scholarly journals Metabolic reduction after long-duration flight is not related to fat-free mass loss or flight duration in a migratory passerine

2020 ◽  
Vol 223 (19) ◽  
pp. jeb215384
Author(s):  
Alexander R. Gerson ◽  
Joely G. DeSimone ◽  
Elizabeth C. Black ◽  
Morag F. Dick ◽  
Derrick J. Groom

ABSTRACTMigratory birds catabolize large quantities of protein during long flights, resulting in dramatic reductions in organ and muscle mass. One of the many hypotheses to explain this phenomenon is that decrease in lean mass is associated with reduced resting metabolism, saving energy after flight during refueling. However, the relationship between lean body mass and resting metabolic rate remains unclear. Furthermore, the coupling of lean mass with resting metabolic rate and with peak metabolic rate before and after long-duration flight have not previously been explored. We flew migratory yellow-rumped warblers (Setophaga coronata) in a wind tunnel under one of two humidity regimes to manipulate the rate of lean mass loss in flight, decoupling flight duration from total lean mass loss. Before and after long-duration flights, we measured resting and peak metabolism, and also measured fat mass and lean body mass using quantitative magnetic resonance. Flight duration ranged from 28 min to 600 min, and birds flying under dehydrating conditions lost more fat-free mass than those flying under humid conditions. After flight, there was a 14% reduction in resting metabolism but no change in peak metabolism. Interestingly, the reduction in resting metabolism was unrelated to flight duration or to change in fat-free body mass, indicating that protein metabolism in flight is unlikely to have evolved as an energy-saving measure to aid stopover refueling, but metabolic reduction itself is likely to be beneficial to migratory birds arriving in novel habitats.

2019 ◽  
Vol 72 (9-10) ◽  
pp. 272-279
Author(s):  
Danijel Slavic ◽  
Dea Karaba-Jakovljevic ◽  
Andrea Zubnar ◽  
Borislav Tapavicki ◽  
Tijana Aleksandric ◽  
...  

Introduction. The difference between 24-hour daily energy intake and total daily energy expenditure determines whether we lose or gain weight. The resting metabolic rate is the major component of daily energy expenditure, which depends on many different factors, but also on the level of physical activity. The aim of the study was to determine anthropometric and metabolic parameters of athletes engaged in different types of training, to compare obtained results and to examine whether there are statistically significant differences among them. Material and Methods. The study included a total of 42 young male athletes divided into two groups. The first group included 21 athletes who were predominantly engaged in aerobic type of training, and the other group of 21 athletes in anaerobic type of training. Anthropometric measurements were taken and resting metabolic rate was assessed using the indirect calorimetry method. The results were statistically analyzed and the differences in parameters between the two groups were compared. Results. Statistically significant differences were established in total body mass, amount of fat-free mass and muscle mass, body mass index, as well as in the relative metabolic indices between two groups of subjects. Conclusion. The percentage of fat-free body mass has the greatest impact on the resting metabolic rate. The rate of metabolic activity of this body compartment is higher in athletes engaged in aerobic than in athletes engaged in anaerobic type of training.


Author(s):  
Jeffrey A. Potteiger ◽  
Erik P. Kirk ◽  
Dennis J. Jacobsen ◽  
Joseph E. Donnelly

Purpose:To determine whether 16 months of moderate-intensity exercise training changes resting metabolic rate (RMR) and substrate oxidation in overweight young adults.Methods:Participants were randomly assigned to nonexercise control (CON, 18 women, 15 men) or exercise (EX, 25 women, 16 men) groups. EX performed supervised and verified exercise 3–5 d/wk, 20–45 min/session, at 60–75% of heart-rate reserve. Body mass and composition, maximal oxygen consumption (VO2max), RMR, and resting substrate oxidation were assessed at baseline and after 9 and 16 months of training.Results:EX men had significant decreases from baseline to 9 months in body mass (94.6 ± 12.4 to 89.2 ± 9.5 kg) and percent fat (28.3 ± 4.6 to 24.5 ± 3.9). CON women had significant increases in body mass (80.2 ± 8.1 to 83.2 ± 9.2 kg) from baseline to 16 months. VO2max increased significantly from baseline to 9 months in the EX men (3.67 ± 0.62 to 4.34 ± 0.58 L/min) and EX women (2.53 ± 0.32 to 3.03 ± 0.42 L/min). RMR increased from baseline to 9 months in EX women (1,583 ± 221 to 1,692 ± 230 kcal/d) and EX men (1,995 ± 184 to 2,025 ± 209 kcal/d). There were no significant differences within genders for either EX or CON in fat or carbohydrate oxidation. Fat oxidation was significantly higher for women than for men at 9 months in both CON and EX groups.Conclusions:Regular moderate-intensity exercise in healthy, previously sedentary overweight and obese adults increases RMR but does not alter resting substrate oxidation. Women tend to have higher RMR and greater fat oxidation, when expressed per kilogram fat-free mass, than men.


2019 ◽  
Vol 286 (1909) ◽  
pp. 20190859 ◽  
Author(s):  
Derrick J. E. Groom ◽  
Jessica E. Deakin ◽  
M. Collette Lauzau ◽  
Alexander R. Gerson

Migratory birds use protein as a fuel source during flight, but the mechanisms and benefits of protein catabolism during migration are poorly understood. The tissue-specific turnover rate hypothesis proposes that lean mass loss depends solely on the constitutive rate of protein degradation for a given tissue, and is therefore independent of metabolic rate or environmental stimuli. However, it has been demonstrated that environmental stressors such as humidity affect the rate of lean mass catabolism during flight, a finding that seemingly contradicts the tissue-specific turnover rate hypothesis. In order to resolve this, we placed migratory Swainson's thrushes in either high (HEWL) or low (LEWL) evaporative water loss conditions at rest and while undergoing simulated migratory flight at 8 m s −1 in a wind tunnel to test the impact of both environmental stressors and metabolic rate on the rate of protein breakdown. The total quantity and rate of lean mass loss was not different between flight and rest birds, but was affected by humidity condition, with HEWL losing significantly more lean mass. These results show that the rate of protein breakdown in migratory birds is independent of metabolic rate, but it can be augmented in response to environmental stressors.


2018 ◽  
Vol 55 (3) ◽  
pp. 278
Author(s):  
Keren Susan Cherian ◽  
Ashok Sainoji ◽  
Prem Raj Dundigalla ◽  
Balakrishna Nagalla ◽  
Venkata Ramana Yagnambhatt

Weightlifters involve in intense strength and resistance training, thus calorie adequacy is a nutritional concern for them. Determining Resting Metabolic rate (RMR) is important to assess energy needs and there is limited scientific evidence in this area. Thus, this study aims to document physical characteristics and RMR of Indian junior weightlifters. It also attempts to identify suitable RMR prediction equations by developing new equations and comparing measured with predicted RMR from seven equations already existing world-wide. In this cross-sectional observation study, twenty one Indian junior weightlifters (Boys = 9; Girls = 12) were assessed for body composition (skinfold technique) and RMR using indirect calorimetry. Regression models for RMR were developed and measured RMR was compared with predicted RMR using paired samples t-test. The 24-hour RMR showed significant (P<0.01) gender differences (Boys = 1675 ± 111.7; Girls = 1425 ± 93.4), whereas, RMR per unit fatfree mass and body mass were similar across gender. The simple equation developed using body mass (RMR = 1206 + 13 × Body Mass (Kg) – 227.7 × Gender; R2 = 0.872; SEE = 60.604) showed good agreement with measured RMR. Out of seven existing RMR models, the equation of ten Haaf and Weijs (2014) showed better predictability. In conclusion, fat-free mass caused a major variation in RMR. Considering the limited scientific evidence, prediction equations newly developed and RMR equation of ten Haaf and Weijs (2014) can be used for periodical monitoring of RMR.


2004 ◽  
Vol 96 (4) ◽  
pp. 1357-1364 ◽  
Author(s):  
Louise C. Mâsse ◽  
Janet E. Fulton ◽  
Kathleen L. Watson ◽  
Matthew T. Mahar ◽  
Michael C. Meyers ◽  
...  

This study investigated the influence of two approaches (mathematical transformation and statistical procedures), used to account for body composition [body mass or fat-free mass (FFM)], on associations between two measures of physical activity and energy expenditure determined by doubly labeled water (DLW). Complete data for these analyses were available for 136 African American (44.1%) and Hispanic (55.9%) women (mean age 50 ± 7.3 yr). Total energy expenditure (TEE) by DLW was measured over 14 days. Physical activity energy expenditure (PAEE) was computed as 0.90 × TEE - resting metabolic rate. During week 2, participants wore an accelerometer for 7 consecutive days and completed a 7-day diary. Pearson's product-moment correlations and three statistical procedures (multiple regressions, partial correlations, and allometric scaling) were used to assess the effect of body composition on associations. The methods-comparison analysis was used to study the effect of body composition on agreement. The statistical procedures demonstrated that associations improved when body composition was included in the model. The accelerometer explained a small but meaningful portion of the variance in TEE and PAEE after body mass was accounted for. The methods-comparison analysis confirmed that agreement with DLW was affected by the transformation. Agreement between the diary (transformed with body mass) and TEE reflected the association that exists between body mass and TEE. These results suggest that the accelerometer and diary accounted for a small portion of TEE and PAEE. Most of the variance in DLW-measured energy expenditure was explained by body mass or FFM.


2020 ◽  
Author(s):  
Seyedeh Forough Sajjadi ◽  
Atieh Mirzababaei ◽  
nasim Ghodoosi ◽  
Sara Pooyan ◽  
Hana Arghavani ◽  
...  

Abstract Objective Resting metabolic rate (RMR) accounts for most of the daily energy expenditure. The low-carb diet attenuates decreases in RMR. This study aims to investigate the relationship between a low-carb diet and resting metabolic rate status. Methods We enrolled 304 overweight and obese women in this cross-sectional study. BMI, fat mass, fat-free mass, visceral fat, insulin level were assessed. RMR was measured using indirect calorimetry. A low carbohydrate diet score was measured using a validated semi-quantitative food frequency questionnaire (FFQ). Results Our results showed no relationship between LCDS and DNR even after adjust for confounders (Inc. RMR: OR: 0.97; 95% CI: 0.92–1.01, P = 0.20; Dec. RMR: OR: 0.97; 95% CI: 0.94-1.00, P = 0.14). Some components of LCDS had significant differences with DNR, such as carbohydrate and Dec. RMR in adjusted model (OR: 1.62; 95% CI: 0.98–1.37, P = 0.08), MUFA and Dec. RMR in adjusted model (OR: 0.48; 95% CI: 0.21–1.10, P = 0.08) and refined grain and Inc. RMR in crude model (OR: 0.87; 95% CI: 0.77–0.99, P = 0.04). Conclusion Our study showed that there is no association between a low-carb diet and RMR status but carbohydrate, MUFA, and refined grain had a significant relationship.


Nutrients ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 3394
Author(s):  
Sarah A. Purcell ◽  
Ryan J. Marker ◽  
Marc-Andre Cornier ◽  
Edward L. Melanson

Many breast cancer survivors (BCS) gain fat mass and lose fat-free mass during treatment (chemotherapy, radiation, surgery) and estrogen suppression therapy, which increases the risk of developing comorbidities. Whether these body composition alterations are a result of changes in dietary intake, energy expenditure, or both is unclear. Thus, we reviewed studies that have measured components of energy balance in BCS who have completed treatment. Longitudinal studies suggest that BCS reduce self-reported energy intake and increase fruit and vegetable consumption. Although some evidence suggests that resting metabolic rate is higher in BCS than in age-matched controls, no study has measured total daily energy expenditure (TDEE) in this population. Whether physical activity levels are altered in BCS is unclear, but evidence suggests that light-intensity physical activity is lower in BCS compared to age-matched controls. We also discuss the mechanisms through which estrogen suppression may impact energy balance and develop a theoretical framework of dietary intake and TDEE interactions in BCS. Preclinical and human experimental studies indicate that estrogen suppression likely elicits increased energy intake and decreased TDEE, although this has not been systematically investigated in BCS specifically. Estrogen suppression may modulate energy balance via alterations in appetite, fat-free mass, resting metabolic rate, and physical activity. There are several potential areas for future mechanistic energetic research in BCS (e.g., characterizing predictors of intervention response, appetite, dynamic changes in energy balance, and differences in cancer sub-types) that would ultimately support the development of more targeted and personalized behavioral interventions.


1990 ◽  
Vol 259 (2) ◽  
pp. E233-E238 ◽  
Author(s):  
N. K. Fukagawa ◽  
L. G. Bandini ◽  
J. B. Young

The relationship between fat-free mass (FFM) and resting metabolic rate (RMR) was compared in young men (n = 24; age 18-33 yr), old men (n = 24; 69-89 yr), and old women (n = 20; 67-75 yr). Body composition was assessed using anthropometry, bioelectrical impedance analysis (BIA), and isotope dilution with 18O-labeled water. RMR was measured at least twice using an open-circuit indirect calorimetry system with a ventilated hood. The results indicate that the different methods for assessing body composition vary substantially and should not be used interchangeably. Anthropometry was not adequate to assess group differences in body fatness, although skinfold measures may be appropriate for within-group comparisons. BIA correlated well with the isotope-dilution technique and may be a useful measure of FFM. Finally, RMR was lower in the old men than the young (1.04 +/- 0.02 vs. 1.24 +/- 0.03 kcal/min, P less than 0.001) and remained lower even when adjusted for FFM estimated by isotope dilution (P less than 0.001). RMR in the women was also lower (0.84 +/- 0.02 kcal/min), but in contrast to the difference between young and old men, RMR adjusted for FFM did not differ (P = 0.16) between old men and women. Therefore, it is clear that differences in FFM cannot fully account for the lower RMR in the old, suggesting that aging is associated with an alteration in tissue energy metabolism.


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