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Medical clearance for vigorous exercise. Clinical evaluation and exercise testing.

The practitioner plays an important role in providing guidance for exercise. Physical activity is one component of a life-style aimed at enhancing the health of the individual. When entered into with appropriate understanding and with reasonable expectations and goals, exercise can also be a major source of enjoyment. The role of the practitioner is to guide the patient to an appropriate level and intensity of exercise carried out in a suitable setting. In identifying the health habits and risk factors of the patient seeking clearance for an exercise program, physicians can do more than simply address the exercise issue. They can seize the opportunity to take a broader look at the patient's entire cardiovascular status and guide the patient into a generally beneficial program of health enhancement.

Coronary Disease↗

Effect of chromium supplementation and exercise on body composition, resting metabolic rate and selected biochemical parameters in moderately obese women following an exercise program.

OBJECTIVE: To investigate the effect of chromium picolinate (CP) supplementation on body composition, resting metabolic rate (RMR), selected biochemical parameters and iron and zinc status in moderately obese women participating in a 12-week exercise program. METHODS: Forty-four women, 27 to 51 years of age, were randomly assigned to two groups based on their body mass index. Subjects received either 400 microg/day of chromium as a CP supplement or a placebo in double-blind fashion and participated in a supervised weight-training and walking program two days per week for 12 weeks. Body composition and RMR were measured at baseline, 6 and 12 weeks. Selected biochemical parameters and iron and zinc status were measured at baseline and 12 weeks. RESULTS: Body composition and RMR were not significantly changed by CP supplementation. No significant differences in fasting plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or in iron and zinc indices were found between the two groups over time. Serum total cholesterol concentration significantly decreased (p = 0.0016) over time for all subjects combined, probably as a result of the exercise training. Exercise training significantly reduced total iron binding capacity (TIBC) by 3% for all subjects combined (p = 0.001 1). CONCLUSIONS: Twelve weeks of 400 microg/day of chromium as a CP supplement did not significantly affect body composition, RMR, plasma glucose, serum insulin, plasma glucagon, serum C-peptide and serum lipid concentrations or iron and zinc indices in moderately obese women placed on an exercise program. The changes in serum total cholesterol levels and TIBC were a result of the exercise program.

Adult↗

A comparative study of the maximum oxygen uptake of regularly exercising and non-exercising health adult men in sedentary occupations.

This study aims to assess and compare the aerobic fitness (max VO2) of 210 healthy adult men in sedentary occupations in Singapore. All the subjects studied were in codes 0 to 2 of the Singapore Standard Occupational Classification, comprising professional, technical, administrative and related workers. Their max VO2 were determined from direct analyses of their expired respiratory gases during an all-out run on a treadmill. Of these 210 men, 71 (33.8 per cent) were recreation-related regular exercisers and their mean max VO2 of 40.9 ml/kg per min STPD (at standard temperature and pressure, dry) and 95 per cent confidence interval of 39.2-42.6 ml/kg per min was significantly higher (p less than 0.001) than that of the remaining 139 men (34.3 ml/kg per min STPD) with 95 per cent confidence intervals of 33.2-35.4 ml/kg per min who were not regular exercisers. The regular exercisers also met the max VO2 requirements for heavy physical work capacity and compared favourably with the recommended standards for aerobic fitness in the National Physical Fitness Award of Singapore as well as Cooper's Standards based on North American men while the non-regular exercisers did not. The study has shown that the recreation-related regular exercise of the study-defined type, intensity, duration and frequency can significantly improve the physical work capacity of healthy adult men in sedentary occupations in Singapore.

Adult↗

Peak exercise hemodynamics in exercising postmenopausal women taking versus not taking supplemental estrogen.

The purpose of this study was to determine whether supplemental estrogen influences cardiovascular hemodynamics at peak exercise in endurance trained and sedentary postmenopausal women. Subjects were 22 women between 3 and 10 yr past menopause who had engaged in endurance exercise at least three times per week for one or more years. Twelve of the women had taken estrogen replacement for at least 1 yr (ER) while the other 10 had never taken supplemental estrogen (NOER). Peak cardiac output (Qpeak) and, subsequently, peak cardiac index (QIpeak) were calculated by regressing submaximal cardiac output values on corresponding oxygen consumptions and extrapolating to peak exercise. Peak oxygen consumption in the two groups were almost identical; however, the ER group demonstrated a higher QIpeak in conjunction with a lower arteriovenous oxygen difference and a lower peripheral resistance. It was concluded that estrogen supplementation may be associated with higher peak cardiac outputs in exercise trained postmenopausal women via alterations in the peripheral vascular and oxygen kinetic responses to maximal exercise.

Cardiac Output↗

Effects of cardiac rehabilitation and exercise programs on exercise capacity, coronary risk factors, behavior, and quality of life in patients with coronary artery disease.

Previous studies have indicated the benefits of cardiac rehabilitation programs after major coronary artery disease (CAD) events. We studied 591 consecutive patients from two academic institutions before and after completion of a cardiac rehabilitation and exercise training program to determine the effects of this therapy on exercise capacity, indices of obesity, plasma lipid values, behavioral characteristics, and quality of life parameters. After cardiac rehabilitation, statistically significant improvements occurred in exercise capacity (+33%), percent body fat (-6%), body mass index (-1%), HDL-C (+5%), triglycerides (-9%), LDL-C/HDL-C (-6%), anxiety score (-39%), depression score (-35%), somatization score (-37%), and in all parameters of quality of life studied (total +14%). These data further support the ability of cardiac rehabilitation and exercise training programs to improve exercise capacity, plasma lipid values, obesity indices, behavioral characteristics, and quality of life parameters in a large cohort of patients who have had major CAD events.

Aged↗

Exercise intensity increased by addition of handheld weights to rebounding exercise.

PURPOSE: Researchers who studied the effects of rebound exercise on fitness have concluded that the intensity of rebound exercise elicited only minimal improvements in fitness. This study determined how the addition of arm pumping with handheld weights (HHW) would increase exercise intensity while rebounding. METHODS: Fifteen male subjects (20 to 43 years) ran in place on a mini-trampoline at a stride frequency of 120 foot strikes per minute, with the sole of the foot 15 cm above the rebounder rim. Oxygen uptake (VO2) and heart rate (HR) were measured while rebounding alone, and also while pumping 0.45 kg, 0.91 kg, and 1.36 kg HHW to heights of 61 and 91 cm. RESULTS: All combinations of weights and pumping levels resulted in significantly (P < .05) higher VO2 and HR than rebounding alone. The estimated mean increase in VO2 was 3.2 mL/kg/min when the weight was increased from 0.91 kg to 1.36 kg at the 91 cm pumping height. The corresponding HR increase was 10.1 bpm. Similarly, when 1.36 kg weights were pumped at 91 cm instead of 61 cm, the mean increase in VO2 and HR was 6.2 mL/kg/min and 11.4 bpm, respectively. CONCLUSIONS: The addition of HHW exercise to rebounding substantially increases exercise intensity. Because rebounding without weights results in a relatively low intensity, the addition of HHW should be considered in the use of rebounding for cardiovascular training.

Adult↗

The effects of the modified intermittent sequential pneumatic device (MISPD) on exercise performance following an exhaustive exercise bout.

The Lymphapress, a pneumatic sequential intermittent device is recognized as one of the most effective conservative treatments for lymphoedema, due to its effective 'milking mechanism'. This led us to hypothesize that accelerated removal of fatigue-causing metabolites by mechanical massage could improve an athlete's performance capacity. We conducted trials with 11 men who exercised at a constant workload, on a cycle ergometer, until exhaustion. During a 20-min recovery period a new modified pneumatic sequential intermittent device (the MISPD) was applied to the subjects' legs. The men then performed a second constant load exercise bout. Cardiorespiratory parameters were measured during exercise and blood was withdrawn during recovery for the determination of lactate, pyruvate, ammonia, bicarbonate and pH. No difference was found in the blood levels of the 'fatigue causing metabolites' during passive recovery (PR) and recovery with the MISPD (MR). However, the MISPD effected a 45% improvement in the subjects' ability to perform the subsequent exercise bout. The accumulation of fluid in the interstitial space after exercise and its disappearance after the use of the MISPD offers one possible explanation for these results, although psychological effects cannot be discounted.

Adult↗

Exercise and training in women, Part I: Influence of gender on exercise and training responses.

Exercise and training responses in women are briefly reviewed. Part I of the paper considers the influence of gender on such responses. The average woman has a smaller inherent aerobic power and less muscular strength than a man, reflecting sociocultural influences, physical size, body composition, and hormonal milieu. Nevertheless, the best-trained women can out-perform sedentary men. The handicap of the average woman is offset by a lighter body mass and a tendency to metabolize fat rather than carbohydrate during exercise. A lack of anabolic hormones may limit training increases of muscle bulk in the female. A low initial fitness may enhance the scope for training tolerance, but it also limits tolerance of conditioning. Nevertheless, women seem less vulnerable than men to exercise-induced sudden death and overtraining. Part II of the review considers the influence of the menstrual cycle and pregnancy upon exercise and training responses. Physical activity programmes for young women should take account of possible pregnancy. Potential dangers to the foetus include an excessive rise of core body temperature, a decrease of maternal blood sugar, and foetal hypoxia. Nevertheless, regular moderate exercise generally has a favourable impact upon pregnancy outcomes.

Cardiovascular Physiological Phenomena↗

Glucose ingestion during exercise blunts exercise-induced gene expression of skeletal muscle fat oxidative genes.

Ingestion of carbohydrate during exercise may blunt the stimulation of fat oxidative pathways by raising plasma insulin and glucose concentrations and lowering plasma free fatty acid (FFA) levels, thereby causing a marked shift in substrate oxidation. We investigated the effects of a single 2-h bout of moderate-intensity exercise on the expression of key genes involved in fat and carbohydrate metabolism with or without glucose ingestion in seven healthy untrained men (22.7 +/- 0.6 yr; body mass index: 23.8 +/- 1.0 kg/m(2); maximal O(2) consumption: 3.85 +/- 0.21 l/min). Plasma FFA concentration increased during exercise (P < 0.01) in the fasted state but remained unchanged after glucose ingestion, whereas fat oxidation (indirect calorimetry) was higher in the fasted state vs. glucose feeding (P < 0.05). Except for a significant decrease in the expression of pyruvate dehydrogenase kinase-4 (P < 0.05), glucose ingestion during exercise produced minimal effects on the expression of genes involved in carbohydrate utilization. However, glucose ingestion resulted in a decrease in the expression of genes involved in fatty acid transport and oxidation (CD36, carnitine palmitoyltransferase-1, uncoupling protein 3, and 5'-AMP-activated protein kinase-alpha(2); P < 0.05). In conclusion, glucose ingestion during exercise decreases the expression of genes involved in lipid metabolism rather than increasing genes involved in carbohydrate metabolism.

AMP-Activated Protein Kinases↗

Impact of heart failure and exercise capacity on sympathetic response to handgrip exercise.

Peak oxygen uptake (VO(2 peak)) in patients with heart failure (HF) is inversely related to muscle sympathetic nerve activity (MSNA) at rest. We hypothesized that the MSNA response to handgrip exercise is augmented in HF patients and is greatest in those with low VO(2 peak). We studied 14 HF patients and 10 age-matched normal subjects during isometric [30% of maximal voluntary contraction (MVC)] and isotonic (10%, 30%, and 50% MVC) handgrip exercise that was followed by 2 min of posthandgrip ischemia (PHGI). MSNA was significantly increased during exercise in HF but not normal subjects. Both MSNA and HF levels remained significantly elevated during PHGI after 30% isometric and 50% isotonic handgrip in HF but not normal subjects. HF patients with lower VO(2 peak) (<56% predicted; n = 8) had significantly higher MSNA during rest and exercise than patients with VO(2 peak) > 56% predicted (n = 6) and normal subjects. The muscle metaboreflex contributes to the greater reflex increase in MSNA during ischemic or intense nonischemic exercise in HF. This occurs at a lower threshold than normal and is a function of VO(2 peak).

Blood Pressure↗

Effects of prior exercise on pulmonary gas-exchange kinetics during high-intensity exercise in humans.

The effects of prior exercise on O2 uptake (VO2) kinetics during supra-lactate threshold (LT) cycling were assessed in 11 subjects. Protocols consisted of two consecutive 6-min work bouts separated by 0 W (6 min) with 1) both bouts sub-LT, 2) both bouts supra-LT, 3) bout 1 sub-LT and bout 2 supra-LT, and 4) bout 1 supra-LT and bout 2 sub-LT. Sub-LT VO2 kinetics were similar whether the prior bout was supra- or sub-LT. The VO2 kinetics for supra-LT work preceded by a sub-LT "warm-up" were similar to those for supra-LT work that was not preceded by exercise (O-W warm-up): the "partial": O2 deficit averaged 2.64 vs. 2.57 liters, and the "effective" VO2 time constant averaged 56 vs. 65 s. Exercise responses (i.e., the change between O W and minute 6 of exercise) were unaffected for lactate concentration (4.58 vs. 4.50 meq/l), pH (-0.08 vs. -0.10), and CO2 output (VCO2; 2.65 vs. 2.49 l/min). However, when the supra-LT work was preceded by a supra-LT warm-up, VO2 kinetics were appreciably faster (O2 deficit = 1.82 liters, VO2 time constant = 37 s) relative to 0-W warm-up; the lactate (0.69 meq/l), pH (-0.01), and VCO2 (2.08 l/min) responses were smaller; and the effective VCO2 time constant was longer (58 vs. 43 s). The mechanism(s) that underlie this speeding of the VO2 kinetics cannot be firmly established, but we suggest that an improved muscle perfusion during the exercise may be involved consequent to the residual metabolic acidemia from the high-intensity warm-up.

Acidosis↗

[Positive exercise test and normal exercise myocardial perfusion SPECT. Clinical significance].

OBJECTIVE: To establish, in our area, the clinical significance of a normal exercise myocardial perfusion study, in patients with an ischemic response of the exercise test. MATERIAL AND METHODS: A retrospective study was carried out in our Service for the last four years. We studied 45 patients (41 women and 4 men) with an ischemic response of the exercise test and normal myocardial perfusion SPECT, during a mean follow-up of 13,2 months. We considered the final clinical diagnosis according to clinical evolution, therapy outcome and coronary angiography results. RESULTS: The presence of positive exercise test and normal SPECT was predominant in women (93.3%). In 35 patients (77.8%), the final diagnosis was chest pain of probable non-coronary origin (not secondary to coronary artery disease): 18 patients were diagnosed of hypertensive cardiomyopathy, 3 of valvulopathy, 2 of vasospastic angina, 1 of hypertrophic obstructive cardiomyopathy, 1 of microvascular angina, 1 of angina due to arrhythmia, and 9 patients diagnosed of atypical chest pain due to functional or non-cardiac origin. In 10 patients (22.2%), the final diagnosis was chest pain of probable coronary origin. We did not observe any major cardiac events (cardiac death and nonfatal myocardial infarction) during the follow-up period. CONCLUSIONS: Patients with chest pain, positive exercise test and normal SPECT have an excellent prognosis within an intermediate follow-up period. 77.8% of patients were diagnosed of chest pain of non-coronary origin. The most common cause of non-coronary chest pain was hypertensive cardiomyopathy (51.4%), followed by functional or non-cardiac chest pain (28.6%).

Aged↗

Improved efficiency of treadmill exercise testing using a multiple lead ECG system and basic hemodynamic exercise response.

One hundred consecutive men with a normal ECG at rest had a maximal treadmill test using 14 leads during and post-exercise. Coronary arteriography performed the following day revealed coronary stenoses greater than or equal to 70% in 66 patients. Test results obtained from a V5 lead were compared to different lead combinations and were correlated with arteriographic findings. A positive exercise test occurred in 37 men using an isolated V5 lead compared to 50 men (P less than 0.05) using 11 leads, 52 men (P less than 0.05) using a combined CM5, CC5, Cl (inferior) lead system and 58 (P less than 0.001) men using all 14 leads. The predictive value of a positive test varied between 89-95% and was not changed significantly by the addition of multiple leads. The 14 lead ECG was positive in 43/45 (96%) patients with multivessel disease. Parameters which helped to predict multivessel disease using 14 leads were 1) the time that ischemia first appeared 2) the pressure-rate product at the time ischemia first appeared, and 3) the maximum workload that could be attained. In general, the magnitude of ST-segment depression and the time required for a positive ECG to return to normal postexercise were not useful predictors of multivessel disease. We conclude that the use of multiple leads improves the sensitivity and efficiency of the maximal treadmill exercise test. The usefulness of exercise test results can be further improved if multiple leads are combined with physiologic data collected during exercise.

Adult↗

Circadian variation of exercise capacity in patients with Prinzmetal's variant angina: role of exercise-induced coronary arterial spasm.

Thirteen patients with Prinzmetal's variant angina performed treadmill exercise tests in the early morning and in the afternoon of the same day. The attacks with ST elevation were induced repeatedly in all 13 patients in the early morning, but in only two patients in the afternoon. Propranolol did not suppress the exercise-induced attacks in all 13 patients. Diltiazem suppressed the attacks in all 13 patients and phentolamine in eight of the nine patients. Coronary arteriograms demonstrated that spasm occluding completely or almost completely the large coronary artery supplying the area of myocardium showing ST elevation appeared during the attacks and disappeared along with the attacks after nitroglycerin administration in all four patients in whom the attacks were induced by arm exercise in the catheterization laboratory. We conclude that there is circadian variation of exercise capacity in patients with Prinzmetal's variant angina caused by coronary arterial spasm induced by exercise in the early morning but not in the afternoon.

Adult↗

Clinical significance of symptomatic and silent myocardial ischemia during exercise test in patients with effort angina pectoris--investigation of hemodynamic responses during supine ergometer exercise test.

Thirty one patients with stable effort angina who had no prior myocardial infarctions underwent symptom-limited ergometer exercise test. Hemodynamic responses during exercise were assessed to determine whether or not the limiting symptoms were related to the severity of exercise-induced myocardial ischemia. Twenty-two subjects (Group I) were limited by angina and nine (Group II) were limited by other symptoms. There were no differences in age, sex distribution, prevalence of diabetes mellitus, and left ventricular ejection fraction between the two groups. Multivessel coronary artery diseases, however, were more frequent in group I (16/22 vs 3/9: p less than 0.05). Maximal work load (46.6 +/- 16.0 vs 62.5 +/- 13.4 W: p less than 0.05), exercise duration (4.7 +/- 2.0 vs 7.2 +/- 1.4 min: p less than 0.005), and maximal oxygen consumption (12.4 +/- 4.1 vs 19.3 +/- 3.3 ml/kg/min: p less than 0.005) were significantly lower in group I. The magnitude of ST depression was not different between the two groups (2.0 +/- 0.8 vs 1.8 +/- 0.7 mm: NS). At maximal exercise, heart rate, mean blood pressure, cardiac index, and stroke work index (SWI) were significantly lower in group I (p less than 0.05) and pulmonary capillary wedge pressure was significantly higher in group I (31.1 +/- 6.1 vs 25.1 +/- 5.6 mmHg: p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

Perceived barriers to exercise and stage of exercise adoption in older women of different racial/ethnic groups.

The purpose of this study was to determine whether barriers to exercise differ among racial/ethnic groups at the same stage of exercise adoption and adjacent stages within racial/ethnic groups. Questions about stage of exercise adoption and perceived barriers to exercise were administered to a cross sectional sample of 745 African American, 660 Hispanic, 738 Native American/Native Alaskan, and 769 Caucasian U.S. women aged 40 years and older. Correlations between rankings of barriers among racial/ethnic groups within the same stage ranged from .43 to .89. For each racial/ethnic group, significant differences existed between adjacent stages in the percentage of women reporting barriers to interfere with exercise (p < .10). Barriers were not similar enough among racial/ethnic groups to recommend that the same barriers be addressed for all races/ethnicities.

Adult↗

Diet and exercise intervention have favourable effects on blood pressure in mild hypertensives: the Oslo Diet and Exercise Study (ODES).

The purpose of this study was to investigate the effect of 1-year diet intervention, exercise intervention and both combined on blood pressure (BP) in normotensives and mild hypertensives. Two hundred and nineteen sedentary middle aged men and women with slightly deranged coronary heart disease (CHD) risk factors were randomised to a control, a diet, an exercise and a diet + exercise group. Based on baseline diastolic BP, participants were divided into tertiles, giving baseline average BP of 141.4/96.7 in tertile 1, 130.7/87.6 in tertile 2 and 121.9/79.0 in tertile 3. The 1-year net-difference in BP between the intervention groups and the control group decreased across the tertiles; in tertile 1 being -11.2/-6.7 (p < 0.05), -11.3/-6.7 (p < 0.05 for systolic BP only) and -7.0/-5.1 (NS) in the combined, diet and exercise group respectively. Triglycerides, HDL cholesterol, and insulin variables were significantly and favourably changed, the changes being most marked in the combined group. The results show that diet and diet + exercise are about equally effective in reducing BP, and the effects may be dependent on the baseline level. Within the upper tertile of baseline BP, the decline in BP in the combined intervention and the diet group are almost comparable to those obtained with drug treatment. In addition, other important CHD risk factors were all changed in a beneficial direction.

Adult↗

[Exercise capacity and cardiovascular responses to exercise in hemiplegic patients].

We studied how the severity of hemiparesis was related to cardiovascular and metabolic responses to exercise. Eleven clinically stable patients who had had strokes were studied two to four weeks after they began walking as rehabilitation. After motor function of the lower limbs was assessed, the patients were divided into two groups according to Brunnstrom stage: one group comprised patients at stages III, IV, and V of lower limb function (n = 5), and the other comprised patients at stage VI (n = 6). A control group of 6 patients who had been hospitalized because of benign paroxysmal postural vertigo was also studied. Exercise consisted of 3-minute walks at speeds of 1.6, 3.2, and 4.8 km/hr. Blood pressure, heart rate, and the concentrations of catecholamines and of lactic acid in blood were measured before and after each stage of exercise. The double product (systolic blood pressure x heart rate) was also calculated. Changes in these variables were compared among the three groups. Increases in walking speed were associated with increases in systolic blood pressure and heart rate in hemiparetic patients, but no such changes occurred in the control group. In the patients at Brunnstrom stages III, IV, and V, the double product and the lactic acid level increased, and after the patients walked at the highest speed these were significantly higher than in the other two groups. Serum catecholamine levels did not differ among the three groups during exercise. Low intensity exercise can increase cardiovascular responses, and anaerobic metabolism can become dominant in patients with poor motor function.

Aged↗