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PubMedDate not supplied

Exercise counseling and programming preferences of cancer survivors.

PURPOSE: Exercise has emerged as an important quality-of-life intervention for cancer survivors, but exercise motivation is a challenge. The purpose of this study was to provide a comprehensive assessment of the exercise preferences of cancer survivors. DESCRIPTION OF STUDY: A mailed, self-administered survey was completed by 307 survivors of prostate, breast, colorectal, or lung cancer. The survey contained questions on demographic and medical variables, past exercise, and various exercise counseling and programming preferences. RESULTS: For exercise counseling, 84% of participants said they preferred or maybe preferred to receive exercise counseling at some point during their cancer experience. Moreover, 85% preferred to receive exercise counseling face to face, and 77% preferred to receive it from an exercise specialist affiliated with a cancer center. For exercise programming, 98% preferred recreational exercises, 8!% preferred walking, 57% preferred unsupervised exercise (57%), and 56% preferred moderate-intensity exercise. In addition, 48% preferred to exercise in the morning, 44% preferred to exercise alone, 40% preferred to exercise at home, and 32% preferred to start their exercise program before treatment. Chi-square analyses revealed that a small number of exercise preferences were moderated by demographic, medical, and exercise variables. CLINICAL IMPLICATIONS: The results of this study indicate that cancer survivors have unique and varied exercise counseling and programming preferences. Fifty-six percent of cancer survivors preferred to exercise at moderate intensity rather than at high intensity. Moderate-intensity exercise has been shown previously to be relatively safe even for cancer survivors who are advanced in age. The key to success for inactive cancer survivors may be to provide reassurance that exercise is a safe and beneficial modality for cancer survivors and to prescribe an exercise program that builds their confidence by slowly increasing the level of exercise intensity.

Age Factors↗

PubMed2005

The effects of carbohydrate supplementation during repeated bouts of prolonged exercise on saliva flow rate and immunoglobulin A.

The purpose of this study was to assess the effect of carbohydrate (CHO) feeding during different periods of two 90-min cycling bouts (the first bout began at 09:00?h and the second bout began at 13:30 h) at 60% maximal oxygen uptake(VO2max) on saliva flow rate and saliva immunoglobulin A (sIgA) responses to the second exercise bout. The study consisted of three investigations: carbohydrate supplementation during (1) the first hour of the recovery interval (CHO-REC), (2) during the first bout of exercise and (3) during the second bout of exercise. Each investigation included two trials completed in a counterbalanced order and separated by at least 4 days. Participants consumed a lemon-flavoured 10% w/v carbohydrate beverage or placebo (22 ml.kg-1 body mass) in the first hour of the recovery interval (n=8) and 500 ml just before exercise, followed by 250 ml every 20 min during exercise in the first (n=9) and second exercise bouts (n=9). Timed unstimulated saliva samples were collected at 10 min before exercise, after 48-50 min of exercise and during the last 2 min of exercise, at 1 h post exercise, 2 h post exercise (first exercise bout only), and 18 h post exercise (second exercise bout only). Venous blood samples were taken 5 min before exercise and immediately after exercise for both exercise bouts in all trials. The main findings of the present study were as follows. First, carbohydrate ingestion during both exercise bouts, but not during the recovery interval, better maintained plasma glucose concentrations and attenuated the increase in plasma adrenaline and cortisol concentrations after the second exercise bout compared with placebo. Second, carbohydrate feeding had no effect on saliva flow rate and sIgA secretion rate compared with placebo. Third, saliva flow rate and sIgA concentration returned to pre-exercise bout 1 values within 2 h in all trials. Fourth, there was no delayed effect of exercise on oral immunity. These findings suggest that carbohydrate ingestion during the first or second bout of exercise, but not during the recovery interval, is likely to better maintain plasma glucose concentrations and attenuate the responses of plasma stress hormones to a second exercise bout than ingestion of fluid alone. Two bouts of 90 min cycling at 60% VO2max on the same day appears to inhibit saliva flow rate during the second exercise bout but does not alter sIgA transcytosis. Our results show that carbohydrate ingestion during any period of two prolonged exercise bouts does not induce different effects on oral immunity compared with placebo.

Adult↗

PubMedDate not supplied

Exercise and the asthmatic.

Physical exercise is not hazardous to asthmatics. Some asthmatics may benefit from physical training, and almost all asthmatics can perform any kind of physical exercise. Free running was earlier thought to induce more asthma than swimming, for example; however, when ventilation is identical during running and swimming, the exercise-induced asthma will also be the same. Hyperventilation alone is as good as physical exercise to induce exercise-induced asthma. If the physical exercise provokes an asthmatic attack, this is most often easily reversed by inhaled beta 2-agonists. Pretreatment of exercise-induced asthma is most efficient by inhaled beta 2-agonist; orally dosed beta 2-agonist is not as efficient as inhaled beta 2-agonist in the pretreatment of exercise-induced asthma. Inhaled sodium cromoglycate diminishes exercise-induced asthma, and the effect seems to be better in children than in adults. Inhaled steroids have no immediate effect on exercise-induced asthma, but long term treatment with steroids diminishes exercise-induced asthma. The pathogenesis of exercise-induced asthma remains obscure. If the water content is low in the inhaled air, e.g. in cold air, the changes in ventilatory capacity following exercise. will be greater than when the exercise is performed while inhaling hot air with high humidity. Almost all asthmatics present changes in the ventilatory capacity following exercise. Seasonal changes in exercise-induced asthma are only present in asthmatics with seasonal allergies, e.g. pollen allergy. No diurnal variation is found in exercise-induced asthma. Asthmatics can do any form of physical exercise. Almost all asthmatics can prevent major changes in ventilatory capacity by pretreatment of exercise-induced asthma or be treated for exercise-induced asthma during the physical activity so that they will not suffer from asthma while performing physical exercise. Asthmatics who have been successfully treated for exercise-induced asthma can do physical exercise at the same level as non-asthmatics. Asthmatic children in particular should be encouraged to perform any sport they like, as the physiological and psychological effects may be beneficial to them. It is concluded that almost all asthmatics have exercise-induced asthma, and that physical training may be beneficial. Exercise-induced asthma is best treated and pretreated by inhalation of beta 2-agonists.

Asthma↗

PubMedDate not supplied

Exercise testing with myocardial perfusion imaging in patients with normal baseline electrocardiograms: cost savings with a stepwise diagnostic strategy.

BACKGROUND: It has been suggested that in patients with a normal resting electrocardiogram (ECG), exercise radionuclide myocardial perfusion imaging (MPI) does not add significant incremental diagnostic information to exercise ECG. METHODS AND RESULTS: Of 840 consecutive patients referred for physical exercise MPI, 313 (37%) had normal resting ECGs. There were 189 men and 124 women with a mean age of 54+/-11.9 years. Exercise MPI was performed with either TI-201 or 99mTc-labeled sestamibi. Overall concordance between exercise ECG result and MPI result was 79% (kappa agreement = .54). One hundred eighty-four patients had normal exercise ECG; 181 (98.4%) of these also had normal exercise MPI. In 271 patients with low (< or =20%) to intermediate (21% to 70%) pre-exercise likelihood of coronary artery disease (CAD), concordance between normal exercise ECG and normal MPI was 100%. In the high likelihood (> or =71%) group 3 (15 %) patients with normal exercise ECG had abnormal exercise MPI. Of 129 patients with abnormal exercise ECG, 67 (52%) patients also had abnormal MPI, but 62 (48%) patients had normal MPI. Complete follow-up was obtained in 89% of patients at 9 months. Only 1 hard cardiac event occurred: nonfatal myocardial infarction. Twenty-one (8%) patients had subsequent coronary revascularization or admission with unstable angina. Although both abnormal stress ECG and abnormal exercise MPI were significantly (P < .0001) associated with hard and "soft" events, the association of abnormal exercise MPI was significantly stronger. Because all patients with a low and intermediate likelihood of CAD who had normal exercise ECG also had normal exercise MPI, we propose a stepwise diagnostic testing strategy whereby exercise MPI imaging is performed only in patients with a low to intermediate likelihood of CAD when the exercise ECG is abnormal. When the exercise ECG is performed first, and exercise MPI is performed only when the exercise ECG is abnormal, substantial (38%) cost savings can be achieved. In patients with a high likelihood of CAD, the exercise ECG may be falsely negative, and exercise MPI is preferred. CONCLUSION: In patients with normal resting ECGs a stepwise diagnostic strategy can reduce costs of exercise testing without compromising diagnostic yield when pretest likelihood of coronary artery disease is taken into consideration.

Adult↗

PubMed1995

Exercise echocardiography is an accurate and cost-efficient technique for detection of coronary artery disease in women.

OBJECTIVES: This study compared the accuracy and cost implications of using exercise echocardiography and exercise electrocardiography for detection of coronary artery disease in women. BACKGROUND: The specificity of exercise electrocardiography in women is lower than in men. Exercise echocardiography accurately identifies coronary artery disease in women, but its utility in place of exercise electrocardiography is unclear. METHODS: One hundred sixty-one women without a previous Q wave infarction underwent exercise echocardiography and coronary angiography. Positive findings were a new or worsening wall motion abnormality on the exercise echocardiogram and ST segment depression > 0.1 mV at 0.08 s after the J point on the exercise electrocardiogram (ECG). RESULTS: Coronary artery stenosis > 50% diameter narrowing was present in 59 patients; the sensitivity (mean +/- SD) of exercise echocardiography was 80 +/- 3%. In 48 patients with an interpretable ECG, the sensitivity of exercise echocardiography was 81 +/- 4%, and that of the exercise ECG was 77 +/- 3% (p = 0.50). In 102 patients without coronary artery disease, the overall specificity of exercise echocardiography was 81 +/- 4%. In 70 patients with an interpretable ECG, the specificity of exercise echocardiography (80 +/- 3%) exceeded that of the exercise ECG (56 +/- 4%, p < 0.0004). The accuracy of exercise echocardiography was also greater than exercise electrocardiography (81 +/- 5% vs. 64 +/- 6%, p < 0.005). Exercise echocardiography stratified significantly more patients of intermediate (20% to 80%) pretest disease probability into the high (> 80%) or low (< 20%) posttest probability group. In women without a previous exercise ECG, the specificity of exercise echocardiography continued to exceed that of exercise electrocardiography (80 +/- 3% vs. 64 +/- 3%, p = 0.05). Exercise echocardiography had the best balance between accuracy and cost for the diagnosis of coronary artery disease in women. CONCLUSIONS: Exercise echocardiography is more specific than exercise electrocardiography for diagnosis of coronary artery disease in women and is a cost-effective approach to the diagnosis of coronary artery disease because of the avoidance of inappropriate angiography.

Adult↗

PubMed1989

Gender differences in the cardiovascular response to exercise.

During an acute bout of dynamic exercise, cardiac output increases in direct proportion to the increase in oxygen uptake. The mechanisms by which the cardiac output is increased during exercise may differ between men and women. The increased blood flow is distributed to the exercising skeletal muscle, to the myocardium, and, if exercise lasts longer than 5 minutes, to the skin. Blood flow to tissues whose metabolic rate has not been increased is reduced as a result of a general, sympathetically mediated vasoconstriction. During dynamic exercise, muscle blood flow, degree of peripheral vasoconstriction, increase in heart rate, and increase in myocardial blood flow and oxygen uptake are all functions of relative workload, often expressed as a %VO2 max. During an acute bout of resistive exercise, the increase in oxygen uptake and cardiac output is small, at least partially because perfusion of the exercising muscles is difficult as a result of high intramuscular pressures. The heart rate increase is also small. Blood pressure increases markedly as a result of increased total peripheral resistance. Dynamic exercise training results in cardiovascular adaptations both at rest and during exercise. At rest, myocardial hypertrophy of the volume overload type is the most common, but not universal, finding. Dynamic exercise that involves a sizable resistive exercise component may produce changes in myocardial structure and function similar to those resulting from static exercise. The effects of dynamic exercise training on myocardial function at rest need further investigation. The cardiovascular effects of dynamic exercise training are manifest during submaximal exercise by reduced heart rates, blood pressures, and less vasoconstriction in nonexercising tissues; increased stroke volumes; and unchanged cardiac outputs and oxygen uptakes at any given exercise load. During maximal exercise, VO2 max, maximal cardiac output, and maximal stroke volume are all increased. Maximal heart rate and blood pressure at maximal exercise are unchanged. Redistribution of the cardiac output to better perfuse the exercising muscles also occurs. Certain other factors that may modify the cardiovascular response to exercise include phase of the menstrual cycle, pregnancy, age, exercise mode, length of the exercise session, and environmental conditions such as heat stress. Although there are some physiologic differences that may affect the mechanism of the changes, the overall response of the cardiovascular system to exercise is similar in men and women.

Age Factors↗

PubMed1995

Changes in the growth hormone axis due to exercise training in male and female rats: secretory and molecular responses.

GH secretion is altered by exercise in humans. In an attempt to investigate the underlying mechanisms, we developed a rodent model. GH secretion was assayed in male and female rats that were sedentary (not exercised), acutely exercised, and chronically exercised. Sedentary males showed typical pulsatile GH secretion. The acutely exercised males had low GH concentrations during the exercise bout, but showed partial recovery of GH pulses during the 5.5-h postexercise period. GH secretion in the chronically exercised males was low during both the exercise and postexercise periods. Sedentary females displayed the typical pattern of GH secretion for this sex. The acutely exercised females had low GH concentrations during the exercise period; the pulsatile pattern of GH secretion did not return during the postexercise period. In contrast, the chronically exercising females had suppressed GH secretion during the exercise bout, but concentrations immediately returned to normal during the postexercise bout. The effects of exercise on GH, GH-releasing hormone (GHRH), and somatostatin messenger RNA (mRNA) levels using Northern and slot blot analyses were also determined. Acutely and chronically exercised male rats had decreased levels of GH mRNA compared to sedentary male rats. The acutely exercised female rats had increased levels of GH mRNA compared to the sedentary females, whereas the chronically exercised females had decreased levels. GHRH mRNA levels in acutely exercising male rats was decreased and in chronically exercising male rats was increased compared to those in the sedentary controls. The pattern of GHRH mRNA in female rats was the opposite of this. Somatostatin mRNA levels decreased in acutely exercised male rats and were not affected in chronically exercised male rats. This signal increased in both acute and chronically exercised female rats. These studies suggest that GH secretion is suppressed in response to exercise in the rat. This contrasts with the increase observed after exercise in humans.

Animals↗

PubMed2001

Exercise and diabetes.

As rates of diabetes mellitus and obesity continue to increase, physical activity continues to be a fundamental form of therapy. Exercise influences several aspects of diabetes, including blood glucose concentrations, insulin action and cardiovascular risk factors. Blood glucose concentrations reflect the balance between skeletal muscle uptake and ambient concentrations of both insulin and counterinsulin hormones. Difficulties in predicting the relative impact of these factors can result in either hypoglycemia or hyperglycemia. Despite the variable impact of exercise on blood glucose, exercise consistently improves insulin action and several cardiovascular risk factors. Beyond the acute impact of physical activity, long-term exercise behaviors have been repeatedly associated with decreased rates of type 2 diabetes. While exercise produces many benefits, it is not without risks for patients with diabetes mellitus. In addition to hyperglycemia, from increased hepatic glucose production, insufficient insulin levels can foster ketogenesis from excess concentrations of fatty acids. At the opposite end of the glucose spectrum, hypoglycemia can result from excess glucose uptake due to either increased insulin concentrations, enhanced insulin action or impaired carbohydrate absorption. To decrease the risk for hypoglycemia, insulin doses should be reduced prior to exercise, although some insulin is typically still needed. Although precise risks of exercise on existing diabetic complications have not been well studied, it seems prudent to consider the potential to worsen nephropathy or retinopathy, or to precipitate musculoskeletal injuries. There is more substantive evidence that autonomic neuropathy may predispose patients to arrhythmias. Of clear concern, increased physical activity can precipitate a cardiac event in those with underlying CAD. Recognizing these risks can prompt actions to minimize their impact. Positive actions that are part of exercise programs for diabetic patients emphasize SMBG, foot care and cardiovascular functional assessment. SMBG provides critical information on the impact of exercise and is recommended for all patients before, during and after exercise. More frequent monitoring (and for longer periods following exercise) is recommended for those with hypoglycemia unawareness or those performing high-intensity exercise. Preventing the sequelae of an exercise-induced severe hypoglycemic reaction can be as simple as carrying glucose tablets or gel, a diabetic identification bracelet or card, or exercising with an individual who is aware of the circumstances. In addition to blood glucose concentrations, proper foot care is critical to people with diabetes who exercise and includes considering type of shoe, type of exercise, inspection of skin surfaces and appropriate evaluation and treatment of lesions (calluses and others). Those with severe neuropathy can consider alternatives to weight-bearing exercises. Precipitation of clinical CAD is of great concern for all diabetic patients participating in exercise activities. Although a sufficiently sensitive and specific screening test for coronary disease has not been identified, those planning an exercise program of moderate intensity or greater should be evaluated. Initial cardiac assessment should include exercise testing as well as identifying risk for autonomic neuropathy. In addition to noting maximal heart rate and blood pressure as well as ischemic changes, exercise tolerance testing can identify anginal thresholds and patients with asymptomatic ischemia. Those without symptoms should be counseled regarding target pulse rates to avoid inducing ischemia. Ischemic changes need to be evaluated for either further diagnostic testing or pharmacological intervention. For patients with diabetes mellitus, the overall benefits of exercise are clearly significant. Clinicians and patients must work together to maximize these benefits while minimizing risks for negative consequences. Identifying and preventing potential problems beforehand can reduce adverse outcomes and promote this important approach to healthy living.

Blood Glucose↗

PubMed2006

Predictors of exercise participation in female hospital nurses.

AIM: This paper presents a study to ascertain the relationship between exercise participation and selected personal factors, perceived benefits of and barriers to exercise, perceived self-efficacy, perceived social support, job demands and motivation. Factors that were the best predictors of exercise participation among Thai female hospital nurses were examined. BACKGROUND: Although current evidence demonstrates positive outcomes from participation in exercise, most individuals do not engage in regular exercise. Perceptions of benefits have been shown to facilitate adoption of exercise. If individuals do not perceive their health to be threatened, they may not see the need to exercise, even though they may believe that exercise improves health. Perceived barriers to exercise, including work, lack of social support, inaccessibility of exercise facilities, the cost of exercise, lack of energy and health reasons also have been shown to affect participation in exercise. Most studies have found that perceived self-efficacy and social support were statistically significant predictors of exercise participation, especially social support from family and friends. METHODS: A correlational cross-sectional study was conducted at a hospital located in Thailand. Social cognitive theory and the Health Promotion Model guided this study. Thai language translations of the questionnaire were distributed to all Thai female nurses. The data were collected in 2002. RESULTS: The response was 87% and resulted in 970 completed questionnaires. There was a statistically significant relationship between exercise participation and the set of selected personal factors, perceived benefits of and barriers to exercise, perceived self-efficacy, and perceived social support (r(2) = 0.17, P < 0.0001). The addition of job demands and its interactions did not contribute statistically significantly to the prediction of exercise participation. The addition of motivation contributed statistically significantly to the prediction of exercise participation, t(947, 0.975) = 2.81, P < 0.01 (two-tailed). Not all variables included in the models were statistically significant independent predictors of exercise participation. CONCLUSIONS: The results indicate that increased exercise participation is dependent on the nurses' perceptions of exercise, self-efficacy and social support as well as their motivation to participate in exercise. Occupational variables, such as occupational stress and work assignment, should be investigated in future studies, to examine their influence on nurses' participation in exercise.

Adult↗

PubMed1999

Rheumatologist-patient communication about exercise and physical therapy in the management of rheumatoid arthritis.

OBJECTIVE: Little is known about the features and role of exercise discussions between rheumatologists and patients. The goals of this study were to: 1) describe rheumatologists' and patients' attitudes and beliefs regarding exercise and physical therapy for rheumatoid arthritis (RA); 2) describe frequency and length of exercise discussions; 3) determine the accuracy of recall for exercise discussions; and 4) assess the influence of attitudes regarding exercise on communication about exercise. METHODS: Goals 1-3 were addressed with analysis of baseline questionnaires and audiotaped encounters. The influence of attitudes and beliefs regarding exercise on the frequency and length of exercise discussions was assessed prospectively. Patients and rheumatologists were enrolled from a large tertiary care institution. Clinical encounters were audiotaped, transcribed, coded, and analyzed to identify specific characteristics of the exercise discussions. RESULTS: One hundred thirty-two patients and 25 rheumatologists participated in the study. Rheumatologists and patients discussed exercise in 53% of the encounters. Rheumatologists' beliefs regarding the usefulness of exercise for RA varied, with the least positive beliefs being reported for aerobic exercise. Exercise discussions were more likely to occur if the patient was currently exercising, odds ratio (OR) = 2.4; 95% confidence interval (CI) (1.2-4.9), and when the rheumatologist believed aerobic exercises were useful in managing RA, OR = 1.4; 95% CI (1.1-1.9). Current exercise behavior was associated with patients' positive attitude toward exercise (chi 2 1 = 8.4; P = 0.004) and perceived social support for exercise (chi 2 1 = 4.5; P = 0.04). When rheumatologists initiated exercise discussions, there was nearly twice as much discussion (beta = -8.4; P = 0.001). CONCLUSIONS: Exercise talk was influenced by patients' and rheumatologists' beliefs and attitudes regarding the effectiveness of exercise and physical therapy in managing RA, patient experience with exercise, and by characteristics of the rheumatologist.

Arthritis, Rheumatoid↗

PubMed2005

Exercise primes a molecular memory for brain-derived neurotrophic factor protein induction in the rat hippocampus.

Exercise is an important facet of behavior that enhances brain health and function. Increased expression of the plasticity molecule brain-derived neurotrophic factor (BDNF) as a response to exercise may be a central factor in exercise-derived benefits to brain function. In rodents, daily wheel-running exercise increases BDNF gene and protein levels in the hippocampus. However, in humans, exercise patterns are generally less rigorous, and rarely follow a daily consistency. The benefit to the brain of intermittent exercise is unknown, and the duration that exercise benefits endure after exercise has ended is unexplored. In this study, BDNF protein expression was used as an index of the hippocampal response to exercise. Both daily exercise and alternating days of exercise increased BDNF protein, and levels progressively increased with longer running duration, even after 3 months of daily exercise. Exercise on alternating days was as effective as daily exercise, even though exercise took place only on half as many days as in the daily regimen. In addition, BDNF protein remained elevated for several days after exercise ceased. Further, after prior exercise experience, a brief second exercise re-exposure insufficient to cause a BDNF change in naïve animals, rapidly reinduced BDNF protein to levels normally requiring several weeks of exercise for induction. The protein reinduction occurred with an intervening "rest" period as long as 2 weeks. The rapid reinduction of BDNF by an exercise stimulation protocol that is normally subthreshold in naïve animals suggests that exercise primes a molecular memory for BDNF induction. These findings are clinically important because they provide guidelines for optimizing the design of exercise and rehabilitation programs, in order to promote hippocampal function.

Animals↗

PubMed2001

Exercise and eating disorders: a 3-year inpatient hospital record analysis.

The purpose of this study was to describe the exercise behavior across the DSM-IV eating disorder diagnosis (anorexia nervosa (AN), bulimia nervosa (BN), and eating disorder not otherwise specified (EDNOS)) and determine if differences exist among exercise category (high level and low level), type of exercise (aerobic, strength, and total), Eating Attitudes Test (EAT), Eating Disorders Inventory (EDI-2), and the length of inpatient hospitalization. This study was a retrospective analysis of 199 inpatient hospital records of female patients (age M=20.6, S.D.=7.03) in the following diagnostic categories: AN (n=115, 58%), BN (n=38, 19%), and EDNOS (n=46, 23%). Patients were also grouped by a median split into low- and high-level exercise categories based on their total amount of weekly exercise. No significant relationship was found between diagnosis and exercise category (high and low) or diagnosis and exercise type (total, aerobic, and strength exercise). This is valuable because exercise specialist may be a worthwhile addition to treatment teams working with all eating disorder diagnostic groups. The high-level exercisers showed significantly greater scores on the EAT [F(2,1,110)=5.117, P<.05] and weight preoccupation [F(1,1010)=4.861, P<.05] than the low-level exercise groups. There were significant relationships between total exercise and EAT (r=.354, P<.01), drive for thinness (r=.262, P<.01), and body dissatisfaction (r=.312, P<.001). Total aerobic exercise was significantly related to EAT (r=.352, P<.001), drive for thinness (r=.272, P<.01), and body dissatisfaction (r=.268, P<.01). Finally, total strength exercise was related to body dissatisfaction (r=.249, P<.05). A significant difference was found among exercise group and length of hospitalization [F(1,155)=14.384, P<.000]. The high-level exercisers were in treatment for 3 weeks longer than their low-level exercisers. A forced stepwise multiple linear regression was calculated to predict the length of hospitalization. At Step 1, diagnosis and Body Mass Index (BMI) on admission explained 27% of the variance in length of inpatient hospitalization [F(4,154)=18.08, P<.004, r(2)=.273]. When two exercise variables were included, aerobic activity explained an additional 5% of variance, whereas strength activity explained an additional 0.3% of the variance. Three-fourths of the predictors explained significant components of the total 32% variance. The present study demonstrates that patients with greater total exercise and a greater total aerobic exercise show a significantly greater drive for thinness and require a longer length of hospitalization. This association was not present with total strength exercise levels. Effective clinical methods to modify total aerobic exercise levels need to be determined with inpatient populations.

Journal Article↗

PubMed1988

Hyperammoniemia during prolonged exercise: an effect of glycogen depletion?

Eight healthy men exercised to exhaustion on a cycle ergometer at a work load of 176 +/- 9 (SE) W corresponding to 67% (range 63-69%) of their maximal O2 uptake (exercise I). Exercise of the same work load was repeated after 75 min of recovery (exercise II). Exercise duration (range) was 65 (50-90) and 21 (14-30) min for exercise I and II, respectively. Femoral venous blood samples were obtained before and during exercise and analyzed for NH3 and lactate. Plasma NH3 was 12 +/- 2 and 19 +/- 6 mumol/l before exercise I and II, respectively and increased during exercise to exhaustion to peak values of 195 +/- 29 (exercise I) and 250 +/- 30 (exercise II) mumol/l, respectively. Plasma NH3 increased faster during exercise II compared with exercise I and at the end of exercise II was threefold higher than the value for the corresponding time of exercise I (P less than 0.001). Blood lactate increased during exercise I and after 20 min of exercise was 3.7 +/- 0.4 mmol/l and remained unchanged until exhaustion. During exercise II blood lactate increased less than during exercise I. It is concluded that long-term exercise to exhaustion results in large increases in plasma NH3 despite relatively low levels of blood lactate. It is suggested that the faster increase in plasma NH3 during exercise II (vs. exercise I) reflects an increased formation in the working muscle that may be caused by low glycogen levels and impairment of the ATP resynthesis.

Adenine Nucleotides↗

PubMed1998

Repeated bouts of exercise alter the blood lactate-RPE relation.

PURPOSE: To examine the effects of repeated bouts of exercise on the blood lactate [HLa]-ratings of perceived exertion (RPE) relation. METHODS: Six moderately trained males were studied on two occasions: a sequential exercise bouts day (SEB: 1000 h, 1130 h, and 1300 h) and a delayed exercise bouts day (DEB: 1000 h, 1400 h, and 1800 h). Each of the three exercise bouts within a given condition were 30 min in duration at the power output (PO) associated with 70% of VO2peak on a cycle ergometer. A standardized meal was provided at 0600 h. VO2, PO, HR, and RER were recorded every min during exercise and blood [HLa] and RPE were measured every 5 min during exercise. RESULTS: A 2 x 3 analysis of variance with repeated measures revealed that blood [HLa] decreased significantly with each repeated exercise bout (X +/- SEM: bout 1: SEB = 3.5 (0.3), DEB = 3.8 (0.4); bout 2: SEB = 2.6 (0.3), DEB = 2.8 (0.3); bout 3: SEB = 2.0 (0.2), DEB = 2.1 (0.4); mM). No differences were observed in the blood [HLa] response to repeated bouts of exercise between SEB and DEB. RPE-peripheral (legs, RPE-L) was higher during bout 3 compared with bout 1 (P <0.05) (bout 1: SEB = 11.8 (0.8), DEB = 12.3 (0.2); bout 2: SEB = 12.3 (0.5), DEB = 13.3 (0.4); bout 3: SEB = 13.5 (0.8), DEB = 14.0 (0.7); RPE-central (chest and breathing, RPE-C) was not affected by repeated bouts of exercise, whereas RPE-Overall (RPE-O) was higher during bout 3 compared with bouts 1 and 2 (P < 0.05) (bout 1: SEB = 12.5 (0.2), DEB = 12.3 (0.4); bout 2: SEB = 12.8 (0.4), DEB = 12.7 (0.4); bout 3: SEB = 13.7 (0.7), DEB = 13.2 (0.3)). No interaction for RPE x condition was observed. HR increased with repeated bouts of exercise with HR during exercise bout 3 being higher than HR during exercise bout 1 (164 vs. 156 bpm, P < 0.05). There was also a strong trend for HR during exercise bout 3 to be higher than HR during exercise bout 2 (P < 0.06). A trend for a reduction in VO2 with repeated exercise was observed (P < 0.07), with the reduction apparently related to the SEB condition (P < 0.12 for VO2 x condition). PO and kcal.min-1 were not affected by repeated bouts of exercise. RER decreased significantly with each repeated bout of exercise (from RER = 0.96 to RER = 0.89, P < 0.05) with no difference observed between SEB and DEB. CONCLUSIONS: We conclude that the blood [HLa]-RPE relation is altered by repeated bouts of exercise and that this alteration does not appear to be affected by recovery time between exercise bouts (up to 3.5 h of recovery). These data suggest that, after the first exercise bout, RPE should not be used to produce a specific blood [HLa] on subsequent exercise bouts.

Adult↗

PubMed2000

Oxygen uptake in one-legged and two-legged exercise.

PURPOSE: The purpose of this study was to determine the primary factors causing the differential oxygen uptake (VO2) response at submaximal intensities between one-legged and two-legged exercise, and whether peak oxygen uptake (VO2peak) increases in proportion to the increase in active muscle mass. METHODS: Two different types of exercise were used for this experiment, each requiring a different movement, a different method of stabilizing posture, and, finally, a different limiting VO2peak. In experiment 1, nine male subjects performed one-legged cycling (OLC) and two-legged cycling exercise (TLC) at a pedaling rate of 80 rpm. The exercise intensity was first set at 80 W and was increased by 40 W every 3 min until exhaustion. In experiment 2, six healthy male subjects performed one-legged knee-extension (OKE) and two-legged knee-extension (TKE) exercise at a rate of 50 contractions per minute. The knee-extension exercise was done at constant work rates for a 3-min session in OKE or a 4-min session in TKE. The exercise bouts were performed intermittently at four to seven different submaximal intensities and VO2 was determined at each intensity in all exercises. RESULTS: At submaximal intensities, VO2 in relation to work rate of one-legged exercise was more steep than those of two-legged exercise, and the mean values of VO2 were significantly higher in one-legged exercise than those in two-legged exercise in both knee extension and cycling exercise. Mean values of VO2peak for two-legged exercise were significantly higher than that for one-legged exercise (P < 0.01); however, it was much lower than two times of that for one-legged exercise even in knee extension exercise where the VO2peak would be limited peripherally. CONCLUSION: The findings of this study suggest that the differential VO2 response between one-legged and two-legged exercise would be attributed not only to the difference in force application throughout the exercise movement and to the effect of a postural component but also to the inhibited circulatory response caused by the multiple limb exercise. In addition, it was supposed that VO2peak does not increase in proportion to the exercising muscle mass even during smaller muscle activity where the cardiac pumping capacity has not reached its upper limit.

Adult↗

PubMed2006

The effects of oxandrolone and exercise on muscle mass and function in children with severe burns.

OBJECTIVES: Severe burns are associated with a significant loss of muscle and strength. Studies have reported that oxandrolone improves lean body mass in muscle-wasting conditions. Also shown previously in burned children is that an exercise program increases lean body mass and muscle strength. We hypothesized that oxandrolone, in combination with exercise, would increase lean body mass and muscle strength in severely burned children more than oxandrolone alone or exercise alone. METHODS AND PATIENTS: Fifty-one burned children (> or = 40% total body surface area burned) were randomly assigned to receive oxandrolone alone (0.1 mg/kg per day orally; n = 9), oxandrolone and exercise (n = 14), placebo and no exercise (n = 11), or placebo and exercise (n = 17). Administration of oxandrolone was started at discharge and continued until 1 year after burn. The 12-week exercise training program was started 6 months after burn. Serum hormones, lean body mass, muscle strength, and peak cardiopulmonary capacity were assessed at 6 (baseline) and 9 months after burn. Data were analyzed using a 1-way analysis of variance, and significance was set at P < .05. RESULTS: The mean percentage of change or increase in weight and lean body mass in the oxandrolone and exercise group was significant compared with placebo and exercise, as well as with the oxandrolone alone group or placebo and no exercise group. Furthermore, lean body mass was significantly improved in the oxandrolone and exercise, oxandrolone alone, and placebo and exercise group compared with the group only receiving placebo. Muscle strength significantly increased in oxandrolone and exercise, placebo and exercise, and the oxandrolone alone group when compared with the placebo and no exercise group. The peak cardiopulmonary capacity was significantly higher in both exercise groups. Insulin-like growth factor 1 was significantly increased in the oxandrolone alone group compared with placebo and exercise and placebo and no exercise. Both exercise groups showed significant changes in insulin-like binding-protein-3 when compared with groups without exercise. CONCLUSIONS: Oxandrolone, in combination with exercise, is beneficial in severely burned children, thus improving their rehabilitation.

Adolescent↗

PubMed1992

Impaired cardiopulmonary response to exercise in moderate hypertension.

OBJECTIVE: To identify the limiting factors of exercise performance in subjects with hypertension associated with left ventricular hypertrophy. The secondary objective was to establish relationship between peripheral function and exercise capacity. DESIGN: Cardiopulmonary exercise testing was conducted using two protocols: a graded exercise test to maximal effort established maximal exercise capacity, followed by a step-incremental test combining gas-exchange measures and radionuclide angiography. The exercise responses were compared within and between groups. SETTING: All hypertensive subjects were selected from the Toronto Tri-Hospital Hypertension Clinic. Normal subjects were recruited from the surrounding community. PATIENTS: Twelve patients with established hypertension and left ventricular hypertrophy (determined by echocardiography) were studied as a referred/volunteer sample. All had no evidence of coincident diseases and were unmedicated at time of testing. A volunteer sample of normal, healthy subjects acted as a control. INTERVENTIONS: Graded exercise to maximum and step-incremental (submaximal and steady-state) exercise was used to quantify cardiopulmonary function during exercise stress. MAIN OUTCOME MEASURES: These included (for exercise performance) maximal oxygen intake (VO2max), the ventilatory anaerobic threshold, total peripheral resistance and blood lactate. Cardiac function measures included ejection fraction and ventricular volumes. RESULTS: Cardiac function data obtained during exercise in hypertensive subjects included an increase in the pressure to volume ratio, but a blunted ejection fraction response at peak exercise (P less than 0.05). Although end-diastolic volume increased during exercise (P less than 0.05), values were lower during both levels of exercise compared with normal subjects. Mean +/- SD end-systolic volume increased from 39 +/- 22 at rest to 42 +/- 23 mL during peak exercise. Hypertensive subjects had a lower VO2 max (mean 27.4 +/- 4.8 mL/kg/min) compared with normals (40.0 +/- 8.5 mL/kg/min) and a lower ventilatory anaerobic threshold (14.4 +/- 2.9 versus 27.6 +/- 5.8 mL/kg/min, P less than 0.005). Furthermore, hypertensive patients had a significantly elevated total peripheral resistance at rest (2.5 +/- 1.0 versus 1.8 +/- 0.4 peripheral resistance units) and at peak exercise (1.6 +/- 0.7 versus 0.8 +/- 0.2, P less than 0.01) compared with normal subjects (P less than 0.05). A correlation coefficient of 0.92 was found between total peripheral resistance and VO2 max in hypertensive subjects (P less than 0.01). CONCLUSIONS: These data suggest that peripheral factors, specifically a failure to reduce significantly total peripheral resistance, limits exercise performance despite a maintenance of left ventricular function during exercise in patients with moderate hypertension. The use of cardiopulmonary exercise testing can help in identifying the underlying cause of exercise intolerance in this population and limited left ventricular reserve at peak exercise, and may offer a sensitive measure of therapeutic end-points.

Adult↗

PubMed1991

Group- vs home-based exercise training in healthy older men and women. A community-based clinical trial.

OBJECTIVE: --To determine the effectiveness of group- vs home-based exercise training of higher and lower intensities among healthy, sedentary older adults. DESIGN: --Year-long randomized, controlled trial comparing (1) higher-intensity group-based exercise training; (2) higher-intensity home-based exercise training; (3) lower-intensity home-based exercise training; or (4) assessment-only control. SETTING: --General community located in northern California. PARTICIPANTS: --One hundred sixty women and 197 men 50 to 65 years of age who were sedentary and free of cardiovascular disease. One out of nine persons contacted through a community random-digit-dial telephone survey and citywide promotion were randomized. INTERVENTIONS: --For higher-intensity exercise training, three 40-minute endurance training sessions per week were prescribed at 73% to 88% of peak treadmill heart rate. For lower-intensity exercise training, five 30-minute endurance training sessions per week were prescribed at 60% to 73% of peak treadmill heart rate. MAIN OUTCOME MEASURES: --Treadmill exercise test performance, exercise participation rates, and heart disease risk factors. RESULTS: --Compared with controls, subjects in all three exercise training conditions showed significant improvements in treadmill exercise test performance at 6 and 12 months (P less than .03). Lower-intensity exercise training achieved changes comparable with those of higher-intensity exercise training. Twelve-month exercise adherence rates were better for the two home-based exercise training conditions relative to the group-based exercise training condition (P less than .0005). There were no significant training-induced changes in lipid levels, weight, or blood pressure. CONCLUSIONS: --We conclude that (1) this community-based exercise training program improved fitness but not heart disease risk factors among sedentary, healthy older adults; (2) home-based exercise was as effective as group exercise in producing these changes; (3) lower-intensity exercise training was as effective as higher-intensity exercise training in the home setting; and (4) the exercise programs were relatively safe.

Aged↗