SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The ETS-domain transcription factor family can be divided into a series of subfamilies. Elk-1 represents the founding member of the ternary complex factor (TCF) subfamily. By focusing on the TCF subfamily, we can demonstrate the complexities that exist in the function and regulation of ETS-domain transcription factors. This article focuses on Elk-1 in detail and summarizes the functions of other TCFs. The key themes covered include the domain structure of the TCFs, the mechanisms of complex formation with serum response factor, regulation of TCFs by mitogen-activated protein kinase cascades, and transcriptional regulatory properties of the TCFs. Finally, the emerging role of the TCFs in vivo is discussed. A picture is developing indicating that, while these proteins exhibit significant sequence and functional conservation, key differences in their structure and regulation are being identified which may relate to unique functions of these proteins in vivo.
We designed two experiments to investigate the relationship between ventilation (VE) and CO2 output (VCO2) during exercise under the conditions of exercising different limbs, the arms as opposed to the legs (experiment 1), and of different physical training states after undergoing standard exercise training for 90 d (experiment 2). Six healthy young subjects underwent submaximal ramp exercise at an incremental work rate of 15 W/min for the arm and leg, and 11 healthy middle-aged subjects underwent an incremental exercise test at the rate of 30 W/3 min before and after exercise training. We measured pulmonary breath-by-breath VE, VCO2, oxygen uptake (VO2), tidal volume (VT), breathing frequency (bf), and end-tidal O2 and CO2 pressures (PETO2, PETCO2) via a computerized metabolic cart. In experiment 1, arm exercise produced significantly greater VE than did leg exercise at the same work rates, as well as significantly higher VO2, VCO2, and bf. The slopes of the regression lines in the VE-VCO2 relationship were not significantly different: the values were 27.8 +/- 2.1 (SD) during the arm exercise, and 25.3 +/- 3.9 during the leg exercise, with no differences in their intercepts. In experiment 2, the VO2, VCO2, and VE responses at the same work rates were similar in both before and after the 90-d exercise training, whereas the heart rate (HR) and mean blood pressure (MBP) were significantly reduced after training. Exercise training did not alter the VE-VCO2 relationship, the slope of which was 31.9 +/- 4.9 before exercise training and 34.2 +/- 4.4 after exercise training. We concluded that the VE-VCO2 relationship during exercise is unaltered, independent of not only working muscle regions but also exercise training states.
Prior heavy exercise (above the lactate threshold, Th(la)) increases the amplitude of the primary oxygen uptake (VVO(2)) response and reduces the amplitude of the VO(2) slow component during subsequent heavy exercise. The purpose of this study was to determine whether these effects required the prior performance of an identical bout of heavy exercise, or if prior short-duration sprint exercise could cause similar effects. A secondary purpose of this study was to determine the effect of elevating muscle temperature (through passive warming) on VO(2) kinetics during heavy exercise. Nine male subjects performed a 6-min bout of heavy exercise on a cycle ergometer 6 min after: (1) an identical bout of heavy exercise; (2) a 30-s bout of maximal sprint cycling; (3) a 40-min period of leg warming in a hot water bath at 42 degrees C. Prior sprint exercise elevated blood [lactate] prior to the onset of heavy exercise (by aproximately 5.6 mM) with only a minor increase in muscle temperature (of approximately 0.7 degrees C). In contrast, prior warming had no effect on baseline blood lactate concentration, but elevated muscle temperature by approximately 2.6 degrees C. Both prior heavy exercise and prior sprint exercise significantly increased the absolute primary VO(2) amplitude (by approximately 230 ml x min(-1) and 260 ml x min(-1), respectively) and reduced the amplitude of the VO(2) slow component (by approximately 280 ml x min(-1) and 200 ml x min(-1), respectively) during heavy exercise, whereas prior warming had no significant effect on the VO(2) response. We conclude that the VO(2) response to heavy exercise can be markedly altered by both sustained heavy-intensity submaximal exercise and by short-duration sprint exercise that induces a residual acidosis. In contrast, passive warming elevated muscle temperature but had no effect on the VO(2) response.
OBJECTIVE: The purpose of this study was to determine whether warming of exercising legs improves exercise capacity in patients with cardiac disease and low exercise tolerance. BACKGROUND: Exercising muscle temperature reflects both muscle metabolic rate and muscle blood flow. Increase in muscle temperature in exercising legs is impaired in patients with chronic heart failure. We hypothesized that the mechanisms responsible for impairment of temperature increase in exercising muscle might be related to those responsible for low exercise tolerance. METHODS: We studied 17 patients with cardiac disease whose anaerobic threshold (AT) ranged from 6.6 to 14.8 ml/kg/min (mean 11.2 +/- 1.9 SD). Subjects performed symptom-limited sitting cycle ergometer exercise with or without warming of the thighs. Both thighs were warmed by use of hot packs fixed by supporters. To determine the effect of the supporters themselves on AT and peak VO2, the same ergometer exercise was performed by 7 patients with or without supporters. Peak VO2 and AT were determined by concomitant respiratory gas monitoring. RESULTS: 1) Warming of the thighs increased deep temperature in the thighs (1.0 approximately 2.8 degrees C). 2) AT and peak VO2 were significantly improved in the warming exercise compared with the non-warming exercise (p < 0.01, p < 0.01). 3) There was no significant difference in AT or peak VO2 between the exercise with and without supporters. CONCLUSION: The findings of this study indicate that warming of exercising legs improves exercise capacity in patients with cardiac disease and low exercise tolerance.
OBJECTIVES: We sought to define the prognostic implications of the extent and severity of exercise echocardiographic abnormalities in patients with good exercise capacity. BACKGROUND; The exercise capacity of patients with known or suspected coronary artery disease (CAD) is of prognostic importance, as is the extent of exercise-related left ventricular (LV) hypoperfusion or dysfunction. METHODS: We examined the outcomes of 1,874 patients with known or suspected CAD (mean age 64 +/- 10 years, 64% men) who had good exercise capacity (> or = 5 metabolic equivalents [METs] for women, > or = 7 METs for men) but abnormal exercise echocardiograms and analyzed the potential association between clinical, exercise and echocardiographic variables and subsequent cardiac events. RESULTS: Multivariate predictors of time to cardiac death or nonfatal myocardial infarction (MI) were diabetes mellitus (risk ratio [RR] 1.88; 95% confidence interval [CI] 1.2 to 3.0), history of MI (RR 2.44; 95% CI 1.6 to 3.6) and an increase or no change in LV end-systolic size in response to exercise (RR 1.61; 95% CI 1.1 to 2.5). Using echocardiographic variables that were of incremental prognostic value, we were able to stratify the cardiac risk of the study population; cardiac death or nonfatal MI rate per person-year of follow-up was 1.6% for patients who had a decrease in LV end-systolic size in response to exercise (n = 1,330) and 1.2% for patients who did not have any severely abnormal LV segments immediately after exercise (n = 868). CONCLUSIONS: In patients with good exercise capacity, echocardiographic descriptors of the extent and severity of exercise-related LV dysfunction were of independent and incremental prognostic value. Stratification of patients into low- and higher risk subgroups was possible using these exercise echocardiographic characteristics.
It is unclear whether echocardiography at peak bicycle exercise adds information to registrations obtained recumbent immediately after the test and what factors influence image quality. Therefore, exercise echocardiography was performed consecutively and prospectively in 66 men, unselected with regard to echocardiography, one month after an episode of unstable coronary artery disease. Of 594 segments (9 x 66), 569 (96%) were adequately visualized recumbent at rest. The corresponding figures recumbent directly after exercise, seated before exercise, and seated at peak exercise were 544 (92%), 474 (80%), and 428 (72%), respectively. In the majority of our patients, acceptable images at peak exercise were obtained for the septal region, while for the anterior, lateral, and inferior segments the success rate varied from 50 to 70%. Recumbent after exercise, the success rate was acceptable for most segments, possibly with the exception of the apical and lateral segments. Fifty-five patients developed new wall motion abnormalities or worsening of wall motion in connection with exercise. Echocardiography at peak exercise provided more information than afterwards in patients with images of good quality. However, in patients with inferior image quality, the registrations obtained recumbent after the test revealed wall motion abnormalities which were not obtained seated at peak exercise. Patients with worse image quality had significantly higher respiratory rate and weight, and rated a higher degree of dyspnoea at peak exercise than those with good quality. We conclude that in middle aged men with coronary artery disease, image acquisition at peak bicycle exercise and immediately after exercise are of complementary value.
PURPOSE: A dance exercise program was performed to investigate the effects of exercise on exercise intention and exercise-related affect as these are important determinants of exercise behavior. METHOD: The subjects were overweight (23< or =BMI< or =25) or obese (BMI> or =25) postmenopausal women (n=14), who participated in an exercise program from May, 2003 through November, 2003 at one public health center located in Kyong-gi Province. Data was analyzed with an SAS PC program. RESULT: Exercise intention was significantly increased after the exercise program (t=-2.24, P=0.04). Exercise-related affect was also increased, but there was no statistically significant change (t=1.81, P=0.09). CONCLUSION: This study suggests that exercise participation can increase the level of future exercise behavior by increasing exercise intention and exercise-related affect.
Adaptation to bed rest or space flight is accompanied by an impaired ability to exercise in an upright position. We hypothesized that a daily, 30-min bout of intense, interval exercise in upright posture or supine against lower body negative pressure (LBNP) would maintain upright exercise heart rate and respiratory responses after bed rest. Twenty-four men (31 +/- 3 yr) underwent 5 d of 6 degree head-down tilt: eight performed no exercise (CON), eight performed upright treadmill exercise (UPex), and eight performed supine treadmill exercise against LBNP at -51.3 +/- 0.4 mm Hg (LBNPex). Submaximal treadmill exercise responses (56, 74, and 85% of VO2peak) were measured pre- and post-bed rest. In CON, submaximal heart rate, respiratory exchange ratio, and ventilation were significantly greater (P < or = 0.05) after bed rest. In UPex and LBNPex, submaximal exercise responses were similar pre- and post-bed rest. Our results indicate that a daily 30-min bout of intense, interval upright exercise training or supine exercise training against LBNP is sufficient to maintain upright exercise responses after 5 d of bed rest. These results may have important implications for the development of exercise countermeasures during space flight.
Effect of weight training exercise and treadmill exercise on postexercise oxygen consumption. Med. Sci. Sports Exerc., Vol. 30, No. 4, pp. 518-522, 1998. To compare the effect of weight training (WT) and treadmill (TM) exercise on postexercise oxygen consumption (VO2), 15 males (mean +/- SD) age = 22.7 +/- 1.6 yr; height = 175.0 +/- 6.2 cm; mass = 82.0 +/- 14.3 kg) performed a 27-min bout of WT and a 27-min bout of TM exercise at matched rates of VO2. WT consisted of performing two circuits of eight exercises at 60% of each subject's one repetition maximum with a work/rest ratio of 45 s/60 s. Approximately 5 d after WT each subject walked or jogged on the TM at a pace that elicited an average VO2 matched with his mean value during WT. VO2 was measured continuously during exercise and the first 30 min into recovery and at 60 and 90 min into recovery. VO2 during WT (1.58 L.min-1) and TM exercise (1.55 L.min-1) were not significantly (P > 0.05) different; thus the two activities were matched for VO2. Total oxygen consumption during the first 30 min of recovery was significantly higher (P < 0.05) as a result of WT (19.0 L) compared with that during TM exercise (12.7 L). However, VO2 values at 60 (0.32 vs 0.29 L.min-1), and 90 min (0.33 vs 0.30 L.min-1) were not significantly different (P > 0.05) between WT and TM exercise, respectively. The results suggest that, during the first 30 min following exercise. WT elicits a greater elevated postexercise VO2 than TM exercise when the two activities are performed at matched VO2 and equal durations. Therefore, total energy expenditure as a consequence of WT will be underestimated if based on exercise VO2 only.
Exercise has an important role to play in the prevention of child and adolescent obesity. Recent school-based interventions have struggled to achieve meaningful and lasting changes to exercise levels. Theorists have suggested that this may, in part, be due to the failure to incorporate psychosocial mediators as they relate to behaviour change. Using a sample of 580 British schoolchildren, a model grounded in self-determination theory was explored to examine the effects of exercise goals on exercise motivation, leisure-time exercise behaviour and quality of life (QoL). Results of structural equation modelling revealed that adolescents perceiving themselves to be overweight and pressurized to lose weight, endorsed extrinsic weight-related goals for exercise. Extrinsic goals negatively predicted, whereas intrinsic goals positively predicted, self-determined motivation, which in turn positively predicted QoL and exercise behaviour. Furthermore, self-determined motivation partially mediated the effects of exercise goals on reported exercise behaviour and QoL. Multi-sample invariance testing revealed the proposed model to be largely invariant across gender. Results suggest that holding extrinsic exercise goals could compromise exercise participation levels and QoL. A role for teachers and parents is proposed with the aim of orienting young people towards intrinsic goals in an attempt to enhance future exercise behaviour and QoL.
OBJECTIVE: To assess the influence of 2 single exercise sessions on blood pressure in sedentary normotensive individuals: one of resistive exercise training (circuit weight training) and the other of aerobic exercise training. METHODS: Using ambulatory blood pressure monitoring, this study assessed 25 individuals as follows: in a controlled situation at rest (ABPM 1); after resistive exercise training (ABPM 2); and after aerobic exercise training (ABPM 3). Resistive exercise training was performed as circuit weight training with an intensity of 40% of each individual's maximum strength. The aerobic exercise training was performed on a cycloergometer with intensity between 60% and 70% of the maximum heart rate (HR) reached during previous exercise testing. RESULTS: Systolic blood pressure (SBP) values during 24 hours and during subperiods of wakefulness and sleep showed no statistically significant variations when the results obtained at rest were compared with those of ABPM2 and ABPM3, and when the results of ABPM2 were compared with those of ABPM3. The mean heart rate during 24 hours and in the wakefulness period showed significant increases (P<0.05), when ABPM2 was compared with ABPM3. CONCLUSION: A single session of resistive exercise training in normotensive individuals was sufficient to cause significant reductions in blood pressure levels after exercise in the period of sleep. The session of aerobic exercise training in these same individuals was more effective in significantly reducing blood pressure levels.
Exercise thallium scintigraphy is widely used to assess prognosis in patients with suspected or proven coronary artery disease. The incremental prognostic value of this technique in patients who have good exercise tolerance has not been well studied. Two hundred ninety-nine patients with known or suspected coronary artery disease without prior myocardial infarction or revascularization procedure referred for exercise myocardial perfusion imaging and able to exercise to greater than or equal to stage III of the Bruce protocol were included. After a mean follow-up of 50 +/- 10 months, there were 15 cardiac events (5%). The incidence of cardiac events was 10 versus 3% (p less than 0.001) in patients with an abnormal versus normal thallium-201 scan, and 9 versus 3% (p = 0.03) for an abnormal versus normal exercise electrocardiogram. When the 185 patients with a normal exercise electrocardiogram were examined, the incidence of cardiac events was 3% (5 of 150) in patients with a normal scan versus 0% (0 of 35) in patients with an abnormal scan. In the 114 patients with an abnormal exercise electrocardiogram, an abnormal thallium-201 scan was predictive of cardiac events (18% [8 of 44] versus 3% [2 of 70]; p = 0.006). Stepwise logistic regression analysis selected an abnormal thallium-201 scan and abnormal exercise electrocardiogram, low peak exercise heart rate, and male gender as independent variables associated with a significant increased risk of cardiac events. Thus, in patients with known or suspected coronary artery disease and good exercise tolerance, the addition of thallium-201 imaging in patients with an abnormal exercise electrocardiogram provides useful prognostic information.(ABSTRACT TRUNCATED AT 250 WORDS)
This study compared perceived exercise self-efficacy, exercise benefits, exercise barriers, and commitment to a plan for exercise between Korean women with a diagnosis of either osteoporosis or osteoarthritis. The influence of exercise self-efficacy, exercise benefits and barriers on commitment to a plan for exercise was also assessed in each group. Participants in the study were 154 Korean women over 40 years of age who were recruited from hospitals, health centers or a nursing home. The two groups differed on commitment to a plan for exercise with commitment greater among women with osteoporosis. Exercise self-efficacy was the most influential variable on commitment to a plan for exercise accounting for 27% of the variance in commitment among osteoporosis patients and 53% of the variance among osteoarthritis patients. This study generated information relevant to tailoring exercise interventions to the differing needs and perceptions of Korean women with osteoporosis and osteoarthritis.
Health care practitioners have the technical skills, frequency of contact and credibility with older adults to use exercise as a health-promoting and disease-preventing intervention. This article acquaints the clinician with how to develop an exercise program specifically for older adults. The health-promotion and disease-prevention outcomes of exercise in older adults, including an explanation of the three stages of exercise programming for older adults, are also reviewed. Stage one is labeled pre-exercise testing and discusses assessment protocols for aerobic capacity, body composition, flexibility and strength. Guidelines for who should and should not exercise are also explored. The second stage of exercise programming is exercise prescription. An explanation of how to develop a beginning level of training and guidelines for how to set goals based on the initial pre-exercise testing are presented. Program maintenance is the third stage; this includes suggestions for designing an exercise program that increases program compliance, reduces attrition and prevents relapses to non-exercise behaviors.
BACKGROUND: Functional mitral regurgitation (MR) is common in patients with heart failure and left ventricular (LV) dysfunction, and its severity may vary over time, depending primarily on the loading conditions. Because dynamic changes in the severity of functional MR may affect forward stroke volume, we hypothesized that exercise-induced changes in MR severity influence the stroke volume response of patients with LV dysfunction to exercise, and hence their exercise capacity. METHODS AND RESULTS: Heart failure patients (n=25; mean age 53+/-12 years) with LV dysfunction underwent dynamic bicycle exercise at steady-state levels of 30%, 60%, and 90% of predetermined peak VO2. During each exercise level, right heart pressures, cardiac output, VO2, and MR severity were measured simultaneously. During exercise, MR severity, as evaluated by the ratio of MR jet over left atrium area, increased from 15+/-8% to 33+/-15%. Peak VO2, exercise-induced changes in stroke volume, and those in capillary wedge pressure correlated with the changes in MR (r=-0.55, -0.87, and 0.62, respectively, P<0.01). The changes in MR severity also correlated with those in end-diastolic (r=-0.75, P<0.01) and end-systolic (r=-0.72, P<0.01) sphericity indexes and those in the coaptation distance (r=0.86, P<0.01). CONCLUSIONS: Our data indicate that in patients with LV dysfunction, exercise-induced changes in MR severity limit the stroke volume adaptation during exercise and therefore contribute to limitation of exercise capacity.
Values of oxygen consumption, carbon dioxide production, ventilation and blood lactate concentration were determined in eight active male subjects during the minute following submaximal square-wave exercise on a treadmill under two sets of conditions. Square-wave exercise was (1) integrated in a series of intermittent incremental exercises of 4-min duration separated by 1-min rest periods; (2) isolated, of 4- and 12-min duration, and of intensity corresponding to each of the intermittent incremental periods of exercise. For square-wave exercise of the same duration (4 min) and intensity, no significant differences in the above-mentioned parameters were noted between intermittent incremental exercise and isolated exercise. Only at high work rate (greater than 92% maximal oxygen uptake), were blood lactate levels in three subjects slightly higher after 12-min of isolated exercise than after the 4-min periods of isolated exercise. Examination of these results suggests that (1) 80-90% of the blood lactate concentration observed under our experimental conditions results from the accumulation of lactate in the blood during the period of oxygen deficit; (2) therefore the blood lactate concentration/exercise intensity relationship, for the most part, appears to represent the lactate accumulated early in the periods of intermittent incremental exercise.