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Resting metabolic rate before exercise vs a control day
Abstract
Investigations on resting and recovery metabolism have used both preexercise and separate control-day measurements as a baseline for comparisons. The purpose of this study was to compare preexercise resting data with nonexercise control-day resting data. Seven active men aged 25 +/- 5 y and weighing 83.2 +/- 15.4 kg followed prescribed dietary (12-h fast) and activity (48-h abstinence) preparatory protocols and were scheduled to exercise for 60 min on three separate occasions. A fourth session involved no exercise (control) and included an extended rest period. Resting metabolic rate (RMR) and heart rate measured in a semirecumbent position were not significantly different among preexercise and control conditions. Respiratory exchange ratio (RER) increased as the control rest was extended to 120 min. Reliabilities for both RMR and RER were initially high but were decreased at the end of the extended rest. These results suggest that preexercise RMR data can be used as a baseline for comparison purposes. In addition, prolonging the rest period does not appear to improve the RMR or RER values.
... In each of these studies, resting metabolism was unchanged and, of note, exercise was also examined in the same session following resting metabolic assessment. Of note, anticipation of exercise may not largely impact RMR compared to a baseline control without exercise on the same day (Thomas et al. 1994). The primary focus of these mentioned studies was, however, not on measuring resting metabolism. ...
To investigate changes in resting metabolic rate and 8-isoprostane, an oxidative stress biomarker, following acute dietary nitrate supplementation in healthy males and females. In a randomised, double-blind, cross-over study, 10 males and seven females (age range 19-25 years) underwent protocol familiarisation (visit 1), baseline assessments (visits 2 and 4) and assessments following supplementation, placebo or 6.2 mmol nitrate, 2 hours prior to visits 3 and 5. Participants completed a 30-minute RMR test with visits 2 and 3 on consecutive days, separated by a week-long washout period concluding with visits 4 and 5 on consecutive days. Plasma nitrate/nitrite (NOx) significantly increased (p 0.05) following dietary nitrate consumption compared to baseline values. No significant effect on resting metabolism (p ¼ 0.194) or 8-isoprostane (p ¼ 0.660) was observed following dietary nitrate supplementation. Dietary nitrate increases NO bioavailability, but acute supplementation does not effect resting metabolism or 8-isoprostane in healthy males and females.
Thesis (M.A.)--University of California, San Diego, 2004. Includes bibliographical references (leaves 82-95).
To measure energy expenditure (EE) of television viewing, sitting, and resting and duration of self-selected television viewing in obese and non-obese men and women.
Cross-over randomized study consisting of two separate 24-h stays in a whole-room indirect calorimeter.
123 obese and non-obese healthy men and women (age: 38 +/- 9, BMI: 29.4 +/- 7.9)
Rates of energy expenditure during resting (RMR), sitting (EEsit) and television viewing (EEtv) using indirect calorimetry technique on two separate 24-h stays in a whole-room indirect calorimeter. Physical activities and work of body movements during these periods using a large force platform system located inside the calorimeter.
Rates of EE for television viewing, adjusted for differences in body composition were 18% higher than resting metabolic rate (RMR), but similar to rates of other sedentary activities. There were no significant differences between obese and non-obese subjects in metabolic rates during resting, television viewing, and other sedentary activities. Average time of self-selected television viewing was significantly greater in obese than in non-obese subjects and also in women than in men.
EE rate for television viewing in adults is higher than RMR and similar to other sedentary activities. Obese adults choose television viewing as a form of leisure activity more often than non-obese individuals and as a result they could significantly reduce other forms of physical activities and total daily EE.
To compare the effectiveness of four dietary preparations for stabilizing resting and exercise measurements, seven male recreational exercisers (27 +/- 4 y) participated in four dietary preparations, each repeated in successive weeks: (1) 24-h random diet including an overnight fast (RAN); (2) 24-h random diet, including fast, followed by a standard meal 3 h before testing (RANM); (3) 24-h prescribed diet including an overnight fast (PRES); and (4) 24-h prescribed diet, including fast, followed by a standard meal (PRESM). After each preparation, metabolic rate (VO2) and respiratory exchange ratio (RER) were measured at rest and in association with moderate treadmill exercise. Plasma was analyzed for glucose, cholesterol, and high-density lipoprotein (HDL)-cholesterol. Repeated measures analyses of variance (ANOVAs) followed by Tukey posthoc tests indicated that resting VO2, RER, and blood parameters were not different between the two trials on the same diet. Exercise RER, however, was slightly different in trial 1 than in trial 2 for all preparations except PRESM. Combining both trials, resting VO2 and exercise RER were higher when a pretesting meal was administered. Plasma values were not different for the four dietary preparations. These results suggest that a standard overnight fast appears to be adequate for establishing representative and reproducible rest and exercise values for the parameters measured, except possibly for exercise RER reliability.
Estimation of basal metabolic rate (BMR) and daily energy expenditure (DEE) in living humans and in fossil hominins can be used to understand the way populations adapt to different environmental and nutritional circumstances. One variable that should be considered in such estimates is climate, which may influence between-population variation in BMR. Overall, populations living in warmer climates tend to have lower BMR than those living in colder climates, even after controlling for body size and composition. Current methods of estimating BMR ignore climate, or deal with its effects in an insufficient manner. This may affect studies that use the factorial method to estimate DEE from BMR, when BMR is not measured but predicted using an equation. The present meta-analysis of published BMR uses stepwise regression to investigate whether the inclusion of climate variables can produce a generally applicable model for human BMR. Regression results show that mean annual temperature and high heat index temperature have a significant effect on BMR, along with body size, age and sex. Based on the regression analysis, equations predicting BMR from body size and climate variables were derived and compared with existing equations. The new equations are generally more accurate and more consistent across climates than the older ones. Estimates of DEE in living and fossil humans using the new equations are compared with estimates using previously published equations, illustrating the utility of including climate variables in estimates of BMR. The new equations derived here may prove useful for future studies of human energy expenditure.
Postexercise oxygen consumption was investigated in eight healthy subjects. The subjects exercised for about 80 minutes at 70% of their maximum V̇O2. Following the exercise the subjects rested in bed for 24 hours. Oxygen uptake was measured continuously during the first hour after exercise, then hourly for the next 11 hours, and finally at 24 hours after exercise. Heart rate and rectal temperature were recorded continuously during the first 12 hours and then at 24 hours after exercise. Blood was sampled hourly after exercise. The results were compared with those of an identical control experiment in which the subjects rested instead of exercising. Oxygen uptake of each time point in each subject was greater after exercise compared with the control experiment. Mean total oxygen consumption after exercise was as compared to in the control experiment (P < 0.001). Also, the heart rate was higher during the first 12 hours following exercise than in the control study. No significant differences were observed in rectal temperature in the two experiments after the initial 30 minutes following exercise. The first meal taken after the cessation of exercise increased markedly the rate of oxygen consumption in comparison to the increase observed following the same meal in the control experiment. The respiratory exchange ratios were lower following exercise than in the control study. In conclusion, we have demonstrated that the excess postexercise oxygen consumption (EPOC), may persist for at least 12 hours, and possibly for 24 hours. Also, exercise caused enhancement of the stimulation in oxygen uptake seen after a meal. Thus, endurance exercise may be of importance in body weight control, not only by increasing the energy requirements during exercise, but also through its effect on basal metabolism following exercise.
1. Skinfold thickness, body circumferences and body density were measured in samples of 308 and ninety-five adult men ranging in age from 18 to 61 years.
2. Using the sample of 308 men, multiple regression equations were calculated to estimate body density using either the quadratic or log form of the sum of skinfolds, in combination with age, waist and forearm circumference.
3. The multiple correlations for the equations exceeded 0.90 with standard errors of approximately ±0.0073 g/ml.
4. The regression equations were cross validated on the second sample of ninety-five men. The correlations between predicted and laboratory-determined body density exceeded 0.90 with standard errors of approximately 0.0077 g/ml.
5. The regression equations were shown to be valid for adult men varying in age and fatness.
We examined the effect of pretesting environment on measurement of resting metabolic rate (RMR). RMR was measured in 18 older (66.1 +/- 1.4 y) individuals after an overnight stay in the Clinical Research Center (ie, inpatient) and after subjects transported themselves to the laboratory (ie, outpatient). Similar measurements were also performed after an 8-wk endurance-training program. RMR was higher (P less than 0.01) before exercise training in subjects who transported themselves to the laboratory (ie, outpatients; 4.9 +/- 0.13 kJ/min) than in inpatients (4.6 +/- 0.13 kJ/min) and after exercise training in outpatients (5.4 +/- 0.08 kJ/min) vs inpatients (5.0 +/- 0.13 kJ/min). Training increased RMR under both inpatient (10%; P less than 0.01) and outpatient (11%; P less than 0.01) conditions. We conclude that RMR is higher when measured under outpatient conditions in older volunteers. Therefore, when daily energy requirements based on the assessment of RMR are being estimated, the pretesting environment should be considered. However, the exercise-training-induced increase in RMR can be detected by using either an inpatient or an outpatient protocol.
While collating basal metabolic rate (BMR) measurements made worldwide it becomes important to know how different instruments compare with each other and whether errors in methodology could account for the differences in BMRs measured. BMRs of 34 healthy individuals were measured by using five different instruments in various combinations. Results show that energy outputs were comparable between the oxylog. Hartmann and Braun Metabolator, ventilated tent and hood, and whole-body indirect calorimeter: small differences, if any, were not statistically significant. However, significant interactions existed between subjects with the ventilated tent and hood and calorimeter when measurements were taken in subjects who were unaccustomed to the apparatus. When converting O2-consumption measurements to energy output, some instruments make assumptions that introduce a variable error in the final result, which may lead to systematic errors during the compilation of large databases of human BMRs.
This study was undertaken to determine the effect of exercise duration on the time course and magnitude of excess postexercise O2 consumption (EPOC). Six healthy male subjects exercised on separate days for 80, 40, and 20 min at 70% of maximal O2 consumption on a cycle ergometer. A control experiment without exercise was performed. O2 uptake, respiratory exchange ratio (R), and rectal temperature were monitored while the subjects rested in bed 24 h postexercise. An increase in O2 uptake lasting 12 h was observed for all exercise durations, but no increase was seen after 24 h. The magnitude of 12-h EPOC was proportional to exercise duration and equaled 14.4 +/- 1.2, 6.8 +/- 1.7, and 5.1 +/- 1.2% after 80, 40, and 20 min of exercise, respectively. On the average, 12-h EPOC equaled 15.2 +/- 2.0% of total exercise O2 consumption (EOC). There was no difference in EPOC:EOC for different exercise durations. A linear decrease with exercise duration was observed in R between 2 and 24 h postexercise. No change was observed in recovery rectal temperature. It is concluded that EPOC increases linearly with exercise duration at a work intensity of 70% of maximal O2 consumption.
In order to explore the magnitude and duration of the long-term residual effect of physical exercise, a mixed meal (55% CHO, 27% fat and 18% protein) was given to 10 young male volunteers on two occasions: after a 4-h resting period, and on the next day, 30 min after completion of a 3-h exercise at 50% VO2max. Energy expenditure and substrate utilization were determined by indirect calorimetry for 17 h after meal ingestion. The fuel mix oxidized after the meal was characterized by a greater contribution of lipid oxidation to total energy expenditure when the meal was ingested during the post-exercise period as compared with the meal ingested without previous exercise. During the night following the exercise, the stimulation of energy expenditure observed during the early recovery period gradually faded out. However, resting energy expenditure measured the next morning was significantly higher (+4.7%) than that measured without previous exercise. It is concluded that intense exercise stimulates both energy expenditure and lipid oxidation for a prolonged period.
This cross-sectional study compared physical characteristics, cardiovascular risk factors, and resting metabolic rate (RMR) in a cohort of 82 young women separated into three groups: sedentary (SED, n = 48), aerobically trained (AT, n = 21), and resistance trained (RT, n = 13). Body mass and fat-free mass (FFM) were not different between groups whereas percent body fat was lower in the AT (16.2 ± 0.7%) and RT (14.7 ± 0.8%) groups than in the SED group (21.8 ± 0.8%). There were no between-group differences for blood pressure or blood lipids. RMRs (kJ/min) for the AT (4.31 ± 0.06) and RT (4.25 ± 0.09) groups were significantly greater than those for the SED group (3.99 ± 0.05). When adjusted for differences in FFM, RMRs for the AT group (4.24 ± 0.05) were different from those of both the RT (4.13 ± 0.05) and SED (4.05 ± 0.03) groups; RMRs for the RT and SED groups were not different from each other. No differences were found in cardiovascular risk in young nonobese women of differing exercise status. Aerobic training in young women seems to increase the rate of metabolic activity of resting tissues whereas resistance training does not.
Rigorous comparison of the reliability coefficients of several tests or measurement procedures requires a sampling theory for the coefficients. This paper sum marizes the important aspects of the sampling theory for Cronbach's (1951) coefficient alpha, a widely used internal consistency coefficient. This theory enables researchers to test a specific numerical hypothesis about the population alpha and to obtain confidence intervals for the population coefficient. It also permits researchers to test the hypothesis of equality among several coefficients, either under the condition of inde pendent samples or when the same sample has been used for all measurements. The procedures are illus trated numerically, and the assumptions and deriva tions underlying the theory are discussed.
This study was undertaken to determine the effect of high intensity exercise on the time course and magnitude of excess postexercise O2 consumption (EPOC). Six healthy male subjects performed three intermittent 2-min exercise bouts on a cycle ergometer at 108% of VO2max with 3-min rest periods (3 x 2 min). O2 uptake, blood lactate, plasma catecholamines, and rectal temperature were measured while the subjects rested in bed for 14 h postexercise, and the results were compared with those of an identical control experiment without exercise. In addition, they were studied on two separate days for 2 h after only two (2 x 2 min) or one (1 x 2 min) exercise bout. O2 uptake was significantly increased for 4 h after 3 x 2 min exercise, for 60 min after 2 x 2 min, and for 30 min after 1 x 2 min exercise. EPOC was 5.6 +/- 0.41 (1 x 2 min), 6.7 +/- 0.41 (2 x 2 min), and 16.3 +/- 3.01 (3 x 2 min), respectively. Over the first hour postexercise, EPOC was linearly related to the change in blood lactate and plasma norepinephrine. However, after exhaustive supramaximal exercise O2 consumption was significantly increased for 4 h, whereas blood lactate and plasma norepinephrine concentrations were significantly increased for only 2 h.
A cross-sectional study was designed to determine the relationship between aerobic fitness and resting metabolic rate (RMR) in 69 males exhibiting a wide range of aerobic fitness levels (VO2max = 32.8-78.1 mL.kg-1.min-1). The results of this study indicated that RMR was not significantly different between trained and untrained individuals when expressed in kJ.kg fat-free weight-1.hr-1 or using an ANCOVA with fat-free weight as the covariate and RMR as the dependent variable (F ratio = 0.353, P less than 0.70). In addition, this study also failed to support a previously suggested hypothesis that an elevated RMR may only be observed in those individuals exhibiting both high VO2max values and currently training a minimum of 12-16 h/wk. Thus, the results of this study strongly suggest that RMR is independent of both a person's current aerobic level and training status.
We examined the effects of an 8-wk endurance training program (cycling exercise) on resting metabolic rate (RMR) and norepinephrine (NE) kinetics in 19 older persons (64 +/- 1.6 yr). Before and after training, RMR, NE kinetics, maximal O2 consumption (VO2max), body composition, supine blood pressure, estimated energy intake, and fasting levels of glucose, insulin, and thyroid hormones were measured. RMR increased 10% after training. Resting concentrations of NE increased 24% after training due to a 21% increase in NE appearance rate and no change in NE clearance. Training increased VO2max (14%; P less than 0.01) and energy intake (12%; P less than 0.01), whereas no change was noted in body composition. Supine blood pressure and plasma glucose were lower after training, whereas no change was noted in fasting levels of plasma insulin. The increase in RMR was associated with a higher rate of NE appearance (r = 0.57; P = 0.05) and with increase in energy intake (r = 0.56; P = 0.05). Together these two factors accounted for 49% (r2) of the variation of the change in RMR. Changes in blood pressure were not associated with changes in NE kinetics. We conclude that endurance training increases total energy expenditure in older individuals by the direct energy cost of physical activity and by elevating RMR. This increase is partially mediated by an increased NE appearance rate and increased food intake in healthy older individuals.
Despite many reports of long-lasting elevation of metabolism after exercise, little is known regarding the effects of exercise intensity and duration on this phenomenon. This study examined the effect of a constant duration (30 min) of cycle ergometer exercise at varied intensity levels [50 and 70% of maximal O2 consumption (VO2max)] on 3-h recovery of oxygen uptake (VO2). VO2 and respiratory exchange ratios were measured by open-circuit spirometry in five trained female cyclists (age 25 +/- 1.7 yr) and five untrained females (age 27 +/- 0.8 yr). Postexercise VO2 measured at intervals for 3 h after exercise was greater (P less than 0.01) after exercise at 50% VO2max in trained (0.40 +/- 0.01 l/min) and untrained subjects (0.39 +/- 0.01 l/min) than after 70% VO2max in (0.31 +/- 0.02 l/min) and untrained subjects (0.29 +/- 0.02 l/min). The lower respiratory exchange ratio values (P less than 0.01) after 50% VO2max in trained (0.78 +/- 0.01) and untrained subjects (0.80 +/- 0.01) compared with 70% VO2max in trained (0.81 +/- 0.01) and untrained subjects (0.83 +/- 0.01) suggest that an increase in fat metabolism may be implicated in the long-term elevation of metabolism after exercise. This was supported by the greater estimated fatty acid oxidation (P less than 0.05) after 50% VO2max in trained (147 +/- 4 mg/min) and untrained subjects (133 +/- 9 mg/min) compared with 70% VO2max in trained (101 +/- 6 mg/min) and untrained subjects (85 +/- 7 mg/min).
After exercise, there is a prolonged increase in O2 consumption termed the excess postexercise O2 consumption (EPOC). In this study, we have assessed the relative contribution of the triglyceride/fatty acid (TG/FA) substrate cycle to EPOC. Six healthy, young men exercised for 2 hours at 51% of maximal O2 uptake. The total energy expenditure and the rate of FA oxidation were estimated from measurements of O2 uptake, respiratory exchange ratio, and urinary nitrogen excretion while the subjects rested in bed for 3.5 hours postexercise. During the last part of the recovery period, the rate of FA mobilization was determined by infusion of glycerol. The rate of TG/FA cycling was calculated from the difference between the rate of FA mobilization and oxidation. An identical control study without exercise was also performed. The total EPOC during the recovery period was 7.82 +/- 1.51 L O2 (a 15% +/- 3% increase above the control O2 consumption). The rate of FA oxidation increased from 252 +/- 36 mumol/min (control) to 360 +/- 27 mumol/min (3 hours postexercise). The rate of FA mobilization increased from 666 +/- 108 mumol/min (control) to 1833 +/- 456 mumol/min (3 hours postexercise). TG/FA cycling was found to increase from 414 +/- 90 mumol FA/min (control) to 1473 +/- 435 mumol FA/min (3 hours postexercise). The energy cost of these rates of TG/FA cycling was found to be 0.09 +/- 0.02 kJ/min (control) and 0.31 +/- 0.09 kJ/min (3 hours postexercise). It is concluded that the energy cost of the increased TG/FA cycling rate may account for as much as half of the delayed component of EPOC.
The purpose of this study was to examine 1) the effect of two exercise intensities of equal caloric output on the magnitude (kcal) and duration of excess postexercise oxygen consumption (EPOC) and 2) the effect of exercise of equal intensity but varying duration on EPOC. Ten trained male triathletes performed three cycle ergometer exercises: high intensity-short duration (HS), low intensity-short duration (LS), and low intensity-long duration (LL). Baseline VO2 was measured for 1 h prior to each exercise condition. Postexercise VO2 was measured continuously until baseline VO2 was achieved. The duration of EPOC was similar for HS (33 +/- 10 min) and LL (28 +/- 14 min), and both were significantly longer (P less than 0.05) than the EPOC following LS (20 +/- 5 min). However, total net caloric expenditure was significantly more (P less than 0.05) for HS (29 +/- 8 kcal) than for either LS (14 +/- 6 kcal) or LL (12 +/- 7 kcal). The exercise conditions used in this study did not produce a prolonged EPOC. However, the exercise intensity was shown to affect both the magnitude and duration of EPOC, whereas the exercise duration affected only the duration of EPOC. Moreover, the duration of EPOC and the subsequent caloric expenditure were not necessarily related. Based on the resulting magnitude of the postexercise energy expenditure, it is possible that EPOC may be of some value for weight control over the long term.
Variations in BMR, body weight and energy intake were measured for 14 consecutive days in 6 young adults on ad libitum energy intakes, whose physical activity was uncontrolled. Energy intakes showed significant differences between days (P less than 0.025, CV = 6.7 per cent), between weeks (P less than 0.005, CV = 8.9 per cent) and between subjects (P less than 0.005, CV = 7.9 per cent). Energy intakes were 14 per cent higher (P less than 0.01) at weekends. Intra-individual variance contributed up to 86 per cent of the total variance in the energy intake. Replicate BMR measurements showed non-significant differences from day to day (CV less than 1.5 per cent), a training effect from week to week (P less than 0.05, CV = 1.5 per cent), and significant differences between subjects (P less than 0.001, CV = 12.4 per cent). Intra-individual variance contributed only 14 per cent to the total variance in BMR. There were no significant changes in body weight (CV = 0.7 per cent) or fat-free mass during the study. Auto-correlations of BMR, body weight and energy intake were non-significant at the different lag times studied. Cross-correlations between the above parameters were also non-significant for each subject. It is concluded that despite wide fluctuations in energy intake from day to day within an individual, the variations in BMR are small with a true CV of less than 1.5 per cent. Hence these variations are unlikely to be important while assessing energy requirements on the basis of the FAO/WHO/UNU (1985) BMR factorial method.
This study compared three techniques for indirect calorimetric measurement of resting energy expenditure: ventilated canopy, face mask, mouthpiece plus noseclips. A total of 18 healthy men and women underwent all three measurement techniques in three consecutive 20-min measurement periods in a Latin square design. No significant effects were found for either period or method with respect to oxygen consumption, respiratory exchange ratio, and caloric expenditure. Oxygen consumption was (mean +/- SD) 250 +/- 45, 251 +/- 47, and 254 +/- 49 mL/min for hood, mask, and mouthpiece, respectively (ns). The respiratory exchange ratio was lower for the hood (0.809 +/- 0.051) than mask (0.837 +/- 0.043) and mouthpiece (0.847 +/- 0.045) but this difference was not statistically significant (p = 0.07). Calculated caloric expenditure was 1.20 +/- 0.22, 1.21 +/- 0.22, and 1.23 +/- 0.23 kcal/min for hood, mask, and mouthpiece, respectively (ns). Thus, in healthy individuals similar results are obtained by the three methods and the face mask and mouthpiece are acceptable alternatives to the ventilated hood for estimation of resting energy expenditure.
This study examined the effects of intensity, mode of exercise, and aerobic fitness on the energy expended during recovery (recovery oxygen consumption, or rec VO2) following steady state exercise. Eight runners (4 males, 4 females; 22-32 yr) walked at 3.2 and 6.4 km X h-1 and ran at 8.1 and 11.3 km X h-1 (18, 33, 50, and 68% peak VO2). All subjects completed 3.2 km of walking or running each session. Eight sedentary adults (4 male, 4 female; 21-33 yr) completed the 6.4 km X h-1 test. For the runners, net rec VO2 for 3.2, 6.4, 8.1 and 11.3 km X h-1 exercise was (X +/- SE) 12.52 +/- 3.00, 29.53 +/- 5.41, 28.64 +/- 2.91, and 44.27 +/- 5.32 ml X kg-1, respectively, for the recovery period (18-48 min). Differences among group means were significant (P less than 0.05), except between 6.4 and 8.1 km X h-1 walking (29.53 +/- 5.41 and 35.09 +/- 9.39 ml X kg-1). Statements attributing substantial energy expenditure to the recovery period may be misleading to people exercising at levels similar to those described in this study, since the recovery energy expenditure only amounted to approximately 13-71 kJ (3-17 kcal).
It has been claimed that there is a prolonged thermogenic effect of aerobic exercise although the evidence is by no means conclusive. We have therefore studied the thermogenic effect of moderate aerobic exercise in the fasted and fed state in four lean subjects during weight maintenance. Exercise was performed at a constant rate on a bicycle ergometer during the initial 20 min for four successive hours. The first two exercise periods were in the fasted state while the last two followed an 800 kcal (3.4 MJ) mixed meal. Oxygen uptake increased 22% over the 165 min after the meal on rest days (p less than 0.001). There was a significant but similar elevation of mean O2 uptake during 40 min postexercise by 13.6% in both the fasted (p less than 0.001) and fed state (p less than 0.001). Sixty minutes after ceasing exercise mean O2 uptake was not different from preexercise levels (p greater than 0.05). We conclude that there is no prolonged thermogenic effect of moderate repeated aerobic exercise in weight-maintaining lean subjects. In addition there was no interaction between exercise and dietary induced thermogenesis.
It is often impossible to measure the reference standard of cardiorespiratory fitness (the maximum oxygen intake) directly, and there is thus a need for subsidiary standard procedures based on body responses to submaximal exercise. In order to reach agreement on such procedures, a recent international working party has compared a variety of possible tests involving step, bicycle, and treadmill exercise; criteria of comparison included the extent of habituation and learning with each procedure, the physiological responses, and practical considerations. There was little to commend submaximal exercise on the treadmill. Anxiety and learning were least on the bicycle ergometer, but significant anaerobic metabolism developed at loads of more than 55% of aerobic power; the main role of the bicycle was thus in laboratory tests requiring arm immobilization. The step test was cheap and portable, subjects showed relatively little anxiety or learning, and good-quality electrocardiograms were obtained: it thus seemed the procedure of choice for field tests. The results of all forms of submaximal test should be extrapolated to maximum oxygen intake in order to overcome difficulties arising from differences in the age and fitness of subjects. Four common extrapolation procedures, based respectively on one to four measurements of oxygen consumption and pulse rate, yielded similar predictions of maximum oxygen intake. A single progressive test, in which the exercise load was increased at the end of every third minute, gave an identical prediction of maximum oxygen intake to that obtained from a series of 4 discontinuous tests. The progressive test was thus the preferred procedure; however, in subjects with some circulatory delay, it might be necessary to replace the four 3-min loads by three 4-min loads.
Restingmetabohic rate and the influence of the pretesting environment Segal KR. Comparison of indirect calorimetric measurements of resting energy expenditure with a ventilated hood, face mask, and mouthpiece The influence of different methods on basal metabolic rate measurements in human subjects
- Em Berke
- Aw Gardner
- Mi Goran
- Poehhman
- Ml Sheela
- Av Kurpad
- Rn Kulkarni
- Shetty
Berke EM, Gardner AW, Goran MI, Poehhman ET. Restingmetabohic rate and the influence of the pretesting environment. Am J Chin Nutr 1992;55:626-9. 2. Segal KR. Comparison of indirect calorimetric measurements of resting energy expenditure with a ventilated hood, face mask, and mouthpiece. Am J Chin Nutr 1987;45:1420-3. 3. Soares Mi, Sheela ML, Kurpad AV, Kulkarni RN, Shetty PS. The influence of different methods on basal metabolic rate measurements in human subjects. Am J Chin Nutr 1989;50:731-6.