scholarly journals Pre- to postexpedition changes in the energy usage of women undertaking sustained expeditionary polar travel

2019 ◽  
Vol 126 (3) ◽  
pp. 681-690 ◽  
Author(s):  
John Hattersley ◽  
Adrian J. Wilson ◽  
Robert M. Gifford ◽  
Rin Cobb ◽  
C. Doug Thake ◽  
...  

This paper reports the metabolic energy changes in six women who made the first unsupported traverse of Antarctica, covering a distance of 1,700 km in 61 days, hauling sledges weighing up to 80 kg. Pre- and postexpedition, measurements of energy expenditure and substrate utilization were made on all six members of the expedition over a 36-h period in a whole body calorimeter. During the study, subjects were fed an isocaloric diet: 50% carbohydrate, 35% fat, and 15% protein. The experimental protocol contained pre- and postexpedition measurement, including periods of sleep, rest, and three periods of standardized stepping exercise at 80, 100, and 120 steps/min. A median (interquartile range) decrease in the lean and fat weight of the subjects of 1.4 (1.0) and 4.4 (1.8) kg, respectively (P < 0.05) was found, using air-displacement plethysmography. No statistically significant difference was found between pre- and postexpedition values for sleeping or resting metabolic rate, nor for diet-induced thermogenesis. A statistically significant difference was found in energy expenditure between the pre- and postexpedition values for exercise at 100 [4.7 (0.23) vs. 4.4 (0.29), P < 0.05] and 120 [5.7 (0.46) vs. 5.5 (0.43), P < 0.05] steps/min; a difference that disappeared when the metabolic rate values were normalized to body weight. The group was well matched for the measures studied. Whereas a physiological change in weight was seen, the lack of change in metabolic rate measures supports a view that women appropriately nourished and well prepared can undertake polar expeditions with a minimal metabolic energy consequence. NEW & NOTEWORTHY This is the first study on the metabolic energy consequences for women undertaking expeditionary polar travel. The results show that participant selection gave a “well-matched” group, particularly during exercise. Notwithstanding this, individual differences were observed and explored. The results show that appropriately selected, trained, and nourished women can undertake such expeditions with no change in their metabolic energy requirements during rest or while undertaking moderate exercise over a sustained period of time.

1990 ◽  
Vol 64 (2) ◽  
pp. 413-425 ◽  
Author(s):  
Jan A. Weststrate ◽  
Ingrid Wunnink ◽  
Paul Deurenberg ◽  
Joseph G. A. J. Hautvast

The impact of alcohol (ethanol) on resting energy expenditure of male non-obese volunteers was determined in two studies. In the first study the thermic effect of alcohol on resting metabolic rate (RMR) was assessed in ten male non-obese volunteers. In the second study the impact of alcohol on diet-induced thermogenesis (DIT) was determined in twelve male non-obese volunteers. Energy expenditure was measured with a ventilated-hood system. RMR was measured for 60 min with the subjects in a fasting state. In the first study subjects received in random order 20 g alcohol in concentrations of 75, 180 and 300 ml/I water respectively. After measurement of the RMR the thermic effect of alcohol was measured for 90 min. In the second study volunteers received in random order and in duplicate either a meal of food (2 MJ) plus an alcoholic aperitif (20 g alcohol in a 180 ml/1 solution) or an isoenergetic meal of food alone (2.55 MJ) plus a placebo aperitif containing no alcohol. DIT was measured for 240 min. Alcohol induced a significant thermic effect, which varied between 0.22 and 0.30 kJ/min. No systematic difference in DIT was observed among the different concentrations. DIT was not significantly affected by the ingestion of alcohol. Total DIT was 219 (SE 14) kJ for the alcohol treatment and 185 (SE 20) kJ for the control treatment. The results do not support the suggestion that alcohol is less efficiently used as an energy source in comparison with, for example, fats and carbohydrates.


1987 ◽  
Vol 73 (1) ◽  
pp. 41-45 ◽  
Author(s):  
P. Leslie ◽  
R. T. Jung ◽  
T. E. Isles ◽  
J. Baty

1. In the management of the non-insulin dependent diabetic patient, metformin often facilitates weight loss whereas sulphonylurea may predispose to weight gain. To investigate whether this is due to alterations in energy expenditure we have studied energy expenditure in seven non-insulin dependent diabetic subjects while on metformin or sulphonylurea therapy. 2. Three components of energy expenditure were measured by indirect calorimetry, namely resting metabolic rate and the thermic responses to infused noradrenaline and to a mixed constituent meal. 3. There was no significant difference in the resting metabolic rate on metformin (5.29 ± 0.41 kJ/min; mean ± se) compared with sulphonylurea (5.34 ± 0.34 kJ/min). The resting metabolic rate was also similar to predicted values for non-diabetic subjects (r = 0.96). 4. The thermic response to infused noradrenaline was similar on metformin (23.14 ± 1.87 kJ) and sulphonylurea (21.40 ± 2.98 kJ). 5. There was no significant difference in the thermic response to the meal on sulphonylurea (75.8 ± 7.5 kJ) or on metformin (86.8 ± 10.8 kJ; 95% confidence limits − 17 to + 39 kJ). 6. We conclude that in non-insulin dependent diabetic subjects metformin does not enhance energy expenditure overall, compared with sulphonylurea.


1991 ◽  
Vol 80 (6) ◽  
pp. 571-582 ◽  
Author(s):  
E. Pullicino ◽  
G. R. Goldberg ◽  
M. Elia

1. Twenty-four hour energy expenditure and its components, i.e. ‘basal metabolic rate', activity energy expenditure and diet-induced thermogenesis were measured, using continuous whole-body indirect calorimetry, in patients receiving total parenteral nutrition while in remission from Crohn's disease (weight 51.9 ± 9.9 kg, body mass index 19.2 ± 2.0 kg/m2). 2. Total parenteral nutrition was infused continuously over 24 h in four subjects and cyclically, between 22.00 and 10.00 hours, in eight subjects. Twenty-four hour energy expenditure (6.83 ± 1.10 MJ/24 h) was lower than total energy intake (10.09 ± 1.63 MJ/24 h), resulting in a positive energy balance (3.26 ± 1.42 MJ) in all subjects. Repeated measurements of resting energy expenditure in the continuously fed subjects (5.82 ± 1.11 MJ/24 h) did not change significantly at different times of day (coefficient of variation 2.2–6.6%). In contrast, in cyclically fed subjects, resting energy expenditure was 24.2 ± 9.0% higher towards the end of the 12 h feeding period than the ‘basal metabolic rate', which was measured just before the start of the feeding period. 3. Diet-induced thermogenesis, calculated as the increment in resting energy expenditure above ‘basal metabolic rate’ over the 24 h period (adjusted for the reduction in energy expenditure during sleep), was found to be 0.60 ± 0.29 MJ or 6.1 ± 3.1% of the energy intake. 4. The energy cost of activity (activity energy expenditure) in the continuously fed patients, calculated as the difference between 24 h energy expenditure and the integrated 24 h measurements of resting energy expenditure, was 0.88 ± 0.53 MJ, i.e. 12.9 ± 5.9% of the 24 h energy expenditure. 5. The non-protein nonglycerol respiratory quotient exceeded 1.0 for varying periods of time (0.5–17 h) in 11 subjects, indicating net lipogenesis from carbohydrate. 6. The results demonstrate favourable rates of deposition, during intravenous feeding, of both energy and nitrogen over a 24 h period in patients recovering from an episode of Crohn's disease. The efficacy of these commonly used total parenteral nutrition regimens in these patients is related to three features that are absent in normal healthy individuals, namely a low basal metabolic rate, a low activity-related energy expenditure and prolonged periods of lipogenesis from carbohydrate.


1998 ◽  
Vol 80 (6) ◽  
pp. 511-519 ◽  
Author(s):  
Béatrice Morio ◽  
Christophe Montaurier ◽  
Gisèle Pickering ◽  
Patrick Ritz ◽  
Nicole Fellmann ◽  
...  

Effects of progressive endurance training on energy expenditure (EE) were studied in thirteen elderly sedentary subjects (62.8 (sd 2.3) years) after 7 and 14 weeks of training. Daily EE (DEE) and energy cost of the various usual activities were measured over 48 h by whole-body indirect calorimetry. Free-living DEE (DEEFLC) was calculated from 7 d activity recordings and the energy costs of activities were measured in the calorimeters using the factorial method. DEEFLC did not vary significantly throughout the training period despite the additional energy cost of training sessions (0·60 (sd 0·15) MJ/d), because energy expended during free-living activities (EEACT) decreased by 4·8 (sd 7·1) % (P < 0·05) and 7·7 (sd 8·6) % (P < 0·01) after 7 and 14 weeks of training respectively. Measurements in the calorimeters showed that sleeping metabolic rate transiently increased by 4·6 (sd 3·2) % after 7 weeks of training (P < 0·001) and returned to its initial level after 14 weeks of training. BMR was 7·6 (sd 7·0)%(P < 0·01) and 4·1 (sd 6·1)% (P = NS) higher after 7 and 14 weeks of training respectively, than before training. Likewise, diet-induced thermogenesis increased from 3·7 (sd 2·5) to 7·2 (sd 2·8) % energy intake after 7 weeks of training (P < 0·05), and returned to its initial level after 14 weeks of training (4·2 (sd 2·6) % energy intake). Despite these changes, energy expended during activities and the corresponding DEE did not vary throughout the training period. It was concluded that: (1) DEEFLC remained constant throughout the training period due to a compensatory decrease in free-living EEACT; (2) progressive endurance training induced a transient increase in sleeping metabolic rate, BMR and diet-induced thermogenesis after 7 weeks which was not reflected in the energy expended during activities and DEE.


Neurology ◽  
2018 ◽  
Vol 91 (23 Supplement 1) ◽  
pp. S24.2-S25
Author(s):  
Samuel R Walton ◽  
Candace Bernitt ◽  
Brooke Daniell ◽  
Steven Malin ◽  
Jacob Resch

ObjectiveAlterations in energy expenditure have been observed following moderate and severe traumatic brain injury (TBI) in animals and humans. However, few data exist characterizing how mild TBI, specifically concussion, affects whole-body energy expenditure. The purpose of this study was to examine resting metabolic rate (RMR) following sport concussion in university and high school student-athletes.MethodsConcussed participants were recruited from a university and local high schools. Concussion diagnosis was made by an athletic trainer or physician. Participants could have no other concurrent injury (e.g., fracture). RMR was determined by indirect calorimetry (VMax Metabolic Cart) with a ventilated hood < 72 hours following a diagnosed concussion (T1), 7 days after T1 (T2), and 7 days after T2 (T3). Predicted RMR (pRMR) was also calculated using 3 validated equations: Harris-Benedict (HB), Mifflin-St. Jeor (MSJ) and Schofield (SCH). These equations were used to examine the magnitude of change in RMR following concussion. Measured and predicted values were compared at each time point using percentages ([RMR/pRMR] × 100). Changes over time in measured RMR were assessed using a repeated measures ANOVA.ResultsTwelve concussed participants (aged 17.7 + 2.15 years, BMI 21.8 + 2.94) completed T1 at 1.8 + 0.84 days post-injury. There were 3 participants of each sex from each academic setting (university and high school). Measured RMR percent of pRMR was below 100% at each time point post-concussion (T1: HB = 53% + 7.6%, MSJ = 55% + 8.6%, SCH = 53% + 9.1%; T2: HB = 54% + 6.6%, MSJ = 56% + 6.7%, SCH = 53% + 8.1%; and T3: HB = 57% + 8.5%, MSJ = 59% + 9.6%, SCH = 57% + 9.0%). Additionally, measured RMR did not change over time (T1 = 909 + 226.0 kcal, T2 = 905 + 154.5 kcal, T3 = 975 + 266.7 kcal; F2 = 1.348, p = 0.28).ConclusionsConcussed student-athletes appear to have suppressed resting metabolism of about 40% following injury when compared with validated prediction equations. Although future studies are needed to confirm our findings by comparing concussed participants to healthy-matched controls, these preliminary data suggest use of prediction equations to estimate concussed student-athletes' dietary energy requirements should be used with caution.


Author(s):  
Heidi K. Byrne ◽  
Jack H. Wilmore

The present cross-sectional study was designed to investigate the relationship between exercise training and resting metabolic rate (RMR). The focus of this investigation was to compare RMR in aerobically trained (AT), resistance trained (RT), and untrained (UNT) women. Subjects were also classified as highly trained (HT), moderately trained (MT), or untrained (UNT) in order to examine the relationship between RMR and level of training. Sixty-one women between the ages of 18 and 46 years volunteered to serve as subjects in this study. Each subject completed measurements of body composition, maximal oxygen uptake (V̇O2max), and two consecutive measurements of RMR. The data presented show that there was no significant difference in resting metabolic rate between resistance-trained, aerobically trained, and control subjects. However, when grouped by intensity of training, there was a trend for an increased resting metabolic rate (kcal/day) in the highly trained subjects, regardless of mode of training.


1997 ◽  
Vol 36 (4) ◽  
pp. 310-312 ◽  
Author(s):  
F. Thielecke ◽  
J. Möseneder ◽  
A. Kroke ◽  
K. Klipstein-Grobusch ◽  
H. Boeing ◽  
...  

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Kristin E Claflin ◽  
Justin L Grobe

The brain renin-angiotensin system (RAS) and leptin contribute to the control of resting metabolic rate (RMR) and their receptors are co-expressed in areas of the brain critical for metabolic control; thus angiotensin and leptin may interact within the brain to regulate RMR and obesity. Inhibition of the brain RAS attenuates sympathetic nerve activity (SNA) responses to leptin, leading us to hypothesize that the brain RAS mediates the RMR effects of leptin. Mice lacking angiotensin AT 1A receptors in leptin receptor-expressing cells (ObRb-Cre x AT 1A flox/flox ; “KO”) exhibited normal body weight (15 weeks of age: control n=28, 26.0 ± 0.7, vs KO n=35, 25.8 ± 0.6 g), food intake (control n=12, 3.1 ± 0.15, vs KO n=15, 3.4 ± 0.14 g) and RMR (control n=13, 0.15 ± 0.004, vs KO n=15, 0.16 ± 0.006 kcal/hr) on standard chow diet. Brown adipose SNA responses to acute leptin injection, however, were completely attenuated in KO mice. When maintained on a 45% high fat diet (HFD), KO mice gained significantly more fat mass (control n=35, 5.6 ± 0.4, vs KO n=31, 7.4 ± 0.5 g, P<0.05) and body mass (control, 27.4 ± 0.6, vs KO, 29.6 ± 0.6 g, P<0.05) due to a loss of diet-induced thermogenesis (control n=22, 0.18 ± 0.008, vs. KO n=12, 0.16 ± 0.004 kcal/hr, P<0.05). KO mice exhibited attenuated hypothalamic proopiomelanocortin (POMC) gene expression and partially attenuated RMR responses to alpha-melanocyte stimulating hormone (αMSH; control n=3, 0.25 ± 0.01, vs KO n=7, 0.2 ± 0.01 kcal/hr, P<0.05) indicating that the interaction between leptin and AT 1A modulates both αMSH production and action. To localize the site of the brain RAS-leptin interaction, we developed novel multi-transgenic mouse models which expresses GFP via the AT 1A promoter (NZ44, from GenSat) and/or conditional activation of a tdTomato reporter (ROSA-stop flox -tdTomato) in cells expressing the leptin receptor (ObRb-Cre) or agouti-related peptide (AgRP-Cre). Immunohistochemical staining of adrenocorticotropin in brain tissue from NZ44 mice revealed no localization of AT 1A to POMC neurons; in contrast, AT 1A was strongly localized with AgRP promoter activity. Taken together, these data support a critical role for angiotensin AT 1A receptors on AgRP neurons in the arcuate nucleus in resting metabolic rate control.


Author(s):  
Jingjing Xue ◽  
Shuo Li ◽  
Rou Wen ◽  
Ping Hong

Background: The purpose of this study was to investigate the accuracy of the published prediction equations for determining level overground walking energy cost in young adults. Methods: In total, 148 healthy young adults volunteered to participate in this study. Resting metabolic rate and energy expenditure variables at speeds of 4, 5, and 6 km/h were measured by indirect calorimetry, walking energy expenditure was estimated by 3 published equations. Results: The gross and net metabolic rate per mile of level overground walking increased with increased speed (all P < .01). Females were less economical than males. The present findings revealed that the American College of Sports Medicine and Pandolf et al equations significantly underestimated the energy cost of overground walking at all speeds (all P < .01) in young adults. The percentage mean bias for American College of Sports Medicine, Pandolf et al, and Weyand et al was 12.4%, 16.8%, 1.4% (4 km/h); 21.6%, 15.8%, 7.1% (5 km/h); and 27.6%, 12%, 6.6% (6 km/h). Bland–Altman plots and prediction error analysis showed that the Weyand et al was the most accurate in 3 existing equations. Conclusions: The Weyand et al equation appears to be the most suitable for the prediction of overground walking energy expenditure in young adults.


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