Assessment of physical activity by means of a calorie counter combined with an accelerometer

To establish an easy and convenient method for assessing the daily physical activity of workers, validity of a calorie counter combined with an accelerometer (KENZ Calorie Counter) was tested and compared with the method of daily survey and Stanford's interview method for energy consumption of daily physical activity. The subjects of this study were 92 volunteers. Energy expenditure of daily physical activity during 3-4 d was measured in 20 volunteers by means of a calorie counter, and the daily energy consumption was calculated from relative metabolic rates of physical activity. In the remaining 72 volunteers the energy consumption over 4-7 d was measured by means of a calorie counter and calculated from the Stanford's interview method. Correlation of the energy expenditure of daily physical activity measured by calorie counter (y) and that calculated from daily survey (x) was y = 0.74 x + 473 (r = 0.91, n = 56). Correlation of the calorie expenditure over 4-7 d measured by the calorie counter (y) and that predicted by Stanford's interview method (x) was high (y = 0.65 x + 3513, r = 0.86, n = 72). Relationship between the energy expenditure measured by the calorie counter (y) and that calculated by both daily survey and Stanford's interview method (x) showed a high correlation (y = 0.84 x + 518, r = 0.98, n = 128). These results suggest that a calorie counter combined with an accelerometer is valid for assessing the daily physical activity of workers.     

Effects of Walking Speed on Total and Regional Body Fat in Healthy Postmenopausal Women

Introduction: This study had two aims: (1) To confirm the efficacy of exercise speed and impulse (session duration at a given speed) to produce total and abdominal fat loss in postmenopausal women, and (2) compare the exercise speed and impulse necessary for the stimulation of fat loss to the suppression of bone mineral loss. Of special interest was to compare these parameters of exercise on fat loss in the same study and with the same subjects where they were found to suppress bone mineral loss. We hypothesized that (1) more total fat will be lost with slow walking and a longer impulse than with fast speed and shorter impulse, and (2) more abdominal subcutaneous (SC) and visceral fat (VF) will be lost with fast walking speed. Materials and Methods: Fat loss and suppression of bone mineral loss were measured in the same 25 subjects after 15 weeks, and fat measurements were also taken after 30 weeks in 16 residual subjects. Study parameters were walking a 4.8 km distance 4 days/week at either 6.6 km/h (120% of ventilatory threshold (VT)) or at 5.5 km/h (101.6% of VT) and expending 300 kcal/session. Body composition (fat and lean body mass, LBM) was measured with dual-energy X-ray absorptiometry (DXA) and anthropometric methods. Results: Slow walkers in the residual group progressively lost a significant percent of total body fat over 30 weeks while no such loss occurred after 15 weeks in fast walkers in either group, supporting hypothesis 1. However, the 20% higher starting body fat in 16 residual slow relative to fast subjects suggests that exercise fat loss is greater in overweight than in lean subjects. In fast walkers, fat loss occurred after 30 weeks of training. Hypothesis 2 was not supported as both speeds led to equal VF loss in 30-week group as estimated by waist circumference (CF) confirming that VF responds to the magnitude of energy expenditure and not the walking speed. Conclusions: Total body fat is lost through walking at all speeds, but the change is more rapid, clear, and initially greater with slow walking in overweight subjects. A longer exercise impulse at a lower speed in our study initially produced greater total fat loss than a shorter one with fast walking speed. This was reversed in comparison to how the same exercise in the same subjects suppressed bone mineral loss. Data from other studies indicate that longer impulses may promote greater fat loss at both slow and high exercise speeds, and our study providing only a 4.8 km walking distance may have limited the walking impulse and the magnitude of fat loss. Increased exercise energy expenditure at either walking speed produces equivalent declines in visceral fat in postmenopausal women, and with sufficiently long impulses, should reduce disabilities associated with central obesity.     

The use of uniaxial accelerometry for the assessment of physical-activity-related energy expenditure: a validation study against whole-body indirect calorimetry

Assessing the total energy expenditure (TEE) and the levels of physical activity in free-living conditions with non-invasive techniques remains a challenge. The purpose of the present study was to investigate the accuracy of a new uniaxial accelerometer for assessing TEE and physical-activity-related energy expenditure (PAEE) over a 24 h period in a respiratory chamber, and to establish activity levels based on the accelerometry ranges corresponding to the operationally defined metabolic equivalent (MET) categories. In study 1, measurement of the 24 h energy expenditure of seventy-nine Japanese subjects (40 (SD 12) years old) was performed in a large respiratory chamber. During the measurements, the subjects wore a uniaxial accelerometer (Lifecorder; Suzuken Co. Ltd, Nagoya, Japan) on their belt. Two moderate walking exercises of 30 min each were performed on a horizontal treadmill. In study 2, ten male subjects walked at six different speeds and ran at three different speeds on a treadmill for 4 min, with the same accelerometer. O2 consumption was measured during the last minute of each stage and was expressed in MET. The measured TEE was 8447 (SD 1337) kJ/d. The accelerometer significantly underestimated TEE and PAEE (91.9 (SD 5.4) and 92.7 (SD 17.8) % chamber value respectively); however, there was a significant correlation between the two values (r 0.928 and 0.564 respectively; P<0.001). There was a strong correlation between the activity levels and the measured MET while walking (r(2) 0.93; P<0.001). Although TEE and PAEE were systematically underestimated during the 24 h period, the accelerometer assessed energy expenditure well during both the exercise period and the non-structured activities. Individual calibration factors may help to improve the accuracy of TEE estimation, but the average calibration factor for the group is probably sufficient for epidemiological research. This method is also important for assessing the diurnal profile of physical activity.     

Speed and exercise intensity of recreational walkers

BACKGROUND: Brisk walking has been identified as an activity suited to meet American College of Sport Medicine/Centers for Disease Control and Prevention recommendations for moderate intensity exercise (55-69% HR(max), 40-59% VO(2)R). However, little is known about whether recreational walkers self-select a pace which elicits this intensity and how they interpret the term "brisk walking." METHODS: The walking speed of 82 adults was covertly observed in a public park. Fifty-nine of these participants demonstrated their interpretation of "brisk walking" and the speed was noted. Eleven of these subjects subsequently walked on a treadmill at their observed and "brisk walk" speeds. Heart rate (HR), respiratory gases, and ratings of perceived exertion (RPE) were measured. RESULTS: Mean observed and "brisk" walking speeds were 1.56 +/- 0.17 m. s(-1) and 1.79 +/- 0.19 m x s(-1) respectively (P < or = 0.001). Mean exercise intensities during the treadmill test (n = 11) were 59.0 +/- 13.4% VO(2max) and 67.3 +/- 11.6% HR(max) for the observed speed (1.60 + 0.24 m x s(-1)). The brisk speed (1.86 +/- 0.12 m x s(-1)) equated to 68.6 +/- 14.9% VO(2max) and 78.5 +/- 15.5% HR(max). CONCLUSION: The speed and intensity selected by this group of walkers meets current recommendations for moderate intensity exercise. Instructing individuals to "walk briskly" prompts more vigorous activity.     

Marginal vitamin C status is associated with reduced fat oxidation during submaximal exercise in young adults

Background

We examined aerobic and anaerobic exercise energy expenditure and excess post-exercise oxygen consumption (EPOC) between a 250 Watt, 1-minute bout of cycling and uphill treadmill running.

Methods

Fourteen active to well-trained subjects volunteered for the investigation (VO₂ max: 57.0 ± 12.9 ml·kg·min^-1 cycle; 59.3 ± 13.7 ml·kg·min^-1 run; p = 0.44). Anaerobic energy expenditure was estimated from △blood lactate. Statistical analysis was completed using a paired t-test (mean ± SD).

Results

Perceived exertion did not differ between exercise bouts (14.0 ± 2.3 cycle; 13.2 ± 2.1 run; p = 0.29). Exercise oxygen uptake was significantly greater for running (41.4 ± 6.9 kJ) compared to cycling (31.7 ± 7.7 kJ) (p = 0.0001). EPOC was not different between cycling and running (p = 0.21) so that exercise oxygen uptake + EPOC was greater for running (103.0 ± 13.5 kJ) as compared to cycling (85.4 ± 20.2 kJ; p = 0.008). Anaerobic energy expenditure was significantly greater for cycling (32.7 ± 8.9 kJ) versus running (22.5 ± 11.1 kJ) (p = 0.009). Aerobic + anaerobic exercise energy expenditure (cycle 64.3 ± 12.2 kJ; run 63.9 ± 10.1 kJ) (p = 0.90) and total energy expenditure (including EPOC; cycle 118.0 ± 21.8 kJ; run 125.4 ± 19.1 kJ; p = 0.36) were similar for cycling and running.

Conclusion

Oxygen-only measures reveal discrepancy in energy expenditure between cycling and uphill running. Measurements of exercise oxygen uptake, △blood lactate and a modified EPOC promote the hypothesis of a similarity in exercise and total energy expenditure between 1-minute work-equivalent bouts of cycling and uphill running.     

Determination of energy expenditure during heavy exercise, normal daily activity, and sleep using the doubly-labelled-water (2H2 18O) method

Energy expenditure of four subjects was measured by the doubly-labelled-water (2H2 18O) method to determine if energy expenditure could be determined over short periods. Three subjects were studied while they performed 8 h of heavy exercise in a laboratory environment. Urine and blood samples were taken before and after exercise. Estimated energy expended during 8 h of high-intensity exercise (55% VO2 max) for three subjects was 757 +/- 118 kcal/h by the doubly-labelled-water method using urine and a two-point calculation, which compared favorably with 735 +/- 82 kcal/h obtained by respiratory gas exchange. For the fourth subject, daytime, nighttime, and daily energy expenditure was calculated by both the two-pair method and decay-curve analysis of urine and saliva samples collected in the morning and at night. Daytime and nighttime energy expenditures differed significantly (p less than 0.05).     

Appetite, energy intake and resting metabolic responses to 60 min treadmill running performed in a fasted versus a postprandial state

This study investigated the effect of fasted and postprandial exercise on appetite, energy intake and resting metabolic responses. Twelve healthy males (mean±SD: age 23±3 years, body mass index 22.9±2.1 kg m(-2), maximum oxygen uptake 57.5±9.7 mL kg(-1) min(-1)) performed three 10 h experimental trials (control, fasted exercise and postprandial exercise) in a Latin Square design. Trials commenced at 8 am after an overnight fast. Sixty min of treadmill running at ～70% of maximum oxygen uptake was performed at 0-1 h in the fasted exercise trial and 4-5 h in the postprandial exercise trial. A standardised breakfast was provided at 1.5 h and ad libitum buffet meals at 5.5 and 9.5 h. Appetite ratings and resting expired air samples were collected throughout each trial. Postprandial exercise suppressed appetite to a greater extent than fasted exercise. Ad libitum energy intake was not different between trials, resulting in a negative energy balance in exercise trials relative to control after accounting for differences in energy expenditure (control: 9774±2694 kJ; fasted exercise: 6481±2318 kJ; postprandial exercise: 6017±3050 kJ). These findings suggest that 60 min treadmill running induces a negative daily energy balance relative to a sedentary day but is no more effective when performed before or after breakfast.     

EFFECTS OF ENDURANCE TRAINING ON ANTIOXIDANT DEFENSE MECHANISMS AND LIPID PEROXIDATION IN TESTIS OF RATS

Male rats were equally divided into trained rest (TR), trained exhaustive exercise (TE), untrained rest (UR), and untrained exhaustive exercise (UE). Endurance training consisted of treadmill running for 1.5 h/d, 5 days a week for 8 weeks reaching the speed of 2.1 km/h at the fortieth week. For acute exhaustive exercise, graded treadmill running was conducted reaching the speed of 2.1 km/h at 95th min, 10% uphill, continued until exhaustion. Testicular tissue malondialdehyde (MDA), antioxidant potential (AOP) levels, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), glutathione-S-transferase (GST), glutathione reductase (GR) and catalase (CAT) activities were determined. There was a slight decrease, but not significant, in the SOD activity in UE group compared to TE and TR groups. Activity of GSH-Px decreased in the UE group compared to UR, TR and TE groups. Acute exhaustive exercise did not affect testicular tissue GSH-Px activity in trained rats. Testicular tissue GST activity of the UE group was similar to TE group, but lower than UR and TR groups. In UE group, testicular tissue AOP values were lower than UR, TR and TE groups. The oxidative effects of acute exhaustive exercise on the rat testis decreased with endurance training. Endurance training prevents oxidative injuries by eliminating oxygen radicals and inhibiting lipid peroxidation via preventing decreases in antioxidant enzyme activities.     

Energy expenditure of nonexercise activity

BACKGROUND: We found recently that changes in nonexercise activity thermogenesis (NEAT) mediate resistance to weight gain with overfeeding in sedentary adults. A potentially important, yet seldom investigated, component of NEAT is the energy expenditure of fidgeting-like activities. OBJECTIVE: Our goal was to measure changes in energy expenditure with fidgeting-like activities. DESIGN: Energy expenditure was measured in 24 subjects (17 women and 7 men x+/- SD body weight: 76 +/- 21 kg) while recumbent at rest, sitting motionless, standing motionless, partaking of self-selected fidgeting-like movements while seated and while standing, and walking on a treadmill at 1.6, 3.2, and 4.8 km/h (1, 2, and 3 mph). Measurements were performed by using a high-precision, indirect calorimeter connected to the subject via a transparent, lightweight facemask that enabled almost unrestricted movement. RESULTS: Compared with metabolic rate in the supine position (5.4 +/- 1.5 kJ/min), energy expenditure increased while sitting motionless by 4 +/- 6%, while fidgeting while seated by 54 +/- 29% (P: < 0.0001), while standing motionless by 13 +/- 8% (P: < 0.0001), while fidgeting while standing by 94 +/- 38% (P: < 0.0001), while walking at 1.6 km/h by 154 +/- 38% (P: < 0.0001), while walking at 3.2 km/h by 202 +/- 45% (P: < 0.0001), and while walking at 4.8 km/h by 292 +/- 81% (P: < 0.0001). There was a significant, positive correlation between changes in energy expenditure and body weight for fidgeting-like activities while standing (r = 0.43, P: = 0.02) but not while seated. CONCLUSIONS: There is marked variance between subjects in the energy expenditure associated with self-selected fidgeting-like activities. The thermogenic potential of fidgeting-like and low-grade activities is sufficiently great to substantively contribute to energy balance.     

The necessity of motivation for acquiring the habit of exercise by means of a calorie counter combined with an accelerometer

The development of the habit of exercise is necessary for workers whose daily occupation prevents them from doing physical activities. However, few workers have acquired this habit of exercise. To motivate such workers, the validity of a calorie counter combined with an accelerometer (KENZ Calorie Counter or KENZ Calorie Counter alpha) was tested as a motivation tool for acquiring this habit. The subjects of this study were 14 volunteers. After 7 days' preliminary measurement of their physical activities by a calorie counter, they continued to measure the energy consumption of their physical activities over one month. Ten volunteers were able to continue the measurement, but 4 volunteers dropped out. The energy consumption of physical activities after one month measurement significantly (P less than 0.001) increased to 70% more than that of the preliminary measurement. At the present time, nine volunteers are continuing to measure their daily energy consumption. The results suggest that the measurement of one's daily physical activities by a calorie counter is one of the best ways to develop the habit of exercise.     

青少年体力活动摄氧量预测方法的实验研究

[目的]建立适用于青少年的体力活动摄氧量预测方法。[方法]将80名青少年随机分为公式组60名和回代验证组20名,每组男女各半。公式组在跑台上以2、3、4、5、6、7、8 km/h的速度运动,每级负荷持续2.5 min,回代验证组以4.8、6.3、8.1 km/h的速度在场地运动,每级负荷持续10 min。在两组青少年按不同运动方案运动时测量其气体代谢参数和心率。公式组用统计学方法建立摄氧量预测方程,用回代验证组测量结果进行回代检验。用公式组4、6、8 km/h三种速度下的摄氧量实测值与所建公式、美国运动医学会(ACSM)推荐公式的预测值比较。[结果]建立了摄氧量预测的回归方程,男性:摄氧量(mL/min)=17.24×负荷心率+8.76×瘦体重(kg)-1288.22;女性:摄氧量(mL/min)=18.72×负荷心率+5.61×瘦体重-1588.79。预测摄氧量的平均相对误差均<10%,标准误差(SE)和总体误差(E)均低于ACSM公式。[结论]以负荷心率和瘦体重为自变量建立的摄氧量预测的多元回归方程,精确性优于ACSM推荐的公式,更适用于我国青少年体力活动摄氧量的预测。     

Effects of exercise intensity on food consumption in the male rat.

The effects of two different levels of exercise of equal caloric cost on food consumption and body weight changes was investigated in 24 male rats (initial body weight = 378.3 g, SD = 22.3 g). Open circuit spirometry was used for the collection of respiratory gas exchange during running on the treadmill and these data were used to equate two intensities of exercise to the same caloric expenditure. Food consumption was measured 1 hr, and every 4 hr thereafter for 24 hr during 2 alternate weeks of exercise and rest. Results showed that high intensity exercise (16 m . min-1, 10% mill grade) resulted in depressed food consumption and depressed body weight gain than low intensity exercise (5 m . min-1, zero percentage mill grade) of equal caloric expenditure. Both exercise groups had depressed food consumption and rate of body weight change compared to nonexercise animals.     

Utility of the actiheart accelerometer for estimating exercise energy expenditure in female adolescent runners

There is a growing need to accurately assess exercise energy expenditure (EEE) in athletic populations that may be at risk for health disorders because of an imbalance between energy intake and energy expenditure. The Actiheart combines heart rate and uniaxial accelerometry to estimate energy expenditure above rest. The authors' purpose was to determine the utility of the Actiheart for predicting EEE in female adolescent runners (N = 39, age 15.7 ± 1.1 yr). EEE was measured by indirect calorimetry and predicted by the Actiheart during three 8-min stages of treadmill running at individualized velocities corresponding to each runner's training, including recovery, tempo, and 5-km-race pace. Repeated-measures ANOVA with Bonferroni post hoc comparisons across the 3 running stages indicated that the Actiheart was sensitive to changes in intensity (p < .01), but accelerometer output tended to plateau at race pace. Pairwise comparisons of the mean difference between Actiheart- and criterion-measured EEE yielded values of 0.0436, 0.0539, and 0.0753 kcal × kg-1 × min-1 during recovery, tempo, and race pace, respectively (p < .0001). Bland-Altman plots indicated that the Actiheart consistently underestimated EEE except in 1 runner's recovery bout. A linear mixed-model regression analysis with height as a covariate provided an improved EEE prediction model, with the overall standard error of the estimate for the 3 speeds reduced to 0.0101 kcal × kg-1 × min-1. Using the manufacturer's equation that combines heart rate and uniaxial motion, the Actiheart may have limited use in accurately assessing EEE, and therefore energy availability, in young, female competitive runners.     

Calorie supply does not alleviate running-based taste aversion learning in rats

Voluntary running establishes aversion to the paired taste in rats. A proposed mechanism underlying this taste aversion learning is energy expenditure caused by the running. The energy expenditure hypothesis predicts that running-based taste aversion should be alleviated by a calorie supply since this would compensate for the energy expended by running. Accordingly, running-based taste aversion would be less readily established to a caloric substance (20% sucrose solution) than to a noncaloric substance (0.2% sodium saccharin solution). Because the sucrose and saccharin aversions were equivalent in Experiment 1, the validity of the energy expenditure hypothesis was questioned. Experiments 2 and 3 also pose a problem for this hypothesis, as post-session calorie supply by glucose tablets failed to alleviate running-based aversion to salty water.     

The evaluation of serum creatine phosphokinase for estimation of energy expenditure in human subjects]

We investigated the relationship between serum creatine phosphokinase (CPK) activity and energy expenditure in young adults and evaluated whether serum CPK activity is a useful index of energy expenditure. These data were obtained from 225 (men: 94, women: 131) healthy young adults. The results of the survey were as follows: In men, there was a statistically significant correlation between serum CPK activity and energy expenditure (r = 0.370; p less than 0.01; y = 1986.0 + 8.2x), energy expenditure/body weight (r = 0.270; p less than 0.01 y = 35.4 + 0.06x) and daily activity index (r = 0.357; p less than 0.01; y = 0.38 + 0.0030x) In women, there was a statistically significant correlation between serum CPK activity and energy expenditure (r = 0.207; p less than 0.05; y = 1895.0 + 3.0x), and daily activity index (r = 0.194; p less than 0.05; y = 0.432 + 0.0017x). The higher the proportion of exercising subjects, the higher was the serum CPK activity. These results suggest that measurement of serum CPK activity can be used to evaluate energy expenditure.     

Energy cost of physical activity in cystic fibrosis

OBJECTIVE: The purpose of this study was to compare the energy cost of standardized physical activity (ECA) between patients with cystic fibrosis (CF) and healthy control subjects. DESIGN: Cross-sectional study using patients with CF and volunteers from the community. SETTING: University laboratory. SUBJECTS: Fifteen patients (age 24.6+/-4.6 y) recruited with consent from their treating physician and 16 healthy control subjects (age 25.3+/-3.2) recruited via local advertisement. INTERVENTIONS: Patients and controls walked on a computerised treadmill at 1.5 km/h for 60 min followed by a 60 min recovery period and, on a second occasion, cycled at 0.5 kp (kilopond), 30 rpm followed by a 60 min recovery. The ECA was measured via indirect calorimetry. Resting energy expenditure (REE), nutritional status, pulmonary function and genotype were determined. RESULTS: The REE in patients was significantly greater than the REE measured in controls (P=0.03) and was not related to the severity of lung disease or genotype. There was a significant difference between groups when comparing the ECA for walking kg radical FFM (P=0.001) and cycling kg radical FFM (P=0.04). The ECA for each activity was adjusted (ECA(adj)) for the contribution of REE (ECA kJ kg radical FFM 120 min(-1)--REE kJ kg radical FFM 120 min(-1)). ECA(adj) revealed a significant difference between groups for the walking protocol (P=0.001) but no difference for the cycling protocol (P=0.45). This finding may be related to the fact that the work rate during walking was more highly regulated than during cycling. CONCLUSIONS: ECA in CF is increased and is likely to be explained by an additional energy-requiring component related to the exercise itself and not an increased REE.     

Effects of respirators under heat/work conditions

Physiological responses and perceived strain of five unacclimatized male subjects were studied. The subjects were exposed to heat during an exercise task and were evaluated while wearing half and full facepiece, cartridge-type, air-purifying respirators, and without a respirator. The exercise consisted of walking on a treadmill for a period of 1 hour in a controlled environmental chamber at each of two different energy expenditure levels (200 and 400 Kcal/hr) (approximately equal to 58 and 116 Watts) and two different heat exposures (air temperatures of 25 degrees C and 43.3 degrees C). The results indicated that wearing a full facepiece respirator imposed significant physiological strain added to that caused by the heat and workloads used in the study. Five of the six physiological measures show this increased physiological strain: heart rate; minute ventilation; oxygen consumption; energy expenditure; and oral temperature. There was no detectable effect on sweat rate. Although subjective ratings indicated more discomfort with increasing physiological strain, the observed correlations between such measures were low (Tb less than .60). The net consequence of the significant effects indicates that workers' tolerance to moderate or higher levels of work under hot conditions while wearing a respirator is reduced. The reduction is more pronounced when wearing a full mask than when wearing a half mask. Changes in respirator design which minimize respiratory dead space are suggested to alleviate this problem. Otherwise, prevention of excessive physiological strain from respirator use when working at moderate or higher levels at hot job sites could necessitate more rest breaks or limiting work time under such conditions.     

Effects of dietary protein level on the energy metabolism of rats during exercise.

The experiments were designed to study the effects of exercise of various intensities in albino rats fed diets containing 8 per cent or 20 per cent casein. Male rats about 7 weeks old were divided into exercise groups and control (non-exercise) groups. The exercise groups were forced to run 57 km or 76 km in total during a 28-day period. The oxygen uptake of rats was measured in order to study the influence of exercise on energy metabolism of rats and the effects of training. Body weight and food intake were also measured. 1. In all exercise groups the total amount of food intake and body weight gain during the exercise period were smaller than those of the control groups, regardless of the protein levels of the diets. but while the rats were kept at rest after the exercise period, the food intake and body weight of these groups increased and approached those of the control groups. 2. No difference in resting metabolism was observed both in the 8 per cent and 20 per cent casein groups. At lower speeds up to 1.5 km/hr the 8 per cent casein group indicated lower oxygen requirement during the exercise but at speeds higher than 2.0 km/hr the oxygen requirement was definitely higher than that of the 20 per cent casein group. The estimated optimum speed for rats weighing 300 g on the average is somewhere between 1.5 and 2.0 km/hr is calculated on the basis of oxygen requirement for running 100 m. 3. The obvious effects of training on oxygen uptake were seen in the 20 per cent casein group after four weeks' training, although no effect was found in the 8 per cent casein group.     

Twenty-four-hour energy expenditure in pregnant and nonpregnant Gambian women, measured in a whole-body indirect calorimeter.

Twenty-four-hour energy expenditure (EE), daily and sleeping EE, and the energy cost of a standardized treadmill exercise were assessed in a respiration chamber in 41 young pregnant Gambian women at 12 (n = 11), 24 (n = 15), and 36 (n = 15) wk of gestation and compared with 13 nonpregnant nonlactating (NPNL) control women. The rate of 24-h EE was significantly higher (P less than 0.001) at 36 wk gestation (8443 +/- 243 kJ/d) than in the NPNL group (6971 +/- 172 kJ/d) or at 12 and 24 wk (7088 +/- 222 and 7188 +/- 192 kJ/d, respectively). Per unit body weight, no more differences in 24-h EE, daily and sleeping EE, or energy cost of walking were observed between pregnant and NPNL women. There was no statistical difference in the 24-h respiratory quotient among the groups. We conclude that the state of pregnancy in Gambian women induces a progressive rise in 24-h EE, which becomes significant in the third trimester and is proportional to body weight.