Agreement between fat-free mass from bioelectrical impedance analysis and dual-energy X-ray absorptiometry and their use in estimating resting metabolic rate in resistance-trained men.

BACKGROUND: This study aimed to determine the agreement between fat-free mass (FFM) estimates from bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) and their use in estimating resting metabolic rate (RMR) in men undergoing resistance training. METHODS: Thirty healthy resistance-trained men (22.7 ± 4.4 years, 70.0 ± 8.7 kg, 174.6 ± 6.7 cm, and 22.9 ± 2.3 kg/m2) were evaluated. The equation developed by Tinsley et al. (RMR = 25.9 × fat-free mass [FFM] + 284) was adopted to calculate the RMR. DXA was used as the reference method for FFM. RESULTS: Furthermore, FFM was also estimated by BIA using a spectral device. No significant difference (p > 0.05) was observed between DXA (1884.2 ± 145.5 kcal) and BIA (1849.4 ± 167.7 kcal) to estimate RMR. A positive and significant correlation (r = 0.89, p < 0.05) was observed between DXA and BIA estimates of RMR. The mean difference between methods indicated that BIA presented a bias of -34.8 kcal. CONCLUSION: These findings suggest that using FFM derived from DXA or BIA results in similar RMR estimates in resistance-trained men.

The association between gut microbiota and resting metabolic rate in overweight/obese women: a case-control study.

Purpose: When examining the underlying processes of obesity, evaluation of gut flora and energy homeostasis can be crucial since disruption of the normal gut microbiota community and energy imbalances are significant factors in the development of obesity. Therefore, this study aimed to compare the relative abundance of important obesity modulator gut microbiota (including Firmicutes, Bacteroidetes, Bifidobactrium spp., Lactobacillus spp., Bacteroides fragilis, Faecalibacterium prausnitzii, Akkermansia muciniphila, and Escherichia coli) in fecal samples of normometabilic and hypometabolic overweight/obese individuals. Methods: This matched case-control study conducted on 36 healthy women aged 18-50 years old. An indirect calorimeter and impedance body analyzer were used to assess resting metabolic rate (RMR) and body composition, respectively. Dietary intake and physical activity were assessed using questionnaires. To determine the abundance of the abovementioned gut microbiota, quantitative polymerase chain reaction (qPCR) method was performed. Moreover, ELISA kits were used to assess leptin, ghrelin, and insulin hormones. Results: The results highlighted higher load of Firmicutes (p = 0.02), F. prausnitzii (p < 0.001), and B. fragilis (p = 0.02) in the normometabolic individuals compared to the hypometabolic ones. Besides, the positive correlation between the abundance of Firmicutes (ß = 7.76 × 10-1, p = 0.01), F. prausnitzii (ß = 1.29 × 10-5, p = 0.01), and B. fragilis (ß = 4.13 × 10-6, p = 0.04) with the RMR have been shown. Whereas the abundance of Bacteroidetes, A. muciniphila, Lactobacillus spp., Bifidobactrium spp., and E. coli showed no significant difference (p > 0.05) and no significant correlation with the RMR except Lactobacillus spp. (ß = 1.73 × 10-4, p = 0.01). Conclusion: It seems that gut microbiota can be a potential target for refining host energy homeostasis and treating obesity and its consequences.

Are resting metabolic rate and clinical symptoms affected by variation of serum thyroid stimulating hormone levels within the normal range in healthy and women with hypothyroidism? A case-control study.

BACKGROUND: It is unclear whether variation in thyroid stimulating hormone (TSH) levels within the reference range affect energy expenditure and clinical symptoms and even within the normal range of TSH levels, resting energy expenditure may alter. The aim of the present study was to determine whether treated hypothyroid subjects and healthy subjects with a low-normal TSH range (0.3-2.3 mIU/L) have better clinical outcomes and increased energy expenditure than those with a high-normal TSH range (2.3-4.3 mIU/L). METHODS: This was a case-control study of 160 overweight/obese women with TSH levels across the reference range of 0.3-4.3 mU/l. Subjects were paired in four groups: healthy subjects with low-normal target TSH (n = 40), healthy subjects with high-normal target TSH (n = 40), subjects with treated hypothyroidism with low-normal target TSH (n = 40), and subjects with treated hypothyroidism with high-normal target TSH (n = 40). Resting energy expenditure (RMR), dietary intake, body composition, physical activity, and biochemical markers were assessed. RESULTS: Subjects with low-normal (≤2.3 mU/L) and high-normal (>2.3 mU/L) TSH levels did not differ in terms of RMR, serum T3 levels, and clinical symptoms except fatigue (P = 0.013). However, serum fT4 levels were found to be significantly different between the study groups (P = 0.002). Serum fT4 concentration was the highest in subjects with treated hypothyroidism with low-normal target TSH. CONCLUSION: Variation in serum TSH levels within the reference range did not significantly affect REE and clinical symptoms except fatigue in healthy and women with hypothyroidism.

Reversal of Soleus Muscle Atrophy in Older Adults: A Non-Volitional Exercise Intervention for a Changing Climate.

The World Health Organization recommends that older adults undertake at least 150 minutes of moderate intensity physical activity over the course of each week in order to maintain physical, mental, and social health. This goal turns out to be very difficult for most community dwelling older adults to achieve, due to both actual and perceived barriers. These barriers include personal health limitations, confinement issues, and self-imposed restrictions such as fear of injury. Climate change exacerbates the confinement issues and injury fears among the elderly. To assist older adults in obtaining the benefits of increased physical activity under increasingly challenging climate conditions, we propose a targeted non-volitional intervention which could serve as a complement to volitional physical activity. Exogenous neuro-muscular stimulation of the soleus muscles is a non-invasive intervention capable of significantly increasing cardiac output in sedentary individuals. Long-term daily use has been shown to improve sleep, reduce bone loss, and reverse age-related cognitive decline, all of which are significant health concerns for older adults. These outcomes support the potential benefit of exogenous neuro-muscular stimulation as a complementary form of physical activity which older adults may find convenient to incorporate into their daily life when traditional forms of exercise are difficult to achieve due to barriers to completing traditional physical activities as a result of in-home or in-bed confinement, perceptual risks, or real environmental risks such as those arising from climate change.

Need to Revise Classification of Physical Activity Intensity in Older Adults? The Use of Estimated METs, Measured METs, and V̇O2 Reserve.

BACKGROUND: Multiples of resting metabolic rate (RMR) are often used to classify physical activity intensity, a concept known as the metabolic equivalent of task (MET). However, the METs metrics may misclassify physical activity intensity in older adults because of age-related changes in RMR and maximal aerobic capacity (V˙O2max). This study aimed to (i) compare classifications of activity intensity by estimated (METsestimated) and measured (METsmeasured) METs and (ii) compare physical activity classified by absolute (METsmeasured) versus relative intensity (%V˙O2Reserve) in older adults. METHODS: Ninety-eight adults aged 75-90 years participated in the study. RMR and V˙O2 during sitting, standing, daily activities, and 6-minute walking test were measured. V˙O2Reserve was defined as the difference between V˙O2max and RMR. Moderate and vigorous intensity was classified as 3 and 6 METs and 40% and 60% of V˙O2Reserve, respectively. Paired t tests and a confusion matrix were used to investigate aims 1 and 2, respectively. RESULTS: METsmeasured was 24% lower than the standard 1 MET of 3.5 mL O2·min-1·kg-1. METsestimated underestimated the intensity during daily and walking activities when compared to METsmeasured. Nevertheless, when comparing METsmeasured to percentages of V˙O2Reserve, a mismatch was shown for moderate intensity in 47%-67% of the participants during daily activities and 21% of the participants during self-selected gait speed. CONCLUSIONS: Applying METsestimated for older adults leads to potential underestimation of physical activity intensity, suggesting that current classification metrics should be revised for older adults. V˙O2Reserve is a candidate metric for establishing precise physical activity intensity cut points for older adults. Clinical Trials Registration Number: NCT04821713.

Effects of post-exercise intake of exogenous lactate on energy substrate utilization at rest.

PURPOSE: This study investigated the effects of exogenous lactate intake on energy metabolism during 1 h of rest after acute exercise. METHODS: Eight-week-old ICR mice were randomly divided into four groups: SED (no treatment), EXE (exercise only), LAC (post-exercise oral lactate administration), and SAL (post-exercise saline administration) (n=8 per group). The exercise intensity was at VO2max 80% at 25 m/min and 15° slope for 50 min. After acute exercise, the LAC and SAL groups ingested lactate and saline orally, respectively, and were allowed to rest in a chamber. Energy metabolism was measured for 1 h during the resting period. RESULTS: LAC and SAL group mice ingested lactate and saline, respectively, after exercise and the blood lactate concentration was measured 1 h later through tail blood sampling. Blood lactate concentration was not significantly different between the two groups. Energy metabolism measurements under stable conditions revealed that the respiratory exchange ratio in the LAC group was significantly lower than that in the SAL group. Additionally, carbohydrate oxidation in the LAC group was significantly lower than that in the SAL group at 10-25 min. No significant difference was observed in the fat oxidation level between the two groups. CONCLUSION: We found that post-exercise lactate intake modified the respiratory exchange ratio after 1 h of rest. In addition, acute lactate ingestion inhibits carbohydrate oxidation during the post-exercise recovery period.

The effects of melatonin and magnesium in a novel supplement delivery system on sleep scores, body composition and metabolism in otherwise healthy individuals with sleep disturbances.

The purpose of this study was to investigate the effects of a novel dietary supplement, including melatonin and magnesium, delivered via coffee pods on sleep quality, resting metabolic rate (RMR), and body composition in individuals with poor sleep quality disturbances. Using a double-blinded, randomized, crossover trial, we recruited 35 participants to a 4-week intervention with both supplements (1.9 mg melatonin + 200 mg elemental magnesium before sleep) and placebo conditions, considering a 7d washout period between treatments. The Pittsburgh Sleep Quality Index (PSQI) questionnaire was applied, RMR (kcal) was measured using indirect calorimetry (canopy ventilated open-circuit system) and body composition was assessed using dual-energy X-ray absorptiometry. Decreases in PSQI and anger - hostility scores, as well as in energy intake and fat mass, were observed (p < 0.05) for both conditions, from baseline to the end of each 4-week intervention. Differences between conditions were also observed for these parameters along with energy spent in activity, number of sedentary breaks, sleep efficiency, latency time, time in bed, total sleep time, awakening time, and movement index (p < 0.05) favouring the supplement condition. However, the final PSQI questionnaire scores still indicated poor sleep quality on average (PSQI > 5), in both conditions, with no changes regarding RMR. A melatonin-magnesium supplement, in a coffee pod format, showed improvements in sleep quality in otherwise healthy individuals with sleep disturbances, however PSQI questionnaire scores still indicated poor quality on average (PSQI > 5).

The relationship between resting metabolic rate and quality of life is moderated by age and body composition in women: a cross-sectional study.

BACKGROUND: Health-related quality of life (HRQOL) is related to body composition, which is also related to resting metabolic rate (RMR). RMR can be increased by exercise and diet interventions that are not dependent on changes in body composition, so a link between RMR and HRQOL may provide interventions that directly improve HRQOL in women. METHODS: One hundred twenty women (median age 63.5 [IQR: 53.0-71.0] years) completed one-time measurement of body composition (multi-frequency bioelectrical impedance), RMR (handheld calorimetry), and HRQOL (RAND-36). Physical (PCS) and mental (MCS) composite scores were calculated for the RAND-36. Pearson correlations were used to identify relationships between RMR, body composition, and HRQOL. Variables at the p < .01 level were entered into multiple regression models. RESULTS: Median body mass index was 26.1 [IQR: 23.2-30.9] kg/m2 and median lean mass index was 16.1 [IQR: 14.6-17.3] kg/m2. Body composition consisted of fat mass (median 27.2 [IQR: 20.3-34.7] kg) and lean mass (median 42.7 [IQR: 38.2-46.9] kg). Median RMR was 1165.0 [IQR: 1022.5-1380.0] kcal/day. Median HRQOL scores were PCS (84.0 [IQR: 74.0-93.0]) and MCS (85.0 [IQR: 74.3-90.0]). RMR was not directly related to PCS, but was directly and negatively related to MCS (p = .002). RMR was significantly and positively related to body composition (lean mass: p < .001; fat mass: p < .001), body mass index (p = .005), and lean mass index (p < .001); but only fat mass (PCS: p < .001; MCS: p < .001) and body mass index (PCS: p < .001; MCS: p < .001) were related to HRQOL, although the relationship was negative. In addition, age was found to be significantly negatively related to RMR (p < .001) and PCS (p = .003). Regression models confirmed the moderating influence of age and body composition on the relationship between RMR and HRQOL. RMR, age, fat mass, and body mass index explained 24% (p < .001) of variance in PCS; and RMR, fat mass, and body mass index explained 15% (p < .001) of variance in MCS. CONCLUSION: In women, the relationship between RMR and HRQOL is moderated by age and body composition. Understanding these pathways will allow clinicians and researchers to direct interventions more effectively.

[Characteristics of resting energy expenditure and evaluation of prediction formulas in young men with different body mass indexes].

OBJECTIVE: To compare the resting energy expenditure (REE) characteristics among young men with different body mass indexes (BMI). METHODS: Thirty young men [average age was (26.93±4.16) years] were enrolled in this study. They underwent resting metabolism tests in the Department of Sports Medicine of Peking University Third Hospital from December 2017 to June 2021. The resting metabolic rate (RMR) was measured by indirect calorimetry, the body composition was measured by bioresistance antibody component analyzer. The REE characteristics were analyzed, and 11 predictive equations were used to estimate RMR and compared with the measured value. The differences were analyzed by paired t-test and intra-class correlation coefficient (ICC). RESULTS: The RMR of the overall 30 young men was (1 960.17±463.11) kcal/d (1 kcal=4.186 8 kJ). Including (1 744.33±249.62) kcal/d in those with normal BMI, which was significantly lower than that in those who were overweight or obese [(2 104.06± 520.32) kcal/d, P < 0.01], but the weight-corrected RMR in those with normal BMI was significantly higher than that in those who were overweight or obese [(24.02±2.61) kcal/(kg·d) vs. (19.98±4.38) kcal/(kg·d), P < 0.01]. The RMR was significantly and positively correlated with body weight, adiposity, lean body mass, body surface area, and extracellular fluid in the subjects with diffe-rent BMI (all P < 0.05). The predicted values of the 11 prediction equations were not in good agreement with the measured values (all ICC < 0.75), with relatively high agreement between the predicted and measured values of the World Health Organization (WHO) equation in overweight obese young men (ICC=0.547, P < 0.01). CONCLUSION: There were significant differences in RMR among young men with different BMI, and the RMR after weight correction should be considered for those who were overweight or obese. The consistency between the predicted values of different prediction equations and the actual measured values of RMR was relatively poor, and it is recommended to accurately measure RMR by indirect calorimetry. For overweight or obese young men, the WHO prediction equation can be considered to calculate RMR, but it is necessary to establish an RMR prediction equation applicable to different BMI populations.

Development of New Predictive Equations for the Resting Metabolic Rate (RMR) of Women with Lipedema.

This study aimed to develop a novel predictive equation for calculating resting metabolic rate (RMR) in women with lipedema. We recruited 119 women diagnosed with lipedema from the Angiology Outpatient Clinic at Wroclaw Medical University, Poland. RMR was assessed using indirect calorimetry, while body composition and anthropometric measurements were conducted using standardized protocols. Due to multicollinearity among predictors, classical multiple regression was deemed inadequate for developing the new equation. Therefore, we employed machine learning techniques, utilizing principal component analysis (PCA) for dimensionality reduction and predictor selection. Regression models, including support vector regression (SVR), random forest regression (RFR), and k-nearest neighbor (kNN) were evaluated in Python's scikit-learn framework, with hyperparameter tuning via GridSearchCV. Model performance was assessed through mean absolute percentage error (MAPE) and cross-validation, complemented by Bland-Altman plots for method comparison. A novel equation incorporating body composition parameters was developed, addressing a gap in accurate RMR prediction methods. By incorporating measurements of body circumference and body composition parameters alongside traditional predictors, the model's accuracy was improved. The segmented regression model outperformed others, achieving an MAPE of 10.78%. The proposed predictive equation for RMR offers a practical tool for personalized treatment planning in patients with lipedema.

Glycerol Phenylbutyrate treatment of two patients with Monocarboxylate Transporter 8 deficiency.

CONTEXT: Monocarboxylate transporter 8 (MCT8) deficiency is a rare genetic disease that leads to severe global developmental delay. MCT8 facilitates thyroid hormone (TH) transport across the cell membrane, and the serum TH profile is characterized by high T3 and low T4 levels. Recent studies have shown that the chemical chaperone sodium phenylbutyrate (NaPB) restored mutant MCT8 function and increased TH content in patient-derived induced pluripotent stem cells, making it a potential treatment for MCT8 deficiency. OBJECTIVE: We aimed to assess the efficacy and safety of glycerol phenylbutyrate (GPB) in MCT8 deficiency. METHODS: We treated two monozygotic twins aged 14.5 years with MCT8 deficiency due to P321L mutation with escalating doses of GPB over 13 months. We recorded TH, Vital signs, anthropometric measurements and neurocognitive functions. Resting metabolic rate (RMR) was measured by indirect calorimetry. Serum metabolites of GPB were monitored as a safety measure. In-vitro effects of NaPB were evaluated in MDCK1 cells stably expressing the MCT8P321L mutation. The effects of GPB were compared to the effects of DITPA and TRIAC, thyromimetic medications that the patients received in the past. RESULTS: NaPB restored mutant MCT8 expression in MDCK1 cells and increased T3 transport into cells carrying the P321L mutation. GPB treatment reduced high T3 and increased low T4 levels. The patients showed a significant weight gain simultaneously with a reduction in RMR. Only minor neuro-cognitive improvement was observed, in hyperreflexia score and in cognitive functions. Serum metabolites did not exceed the toxic range but elevated liver transaminases were observed. CONCLUSIONS: In the first report of GPB treatment in MCT8 deficiency we found an improvement in TH profile and body-mass index, with minor neuro-developmental changes.

What could be the reasons for not losing weight even after following a weight loss program?

INTRODUCTION: Approximately four million people worldwide die annually because of obesity. Weight loss is commonly recommended as a first-line therapy in overweight and obese patients. Although many individuals attempt to lose weight, not everyone achieves optimal success. Few studies point out that weight loss eventually slows down, stagnates or reverses in 85% of the cases. RESEARCH QUESTION: What could be the reasons for not losing weight even after following a weight loss program? METHODS: A scoping review of the literature was performed using weight loss-related search terms such as 'Obesity,' 'Overweight,' 'Lifestyle,' 'weight loss,' 'Basal Metabolism,' 'physical activity,' 'adherence,' 'energy balance,' 'Sleep' and 'adaptations. The search involved reference tracking and database and web searches (PUBMED, Science Direct, Elsevier, Web of Science and Google Scholar). Original articles and review papers on weight loss involving human participants and adults aged > 18 years were selected. Approximately 231 articles were reviewed, and 185 were included based on the inclusion criteria. DESIGN: Scoping review. RESULTS: In this review, the factors associated with not losing weight have broadly been divided into five categories. Studies highlighting each subfactor were critically reviewed and discussed. A wide degree of interindividual variability in weight loss is common in studies even after controlling for variables such as adherence, sex, physical activity and baseline weight. In addition to these variables, variations in factors such as previous weight loss attempts, sleep habits, meal timings and medications can play a crucial role in upregulating or downregulating the association between energy deficit and weight loss results. CONCLUSION: This review identifies and clarifies the role of several factors that may hinder weight loss after the exploration of existing evidence. Judging the effectiveness of respective lifestyle interventions by simply observing the 'general behavior of the groups' is not always applicable in clinical practice. Each individual must be monitored and advised as per their requirements and challenges.

The relationship between mitochondrial respiration, resting metabolic rate and blood cell count in great tits.

Although mitochondrial respiration is believed to explain a substantial part of the variation in resting metabolic rate (RMR), few studies have empirically studied the relationship between organismal and cellular metabolism. We therefore investigated the relationship between RMR and mitochondrial respiration of permeabilized blood cells in wild great tits (Parus major L.). We also studied the correlation between mitochondrial respiration traits and blood cell count, as normalizing mitochondrial respiration by the cell count is a method commonly used to study blood metabolism. In contrast to previous studies, our results show that there was no relationship between RMR and mitochondrial respiration in intact blood cells (i.e. with the ROUTINE respiration). However, when cells were permeabilized and interrelation re-assessed under saturating substrate availability, we found that RMR was positively related to phosphorylating respiration rates through complexes I and II (i.e. OXPHOS respiration) and to the mitochondrial efficiency to produce energy (i.e. net phosphorylation efficiency), though variation explained by the models was low (i.e. linear model: R2=0.14 to 0.21). However, unlike studies in mammals, LEAK respiration without [i.e. L(n)] and with [i.e. L(Omy)] adenylates was not significantly related to RMR. These results suggest that phosphorylating respiration in blood cells can potentially be used to predict RMR in wild birds, but that this relationship may have to be addressed in standardized conditions (permeabilized cells) and that the prediction risks being imprecise. We also showed that, in our conditions, there was no relationship between any mitochondrial respiration trait and blood cell count. Hence, we caution against normalising respiration rates using this parameter as is sometimes done. Future work should address the functional explanations for the observed relationships, and determine why these appear labile across space, time, taxon, and physiological state.

Elevational variation in metabolic rate, feeding capacity and their associations in the Asiatic toad Bufo gargarizans.

Foraging behavior is known to place demands on the metabolic characteristics of anurans. Active foragers feeding on sedentary prey typically have high aerobic capacity and low anaerobic capacity, whereas sit-and-wait foragers feeding on active and mobile prey have the opposite pattern. Thus, the energetic demands of foraging may influence their metabolic adaptations to harsh environments, such as high elevations. Anurans that engage in active foraging have been found to increase maximum metabolic rate (MMR) and aerobic scope (AS, the difference between MMR and resting metabolic rate, RMR) at high elevations. However, data are lacking in amphibian ambush foragers. In this study, we examined the RMR, MMR, AS, and feeding capacity of a sit-and-wait forager ─the Asiatic toad (Bufo gargarizans), from two populations that are in close geographic proximity but differ by 1350 m in elevation. Our results show that there is no elevational variation in RMR and feeding capacity in either males or females. However, there are sex-specific variations in MMR and AS along an elevational gradient; females from high elevations have lower MMR and smaller net AS than their counterparts from low elevations while males maintain similar MMR and net AS across elevations. Furthermore, aerobic performances do not appear to be associated with feeding capacity at either the individual or population level. Our results support the hypothesis that sit-and-wait foragers may not increase their aerobic capacity as a strategy in hypoxic and low food availability environments and the role of sex in these adaptive adjustments should not be overlooked.

The Physiological Effects of Weight-Cycling: A Review of Current Evidence.

PURPOSE OF REVIEW: There is a common perception among the public that yo-yo dieting, defined as repeated cycles of weight loss followed by weight regain, results in accumulation of fat in the body and lower metabolic rate, thus hindering subsequent attempts to lose weight. We evaluated the effects of weight-cycling on body weight and body mass index (BMI), body composition including fat mass (FM) and lean body mass (LBM), and resting metabolic rate (RMR), by systematically reviewing existing scientific literature. RECENT FINDINGS: Twenty-three cross-sectional and cohort studies (including subjects with a history of weight-cycling compared to those without such history) and interventional studies (evaluating physiological effects during one or more cycles of weight loss and regain) were identified, conducted in generally healthy adults across various age groups, races, and both genders, who had normal weight, overweight, or obesity. Eighteen studies investigated the association between weight-cycling and body weight or BMI, and thirteen of them found no significant association. Fifteen out of twenty studies also found no increase in FM, and none of eighteen studies found a decrease in LBM. Twelve out of fourteen studies reported no adverse changes in RMR either. The overwhelming majority of evidence suggests that weight-cycling (yo-yo effect) is not associated with any adverse effects in body weight, body composition, and metabolic rate. Accordingly, healthy individuals who struggle with overweight or obesity should not be discouraged from repeated attempts to lose the excess weight.

Intermittent normobaric hypoxia alters substrate partitioning and muscle oxygenation in individuals with obesity: implications for fat burning.

This single-blind, crossover study aimed to measure and evaluate the short-term metabolic responses to continuous and intermittent hypoxic patterns in individuals with obesity. Indirect calorimetry was used to quantify changes in resting metabolic rate (RMR), carbohydrate (CHOox, %CHO), and fat oxidation (FATox, %FAT) in nine individuals with obesity pre and post: 1) breathing normoxic air [normoxic sham control (NS-control)], 2) breathing continuous hypoxia (CH), or 3) breathing intermittent hypoxia (IH). A mean peripheral oxygen saturation ([Formula: see text]) of 80-85% was achieved over a total of 45 min of hypoxia. Throughout each intervention, pulmonary gas exchanges, oxygen consumption (V̇o2) carbon dioxide production (V̇co2), and deoxyhemoglobin concentration (Δ[HHb]) in the vastus lateralis were measured. Both RMR and CHOox measured pre- and postinterventions were unchanged following each treatment: NS-control, CH, or IH (all P > 0.05). Conversely, a significant increase in FATox was evident between pre- and post-IH (+44%, P = 0.048). Although the mean Δ[HHb] values significantly increased during both IH and CH (P < 0.05), the greatest zenith of Δ[HHb] was achieved in IH compared with CH (P = 0.002). Furthermore, there was a positive correlation between Δ[HHb] and the shift in FATox measured pre- and postintervention. It is suggested that during IH, the increased bouts of muscle hypoxia, revealed by elevated Δ[HHb], coupled with cyclic periods of excess posthypoxia oxygen consumption (EPHOC, inherent to the intermittent pattern) played a significant role in driving the increase in FATox post-IH.

Altered carbohydrate oxidation during exercise in overreached endurance athletes is applicable to training monitoring with continuous glucose monitors.

PURPOSE: The purpose of the study was to investigate whether carbohydrate utilization is altered during exercise in overreached endurance athletes and examine the utility of continuous glucose monitors (CGM) to detect overreaching status. METHODS: Eleven endurance athletes (M:8, F:3) completed a 5-week training block consisting of 1 week of reduced training (PRE), 3 weeks of high-intensity overload training (POST), and 1 week of recovery training (REC). Participants completed a Lamberts and Lambert Submaximal Cycling Test (LSCT) and 5 km time-trial at PRE, POST, and REC time points, 15 min following the ingestion of a 50 g glucose beverage with glucose recorded each minute via CGM. RESULTS: Performance in the 5 km time-trial was reduced at POST (∆-7 ± 10 W, p = 0.04, η p 2 = 0.35) and improved at REC (∆12 ± 9 W from PRE, p = 0.01, η p 2 = 0.66), with reductions in peak lactate (∆-3.0 ± 2.0 mmol/L, p = 0.001, η p 2 = 0.71), peak HR (∆-6 ± 3 bpm, p < 0.001, η p 2 = 0.86), and Hooper-Mackinnon well-being scores (∆10 ± 5 a.u., p < 0.001, η p 2 = 0.79), indicating athletes were functionally overreached. The respiratory exchange ratio was suppressed at POST relative to REC during the 60% (POST: 0.80 ± 0.05, REC: 0.87 ± 0.05, p < 0.001, η p 2 = 0.74), and 80% (POST: 0.93 ± 0.05, REC: 1.00 ± 0.05, p = 0.003, η p 2 = 0.68) of HR-matched submaximal stages of the LSCT. CGM glucose was reduced during HR-matched submaximal exercise in the LSCT at POST (p = 0.047, η p 2 = 0.36), but not the 5 km time-trial (p = 0.07, η p 2 = 0.28) in overreached athletes. CONCLUSION: This preliminary investigation demonstrates a reduction in CGM-derived glucose and carbohydrate oxidation during submaximal exercise in overreached athletes. The use of CGM during submaximal exercise following standardized nutrition could be employed as a monitoring tool to detect overreaching in endurance athletes.

Very low-calorie ketogenic diet in the treatment of adaptive thermogenesis: A case report.

OBJECTIVES: The management of the phenomenon of adaptive thermogenesis poses a challenge to the successful treatment of overweight/obesity with a nutritional intervention that minimizes the loss of muscle mass, with little cognitive restraint use and disorganization of eating behavior. On the other hand, it creates a significant calorie deficit for the reduction of body fat. The aim of this case report was to discuss the effects of a very low-calorie ketogenic diet in a woman with obesity and low resting metabolic rate. CASE DESCRIPTION: A 36-y-old white woman with a history of obesity and bulimia nervosa who has had difficulty losing and maintaining weight despite numerous dietary and pharmacologic treatments. RESULTS: There was a loss of 12 kg in 115 d, reaching 13.4 kg, with 11.4 kg of fat mass (FM). The resting metabolic rate showed an increase of 79% in relation to the initial rate, reaching normal levels for the predictive equations and maintaining this level in the first-year follow-up. Additionally, improvement of metabolic laboratory parameters and eating behavior traits were described. CONCLUSIONS: In this specific case of bulimia nervosa resulting in hypometabolism (low resting metabolic rate/fat-free mass) and obesity, the very low-calorie ketogenic diet intervention has demonstrated a possibility of weight loss with little cognitive restraint use, thereby increasing resting metabolic rate in the short and medium terms, ultimately promoting a negative energy balance. In relation to the numeric results, it seems positive; however, more research is necessary to evaluate the effects on the overall relationship with food and its long-term repercussions.

Oral Motor Impairments Contribute to Weight Status of Adults with Severe Cerebral Palsy.

Adults with severe cerebral palsy (CP) are susceptible to malnutrition and metabolic disorders due to limited daily physical activity and challenges related to eating. We hypothesized that the condition of being underweight arises from inadequate energy intake due to difficulties in eating, rather than heightened total energy expenditure or an elevated resting metabolic rate. The present study encompassed 17 adults with severe CP (classified as GMFSC III-V). Energy intake, utilization, and expenditure were gauged via thorough dietary recordings and double-labeled water (DLW) analyses. Resting metabolic rates were assessed through indirect calorimetry, and metabolic health was investigated via blood samples. Oral motor function, eating assessment during meals, and weight fluctuations throughout the experimental period were also evaluated. We found significant correlations between weight, oral impairments (p < 0.01), and eating difficulties (p < 0.05). While total energy expenditure and daily consumption were similar between underweight (UW) and overweight (OW) individuals, significant variability in both expenditure and intake was evident within the UW group. Particularly, those with lower BMIs experienced heightened mealtime impairments and complications. Our present findings indicate that eating difficulties are the central concern for UW status in this population.

Relative Energy Deficiency in Sport (REDs) Indicators in Male Adolescent Endurance Athletes: A 3-Year Longitudinal Study.

Longitudinal measurements of Relative Energy Deficiency in Sport (REDs) among adolescent male elite athletes are lacking. We aimed to monitor REDs indicators and their possible impact on performance in elite high-school cross-country skiing and biathlon athletes (n = 13) (16.3 ± 0.4 years, 179.4 ± 7.6 cm, 63.6 ± 8.2 kg body mass (BM), and peak oxygen uptake (VO2peak): 61.5 ± 5.3 mL/kg BM/min) every 6 months for 3 years. Protocols included assessments of energy availability (EA), body composition and bone mineral density (BMD), resting metabolic rate (RMR), disordered eating behavior, exercise addiction, VO2peak, and muscle strength. Data were analyzed using a linear mixed model. At baseline, 38% had low lumbar BMD (Z-score ≤ -1), and overall, bone health increased only slightly. VO2peak and muscle strength improved (p < 0.001), RMR decreased (p = 0.016), and no change was observed in EA or physiological or psychological REDs indicators. Conclusively, many of these young male athletes had poor bone health at baseline, and most either lost or did not achieve the expected pubertal bone mineral accrual, although no other indication of REDs was observed, while performance improved during the study period. Our findings highlight the importance of elite sports high schools focusing on screening for early detection of impaired bone health in male athletes.