Search results for "metabolic rate"
showing 10 items of 84 documents
Post-prandial alterations in LDL size and subclasses in patients with growth hormone deficiency
2008
Abstract Objective Several studies have suggested that lipoproteins generated during the post-prandial phase are highly atherogenic, with modifications in low-density lipoproteins (LDL) size and density. In the present study we assessed post-prandial variations in LDL size and subclasses in patients with growth hormone deficiency (GHD). Design We studied in 12 hypopituitary patients with GHD and 10 healthy control subjects matched for gender, age and body mass index (BMI) post-prandial variations after a standardized meal consisting of 35% fat, 45% carbohydrate and 20% of protein (Clinutren Mix ® , Nestle) and containing calories corresponding to 1/3 of estimated basal metabolic rate. Blood…
Sex-specific selection on energy metabolism - selection coefficients for winter survival
2010
Selection for different fitness optima between sexes is supposed to operate on several traits. As fitness-related traits are often energetically costly, selection should also act directly on the energetics of individuals. However, efforts to examine the relationship between fitness and components of the energy budget are surprisingly scarce. We investigated the effects of basal metabolic rate (BMR, the minimum energy required for basic life functions) and body condition on long-term survival (8 winter months) with manipulated densities in enclosed populations of bank voles (Myodes glareolus). Here, we show that survival selection on BMR was clearly sex-specific but density-independent. Both…
On the thermodynamic origin of metabolic scaling
2018
The origin and shape of metabolic scaling has been controversial since Kleiber found that basal metabolic rate of animals seemed to vary as a power law of their body mass with exponent 3/4, instead of 2/3, as a surface-to-volume argument predicts. The universality of exponent 3/4 -claimed in terms of the fractal properties of the nutrient network- has recently been challenged according to empirical evidence that observed a wealth of robust exponents deviating from 3/4. Here we present a conceptually simple thermodynamic framework, where the dependence of metabolic rate with body mass emerges from a trade-off between the energy dissipated as heat and the energy efficiently used by the organi…
Aerobic fitness, energy balance, and body mass index are associated with training load assessed by activity energy expenditure
2009
The present study examined whether activity energy expenditure related to body mass (AEE/kg) is associated with maximal aerobic fitness (VO(2max)), energy balance, and body mass index (BMI) during the 2 hardest weeks of the military basic training season (BT). An additional purpose was to study the accuracy of the pre-filled food diary energy intake. Energy expenditure (EE) with doubly labeled water, energy intake (EI), energy balance, and mis-recording was measured from 24 male conscripts with varying VO(2max). AEE/kg was calculated as (EE x 0.9-measured basal metabolic rate)/body mass. The reported EI was lower (P<0.001) than EE (15.48 MJ/day) and mis-recording of the pre-filled diary …
Impact of a 4-Week Intensified Endurance Training Intervention on Markers of Relative Energy Deficiency in Sport (RED-S) and Performance Among Well-T…
2020
Cyclists often apply block periodization to high training volumes in meso- and macrocycles to optimize training adaptation and to prepare for competition. Body mass influences performance in many sports, including endurance disciplines, and conditions related to the syndrome Relative Energy Deficiency in Sports (RED-S) such as metabolic adaptations and premature osteoporosis have also been reported in male cyclists. This study aimed to determine how a 4-week mesocycle of intensified endurance training designed to increase performance, would affect markers of RED-S in well-trained male cyclists. Twenty-two participants (age: 33.5 ± 6.6 years, height: 181.4 ± 5.2 cm, weight: 76.5 ± 7.4 kg, pe…
2021
Social insects are hosts of diverse parasites, but the influence of these parasites on phenotypic host traits is not yet well understood. Here, we tracked the survival of tapeworm-infected ant workers, their uninfected nest-mates and of ants from unparasitized colonies. Our multi-year study on the ant Temnothorax nylanderi, the intermediate host of the tapeworm Anomotaenia brevis, revealed a prolonged lifespan of infected workers compared with their uninfected peers. Intriguingly, their survival over 3 years did not differ from those of (uninfected) queens, whose lifespan can reach two decades. By contrast, uninfected workers from parasitized colonies suffered from increased mortality comp…
Is it advantageous for Atlantic salmon to be triploid at lower temperatures?
2020
Marine organisms living at low temperatures tend to have larger genomes and larger cells which suggest that these traits can be beneficial in colder environments. In fish, triploidy (three complete sets of chromosomes) can be induced experimentally following fertilization, which provides a model system to investigate the hypothesis that larger cells and genomes offers a physiological advantage at low temperatures. We tested this hypothesis by measuring metabolic rates and swimming performance of diploid and triploid Atlantic salmon (Salmo salar) post smolts acclimated to 3 or 10.5 °C. At 10.5 °C, triploids had significantly lower maximum metabolic rates which resulted in a lower aerobic sco…
Adverse metabolic response to regular exercise: Is it a rare or common occurrence?
2012
Background. Individuals differ in the response to regular exercise. Whether there are people who experience adverse changes in cardiovascular and diabetes risk factors has never been addressed. Methodology/Principal Findings. An adverse response is defined as an exercise-induced change that worsens a risk factor beyond measurement error and expected day-to-day variation. Sixty subjects were measured three times over a period of three weeks, and variation in resting systolic blood pressure (SBP) and in fasting plasma HDL-cholesterol (HDL-C), triglycerides (TG), and insulin (FI) was quantified. The technical error (TE) defined as the within-subject standard deviation derived from these measur…
Effects of Two Months of Very Low Carbohydrate Ketogenic Diet on Body Composition, Muscle Strength, Muscle Area, and Blood Parameters in Competitive …
2021
Background: Ketogenic diet (KD) is a nutritional approach that restricts daily carbohydrates, replacing most of the reduced energy with fat, while maintaining an adequate quantity of protein. Despite the widespread use of KD in weight loss in athletes, there are still many concerns about its use in sports requiring muscle mass accrual. Thus, the present study sought to investigate the influence of a KD in competitive natural body builders. Methods: Nineteen volunteers (27.4 ±
Resting metabolic rate can vary with age independently from body mass changes in the Colorado potato beetle, Leptinotarsa decemlineata.
2009
Temperature and mass dependency of insect metabolic rates are well known, while less attention has been given to other factors, such as age. Among insect species that experience seasonal variation in environmental conditions, such as in temperate latitudes, age may also have indirect effects on the metabolic rate. We examined the effect of age on the resting metabolic rate of Leptinotarsa decemlineata during 11 days after adult emergence by using flow-through respirometry. Age had a significant mass-independent effect on metabolic rate of beetles. A twofold increase in metabolic rate occurred during the first 2 days of adult life after which metabolic rate decreased with age relatively slow…