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At least 199 records · Page 11Linked to original sources
PubMed1983

Sudden cardiac death at exertion.

In order to investigate sudden cardiac death at exertion (sports, and light work in daily life), 226 cases of sudden death during sports and 1,729 autopsy cases of sudden death were studied, and exercise tests were performed on 138 patients with various cardiac diseases. Among sports, marathon or jogging caused sudden death most frequently (52.7%). It occurred often immediately after goal (41.3%) or before goal (28.0%), but cases with a history of heart disease died at the beginning of the race. Severe heat, overwork and other factors may precipitate the sudden death. In autopsy cases of sudden cardiac death which occurred at exertion, coronary arteriosclerosis (C) was found in 67.0%, cardiac hypertrophy of unknown etiology (H) in 7.8% and valvular heart diseases (V) in 7.1%. Sudden death in patients with C or H were more frequent at exertion than at rest. Patients with C were older and died at light work. Those with H of a high degree also died at light work, but the younger ones with a mild H died at sports activity. At exercise test, in patients with arrhythmia or hypertrophic cardiomyopathy, abnormalities may occur after exercise. Sudden death at exertion may depend on the predisposing heart disease. Care should be taken especially at the end of the race.

Adolescent↗
PubMed1996

[Evaluation of Borg's perceived exertion scale in cardiac rehabilitation].

Borg's perceived exertion scale measures the extent of perceived exertion which a person experiences during exercise. The perceived exertion scale is used to adjust exercise intensity (workload) for predictions and prescriptions of exercise intensities in sports and medical rehabilitation (BORG, 1982). In addition, Borg's scale can be used in the athletic arena, space, industry, military settings, or under everyday circumstances. The concept of perceived exertion is a subjective rating, indicating the subject's opinion about the intensity of the work being performed (MORGAN, 1973). The task of exercising subjects is to assign a number (from 1-20) to represent the subjective sensation of the amount of work being performed. This is a valuable tool in human performance setting, where an important consideration is not "what the individual is doing, but what he thinks and is doing" (MORGAN, 1973).

Exercise Test↗
PubMedDate not supplied

A critical review of the literature on ratings scales for perceived exertion.

The study of human performance and perceived exertion during physical activity has been an area of considerable interest and research for over 50 years. This review considers the evidence of many investigators who have been researching the physiological basis as well as non-physiological basis for the ratings of perceived exertion. During low levels of activity, physical perception in the working muscles appears to be the primary stimulus for effort perception. When work intensity exceeds the lactate threshold, incremental elevations in blood lactate complement peripheral input from the neuromuscular mechanisms. Once a critical absolute ventilatory threshold is reached, central input also contributes to effort perception. In most instances, peripheral input predominates over central cues, although it has been shown that pronounced central cues may dominate the perception of effort. Central (heart rate, VE, VO2) or local (muscle and blood lactate, adenosine triphosphate, creatine phosphokinase, glycogen) cues highlighted in these studies demonstrate both the complexity of effort perception, and the need for better understanding of the physiological components upon which it is based. Athletes have been shown to have a greater tendency to reduce perceptual ratings than their non-active counterparts. In view of these observations, it is apparent that a theoretical framework based upon physiological and psychological considerations may exist to support the concept of training-induced alterations in perceived exertion. This appears to be particularly true in higher ranges of exercise intensity. Part of the problem in reaching a conclusion on the issue of perceptual ratings trainability centres upon the agreement on what should be recognised as a significant decrement in perceived exertion. It is concluded that there is considerable variation in the findings of the literature and that any reported variations in performance may well be greatly influenced by intersubject variability, the type of exercise, and nutritional status of subject. Further research is required to understand this issue better.

Aerobiosis↗
PubMed2005

Controlled exertion of force by developmentally delayed young men and women.

Present purposes were to examine the characteristics of controlled force exertion in 28 developmentally delayed young people (14 men, 14 women), and sex differences compared to 28 normal young students (14 men, 14 women). The subjects matched their submaximal grip strength to changing demand values displayed in a bar chart on the display of a personal computer. The total sum of the differences between the demand value and grip exertion value for 25 sec. was used as an evaluation parameter for the test. The controlled force exertion was significantly poorer for he developmentally delayed group than for controls, and there were large individual differences. The developmentally delayed men scored poorer than women in coordination. Like the controls, the means between trials did not decrease significantly. For these developmentally delayed subjects, performance did not improve after only a few trials. The controlled force-exertion test is useful as a voluntary movement-function test for developmentally delayed subjects.

Adolescent↗
PubMed1979

Differentiated perceptions of exertion: part II. relationship to local and central physiological responses.

Differentiated ratings of perceived exertion in the legs and chest were compared to local and central physiological adjustments during submaximal cycle ergometer exercise. 50 male subjects performed three separate cycle ergometer tests. Power output was held constant at 840 kpm/min., while pedalling rate was randomly set at 40, 60, or 80 rpm. Differentiated reports of exertion from the legs were considered to be local signals and reports from the chest to be central signals. Ratings of exertion for the legs, chest and over-all body were each significantly higher at 40 rpm than 60 or 80 rpm. Heart rate, oxygen uptake, ventilation and respiratory rate were also higher at 40 rpm. Lactic acid, pH, and pCO2 were similar between pedalling rates. Lactic acid did not operate differentially to influence local perceptual signals from the legs. Central measures of respiratory and aerobic metabolic adjustments were consistent with the more intense regional report of chest exertion at 40 rpm.

Adult↗
PubMed1983

Effect of endurance training on perceived exertion and stress hormones in women.

Fifteen women (20- to 23-yr.-old), engaged in an intensive 6- to 8-wk. endurance running program, progressively increased distance from 20 miles during the first week to 50 miles during the fifth week and thereafter. Before (T1), during (T2), and after training (T3), submaximal treadmill runs of 1-hr. duration subdivided into three successive 20-min. segments were completed at approximately 60, 70, and 80% of maximal oxygen uptake, respectively. Ratings of perceived exertion (RPE) were differentiated to obtain local (L), central (C), and over-all (O) responses during these 20-min. segments. Subjects rated the effort during the final 30 sec. of each 5-min. interval. Upon completion of each exercise segment, blood samples were drawn for analysis of lactate (Hla), epinephrine (E), and norepinephrine (NE) to determine the relationship between the differentiated RPEs and these stress markers. Endurance training significantly lowered central and over-all ratings of perceived exertion between T1 and T3 runs but no change occurred in the L-RPE responses to muscular and joint strain. Significant correlations between the stress markers and RPE pooled across sessions were observed during the three treadmill sessions (Hla vs L-RPE, eta = 0.68; E vs C-RPE, eta = 0.54; and NE vs C-RPE, eta = 0.63). These findings indicate that central and over-all ratings of perceived exertion may be more readily influenced by intensive endurance training than local ratings. In addition, while lactate levels may be related to local ratings of perceived exertion, catecholamine levels appear to be associated with central ratings.

Adult↗
PubMed2002

An assessment of the validity and reliability of two perceived exertion rating scales among Hong Kong children.

This study evaluated the validity and reliability of the Chinese-translated (Cantonese) versions of the Borg 6-20 Rating of Perceived Exertion (RPE) scale and the Children's Effort Rating Table (CERT) during continuous incremental cycle ergometry with 10- to 11-yr.-old Hong Kong school children. A total of 69 children were randomly assigned, with the restriction of groups being approximately equal, to two groups using the two scales, CERT (n = 35) and RPE (n = 34). Both groups performed two trials of identical incremental continuous cycling exercise (Trials 1 and 2) 1 wk, apart for the reliability test. Objective measures of exercise intensity (heart rate, absolute power output, and relative oxygen consumption) and the two subjective measures of effort were obtained during the exercise. For both groups, significant Pearson correlations were found for perceived effort ratings correlated with heart rate (rs > or = .69), power output (rs > or = .75), and oxygen consumption (rs > or = .69). In addition, correlations for CERT were consistently higher than those for RPE. High test-retest intra-class correlations were found for both the effort (R = .96) and perceived exertion (R = .89) groups, indicating that the scales were reliable. In conclusion, the CERT and RPE scales, when translated into Cantonese, are valid and reliable measures of exercise intensity during controlled exercise by children. The Effort rating may be better than the Perceived Exertion scale as a measure of perceived exertion that can be more validly and reliably used with Hong Kong children.

Attitude to Health↗
PubMed2003

Effect of amino acid mixture intake on physiological responses and rating of perceived exertion during cycling exercise.

This study examined the effects of an amino acid mixture supplement on physiological response and ratings of perceived exertion during submaximal cycle-ergometer exercise in 15 healthy, untrained male students. Subjects performed submaximal sustained exercise (oxygen uptake at anaerobic threshold: 54.6 +/- 12.5% of maximum oxygen uptake capacity) with a cycle-ergometer ride for 60 min. after resting for 1 min. and unloaded cycling for 2 min. They drank either a 380-ml supplement containing vespa amino acids or a lemon-flavored placebo at 30 min. before starting exercise in a double-blind design. The subjects participated in both experiments over a 1-wk. interval. Oxygen uptake, respiratory exchange ratio, heart rate, ratings of perceived exertion, and plasma lactate concentration were measured during the exercise. The change-rate of respiratory exchange ratio for the Supplement group was significantly lower than that for the Placebo group at 10 min. after starting exercise. The change-rate of the ratings of perceived exertion for the Supplement group was significantly lower than that for the Placebo group at 50 min. after starting exercise. There were no significant changes in the rates in oxygen uptake, heart rate, and plasma lactate concentration between groups. We inferred that ingesting the supplement before starting exercise has a significant effect on the respiratory exchange ratio and ratings of perceived exertion during submaximal sustained exercise for 60 min. but not on oxygen uptake, heart rate, and plasma lactate concentration.

Adolescent↗
PubMed2004

Concurrent validity of tests to measure the coordinated exertion of force by computerized target pursuit.

The purpose of this study was to examine concurrent validity of a new test for coordinated exertion of force. Coordinated exertion of force was measured using computerized target pursuit from the following viewpoints: the relations between the new test, a pursuit-rotor test, and a pegboard test. College students (24 men and 24 women) were required to change their grip exertion to match changing demand values (displayed in either a bar chart or a wave form) appearing on the display of a personal computer. The sum of the differences between the demanded values and grip-exertion values for 25 sec. was a parameter to evaluate the new test. The reliabilities of the new test, the pursuit-rotor, and the pegboard test were acceptable (ICC = .70 to .99). Scores on the new test showed low correlations with the pursuit-rotor and the pegboard test. The relation between the two different displays in the new test was significant but low (r = .49, p < .05). It was inferred that the new test measures a somewhat different ability than that measured by the pursuit-rotor and pegboard test and that the abilities tested by the types of displayed demand values are somewhat different.

Adult↗
PubMed2004

Ratings of perceived exertion are not influenced by exercise stage of change in physically active college students.

Comparisons of ratings of perceived exertion based on fitness have been equivocal but have not accounted for recent exercise history. The purpose of this study was to test mean differences in ratings of perceived exertion among individuals of differing exercise histories as measured by exercise stage of change. Participants completed questionnaires to measure exercise stage of change and physical activity [preparation stage (n=32), action stage (n=31), and maintenance stage (n=41)]. Ratings of perceived exertion were measured during a graded maximal exercise test. Individual regression equations were computed to estimate the ratings for 50%, 60%, 70%, and 80% of VO2 max. There were no significant differences in the ratings across the preparation, action, and maintenance stages. Therefore, the hypothesis that recent exercise history would influence ratings of perceived exertion during an aerobic fitness test was rejected.

Adult↗
PubMed2001

Do psychosocial strain and physical exertion predict onset of low-back pain among nursing aides?

OBJECTIVES: The aim of this study was to investigate psychosocial factors and physical exertion at work in relation to the onset of low-back pain. METHODS: The study was carried out as a case-crossover investigation of nursing aides caring for the elderly. Cases were identified among 157 nursing aides over a period of 2 years. Psychosocial factors, physical exertion, and low-back pain were reported daily in diary questionnaires over three consecutive days at work, repeated in six periods of 3 days. For each subject, case observations were identified as pain onset from one day to the next and matched with reference observations with no pain onset from the same person. Prospective data collection allowed analyses to be conducted with and without a lag in time between exposure and pain onset. RESULTS: The results of the analyses with time lag (longitudinal) did not support the hypothesis that psychosocial and physical strain from 1 day of work predicts pain onset the following day. However, physical exertion, stress, and, to some extent, time pressure were associated with pain on the day of onset. CONCLUSION: The effect period, if any, of exposure to physical exertion, stress, and time pressure on the onset of acute low-back pain is considered to be less than 24 hours.

Adolescent↗
PubMed2000

Exercise hemodynamic findings in patients with exertional dyspnea.

To determine whether upright bicycle exercise could provide useful information about disabling exertional dyspnea in the absence of severe abnormalities (as shown by traditional testing methods), we evaluated 13 such patients. There were 3 men and 10 women with a mean age of 49+/-15 (SD) years. We used pulmonary artery catheterization at rest and during upright bicycle exercise to evaluate these patients. All patients had normal left ventricular function except for 1, who had an ejection fraction of 45%. The mean duration to peak exercise was 9+/-6 minutes. Normal systolic pulmonary artery pressure was defined as 25+/-5 mmHg. Four patients had normal systolic pulmonary pressure, and 9 exhibited pulmonary hypertension with exercise. In those 9, the mean mixed pulmonary venous oxygen saturation at rest was 61%+/-9% and fell to 32%+/-9% at peak exercise. Six of the 9 patients also had some degree of resting pulmonary hypertension that worsened with exercise: their mean pulmonary artery systolic pressure at rest was 47+/-14 mmHg and rose to 75+/-25 mmHg at peak exertion (P = 0.01). The other 3 patients showed no pulmonary hypertension at rest; their mean pulmonary artery systolic pressure was 27+/-6 mmHg. However, this level rose to 53+/-4 mmHg at peak exertion (P = 0.04). In this pilot study of patients with dyspnea, 9 of 13 (69%) displayed marked pulmonary hypertension with exercise. The resting hemodynamic levels were normal in 3 (33%) of those with exercise pulmonary hypertension. We conclude that hemodynamic data from bicycle exercise tests can provide additional information regarding the mechanisms of exertional dyspnea.

Catheterization, Swan-Ganz↗
PubMed1975

The importance of adrenal glands in the improved adaptation of trained animals to physical exertion.

The importance of adrenal glands in the adaptation of rats to physical exertion was studied. Exercise training, significantly increased the working ability and prevented the water accumulation in myocardial cells during acute exertion. The latter shift was characteristic of untrained animals. However, adrenalectomy abolished the benefical effect of training on working ability and myocardial adaptation to exertion. The results obtained supported the view that the effect of training is partly mediated through the improved adrenocortical function while adrenal hormones, by regulating the heart metabolism and function, significantly influenced the adaptation of rats to physical exertion.

Adaptation, Physiological↗
PubMed2003

Exertional heat illness in Air Force basic military trainees.

OBJECTIVE: Exertional heat illnesses (heat stroke, heat exhaustion, and heat cramps) are a serious problem in military operations. Air Force basic military training at Lackland Air Force Base is a prime example of where exertional heat illnesses can occur. This project was conducted to evaluate the problem o exertional heat illnesses during basic military training a Lackland Air Force Base. METHODS: Data were obtained from the Ambulatory Data System, the Air Force Reportable Event Surveillance System, and a published report in the December 1999 issue of Military Medicine (Drehner, Neuhauser, Neuhauser, and Blackwood). RESULTS: In 1999, there were 51 cases of heat illness (not necessarily exertional) among basic trainees at Lackland Air Force Base, for a rate of 1.3 per 1,000 trainees. Many of the cases (21) had the nonspecific diagnosis of "heat effect," 4 were diagnosed as heat syncope, 22 as heat exhaustion, and 5 as heat stroke. From 1956 to 1999, there were seven deaths among trainees at Lackland Air Force Base due to heat stroke. CONCLUSION: After reviewing Air Force basic military training, it is apparent that the heat stress incident rates are low. Heat injury rates are low despite being located in an area that has extremely hot temperatures. However, there are some areas, such as tracking and reporting heat illness that need improvement.

Adaptation, Physiological↗
PubMed2003

Transient cardiac dysfunction and pulmonary edema in exertional heat stroke.

Exertional heat stroke is a medical emergency that uncommonly results in severe cardiac dysfunction. The military physician diagnosed a 19-year-old military recruit from an elite unit to have exertional heat stroke. Immediate treatment in the field with rapid ice water cooling and vigorous fluid administration resulted in pulmonary edema. Transthoracic echocardiography on admission to the emergency department revealed moderate reduction in left and right ventricular function. After treatment, within a few days, rapid myocardial recovery was noted and persisted after 6 months of follow-up. Possible mechanisms of cardiac dysfunction in exertional heat stroke and treatment strategies are discussed. It is suggested that intravenous fluid administration to patients with suspected exertional heat stroke should preferably be done with appropriate hemodynamic monitoring and after cardiac dysfunction has been ruled out.

Adult↗
PubMed2003

Do Thoroughbred and Standardbred horses have similar increases in pulmonary vascular pressures during exertion?

To test the hypothesis that the pulmonary vascular pressures of Thoroughbred and Standardbred horses behave similarly during exertion. Measurements were made on 5 Thoroughbred and 5 Standardbred horses on a treadmill at rest and during 3-minute exercise intervals at speeds predicted to produce 75%, 90%, and 100% maximal heart rate. Left forelimb acceleration, heart rate, esophageal pressure, and pulmonary artery pressure were measured continuously. Pulmonary capillary and wedge pressures were measured during intermittent occlusion of the pulmonary artery. Breathing rate and gait frequency were the fundamental frequencies of the esophageal pressure and limb acceleration signals respectively. The ratio of speed:gait frequency gave stride length. The effects of exertion and breed were evaluated using two-way analysis of variance. Exertion produced significant increases in pulmonary artery (P = 0.001), capillary (P = 0.002), and wedge (P = 0.005) pressures. No significant effect of breed was detected on pulmonary artery pressure, but at exertion pulmonary capillary and wedge pressures were 15% (P = 0.03) and 23% (P = 0.04) greater in Thoroughbreds, respectively. Treadmill speed was approximately 12% greater (P = 0.04), stride length was approximately 25% greater (P = 0.0003), gait frequency was approximately 10% less (P = 0.006), breathing rate was approximately 10% less (P = 0.001), and heart rate was approximately 6% less (P = 0.06) for Thoroughbreds. There was no effect of breed on inspiratory or expiratory esophageal pressure although mean esophageal pressure was approximately 2 mmHg greater (P = 0.03) in exercising Standardbreds. In conclusion, pulmonary capillary and wedge pressures are greater in Thoroughbreds than in Standardbreds at similar fractions of maximal heart rate. This is compatible with the higher incidence of exercise-induced pulmonary hemorrhage observed in Thoroughbreds.

Analysis of Variance↗
PubMed2003

Physiologic response to a prescribed rating of perceived exertion on an elliptical fitness cross-trainer.

AIM: Perceived exertion during physical exercise is a major intrinsic factor for making decisions regarding intensity levels. The use of perceptual indices as a prescriptive guide of exercise intensity may be a valuable tool, should it be concomitant with physiological responses. The purpose of this study was to evaluate the physiologic response during exercise on an elliptical fitness cross-trainer at a prescribed level of perceived exertion. METHODS: Twenty, recreational exercisers (8 males, 12 females) were habituated to the elliptical cross-trainer and then assessed for their peak oxygen utilization (VO(2)) and peak heart rate (HR) using an incremental protocol. The point of volitional fatigue during the maximal test was used to anchor a modified Borg Category Ratio (CR-10) scale. Following a rest period of 48-72 hours, a second exercise session was performed at a prescribed perceived exertion level of 6. The subjects were instructed to manipulate the resistance and striding cadence to maintain the prescribed perceived exertion level for 15 min, during which VO(2) and HR were analyzed. RESULTS: The results from this study demonstrated that at exercise steady state, which occurred 4 min after the start of the protocol, relative VO(2) averaged 75.2+/-12.9% and relative HR was 91+/-.01%. Oxygen utilization and HR values were found to be significantly higher than a corresponding relative RPE in 20 recreational exercises when exercising on an elliptical fitness cross-trainer. CONCLUSION: This response has implications when using RPE as a prescriptive means of intensity regulation.

Adult↗
PubMed2004

The effects of rest interval and resistance training on quadriceps femoris muscle. Part II: EMG and perceived exertion.

AIM: The purpose of this study was to examine the effects of rest interval on quadriceps femoris muscle activation and perceived exertion, during short-term resistance training. METHODS: Vastus medialis (VM) and vastus lateralis (VL) muscle electromyograms (EMG) were assessed in 15 males during a sustained 80% maximal voluntary contraction (MVC). During the pre-training evaluation, the absolute value of the 80% MVC (N.m) and contraction duration (s) was performed at 2, 4, and 6 weeks during the training period. Perceived exertion was measured via the Borg category-ratio scale every 5 s during the 80% MVC. Subjects were randomly assigned to 3 groups: group 1 received a 40 s rest interval in between exercise sets, group 2 received a rest period of 160 s, and the control group did not participate in training. Groups 1 and 2 performed isokinetic knee extensions at 180 deg.s(-1) 2 days per week for 6 weeks. RESULTS: The results demonstrated a significant decrease in VM EMG within the initial portion of the 80% MVC across the training period in the short rest interval group. The long rest interval and control groups showed no significant changes in VM EMG during 1st part of the contraction across the training period, whereas the control group exhibited a significant reduction in VL EMG across weeks 4 to 6. VL EMG increased during the 80% MVC in the control group across the training period. VM EMG increased during the sustained contractions in the long rest interval and control groups across the training period. The perceived exertion response was lower in the 1st part of the 80% MVC in the short and long rest interval groups, but not in the control group, across the training period. The results also showed a significant decrease in perceived exertion at the end of the sustained contraction in the short rest interval group, but not in the long rest interval group or the control group. CONCLUSIONS: The findings from this study suggest that the application of relatively short rest intervals in between sets of resistance exercise induced a greater neuromuscular response of the VM muscle during short-term training.

Adult↗