scholarly journals Low intensity blood parasite infections do not reduce the aerobic performance of migratory birds

2018 ◽  
Vol 285 (1871) ◽  
pp. 20172307 ◽  
Author(s):  
Steffen Hahn ◽  
Silke Bauer ◽  
Dimitar Dimitrov ◽  
Tamara Emmenegger ◽  
Karina Ivanova ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Aerobic Capacity ◽  
Migratory Birds ◽  
Resting Metabolic Rate ◽  
Blood Parasites ◽  
Aerobic Performance ◽  
Chronic Infections ◽  
Free Living ◽  
Migratory Capacity ◽  
Exercise Endurance

Blood parasites (Haemosporidia) are thought to impair the flight performance of infected animals, and therefore, infected birds are expected to differ from their non-infected counterparts in migratory capacity. Since haemosporidians invade host erythrocytes, it is commonly assumed that infected individuals will have compromised aerobic capacity, but this has not been examined in free-living birds. We tested if haemosporidian infections affect aerobic performance by examining metabolic rates and exercise endurance in migratory great reed warblers ( Acrocephalus arundinaceus ) experimentally treated with Plasmodium relictum pGRW04 and in naturally infected wild birds over consecutive life-history stages. We found no effect of acute or chronic infections on resting metabolic rate, maximum metabolic rate or exercise endurance in either experimentally treated or free-living birds. Oxygen consumption rates during rest and while undergoing maximum exercise as well as exercise endurance increased from breeding to migration stages in both infected and non-infected birds. Importantly, phenotypic changes associated with preparation for migration were similarly unaffected by parasitaemia. Consequently, migratory birds experiencing parasitaemia levels typical of chronic infection do not differ in migratory capacity from their uninfected counterparts. Thus, if infected hosts differ from uninfected conspecifics in migration phenology, other mechanisms besides aerobic capacity should be considered.

The Effects of a 20-Week Exercise Training Program on Resting Metabolic Rate in Previously Sedentary, Moderately Obese Women

2001 ◽  
Vol 11 (1) ◽  
pp. 15-31 ◽  
Author(s):  
Heidi K. Byrne ◽  
Jack H. Wilmore
Keyword(s):  
Resistance Training ◽  
Exercise Training ◽  
Metabolic Rate ◽  
Training Program ◽  
Body Fat ◽  
Aerobic Capacity ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Obese Women ◽  
Resistance Training Program

The present study was designed to investigate the effects of exercise training on resting metabolic rate (RMR) in moderately obese women. It was hypothesized that exercise training would increase resting metabolic rate. Nineteen previously sedentary, moderately obese women (age = 38.0 ± 0.9 years, percent body fat = 37.5 ± 0.8) trained for 20 weeks using either resistance training (RT) or a combination of resistance training arid walking (RT/W). The high intensity resistance training program was designed to increase strength and fat-free mass and the walking program to increase aerobic capacity. There was also a non-exercising control group (C) of 9 subjects in this study. Fat-free mass was significantly increased in both the RT (+1.90 kg) and RT/W (+1.90 kg) groups as a result of the training program. No group showed significant changes in fat mass or relative body fat from pre- to post-training. Aerobic capacity was slightly, though significantly, increased in the RT/W group only. The RT group showed a significant increase (+44 kcal · day−1), while the RT/W group showed a significant decrease (-53 kcal · day−1) in resting metabolic rate post-training. RT can potentiate an increase in RMR through an increase in fat-free mass, and the decrease in RMR in the RT/W group may have been a result of heat acclimation from the walk training.

scholarly journals Indirect Calorimetry Protocol Development for Measuring Resting Metabolic Rate as a Component of Total Energy Expenditure in Free-Living Postmenopausal Women

2001 ◽  
Vol 131 (8) ◽  
pp. 2215-2218 ◽  
Author(s):  
Neilann K. Horner ◽  
Johanna W. Lampe ◽  
Ruth E. Patterson ◽  
Marian L. Neuhouser ◽  
Shirley A. Beresford ◽  
...  
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Total Energy ◽  
Postmenopausal Women ◽  
Indirect Calorimetry ◽  
Resting Metabolic Rate ◽  
Total Energy Expenditure ◽  
Free Living ◽  
Protocol Development

scholarly journals The Energy Expenditure of Free-Living Physical Activities in Primary Schoolchildren

2016 ◽  
Vol 13 (s1) ◽  
pp. S57-S61 ◽  
Author(s):  
Alison L. Innerd ◽  
Liane B. Azevedo
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Metabolic Rate ◽  
Indirect Calorimetry ◽  
Resting Metabolic Rate ◽  
Physical Activities ◽  
Free Living ◽  
Metabolic Equivalent ◽  
Primary Schoolchildren ◽  
Vigorous Intensity

Background:The aim of this study is to establish the energy expenditure (EE) of a range of child-relevant activities and to compare different methods of estimating activity MET.Methods:27 children (17 boys) aged 9 to 11 years participated. Participants were randomly assigned to 1 of 2 routines of 6 activities ranging from sedentary to vigorous intensity. Indirect calorimetry was used to estimate resting and physical activity EE. Activity metabolic equivalent (MET) was determined using individual resting metabolic rate (RMR), the Harrell-MET and the Schofield equation.Results:Activity EE ranges from 123.7± 35.7 J/min/Kg (playing cards) to 823.1 ± 177.8 J/min/kg (basketball). Individual RMR, the Harrell-MET and the Schofield equation MET prediction were relatively similar at light and moderate but not at vigorous intensity. Schofield equation provided a better comparison with the Compendium of Energy Expenditure for Youth.Conclusion:This information might be advantageous to support the development of a new Compendium of Energy Expenditure for Youth.

Weight Loss and Weight Cycling in Amateur Wrestlers: Implications for Performance and Resting Metabolic Rate

1993 ◽  
Vol 3 (3) ◽  
pp. 245-260 ◽  
Author(s):  
Craig A. Horswill
Keyword(s):  
Weight Loss ◽  
Metabolic Rate ◽  
Resting Metabolic Rate ◽  
Recovery Period ◽  
Aerobic Performance ◽  
Anaerobic Performance ◽  
Rapid Weight Loss ◽  
Weight Class ◽  
Weight Cycling ◽  
Glycogen Depletion

Amateur wrestlers practice weight loss for ergogenic reasons. The effects of rapid weight loss on aerobic performance are adverse and profound, but the effects on anaerobic performance are equivocal Anaerobic performance—strength and power—may be the most relevant type of performance to the wrestler. Maintenance of or even small decrements in anaerobic performance may translate into improvements in performance relative to the weight class, the factor by which wrestlers are matched for competition. During the recovery period between the official weigh-in and competition, wrestlers achieve at least partial nutritional recovery, which appears to benefit performance. Successive bouts of (a) weight loss to make weight and (b) recovery for performance lead to weight cycling. There is speculation that weight cycling may contribute to chronic glycogen depletion, reductions in fat-free weight, a decrease in resting metabolic rate, and an increase in body fat. The latter two would augment the difficulty of losing weight for subsequent weigh-ins. Most research indicates that the suppressed resting metabolic rate with weight loss in wrestlers appears to be transient, but subsequent research is needed for confirmation.

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
Keyword(s):  
Metabolic Rate ◽  
Mass Loss ◽  
Body Mass ◽  
Lean Mass ◽  
Migratory Birds ◽  
Resting Metabolic Rate ◽  
Fat Free Mass ◽  
Flight Duration ◽  
Long Duration ◽  
Resting Metabolism

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.

scholarly journals Inferring Whole-Organism Metabolic Rate From Red Blood Cells in Birds

2021 ◽  
Vol 12 ◽  
Author(s):  
Kasja Malkoc ◽  
Stefania Casagrande ◽  
Michaela Hau
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Red Blood Cells ◽  
Stress Responses ◽  
Blood Cells ◽  
Aerobic Performance ◽  
Activity Period ◽  
Activity Levels ◽  
Free Living ◽  
Blood Samples

Metabolic rate is a key ecological variable that quantifies the energy expenditure needed to fuel almost all biological processes in an organism. Metabolic rates are typically measured at the whole-organism level (woMR) with protocols that can elicit stress responses due to handling and confinement, potentially biasing resulting data. Improved, non-stressful methodology would be especially valuable for measures of field metabolic rate, which quantifies the energy expenditure of free-living individuals. Recently, techniques to measure cellular metabolic rate (cMR) in mitochondria of blood cells have become available, suggesting that blood-based cMR can be a proxy of organismal aerobic performance. Aerobic metabolism actually takes place in the mitochondria. Quantifying cMR from blood samples offers several advantages such as direct estimates of metabolism and minimized disturbance of individuals. To our knowledge, the hypothesis that blood-based cMR correlates with woMR has not yet been directly tested. We measured cMR in red blood cells of captive great tits (Parus major), first during their morning activity period and second after subjecting them to a 2.5 h day-time respirometry protocol to quantify woMR. We predicted cMR to decrease as individuals transitioned from an active to a resting state. In the two blood samples we also assessed circulating corticosterone concentrations to determine the perceived disturbance of individuals. From respirometry traces we extracted initial and final woMR measures to test for a predicted positive correlation with cMR measures, while accounting for corticosterone concentrations. Indeed, cMR declined from the first to the second measurement. Furthermore, woMR and cMR were positively related in individuals that had relatively low corticosterone concentrations and displayed little locomotor activity throughout respirometry. By contrast, woMR and cMR covaried negatively in birds that increased corticosterone concentrations and activity levels substantially. Our results show that red blood cell cMR represents a proxy for woMR when birds do not display signs of stress, i.e., either before increases in hormonal or behavioral parameters have occurred or after they have abated. This method represents a valuable tool for obtaining metabolic data repeatedly and in free-living individuals. Our findings also highlight the importance of accounting for individual stress responses when measuring metabolic rate at any level.

scholarly journals Physiological Differences Between Advanced Crossfit Athletes, Recreational Crossfit Participants, and Physically-Active Adults

2019 ◽  
Author(s):  
Gerald T. Mangine ◽  
Matthew T. Stratton ◽  
Christian G. Almeda ◽  
Michael D. Roberts ◽  
Tiffany A. Esmat ◽  
...  
Keyword(s):  
Metabolic Rate ◽  
Aerobic Capacity ◽  
Resting Metabolic Rate ◽  
Cycle Ergometer ◽  
Fat Percentage ◽  
Muscle Morphology ◽  
Physically Active ◽  
The Past ◽  
Peak Aerobic Capacity ◽  
Physiological Differences

ABSTRACTThis investigation examined anthropometric, hormonal, and physiological differences between advanced (ADV; n = 8, 27.8 ± 4.2 years, 170 ± 11 cm, 79.8 ± 13.3 kg) and recreational (REC; n = 8, 33.5 ± 8.1 years, 172 ± 14 cm, 76.3 ± 19.5 kg) CrossFit (CF) trained participants in comparison to physically-active controls (CON; n = 7, 27.5 ± 6.7 years, 171 ± 14 cm, 74.5 ± 14.3 kg). ADV and REC were distinguished by their past competitive success. REC and CON were resistance-trained (>2 years) and exercised on 3-5 days·wk-1 for the past year, but CON utilized traditional resistance and cardiovascular exercise. All participants provided a fasted, resting blood sample and completed assessments of resting metabolic rate, body composition, muscle morphology, isometric mid-thigh pull strength, peak aerobic capacity, and a 3-minute maximal cycle ergometer sprint across two separate occasions (separated by 3-7 days). Blood samples were analyzed for testosterone, cortisol, and insulin-like growth factor-1. One-way analysis of variance revealed ADV to possess lower body fat percentage (6.7-8.3%, p = 0.007), greater bone and non-bone lean mass (12.5-26.8%, p ≤ 0.028), muscle morphology characteristics (14.2-59.9%, p < 0.05), isometric strength characteristics (15.4-41.8%, p < 0.05), peak aerobic capacity (18.8-19.1%, p = 0.002), and anaerobic performance (15.4-51.1%, p ≤ 0.023) compared to both REC and CON. No differences were seen between REC and CON, or between all groups for resting metabolic rate or hormone concentrations. These data suggest ADV possess several physiological advantages over REC and CON, whereas similar physiological characteristics were present in individuals who have been regularly participating in either CF or resistance and cardiovascular training for the past year.

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