Extra Energy Expenditure Research Articles

Influence of palatability on motivation to operate for caloric and non-caloric food in non food-deprived and food-deprived rats

Palatability is the hedonic food component that is considered to override the homeostatic mechanisms that control food intake, and we compared how much effort non food-deprived and food-deprived rats were willing to spend in order to earn a palatable caloric (sucrose) or non-caloric (saccharin) snack. We first studied the dopaminergic response, in terms of dopamine levels and dopamine and cAMP-regulated phosphoprotein Mr 32,000 (DARPP-32) phosphorylation pattern, to two consecutive palatable caloric or non-caloric snacks in the nucleus accumbens shell (NAcS) of non food-deprived and fasted rats. We report that non food-deprived rats developed rapid habituation in the NAcS dopaminergic response to the second consumption of both caloric and non-caloric palatable food, while food-deprived rats developed rapid habituation only to saccharin. Next, we show that in self-administration experiments, non food-deprived rats spent a similar effort when operating for sucrose or saccharin. However, the same rats showed an increased response specifically for sucrose after 18-h fasting. After pre-feeding devaluation, rats reduced their response to sucrose but not for saccharin.These results strengthen the hypothesis that food intake is mainly controlled by palatability in non food-deprived rats and by caloric content in food-deprived rats. Moreover, they show that rapid habituation development was associated with a similar, basal working activity aimed at ingesting both caloric and non-caloric food, as observed in non food-deprived rats consuming sucrose or saccharin and in fasted rats consuming saccharin. Conversely, lack of habituation, as present in fasted rats consuming a caloric food, was associated with extra energy expenditure.

Energy Expenditure And Comfort During Nordic Walking And Ordinary Walking

It is a characteristic of Nordic Walking that energy expenditure is greater during this fitness activity than during ordinary walking. As much as 23% greater energy expenditure has been reported. The amount of extra energy expenditure during Nordic Walking most likely depends on how vigorously the Nordic Walking is performed. However for another important characteristic of fitness exercise, it is unknown how comfort compares for Nordic Walking and ordinary walking. PURPOSE: To compare energy expenditure and comfort during Nordic Walking and ordinary walking. METHODS: Twelve participants (mean±SEM: 171.5±1.5 cm, 67.0±2.7 kg, 50.6±2.4 years, maximal oxygen uptake of 43.4±2.8 ml kg-1 min-1) performed 6-min bouts of uphill (12°), downhill (12°), and horizontal Nordic Walking as well as ordinary walking on a motorized treadmill with their preferred pole length of 67.6±0.6% of body height. Energy expenditure was calculated from measured oxygen uptake while comfort was self-rated on a 1- to 10-point scale where 1 and 10 corresponded to "very, very uncomfortable" and "very, very comfortable", respectively. RESULTS: Nordic Walking required as much as 65±12% greater energy expenditure (p<0.05) than ordinary walking with the greatest difference observed for the horizontal condition. During uphill and downhill conditions, energy expenditure for Nordic Walking was 8±2% and 55±12% higher, respectively (p<0.05). Nevertheless, comfort was similar for the two types of locomotion for each slope (p>0.05). Illustrating the peculiarity of Nordic Walking, comfort was 7.3±0.6 at the same time as participants exercised at more than 85% of their maximal oxygen uptake during uphill Nordic Walking. CONCLUSION: Comfort responses were generally high and at the same time similar for Nordic Walking and ordinary walking for each slope condition despite greater energy expenditure during Nordic Walking. The substantially larger energy expenditure of Nordic Walking compared to previous studies reflects the particularly vigorous Nordic Walking technique used here. From a physical activity and public health perspective it is noteworthy that Nordic Walking (vs. other forms of physical activity, e.g. running) is comfortable and apparently gentle on the body for many people, even when performed at a considerable cardiovascular load.

Rotational and continuous grazing of sheep in the Inner Mongolian steppe of China

The aim of this study was to compare the effects of rotational and continuous grazing on herbage mass (HM), organic matter digestibility (dOM) and intake (OMI) and live weight gain (LWG) of sheep grazing on the inner Mongolian steppe, China at a stocking rate of 4.5 sheep/ha during the growing season. In the years 2005 and 2006, four 2-ha plots were used of which two were divided into four 0.5 ha paddocks each for rotational grazing, where sheep were moved each 10 days to the next paddock. The dOM was estimated from faecal crude protein concentration and OMI by oral administration of titanium dioxide. Herbage mass was similar in both grazing systems and dOM and OMI were higher (p < 0.05) at continuous grazing than at rotational grazing, but LWG did not differ probably because of extra energy expenditure for grazing and walking in a larger area. The dOM and OMI decreased (p < 0.05) with progress of the growing season and differed between years. Since precipitation during the growing season in both years was lower than the 30 years average which was probably the reason that positive effects of non-grazing periods on herbage regrowth and quality at rotational grazing could not occur, further studies are required in years with average precipitations before a final evaluation of these grazing systems can be made. Moreover, it seems necessary to quantify energy expenditure for physical activity of animals in grazing studies.

Growth in response to sustained swimming in young montezumae swordtails, Xiphophorus montezumae

This study tested the effect of sustained swimming on growth, ingestion rate, and morphology of juvenile montezumae swordtails (Xiphophorus montezumae). Because montezumae swordtails inhabit running freshwater systems, it was expected that moderate exercise would increase feeding and growth rates, promoting also the hydrodynamic form of the fish. Experimental groups were subjected to different levels of sustained exercise by being forced to swim against water currents at four different velocities (0, 4.1, 7.8, and 12.9 cm/s). The results showed that growth-rate decrease in fish forced to swim, while the increase in exercise did not modify the ingestion rate. Thus, it is likely that the extra energy expenditure associated with the swimming cost was not compensated by an increase in food ingestion. Sustained exercise increased the fineness ratio towards a more hydrodynamic form. Morphological traits linked with minimum drag, such as caudal peduncle depth and amplitude of the caudal fin were not modified. Our results suggest that water velocity has an important role determining the physiology and, to a lesser extent, the morphology of young montezumae swordtails.

Energy expenditure of walking at different intensities in Brazilian college women

Current recommendations state that all subjects should engage in at least 30 min of moderate intensity physical activity assuming an extra energy expenditure (EE) of 836kJ. To determine the EE of walking at different intensities, to check whether the EE of walking could be estimated by intensity codes and to determine the time necessary to expend 836 kJ while walking. Resting and walking EE in a treadmill (67/0; 93.8/0; and 93.8 m min(-1)/2.5% slope) were measured by indirect calorimetry in 58 healthy college-aged women. Walking EE was compared (paired Student t-tests) with estimated EE using the physical activity ratio values from FAO/WHO/UNU and the MET codes published in the Compendium of Physical Activities. Average EE increased from 12.1 (1.9) to 18.6 (2.9) kJ min(-1) or 3.5 (0.5) to 5.4 (0.7) kJ min(-1) multiples of measured MET. Walking EE at the two first intensities could be correctly estimated by the MET codes but according to age-dependent classification walking could only be considered moderate at the highest intensity. For the extra amount of 836 kJ these women would have to walk for at least 46 min at the highest intensity. EE of walking at ground level can be accurately estimated by MET codes but it is necessary to walk much longer than 30 min to reach the recommended level of EE for good health in college-aged Brazilian women.

Effort/gains dynamics in heterogeneous networks

AbstractWe investigate the behaviour of TCP(α, β) protocols in the presence of wireless networks. We seek an answer to strategic issues of maximizing energy and bandwidth exploitation, without damaging the dynamics of multiple‐flow equilibrium. We take a fresh perspective on protocol design: What is the return of the effort that a protocol expends? Can we achieve more gains with less effort? We study first the design assumptions of TCP(α, β) protocols and discuss the impact of equation‐based modulation of α and β on protocol efficiency. We introduce two new measures to capture protocol behaviour: the ‘Extra Energy Expenditure’ and the ‘Unexploited Available Resource Index’. We confirm experimentally that, in general, smoothness and responsiveness constitute a tradeoff; however, we show that this tradeoff does not graft its dynamics into a conservative/aggressive behaviour, as it is traditionally believed. We uncover patterns of unjustified tactics; our results suggest that an adaptive congestion control algorithm is needed to integrate the dynamics of heterogeneous networks into protocol behaviour. Copyright © 2007 John Wiley &amp; Sons, Ltd.

A NEAT Way to Control Weight?

Why do some people remain slimmer than others? The answer may be in the amount of time lean individuals spend fidgeting, standing and walking around compared with sitting still. As [Ravussin][1] explains in a Perspective, a followup study by [ Levine et al .][2] now pinpoints sitting as an important culprit of weight gain. Just sitting for 2.5 hours less each day would result in an extra energy expenditure of 350 kcal/day, which the authors calculate could translate into preventing the gain of extra pounds. [1]: http://www.sciencemag.org/cgi/content/full/307/5709/530 [2]: http://www.sciencemag.org/cgi/content/short/307/5709/584

Energy effects associated with e-commerce: A case-study concerning online sales of personal computers in The Netherlands

The introduction of e-commerce is changing purchase and distribution patterns dramatically. One of the observed effects is that logistics become more efficient as products are directly shipped from a manufacturer or wholesaler to an end-user. Another effect is that market transparency increases, which has a downward pressure on prices of many products sold via the Internet. This article addresses the energy implications of e-commerce at the micro level. This is done by quantifying the transport related energy savings in the case of a Dutch online computer reseller and by assessing the extra energy expenditure associated with increased buying power of online buyers. It is found that energy use per article sold by the online computer reseller is lower. However, taking into account indirect effects such as increased consumer buying power, there are scenarios that lead to an overall increase in energy use.

MOLT DURING SPRING MIGRATION: A COMPARISON OF FOUR SPECIES OF RAPTORS

We quantified the extent of molt in Steppe Buzzards (Buteo buteo vulpinus), Marsh Harriers (Circus aeruginosus), Levant Sparrowhawks (Accipiter brevipes), and Eurasian Sparrowhawks (A. nisus) caught during spring migration 1985–1988 in Elat, southern Israel. Ten percent of yearling Steppe Buzzards (58 of 550) and four percent of yearling Marsh Harriers (3 of 77) were actively molting their remiges while on migration. These findings are contrary to suggestions that birds do not molt their flight feathers during migration when they should avoid extra energy expenditure and maintain flight performance. Active molt of primaries and secondaries, however, was not found among adult buzzards and harriers, or in any individual of the two Accipiter species. Molt strategies may be related to differences in flight mode during migration between species that primarily soar (buzzards and harriers) and species that flap more (sparrowhawks). Body condition was not related to the state of molt. This, and the fact that only yearling birds were in active molt of remiges, suggest that a delay in arrival on the breeding grounds may be a significant cost of molt during spring migration.

Goats Locomotion Energy Expenditure under Range Grazing Conditions: Seasonal Variation

The estimation of the energy cost of various activities using calorimetric techniques in conjunction with direct field observations can be used to estimate energy expended in the daily activities of free-ranging animals. The objective of this study was to observe and quantify the grazing activities and to estimate the energy expenditure due to locomotion of goats in open range. The study was carried out at 'Finca de Bonaya' privatelyowned site, which extends over 1,482 ha, located in the Nevada mountain-range, Almeria. The local altitude varies from 1,100 to 2,000 m above sea level. The area has a mediterranean mountain climate, with annual precipitation ranging from 400 to 700 mm and average daily temperatures from 4.7?C in winter to 23.0?C in summer. Landscape is characterised by holm-oak wood and pine wood, degradation scrubs and hydrophilic grasses communities. The experimental flock grazed on 3 routes during the whole year. The goats were released to graze during the day and then returned to an enclosed shed. The type of goat management was considered as semi-extensive. Direct observation was used to simulate the total distance walked, the vertical ascent or descent, and to quantify other grazing activities. Data on activities on range and distance travelled were taken on 3 days in each season. The energy expenditure of locomotion was calculated from the horizontal and vertical components of travel and the corresponding costs, which had been previously obtained by calorimetry. There was no significant seasonal effect on period devoted to specific activities on range (P>0.05). However, significant changes in the estimated daily energy expenditure and extra energy expenditure due to locomotion of the animals at pasture were found in different seasons (P<0.05). Grazing and walking were the primary activities of goats throughout the study, accounting for 51.7 and 42.0% of the animals' daily period on range, respectively. Daily travelled distances by goats on range fluctuated from 12,777 m in summer to 8,100 m in autumn, with an annual average of 9,954 m, which represents a mean speed of 20.8 m/min calculated over the whole period on range. The mean annual vertical ascent or descent was 500 m. Estimated heat production due to locomotion ranged from 130.9 to 88.5 kJ/kg0 75 per day in summer and autumn respectively. These values account for an increased metabolizable energy (ME) requirement at pasture above maintenance of 46.6 and 31.6%, respectively, assuming a ME requirement for maintenance of 401 kJ/kg075 per day for the restrained goat.

Effect of moderate physical activity on plasma leptin concentration in humans.

In subjects who maintain a constant body mass, the increased energy expenditure induced by exercise must be compensated by a similar increase in energy intake. Since leptin has been shown to decrease food intake in animals, it can be expected that physical exercise would increase energy intake by lowering plasma leptin concentrations. This effect may be secondary either to exercise-induced negative energy balance or to other effects of exercise. To delineate the effects of moderate physical activity on plasma leptin concentrations, 11 healthy lean subjects (4 men, 7 women) were studied on three occasions over 3 days; in study 1 they consumed an isoenergetic diet (1.3 times resting energy expenditure) over 3 days with no physical activity; in study 2 the subjects received the same diet as in study 1, but they exercised twice daily during the 3 days (cycling at 60 W for 30 min); in study 3 the subjects exercised twice daily during the 3 days, and their energy intake was increased by 18% to cover the extra energy expenditure induced by the physical activity. Fasting plasma leptin concentration (measured on the morning of day 4) was unaltered by exercise [8.64 (SEM 2.22) 7.17 (SEM 1.66), 7.33 (SEM 1.72) 1 microg x l(-1) in studies 1, 2 and 3, respectively]. It was concluded that a moderate physical activity performed over a 3-day period does not alter plasma leptin concentrations, even when energy balance is slightly negative. This argues against a direct effect of physical exercise on plasma leptin concentrations, when body composition is unaltered.

The effect of moderate exercise on postprandial glucose homeostasis in NIDDM patients.

The influence of exercise on glycaemia in the post-prandial state was studied for the first time in non-insulin-dependent diabetic (NIDDM) patients. Meal-induced glucose responses were followed for 8 h in 9 diet-treated patients with NIDDM. Subjects consumed a standardized breakfast and 4 h later a standardized lunch. They were studied in the resting state (control day (CD)) and on another day 45 min of bicycle exercise (53 +/- 2% VO2max (mean +/- SEM)) was performed 45 min after breakfast (exercise day (ED)). On day 3 (diet day (DD)), the breakfast meal was reduced corresponding to the extra energy expenditure during the exercise period on ED. Responses were calculated as areas under the plasma concentration curve (AUC) during 4 h after either breakfast (B-AUC) or lunch (L-AUC). B-AUC for glucose was identical on ED (215 +/- 63 mmol/l.240 min) and DD (219 +/- 60 mmol/l.240 min) and on these days lower (p < 0.05) than on CD (453 +/- 78 mmol/l.240 min). L-AUC for glucose on CD, ED and DD did not differ significantly. B-AUCs for both insulin and C-peptide were also significantly lower on ED and DD as compared to CD (Insulin: 31337 +/- 8682, 26092 +/- 6457 and 47649 +/- 15046 mmol/l.240 min, respectively. C-peptide: 99 +/- 19, 104 +/- 26 and 195 +/- 31 pmol/ml.240 min, respectively). Rate of appearance (Ra) for glucose was unaffected by exercise whereas rate of disappearance (Rd) increased significantly. No differences in Ra or Rd were observed after lunch. In conclusion, post-prandial exercise of moderate intensity decreases glycaemia and plasma insulin levels after breakfast in NIDDM patients, but this effect does not persist during and after the following lunch meal. Reduction of breakfast caloric intake has the same effect on post-prandial glycaemia and insulin secretion as an equivalent exercise-induced increase in caloric expenditure.

Resting Energy Expenditure in Interstitial Lung Disease

Because interstitial lung disease increases the work of breathing, the aim of this study was to determine if this condition is associated with increased energy requirements. A group of 12 clinically stable patients with interstitial lung disease was studied. Patients with a history of weight loss had significantly more severe lung volume restriction. Regression analysis showed that 42% of body weight variation was explained by vital capacity (p less than 0.025). Resting energy expenditure was measured by standard methods of indirect calorimetry. The measurements were performed with a ventilated hood during prolonged steady-state periods after an overnight fast. We found that resting energy expenditure was increased to 117.3 and 118.7% of the predicted basal metabolic rate, according to Fleisch and to Harris and Benedict reference values, respectively (p less than 0.001). Furthermore, resting energy expenditure was increased to 120.8% of the predicted value according to body fat-free mass (p less than 0.001). This extra energy expenditure in patients with interstitial lung disease is similar to that recently reported in patients with chronic obstructive pulmonary disease.

Role of thermogenesis in the regulation of energy balance in relation to obesity.

Obligatory thermogenesis is a necessary accompaniment of all metabolic processes involved in maintenance of the body in the living state, and occurs in all organs. It includes energy expenditure involved in ingesting, digesting, and processing food (thermic effect of food (TEF]. At certain life stages extra energy expenditure for growth, pregnancy, or lactation would also be obligatory. Facultative thermogenesis is superimposed on obligatory thermogenesis and can be rapidly switched on and rapidly suppressed by the nervous system. Facultative thermogenesis is important in both thermal balance, in which control of thermoregulatory thermogenesis (shivering in muscle, nonshivering in brown adipose tissue (BAT] balances neural control of heat loss mechanisms, and in energy balance, in which control of facultative thermogenesis (exercise-induced in muscle, diet-induced thermogenesis (DIT) in BAT) balances control of energy intake. Thermal balance (i.e., body temperature) is much more stringently controlled than energy balance (i.e., body energy stores). Reduced energy expenditure for thermogenesis is important in two types of obesity in laboratory animals. In the first type, deficient DIT in BAT is a prominent feature of altered energy balance. It may or may not be associated with hyperphagia. In a second type, reduced cold-induced thermogenesis in BAT as well as in other organs is a prominent feature of altered thermal balance. This in turn results in altered energy balance and obesity, exacerbated in some examples by hyperphagia. In some of the hyperphagic obese animals it is likely that the exaggerated obligatory thermic effect of food so alters thermal balance that BAT thermogenesis is suppressed. In all obese animals, deficient hypothalamic control of facultative thermogenesis and (or) food intake is implicated.

Energy Balance, Physical Activity, and Thermogenic Effect of Feeding in Premature Infants

In order to assess the contribution of the thermogenic effect of feeding and muscular activity to total energy expenditure, nine premature infants were studied for 2 consecutive days during which time repeated measurements of energy expenditure by indirect calorimetry were performed throughout the day, combined with a visual activity score based on body movement. The infants were growing at 16.6 +/- 4.0 g/kg/day (mean +/- SD) and received 110 +/- 8 kcal/kg/day metabolizable energy (milk formula) and 522 +/- 40 mgN/kg/day. Their total energy expenditure was 68 +/- 4 kcal/kg/day indicating that 41 +/- 7 kcal/kg/day was retained for growth. Based on the combination of energy + N balances it was estimated that 80% of the weight gain was fat-free tissue and 20% was fat tissue. The rate of energy expenditure measured minute-by-minute was significantly and linearly correlated with the activity score in both the premeal (r = 0.75;p less than 0.001) and the postmeal periods (r = 0.74; p less than 0.001) with no difference in the regression slope, but with a significant difference in intercept. In preset feeding schedules the latter allowed an estimation of the thermogenic effect without the confounding effect of activity. This was found to be 3.1 +/- 1.8% when expressed as a percentage of metabolizable energy intake. However when the "classical" approach was used as a comparison (integration of extra energy expenditure induced by the meal), the thermogenic effect was found to be greater, i.e. 9.5 +/- 3.8% of the meal's metabolizable energy, due to the superimposed effect of physical activity in the postprandial state.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral energy reserves of mice during seizures induced by 3-mercaptopropionic acid

Convulsions were induced in mice by the intraperitoneal injection of 3-mercaptopropionic acid. Energy metabolism of the cerebral cortex was studied during the first clonic seizure and during the recovery period (10 and 30 min after the end of convulsions). At the onset of a seizure the content of phosphocreatine, adenosine triphosphate, glucose and glycogen decreased and the level of lactate, adenosine di- and monophosphate increased; the ‘energy charge potential’ of the adenine nucleotide pool was diminished. The calculated extra energy expenditure during seizure was about 40 μequiv. ~ P g −1.min −1. Ten minutes after the end of convulsions normal values of phosphocreatine, adenylates and energy charge potential were attained, the content of glucose was increased, while lactate and glycogen levels were partly restored. Lactate content returned to control values after 30 min of recovery, whereas glycogen did not reach its control level until 1 h after the end of convulsions. Na-phenobarbital in a non-anaesthetic dose not only prevented clinical manifestation of 3-mercaptopropionic acid-induced seizures, but also all changes of brain metabolite levels accompanying the convulsions. These observations are discussed and compared with those obtained previously in studies on seizures induced by homocysteine and methionine sulphoximine, i.e. other sulphur-containing convulsants; the changes in brain energy metabolism during seizures induced by 3-mercaptopropionic acid are similar to those observed during homocysteine-induced seizures and differ substantially from changes accompanying convulsions induced by methionine sulphoximine.

Sliding set points for body weight in ground squirrels during the hibernation season.

The duration of the hibernation season of 13-lined ground squirrels, Citellus tridecemlineatus, repeatedly aroused over the winter, was only slightly less than that of undisturbed animals. The aroused animals ate more than eight times as much food during the middle of their hibernation season. This suggests that ground squirrels compensate by increased food intake for extra energy expenditure forced on them by repeated arousals. Aroused animals deprived of food lost weight at a greater rate than undisturbed animals. When food was returned they gained weight rapidly. However, weights did not return to predeprivation levels, but only to levels appropriate for the stage of the cycle at the time food was returned. These findings suggest that, even when ground squirrels are losing weight over the winter, they regulate their weight, but at a level that progressively declines. The underlying mechanisms probably depend on adjustments to the balance between medial and lateral hypothalamic areas.

ENERGY METABOLISM AND BODY TEMPERATURE OF THE AMA.

Rectal temperature and oxygen consumption were determined in the ama while diving during the summer and winter. In addition, a dietary survey and a physical-fitness test were conducted. The average rectal temperature fell to 35.3 C after 45 min of work in summer (water temp., 22–26 C) and to 34.8 C after 30 min of work in winter (water temp., 10–13 C). The lowest rectal temperature was 33.2 C in summer and 34.3 C in winter. Vo2 increased to nearly 1 liter/min in summer and to 1.4 liter/min in winter. One can calculate that the total extra energy expenditure for diving work is approximately 1,000 kcal/day in both winter and summer. The actual dietary survey showed that the total caloric intake of the ama is 3,000 kcal/day in both summer and winter, which exceeds the daily requirement for nondiving women of comparable age by 1,000 kcal. The protein intake was not different between summer and winter. Physical fitness, as judged by the score of Harvard step-up test, was significantly better in the ama than in the control in both summer and winter. Moreover, physical fitness was poorer in winter as compared to summer in the control, whereas it was excellent throughout a year in the ama. cold stress; physical fitness Submitted on January 15, 1964