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1.
Int J Exerc Sci ; 17(4): 172-182, 2024.
Article in English | MEDLINE | ID: mdl-38665851

ABSTRACT

The Army Combat Fitness Test (ACFT) is used to evaluate the fitness level of potential Cadets for military readiness. The purpose of this study was to evaluate the effectiveness of the exercise training program implemented by an Army Reserve Officers' Training Corps (ROTC) program to gauge the performance metrics of the ACFT. METHODS: Twenty-six student Cadets of the ROTC at the University of Alabama at Birmingham (UAB) program participated in the study. Over an 8-month period, the ROTC Cadets trained on campus three days per week. Training was performed in a circuit training format and each participant cycled through each of the four training stations (Strength, Conditioning, Core, and Endurance) for 15 minutes each session (for a total training time of 60 minutes). Each Cadet had body mass and body composition assessed as well as each component of the ACFT [maximum dead lift (MDL), standing power throw (SPT), hand release push-up (HRP), sprint-drag-carry (SDC), leg tuck/plank (LTK/PLK), and 2-mile run (2MR)]. Each variable was evaluated at three time points (pre-, mid-, and post-training program). RESULTS: There was a significant difference in the 2MR score between time points [F(2,50) = 4.530, p = .016, η2 = 0.153] with a significant difference between time point at pre- and post-training (p = .02). No other variables displayed a significant change: body mass (p = .741), body fat percentage (p = .238), MDL (p = .061), SPT (p = .308), HRP (p = .126), SDC (p = 0.132), LTK/PLK (p = 0.583). CONCLUSION: The results of this study suggest that the short-term training program used improves 2MR, but not other components of the ACFT over the course of an academic year.

2.
Nutrients ; 15(23)2023 Nov 22.
Article in English | MEDLINE | ID: mdl-38068734

ABSTRACT

Exogenous ketone ester and ketone ester mixed with ketone free acid formulations are rapidly entering the commercial marketspace. Short-term animal and human studies using these products suggest significant potential for primary or secondary prevention of a number of chronic disease conditions. However, a number of questions need to be addressed by the field for optimal use in humans, including variable responses among available exogenous ketones at different dosages; frequency of dosing; and their tolerability, acceptability, and efficacy in long-term clinical trials. The purpose of the current investigation was to examine the tolerability, acceptability, and circulating R-beta-hydroxybutyrate (R-ßHB) and glucose responses to a ketone monoester (KME) and ketone monoester/salt (KMES) combination at 5 g and 10 g total R-ßHB compared with placebo control (PC). Fourteen healthy young adults (age: 21 ± 2 years, weight: 69.7 ± 14.2 kg, percent fat: 28.1 ± 9.3%) completed each of the five study conditions: placebo control (PC), 5 g KME (KME5), 10 g KME (KME10), 5 g (KMES5), and 10 g KMES (KMES10) in a randomized crossover fashion. Circulating concentrations of R-ßHB were measured at baseline (time 0) following an 8-12 h overnight fast and again at 15, 30, 60, and 120 min following drink ingestion. Participants also reported acceptability and tolerability during each condition. Concentrations of R-ßHB rose to 2.4 ± 0.1 mM for KME10 after 15 min, whereas KMES10 similarly peaked (2.1 ± 0.1 mM) but at 30 min. KME5 and KMES5 achieved similar peak R-ßHB concentrations (1.2 ± 0.7 vs. 1.1 ± 0.5 mM) at 15 min. Circulating R-ßHB concentrations were similar to baseline for each condition by 120 min. Negative correlations were observed between R-ßHB and glucose at the 30 min time point for each condition except KME10 and PC. Tolerability was similar among KME and KMES, although decreases in appetite were more frequently reported for KMES. Acceptability was slightly higher for KMES due to the more frequently reported aftertaste for KME. The results of this pilot investigation illustrate that the KME and KMES products used increase circulating R-ßHB concentrations to a similar extent and time course in a dose-dependent fashion with slight differences in tolerability and acceptability. Future studies are needed to examine variable doses, frequency, and timing of exogenous ketone administration for individuals seeking to consume ketone products for health- or sport performance-related purposes.


Subject(s)
Hydroxybutyrates , Ketones , Humans , Young Adult , 3-Hydroxybutyric Acid , Dietary Supplements , Esters , Glucose , Sodium Chloride , Sodium Chloride, Dietary
3.
Front Physiol ; 14: 1165224, 2023.
Article in English | MEDLINE | ID: mdl-37113697

ABSTRACT

Objective: The ketone diester, R,S-1,3-butanediol diacetoacetate (BD-AcAc2), attenuates the accretion of adiposity and reduces hepatic steatosis in high-fat diet-induced obese mice when carbohydrate energy is removed from the diet to accommodate energy from the ester. Reducing carbohydrate energy is a potential confounder due to the well-known effects of carbohydrate restriction on components of energy balance and metabolism. Therefore, the current investigation was designed to determine whether the addition of BD-AcAc2 to a high-fat, high-sugar diet (with no reduction in carbohydrate energy) would attenuate the accretion of adiposity and markers of hepatic steatosis and inflammation. Methods: Sixteen 11-week-old male C57BL/6J mice were randomized to one of two groups for 9 weeks (n = 8 per group): 1) Control (CON, HFHS diet) or 2) Ketone ester (KE, HFHS diet + BD-AcAc2, 25% by kcals). Results: Body weight increased by 56% in CON (27.8 ± 2.5 to 43.4 ± 3.7 g, p < 0.001) and by 13% in KE (28.0 ± 0.8 to 31.7 ± 3.1 g, p = 0.001). Non-alcoholic fatty liver disease activity scores (NAS) for hepatic steatosis, inflammation, and ballooning were lower in the KE group compared to CON (p < 0.001 for all). Markers of hepatic inflammation [Tnfα (p = 0.036); Mcp1 (p < 0.001)], macrophage content [(Cd68 (p = 0.012)], and collagen deposition and hepatic stellate cell activation [(αSma (p = 0.004); Col1A1 (p < 0.001)] were significantly lower in the KE group compared to CON. Conclusion: These findings extend those of our previous work and show that BD-AcAc2 attenuates the accretion of adiposity and reduces markers of liver steatosis, inflammation, ballooning, and fibrosis in lean mice placed on a HFHS diet where carbohydrate energy was not removed to accommodate energy from addition of the diester.

4.
Mil Med ; 188(1-2): e1-e5, 2023 01 04.
Article in English | MEDLINE | ID: mdl-33449115

ABSTRACT

INTRODUCTION: The cadets in the U.S. Army Reserve Officers' Training Corps (ROTC) consist of students from varied backgrounds. As part of collegiate ROTC programs, cadets must pass fitness tests and adhere to body composition standards in addition to completing their education. The previous fitness test of record was the Army Physical Fitness Test (APFT), but it was recently changed to the Army Combat Fitness Test (ACFT) to better test soldiers for combat capabilities. As part of the standardized scoring, the ACFT is no longer separated by sex or age as in the APFT, but rather by job duty. The purpose of this study was to characterize the modern ROTC cadet based on body composition measures and APFT and ACFT scores and then determine how those factors are related. MATERIALS AND METHODS: We calculated body mass index (BMI), fat mass, fat-free mass (FFM), fat-free mass index (FFMI), and fat mass index (FMI) (n = 68, 42 males, 26 females). We used Pearson correlations to compare the scores to body composition assessments and Student's t-tests to determine if there were differences between sexes. We hypothesized that those with higher FFM and FFMI will have a higher passing rate on the ACFT and that males would perform better on the ACFT because of having more FFM. RESULTS: We found that cadets, regardless of sex, were borderline overweight using BMI standards and that BMI did not correlate with any fitness tests. When comparing sexes, both males and females had high passing rates on the APFT, but females struggled to pass the ACFT mostly because of the leg tuck. We also found that ACFT scores were strongly correlated with FFM and FFMI, yet no body composition measures were correlated with APFT scores. CONCLUSIONS: It is clear from our data that structured training programs and nutrition guidance are needed with an emphasis on changing body composition to increase lean mass and strength to increase the performance of ROTC cadets on the ACFT.


Subject(s)
Military Personnel , Sex Characteristics , Humans , Male , Female , Exercise , Physical Fitness , Body Composition
5.
Front Nutr ; 9: 1041026, 2022.
Article in English | MEDLINE | ID: mdl-36458175

ABSTRACT

Exogenous ketone ester supplementation provides a means to increase circulating ketone concentrations without the dietary challenges imposed by ketogenic diets. Our group has shown that oral R,S-1,3, butanediol diacetoacetate (BD-AcAc2) consumption results in body weight loss or maintenance with moderate increases in circulating ketones. We have previously shown a diet consisting of 25% BD-AcAc2 can maintain lean body mass (LBM) and induce fat mass (FM) loss in young, healthy male mice, but the underlying mechanisms are still unknown. Therefore, the purpose of this study was to determine if a diet consisting of 25% BD-AcAc2 (ketone ester, KE) would alter body composition, transcriptional regulation, the proteome, and the lipidome of skeletal muscle in aged mice. We hypothesized that the KE group would remain weight stable with improvements in body composition compared to controls, resulting in a healthy aging phenotype. Male C57BL/6J mice (n = 16) were purchased from Jackson Laboratories at 72 weeks of age. After 1 week of acclimation, mice were weighed and randomly assigned to one of two groups (n = 8 per group): control (CON) or KE. A significant group by time interaction was observed for body weight (P < 0.001), with KE fed mice weighing significantly less than CON. FM increased over time in the control group but was unchanged in the KE group. Furthermore, LBM was not different between CON and KE mice despite KE mice weighing less than CON mice. Transcriptional analysis of skeletal muscle identified 6 genes that were significantly higher and 21 genes that were significantly lower in the KE group compared to CON. Lipidomic analysis of skeletal muscle identified no differences between groups for any lipid species, except for fatty acyl chains in triacylglycerol which was 46% lower in the KE group. Proteomics analysis identified 44 proteins that were different between groups, of which 11 were lower and 33 were higher in the KE group compared to CON. In conclusion, 72-week-old male mice consuming the exogenous KE, BD-AcAc2, had lower age-related gains in body weight and FM compared to CON mice. Furthermore, transcriptional and proteomics data suggest a signature in skeletal muscle of KE-treated mice consistent with markers of improved skeletal muscle regeneration, improved electron transport chain utilization, and increased insulin sensitivity.

6.
Nutrients ; 13(10)2021 Oct 12.
Article in English | MEDLINE | ID: mdl-34684564

ABSTRACT

Despite remarkable improvements in screening, diagnosis, and targeted therapies, cancer remains the second leading cause of death in the United States. It is increasingly clear that diet and lifestyle practices play a substantial role in cancer development and progression. As such, various dietary compositions have been proposed for reducing cancer risk and as potential adjuvant therapies. In this article, we critically assess the preclinical and human trials on the effects of the ketogenic diet (KD, i.e., high-fat, moderate-to-low protein, and very-low carbohydrate content) for cancer-related outcomes. The mechanisms underlying the hypothesized effects of KD, most notably the Warburg Effect, suggest that restricting carbohydrate content may impede cancer development and progression via several pathways (e.g., tumor metabolism, gene expression). Overall, although preclinical studies suggest that KD has antitumor effects, prolongs survival, and prevents cancer development, human clinical trials are equivocal. Because of the lack of high-quality clinical trials, the effects of KD on cancer and as an adjunctive therapy are essentially unknown. We propose a set of research recommendations for clinical studies examining the effects of KD on cancer development and progression.


Subject(s)
Diet, Ketogenic , Neoplasms/diet therapy , Research , Clinical Trials as Topic , Humans
7.
Sci Rep ; 11(1): 8937, 2021 04 26.
Article in English | MEDLINE | ID: mdl-33903670

ABSTRACT

The aim of the current meta-analysis was to determine the effects of acute and chronic interval training (IT) on serum and plasma BDNF concentrations in healthy young adults. A literature search was performed using six databases until February 2020. The TESTEX scale was used to assess the quality of studies. Effect sizes (ES) were computed and two-tailed α values < 0.05 and non-overlapping 95% confidence intervals (95% CI) were considered statistically significant. Heterogeneity, inconsistency (I2), and small-study effects using the Luis Furuya-Kanamori (LFK) index were examined. Fifteen studies (n = 277 participants, age = 24 ± 3 years) were included. The overall effects of IT on circulating BDNF concentrations were moderate and significant (ES = 0.62, 95% CI 0.00, 1.24, heterogeneous (p < 0.001), highly inconsistent (I2 = 90%), and with major asymmetry (LFK index = 2.76). The acute effect of IT on peripheral BDNF levels was large and significant (ES = 1.10, 95% CI 0.07, 2.14), heterogeneous (p < 0.001), highly inconsistent (I2 = 92%), and with major asymmetry (LFK index = 3.34). The chronic effect of IT on circulating BDNF was large and significant (ES = 0.93, 95% CI 0.40, 1.46), heterogeneous (p < 0.001), with moderate inconsistency (I2 = 70%), and minor asymmetry (LFK index = 1.21). Acute and chronic IT elicited a moderate increase in serum and plasma BDNF concentrations in a healthy young population.


Subject(s)
Brain-Derived Neurotrophic Factor/blood , High-Intensity Interval Training , Adult , Female , Humans , Male , Young Adult
8.
Am J Physiol Gastrointest Liver Physiol ; 320(4): G564-G572, 2021 04 01.
Article in English | MEDLINE | ID: mdl-33501889

ABSTRACT

Nutritional ketosis as a therapeutic tool has been extended to the treatment of metabolic diseases, including obesity, type 2 diabetes, and nonalcoholic fatty liver disease (NAFLD). The purpose of this study was to determine whether dietary administration of the ketone ester (KE) R,S-1,3-butanediol diacetoacetate (BD-AcAc2) attenuates markers of hepatic stellate cell (HSC) activation and hepatic fibrosis in the context of high-fat diet (HFD)-induced obesity. Six-week-old male C57BL/6J mice were placed on a 10-wk ad libitum HFD (45% fat, 32% carbohydrates, 23% proteins). Mice were then randomized to one of three groups (n = 10 per group) for an additional 12 wk: 1) control (CON), continuous HFD; 2) pair-fed (PF) to KE, and 3) KE (HFD + 30% energy from BD-AcAc2, KE). KE feeding significantly reduced histological steatosis, inflammation, and total NAFLD activity score versus CON, beyond improvements observed for calorie restriction alone (PF). Dietary KE supplementation also reduced the protein content and gene expression of profibrotic markers (α-SMA, COL1A1, PDGF-ß, MMP9) versus CON (P < 0.05), beyond reductions observed for PF versus CON. Furthermore, KE feeding increased hepatic markers of anti-inflammatory M2 macrophages (CD163) and also reduced proinflammatory markers [tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and cellular communication network factor 1 (CCN1)] versus CON and PF (P ≤ 0.05), in the absence of changes in markers of total hepatic macrophage content (F4/80 and CD68; P > 0.05). These data highlight that the dietary ketone ester BD-AcAc2 ameliorates histological NAFLD and inflammation and reduces profibrotic and proinflammatory markers. Future studies to further explore potential mechanisms are warranted.NEW & NOTEWORTHY To our knowledge, this is the first study focusing on hepatic outcomes in response to dietary ketone ester feeding in male mice with HFD-induced NAFLD. Novel findings include that dietary ketone ester feeding ameliorates NAFLD outcomes via reductions in histological steatosis and inflammation. These improvements were beyond those observed for caloric restriction alone. Furthermore, dietary ketone ester feeding was associated with greater reductions in markers of hepatic fibrogenesis and inflammation compared with control and calorie-restricted mice.


Subject(s)
Acetoacetates/pharmacology , Butylene Glycols/pharmacology , Diet, High-Fat , Liver Cirrhosis, Experimental/prevention & control , Liver/drug effects , Non-alcoholic Fatty Liver Disease/prevention & control , Animals , Biomarkers/metabolism , Caloric Restriction , Gene Expression Regulation , Hepatic Stellate Cells/drug effects , Hepatic Stellate Cells/metabolism , Inflammation Mediators/metabolism , Liver/metabolism , Liver/pathology , Liver Cirrhosis, Experimental/genetics , Liver Cirrhosis, Experimental/metabolism , Liver Cirrhosis, Experimental/pathology , Macrophage Activation/drug effects , Male , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/metabolism , Non-alcoholic Fatty Liver Disease/pathology , Phenotype
9.
Obesity (Silver Spring) ; 28(8): 1447-1455, 2020 08.
Article in English | MEDLINE | ID: mdl-32618116

ABSTRACT

OBJECTIVE: The aim of this study was to examine the effects of a ketone ester (KE)-supplemented diet on energy expenditure (EE) and adiposity in mice housed at 23 °C versus thermoneutrality (30 °C), in which sympathetic nervous system activity is diminished. METHODS: Thirty-two 10-week-old male C57BL/6J mice were assigned to 1 of 4 groups (n = 8 per group): 30% KE diet + 23 °C (KE23), control (CON) diet + 23 °C (CON23), 30% KE diet + 30 °C (KE30), or CON diet + 30 °C (CON30). CON mice were pair-fed to the average intake of mice consuming the KE diet (ad libitum) for 8 weeks. Body composition and components of energy balance were measured at completion of the study. RESULTS: CON23 (mean ± SD, 26.0 ± 1.6 g) and CON30 (29.7 ± 1.4 g) mice weighed more than KE groups (P < 0.03 for both) and were also different from each other (CON23 vs. CON30, P < 0.01). However, KE23 (23.4 ± 2.7 g) and KE30 (23.1 ± 1.9 g) mice were not different in body weight. As expected, food intake at 30 °C (2.0 ± 0.3 g/d) was lower than at 23 °C (2.6 ± 0.3 g/d, P < 0.01). Diet did not influence resting and total EE, but mice housed at 30 °C had lower EE compared with mice at 23 °C (P < 0.01). CONCLUSIONS: Dietary KEs attenuate body weight gain at standard (23 °C) and thermoneutral (30 °C) housing temperatures, and this effect is not mediated by increased EE under these conditions.


Subject(s)
Adiposity/physiology , Body Weight/drug effects , Esters/metabolism , Animals , Dietary Supplements , Disease Models, Animal , Energy Metabolism , Male , Mice
10.
Article in English | MEDLINE | ID: mdl-32605106

ABSTRACT

Perceived lack of time is one of the most often cited barriers to exercise participation. High intensity interval training has become a popular training modality that incorporates intervals of maximal and low-intensity exercise with a time commitment usually shorter than 30 min. The purpose of this study was to examine the effects of short-term run interval training (RIT) on body composition (BC) and cardiorespiratory responses in undergraduate college students. Nineteen males (21.5 ± 1.6 years) were randomly assigned to a non-exercise control (CON, n = 10) or RIT (n = 9). Baseline measurements of systolic and diastolic blood pressure, resting heart rate (HRrest), double product (DP) and BC were obtained from both groups. VO2max and running speed associated with VO2peak (sVO2peak) were then measured. RIT consisted of three running treadmill sessions per week over 4 weeks (intervals at 100% sVO2peak, recovery periods at 40% sVO2peak). There were no differences in post-training BC or VO2max between groups (p > 0.05). HRrest (p = 0.006) and DP (p ≤ 0.001) were lower in the RIT group compared to CON at completion of the study. RIT lowered HRrest and DP in the absence of appreciable BC and VO2max changes. Thereby, RIT could be an alternative model of training to diminish health-related risk factors in undergraduate college students.


Subject(s)
Hemodynamics/physiology , High-Intensity Interval Training , Running , Humans , Male , Oxygen Consumption , Students
11.
Biochim Biophys Acta Mol Basis Dis ; 1866(8): 165820, 2020 08 01.
Article in English | MEDLINE | ID: mdl-32360396

ABSTRACT

Glycemic control is essential to reduce the risk of complications associated with metabolic syndrome (MetS) and type 2 diabetes (T2D). Aerobic and resistance exercise performed alone or in combination improve glycemic control in both conditions. However, perceived lack of time and commitment are considered principal barriers to performing exercise regularly. High intensity interval training (HIIT) and sprint interval training (SIT) can be performed in a fraction of the time required for continuous aerobic exercise. A substantial scientific evidence indicates that HIIT/SIT improve glycemic control to a similar or greater extent than aerobic exercise in populations without MetS or T2D. Likewise, growing evidence suggest that HIIT/SIT improve the glycemic control during MetS and T2D. The aim of this review is to discuss the effects of interval training protocols on peripheral markers of glucose metabolism in patients with MetS and T2D.


Subject(s)
Blood Glucose/metabolism , Diabetes Mellitus, Type 2/metabolism , Glycemic Control/methods , High-Intensity Interval Training/methods , Insulin/blood , Metabolic Syndrome/metabolism , Biomarkers/metabolism , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/pathology , Energy Metabolism , Glycated Hemoglobin/metabolism , Humans , Insulin Resistance , Liver/metabolism , Liver/pathology , Metabolic Syndrome/genetics , Metabolic Syndrome/pathology , Oxygen Consumption , Pancreas/metabolism , Pancreas/pathology
12.
Nutr Res ; 77: 1-11, 2020 05.
Article in English | MEDLINE | ID: mdl-32193016

ABSTRACT

To reduce the health burden of obesity, it is important to identify safe and practical treatments that are effective for weight loss while concurrently preventing weight regain. Diet-induced weight loss is usually followed by a concomitant increase in ghrelin secretion and feelings of hunger, which may compromise weight loss goals and increase the risk of weight regain. The aim of this review is to describe the status of knowledge regarding the impact of ketosis, induced by diet or exogenous ketones (ketone esters), on appetite and the potential mechanisms involved. Ketogenic diets (KDs) have been shown to prevent an increase in ghrelin secretion, otherwise seen with weight loss, as well as to reduce hunger and/or prevent hunger. However, the exact threshold of ketosis needed to induce appetite suppression, as well as the exact mechanisms that mediate such an effect, has yet to be elucidated. Use of exogenous ketones may provide an alternative to KDs, which have poor long-term adherence due to their restrictive nature. Ketone esters have been shown to have concentration-dependent effects on food intake and body weight in rodent models, with effects becoming apparent when 30% of total dietary energy comes from ketone esters (threshold effect). In humans, acute consumption of a ketone ester drink reduced feelings of hunger and increased satiety compared to a dextrose drink. With the emerging widespread acceptance of KDs and exogenous ketones in mainstream media and the diet culture, it is important to fully understand their role on appetite control and weight management and the potential mechanisms mediating this role.


Subject(s)
Appetite Regulation , Diet, Ketogenic , Dietary Supplements , Ketones/administration & dosage , Ketosis , Obesity/diet therapy , 3-Hydroxybutyric Acid/administration & dosage , 3-Hydroxybutyric Acid/metabolism , Animals , Body Weight , Diet, Reducing , Eating , Esters/administration & dosage , Esters/metabolism , Female , Ghrelin/metabolism , Humans , Hydroxybutyrates/administration & dosage , Ketones/metabolism , Male , Satiation
13.
Article in English | MEDLINE | ID: mdl-31906523

ABSTRACT

This study examines the association of emotional and physical reactions to perceived discrimination with depressive symptoms among a sample of African American (AA) men in the southeastern United States. Analysis of the 2010 Behavioral Risk Factor Surveillance System (BRFSS) data set provides an examination of demographic, perceived discrimination context, and health status differences in depressive symptoms measured by the Patient Health Questionnaire-2 (PHQ-2). The analysis also assesses individual differences among AA men related to experiencing physical symptoms and feeling emotionally upset due to perceived discrimination. A focused examination investigates the role of adverse reactions to perceived discrimination in association with depressive symptomology. Findings illuminate the significance of experiences of and reactions to perceived discrimination in relationship with depressive symptomology among AA men living in the southeastern United States. Findings also demonstrate the need for additional research focusing on perceived discrimination experiences in relation to depressive symptoms experienced among the AA male subgroup. Continued investigation of within-group differences among AA men, with health promotional strategies to foster social-emotional support, will further the improvement in health and wellness for AA men.


Subject(s)
Black or African American/psychology , Depression/etiology , Health Status , Racism , Adult , Depression/epidemiology , Emotions , Female , Humans , Male , Middle Aged , Social Support , Southeastern United States
14.
J Strength Cond Res ; 34(5): 1340-1344, 2020 May.
Article in English | MEDLINE | ID: mdl-31524783

ABSTRACT

Hunter, GR, Neumeier, WH, Chandler-Laney, PC, Carter, SJ, Borges, JH, Hornbuckle, LM, Plaisance, EP, and Fisher, G. Ratings of perceived exertion during walking predicts endurance independent of physiological effort in older women. J Strength Cond Res 34(5): 1340-1344, 2020-This study aimed to determine whether ratings of perceived exertion (RPE) and physiological effort at different exercise intensities relate to exercise endurance. Ninety-eight sedentary women (older than 60 years) completed 3 submaximal locomotion tasks: (a) stair climbing, (b) flat walking at 2 mph, and (c) grade walking at 2 mph. Maximal treadmill endurance was measured at least 3 days before the submaximal tests. Oxygen uptake was measured during all tests, and RPE were collected for the submaximal tasks. Ratings of perceived exertion during moderate-intensity exercise (walking on the flat at 43% V[Combining Dot Above]O2max, partial R = -0.35, p < 0.01), but not higher intensity exercise (grade walk at 59% V[Combining Dot Above]O2max, p = 0.49, and stair climbing at 67% V[Combining Dot Above]O2max, p = 0.17), were related to endurance even after adjusting for aerobic capacity and physiological effort (composite of maximal heart rate, ventilation, and respiratory exchange ratio). However, physiological effort was significantly related to endurance for the higher intensity exercise (both grade walk and stair climbing partial R >-0.24, p < 0.02). Similar to previous findings that subjective ratings of fatigue at rest were related to RPE during low/moderate-intensity exercise, but not higher intensity exercise, these data further support Ekkekakis's dual-mode hypothesis that cognitive factors influence RPE during low/moderate-intensity exercise. A practical application is that the coach and personal trainer should know that physiological effort seems to play a greater role in influencing endurance than RPE as intensity of exercise increases.


Subject(s)
Physical Endurance/physiology , Physical Exertion/physiology , Walking/physiology , Walking/psychology , Aged , Exercise/physiology , Exercise Test , Exercise Tolerance , Female , Heart Rate/physiology , Humans , Middle Aged , Nutritional Status , Oxygen Consumption/physiology , Respiratory Function Tests
15.
Eur J Sport Sci ; 20(4): 516-524, 2020 May.
Article in English | MEDLINE | ID: mdl-31386821

ABSTRACT

BACKGROUND: Brain-derived neurotrophic factor (BDNF) increases neuronal viability and cognitive function, peripheral lipid metabolism and skeletal muscle repair. The primary purpose of this study was to determine the effect of short-term high-intensity interval training (HIIT) on serum BDNF concentrations in healthy young women. METHODS: Seventeen women (age:22 ± 1 years); body mass index (BMI:24.2 ± 2.2 kg/m²), body fat percentage (% fat:25.8 ± 4.7) participated in the study. Participants were randomly assigned to a control (n = 8) or HIIT group (n = 9). All participants performed a graded exercise test (GXT) on an electronically-braked cycle ergometer to determine maximal aerobic power (MAP, Watts). HIIT was performed three days per week for four weeks. Each HIIT session consisted of three to five cycling bouts of 30 s each at 80% MAP, followed by four-minutes of recovery at 40% MAP. Forty-eight hours after the last bout of exercise, both groups performed a follow-up GXT. Non-fasting blood samples were collected before and immediately after each GXT. Mixed factorial (2 groups x 4 measures, and 2 groups x 2 measures) ANOVA was used to assess BDNF concentrations, performance and anthropometric variables. RESULTS: Serum BDNF concentrations in the HIIT group (21.9 ± 1.3 ng/mL) increased compared to control (19.2 ± 2.8 ng/mL) (∼12%, P < 0.05) following HIIT. In contrast, circulating BDNF concentrations were reduced following the GXT (P < 0.05). The MAP and % Fat did not change with HIIT. CONCLUSIONS: Twelve sessions of HIIT increases circulating BDNF concentrations in healthy young women despite no change in physical performance or % fat.


Subject(s)
Brain-Derived Neurotrophic Factor/blood , High-Intensity Interval Training , Adult , Body Composition , Exercise Test , Female , Healthy Volunteers , Humans , Young Adult
16.
Front Nutr ; 6: 56, 2019.
Article in English | MEDLINE | ID: mdl-31119133

ABSTRACT

Objectives: Exogenous ketones may provide therapeutic benefit in treatment of obesity. Administration of the ketone ester (KE) R,S-1,3-butanediol acetoacetate diester (BD-AcAc2) decreases body weight in mice, but effects on energy balance have not been extensively characterized. The purpose of this investigation was to explore concentration-dependent effects of BD-AcAc2 on energy intake and expenditure in mice. Methods: Forty-two male C57BL/6J mice were randomly assigned to one of seven isocaloric diets (n = 6 per group): (1) Control (CON, 0% KE by kcals); (2) KE5 (5% KE); (3) KE10 (10% KE); (4) KE15 (15% KE); (5) KE20 (20% KE); (6) KE25 (25% KE); and (7) KE30 (30% KE) for 3 weeks. Energy intake and body weight were measured daily. Fat mass (FM), lean body mass (LBM), and energy expenditure (EE) were measured at completion of the study. Differences among groups were compared to CON using ANOVA and ANCOVA. Results: Mean energy intake was similar between CON and each concentration of KE, except KE30 which was 12% lower than CON (P < 0.01). KE25 and KE30 had lower body weight and FM compared to CON, while only KE30 had lower LBM (P < 0.03). Adjusted resting and total EE were lower in KE30 compared to CON (P < 0.03), but similar for all other groups. Conclusions: A diet comprised of 30% energy from BD-AcAc2 results in lower energy intake, coincident with lower body weight and whole animal adiposity; while KE20 and KE25 have significantly lower body weight and adiposity effects independent of changes in energy intake or expenditure.

17.
FASEB J ; 33(2): 2409-2421, 2019 02.
Article in English | MEDLINE | ID: mdl-30303740

ABSTRACT

The dietary R-3-hydroxybutyrate- R-1,3-butanediol monoester increases resting energy expenditure (REE) and markers of brown and white adipose thermogenesis in lean mice. The purpose of this investigation was to determine whether the ketone ester, R, S-1,3-butanediol diacetoacetate (BD-AcAc2), increases energy expenditure and markers of adipose tissue thermogenesis in the context of high-fat diet (HFD)-induced obesity. Thirty-five-week-old male C57BL/6J mice were placed on an ad libitum HFD (45% kcal) for 10 wk. The mice were then randomized to 1 of 3 groups ( n = 10 per group) for an additional 12 wk: 1) control (Con), continuous HFD, 2) pair-fed (PF) to ketone ester (KE); and 3) KE: HFD+30% energy from BD-AcAc2. Mean energy intake throughout the study was ∼26% lower in the KE compared to the Con group (8.2 ± 0.5 vs. 11.2 ± 0.7 kcal/d; P < 0.05). Final body weight (26.8 ± 3.6 vs. 34.9 ± 4.8 g; P < 0.001) and fat mass (5.2 ± 1.2 vs. 11.3 ± 4.5 g; P < 0.001) of the KE group was significantly lower than PF, despite being matched for energy provisions. Differences in body weight and adiposity were accompanied by higher REE and total energy expenditure in the KE group compared to PF after adjustment for lean body mass and fat-mass ( P = 0.001 and 0.007, respectively). Coupled or uncoupled mitochondrial respiratory rates in skeletal muscle were not different among groups, but markers of mitochondrial uncoupling and thermogenesis (uncoupling protein-1, deiodinase-2, and peroxisome proliferator-activated receptor γ coactivator-1α) were higher in interscapular brown adipose tissue (BAT) of mice receiving the KE diet. The absence of mitochondrial uncoupling in skeletal muscle and increased markers of mitochondrial uncoupling in BAT suggest that BD-AcAc2 initiates a transcriptional signature consistent with BAT thermogenesis in the context of HFD-induced obesity.-Davis, R. A. H., Deemer, S. E., Bergeron, J. M., Little, J. T., Warren, J. L., Fisher, G., Smith, D. L., Jr., Fontaine, K. R., Dickinson, S. L., Allison, D. B., Plaisance, E. P. Dietary R, S-1,3-butanediol diacetoacetate reduces body weight and adiposity in obese mice fed a high-fat diet.


Subject(s)
Acetoacetates/administration & dosage , Adiposity/drug effects , Body Weight/drug effects , Butylene Glycols/administration & dosage , Diet, High-Fat/adverse effects , Energy Metabolism/drug effects , Obesity/prevention & control , Adipose Tissue, Brown/drug effects , Adipose Tissue, White/drug effects , Animals , Body Composition , Energy Intake , Male , Mice , Mice, Inbred C57BL , Mice, Obese , Obesity/physiopathology
18.
Nutr Diet ; 75(1): 73-78, 2018 02.
Article in English | MEDLINE | ID: mdl-29411495

ABSTRACT

AIM: Derangements in blood lipid and lipoprotein metabolism are one of the leading causes of coronary heart disease (CHD). Therapeutic lifestyle changes such as diet and exercise are often prescribed to improve blood lipid and lipoprotein characteristics, but the efficacy of a telephone-based health coaching program has not been thoroughly explored. Our purpose was to examine effects of the Our Healthy Heart (OHH) Program on blood lipid and lipoprotein characteristics of individuals with mixed dyslipidaemia. METHODS: Cholesterol content of serum very low-density lipoprotein (VLDL), low-density lipoprotein (LDL) and high-density (HDL) subfractions and apolipoprotein concentrations were measured by vertical-density ultracentrifugation (Vertical Auto Profile (VAP)) from 1522 individuals with mixed dyslipidaemia (age 18-99 years, body mass index (BMI) 25-40, 62.7% female). Telephone-based health coaching (OHH, n = 722) or standard care (Control, n = 800) was provided for six months followed by VAP to evaluate changes in lipid and lipoprotein concentrations. Controls were obtained from individuals with similar blood lipid/lipoprotein characteristics who did not participate in the OHH Program. Coaches collected baseline self-reported data on anthropometrics, food intake and exercise. Participants in the OHH group were then prescribed a hypocaloric 500 kcal/day caloric deficit with encouragement to participate in physical activity. A two-way ANOVA was used to examine differences between groups over time, with results presented as means ± standard deviation. RESULTS: Health coaching significantly decreased serum concentrations of apoB100 (104.5 ± 25.8-94.3 ± 24.8 mg/dL), shifted LDL pattern size from B to A or A/B in over 60% of the OHH group and decreased cholesterol content of all VLDL subfractions (P < 0.05) compared to the control. CONCLUSIONS: Telephone-based health coaching recommendations to reduce dietary energy intake and increase physical activity produced significant improvements in cholesterol content of atherogenic lipoproteins, which are known to increase CHD risk.


Subject(s)
Cholesterol/blood , Energy Intake/physiology , Exercise/physiology , Health Promotion/methods , Lipids/blood , Lipoproteins/blood , Telephone , Adult , Aged , Aged, 80 and over , Australia , Body Mass Index , Cholesterol/metabolism , Female , Humans , Lipoproteins/metabolism , Male , Middle Aged , Program Evaluation , Young Adult
19.
Clin Nutr ; 37(1): 56-60, 2018 02.
Article in English | MEDLINE | ID: mdl-28214041

ABSTRACT

Age-related declines in health and function make locomotion increasingly difficult leading to reductions in non-exercise activity thermogenesis (NEAT), skeletal muscle size and strength, and increased adiposity. Exercise is an important strategy to attenuate loss of function through the life cycle. Despite claims to the contrary, high-intensity exercise is important for the prevention of obesity and sarcopenia with advancing age. Therefore, the purpose of this mini-review is to present literature supporting the contention that low volume, high-intensity aerobic and/or resistance training can slow sarcopenia, sustain ease of movement, stimulate NEAT, and attenuate the accretion of fat mass.


Subject(s)
Exercise , Health Behavior , Health Status , Resistance Training , Adult , Aged , Aged, 80 and over , Energy Metabolism , Female , Humans , Male , Middle Aged , Obesity/prevention & control , Sarcopenia/prevention & control
20.
Obesity (Silver Spring) ; 26(1): 17-21, 2018 01.
Article in English | MEDLINE | ID: mdl-29265775

ABSTRACT

Increased rates of obesity have occurred within virtually every race, age, sex, ethnicity, and economic group. Despite substantial punditry on the issue, the exact reasons are incompletely known. The two most common factors cited as contributing to the obesity epidemic, and those whose causal influence on increasing obesity levels in the population are often presumed unequivocally, are food marketing practices and institutionally driven reductions in physical activity. These have been called "the big two." This Perspective builds on previous writings in this area to introduce additional factors that may contribute to the obesity epidemic. It is emphasized that there may be other factors working in combination with the big two, influencing body fatness through effects on energy intake, energy expenditure, and/or nutrient partitioning.


Subject(s)
Obesity/epidemiology , Female , Humans , Male
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