anaerobic capacity and power capabilities throughout the study period as he prepared for the 2000 Olympic freestyle wrestling trials.

Physiological Profile of an Elite Freestyle Wrestler Preparing for Competition: A Case Study

The purpose of the present investigation was to describe the physiological changes of a nationally ranked older elite freestyle wrestler during a 7-month observation period as he prepared for the 2000 Olympic freestyle wrestling trials. A 33-year-old male wrestler was evaluated 3 times during the study for measurements of body composition, resting energy expenditure, maximal oxygen consumption, isometric strength, anaerobic power and capacity, nutritional intake, and various serum plasma constituents. Body weight decreased by 1 kg, which consisted of fat-free mass (FFM), whereas body fat remained stable at 5.8%. Muscular strength and aerobic power were maintained throughout the study. Measures of anaerobic work capacity tended to be higher and blood lactate lower as the subject progressed throughout the investigation. All serum plasma constituents were within clinically normal ranges and remained relatively stable. Despite a small loss of FFM, the subject was able to maintain muscular strength and aerobic fitness while concomitantly enhancing anaerobic capacity and power capabilities throughout the study period as he prepared for the 2000 Olympic freestyle wrestling trials.

Predictability of Oxygen Desaturation During Sleep in Patients With Cystic Fibrosis: Clinical, Spirometric, and Exercise Parameters

The purpose of this study was to determine how common sleep-related desaturation with preserved awake resting pulse oximetric saturation (SpO(2)) was in a large cohort of adult cystic fibrosis (CF) patients with variable degrees of pulmonary disease. We then determined whether nocturnal desaturation could reliably be predicted from standard clinical and exercise parameters. Seventy CF patients participated in the study (mean [SD] age, 27.3 [8.7] years; women, 54%; percent predicted FEV(1) [%predFEV(1)], 55.7% [23.9%]). Nocturnal, resting, and exercise SpO(2) were measured. Nocturnal oximetry was measured in the patient's home. Maximal oxygen capacity (Vo(2)max) was determined from a graded exercise test on a stationary bicycle ergometer. The Shwachman-Kulczycki (S-K) illness severity score was calculated incorporating categories of functional capacity, physical examination, nutrition, and chest radiograph. Multivariate analysis reported significant differences (p < 0.0001) between pulmonary disease severity and overall distribution of nocturnal SpO(2), with the main difference being for patients with severe pulmonary disease (%predFEV(1) of < 50%) compared to patients with mild or moderate disease in the SpO(2) intervals of 100 to 96% (p < 0.0001) and 90 to 86% (p = 0.0001). Pulmonary function, S-K clinical scores, f1.gif" BORDER="0">O(2)max, and resting and maximal SpO(2) correlated significantly (p < 0.05) with nocturnal SpO(2) levels. Stepwise discriminant analysis identified %predFEV(1) (or S-K scores) and resting SpO(2) as the parameters that could best discriminate patients not likely to experience nocturnal desaturation. Specifically, our equation could predict 91% of cases less likely to nocturnally desaturate, but could only modestly predict those more likely to desaturate (i.e., 26% of cases). Spirometric parameters and measurements of awake resting oxygenation are of limited utility in predicting nocturnal desaturation. Nocturnal oximetry should be considered in patients with moderate to severe lung disease even with preserved awake resting SpO(2).

Caffeine and exercise: metabolism, endurance and performance.

Caffeine is a common substance in the diets of most athletes and it is now appearing in many new products, including energy drinks, sport gels, alcoholic beverages and diet aids. It can be a powerful ergogenic aid at levels that are considerably lower than the acceptable limit of the International Olympic Committee and could be beneficial in training and in competition. Caffeine does not improve maximal oxygen capacity directly, but could permit the athlete to train at a greater power output and/or to train longer. It has also been shown to increase speed and/or power output in simulated race conditions. These effects have been found in activities that last as little as 60 seconds or as long as 2 hours. There is less information about the effects of caffeine on strength; however, recent work suggests no effect on maximal ability, but enhanced endurance or resistance to fatigue. There is no evidence that caffeine ingestion before exercise leads to dehydration, ion imbalance, or any other adverse effects. The ingestion of caffeine as coffee appears to be ineffective compared to doping with pure caffeine. Related compounds such as theophylline are also potent ergogenic aids. Caffeine may act synergistically with other drugs including ephedrine and anti-inflammatory agents. It appears that male and female athletes have similar caffeine pharmacokinetics, i.e., for a given dose of caffeine, the time course and absolute plasma concentrations of caffeine and its metabolites are the same. In addition, exercise or dehydration does not affect caffeine pharmacokinetics. The limited information available suggests that caffeine non-users and users respond similarly and that withdrawal from caffeine may not be important. The mechanism(s) by which caffeine elicits its ergogenic effects are unknown, but the popular theory that it enhances fat oxidation and spares muscle glycogen has very little support and is an incomplete explanation at best. Caffeine may work, in part, by creating a more favourable intracellular ionic environment in active muscle. This could facilitate force production by each motor unit.

Maximal oxygen uptake, muscle strength and walking speed in 85-year-old women: effects of increased physical activity.

This study explores the effect of regular training on blood pressure, maximal oxygen uptake, maximal isometric muscle strength, and walking speed in the very old. A total of 55 community-dwelling women, 85-year-old, were enrolled in a training group (N = 22) or a control group (N = 33). These groups were reduced to 19 and 26 subjects, respectively, after the training period. Training was performed once a week over eight months, and consisted of various exercises with particular attention to movements important for everyday activities. Training reduced diastolic blood pressure (p < 0.05), and showed a similar trend for systolic blood pressure. Measurements of maximal oxygen uptake before the start of the training (15 mL min-1 kg-1) revealed a level close to the presumed limit for independent living (13 mL min-1 kg-1). Training improved VO2 max by 18% (p < 0.05), whereas the control group experienced a trend towards a reduction. Maximal isometric muscle strength of both the right and left leg showed a tendency to increase with training, but no significant changes were evident in the trunk flexor and extensor muscles. The training group showed a significant increase of 17% in maximal walking speed after the training period. However, one year later, without training, this improvement was reduced to 8% (p < 0.05). No major changes were observed in the control group for any of these parameters. This study demonstrates a maximal oxygen capacity in very old community-dwelling women close to a threshold level indicating dependency. Furthermore, 8 months of regular training appears to lower blood pressure, and to increase maximal oxygen uptake and maximal walking speed. This suggests that physical reactivation of the very old may reduce the risk for acquiring age-related diseases associated with an elevated blood pressure, and may improve parameters crucial for independence.

The effects of exercise on iron status and aerobic capacity in moderately exercising adult women

The purpose of this study was to examine the effects of a 10-week moderate exercise on iron status and aerobic capacity of adult women. Seventeen women, 56- to 67-years, served either as controls (no exercise, n = 9) or participated in a supervised exercise program (n = 8). Women in the exercise group cycled on an ergometer three days per week, for 40 minutes at 70 to 75% maximal heart rate for 10 weeks. Pre- and post- (weeks 0 and 11) submaximal treadmill stress tests were obtained. Aerobic capacity was evaluated by heart rate per grade, maximum oxygen capacity, and time to reach 70% maximum heart rate. The results indicated that average heart rate per grade decreased and time to reach 70% max heart rate increased in the exercise group (p < .05) after 10 weeks of moderate exercise training. Iron status as determined by serum ferritin, transferrin saturation, serum iron, total iron binding capacity, hemoglobin and hematocrit was normal and comparable between both groups. Hemoglobin increased (p < .05) after 10 weeks of supervised moderate exercise. The results suggest that 10 weeks of moderate exercise enhances aerobic capacity of older women but does not compromise iron status.

Adaptations of immature trabecular bone to exercise and augmented dietary protein

Exercise and diet synergistically influence bone, but it remains unclear whether augmenting dietary protein intake during moderate exercise has a beneficial or negative effect on immature bone mechanical integrity. Thus, we examined lumbar vertebral bodies (L6) and femoral necks (FN) in trained and untrained rats fed either a recommended protein (15%) or higher protein (30%) diet. Male Wistar rats (8 wk old) were assigned to one of two exercise groups (high protein exercise [HPE], recommended protein exercise [RPE], run 3 d.wk-1 on a motor-driven treadmill at approximately 80% of their maximum oxygen capacity) or to one of two sedentary caged-control groups (high protein control [HPC], recommended protein control [RPC]. After 8 wk, in the HPE group, FN maximum normal stress was significantly greater than all other groups, and FN maximum load and energy at maximum load (per unit body mass) were significantly greater than the sedentary control groups. L6 stress at the proportional limit and initial-maximum stress did not differ among groups, but L6 percent ash was significantly greater in the HPE and RPC groups. Thus, coupling high dietary protein with moderate exercise can produce positive effects on immature rat femoral neck mechanical properties and structure.

Hormonal Ergogenic Aids

Most hormonal agents used for nonmedical purposes in athletes have legitimate medical uses. This review introduces each compound by its pharmacology, clinical pharmacology, and legitimate medical use and reviews information on its abuse. Human growth hormone is presently available in virtually unlimited quantities due to its production by recombinant DNA technology. Its use in athletes is considered for its muscle-building, fat-depleting properties. Erythropoietin is a kidney hormone that increases red cell mass. It is used for renal dialysis patients to avoid blood transfusions. Its use in athletes is to raise red blood cell mass in an attempt to augment maximal oxygen capacity and the ability to do endurance work. Human chorionic gonadotropin has the biological activity of luteinizing hormone to increase testosterone synthesis and to maintain (partially) testicular volume when exogenous androgens are taken. Clenbuterol is a beta2adrenergic agonist with muscle-building properties that are seemingly specific to striated muscle; clenbuterol may cause reduction in body fat.