Prior acute exercise restores postprandial fat oxidation in active cannabis users.

Data suggest cannabis users have similar or lower levels of blood lipids compared to nonusers. However, the extent to which cannabis users experience postprandial lipemia is not known. Eleven cannabis users and 11 nonusers completed either rest or 1 h of exercise at their ventilatory threshold the evening before a meal tolerance test (MTT). Substrate oxidation, blood pressure, and capillary blood were obtained before and every 30-60 min post-meal for 3 h. Linear mixed models were utilized to examine differences in variables between groups, conditions, across time, and their interactions. Exercise led to increased fat oxidation post-MTT (p < 0.05), with cannabis users exhibiting higher AUC compared to the control trial (p < 0.05). Exercise also caused significantly lower levels of triglycerides (p < 0.05). Metabolic flexibility was improved in cannabis users in the exercise trial only (p < 0.05). No effect of group, trial, or interactions were detected for other variables of interest (all p > 0.05). This study indicated that prior exercise improves lipid metabolism in cannabis users and nonusers after a high-fat meal test. Cannabis users appear sensitive to the effects of exercise. Future studies should incorporate additional meals and variables related to cardiovascular health and metabolism.

Strength, Cardiovascular Fitness, and Blood Lipid Measures in Law Enforcement Personnel After a 12-Week Health Promotion Program.

ABSTRACT: Hibbert, JE, Klawiter, DP, Schubert, MM, Nessler, JA, and Asakawa, DS. Strength, cardiovascular fitness, and blood lipid measures in law enforcement personnel after a 12-week health promotion program. J Strength Cond Res 36(11): 3105-3112, 2022-Law enforcement personnel often have high rates of cardiovascular disease and injury. Health promotion programs have been found to successfully encourage behavior change among law enforcement personnel, but these programs can often be intensive and expensive. Thus, the purpose of this study was to examine the efficacy of a health promotion program on body composition, metabolic health, muscle strength, and cardiovascular endurance in law enforcement personnel. Active duty officers from a local law enforcement agency were invited to participate in a 12-week health promotion program that included activity tracking and exercise and nutrition education. Eighteen subjects underwent measurements of body composition, V̇ o2 max through treadmill test, knee extensor strength, and blood lipids. An a priori alpha level for significance was set at 0.05, and comparisons were assessed using paired t -tests. Overall, subjects improved blood lipid levels evidenced by movement of mean values toward established healthy ranges. Although 8 subjects improved their V̇ o2 max (range: 1.3-30% change), there was large variability and no statistically significant differences in measures of V̇ o2 max (pre: 38.48 ± 5.86 ml·kg·min -1 ; post: 39.27 ± 5.26 ml·kg·min -1 ), body composition (pre: 26.52 ± 8.02% body fat; post: 26.44 ± 7.45% body fat), and strength normalized to body mass (isometric pre: 1.45 ± 0.45; post: 1.08 ± 0.36). Although no significant changes were noted, promising trends in these data suggest that health promotion programs with a modified focus may lead to positive changes in overall health.

The Hydration Status of Female Collegiate Soccer Players Over Consecutive Training and Match Days / Estado de Hidratación de Jugadoras de Fútbol Universitarias Durante Días de Entrenamiento y Partidos Consecutivos

Abstract Purpose: Hydration has been shown to play a pivotal role in sport. Soccer is a team sport in which the integrity of all players is vital for team performance; thus, individual player hydration status is important. The primary aim of this study was to investigate the hydration status of female collegiate soccer players during regular season. Methods: Sixteen collegiate female soccer players (age: 20.4 ± 0.8 years; height: 163.6 ± 6.9 cm; weight: 65.3 ± 12 kg) provided urine over 9 days to monitor their hydration status. Hydration was determined by urine specific gravity (Usg). Usg was analyzed in the morning (AM) and in the afternoon before practice/game (PM). Results: All 16 players were at least minimally hypohydrated (Usg > 1.010) in the AM on 5 of the 9 days tested. Players had significantly higher Usg values in the AM as compared to PM (F(1,250) = 23.09; p < 0.0001); however, there was no significant time*day interaction (F(1,250) = 1.98; p = 0.16). Conclusion: Data show a high prevalence of hypohydration occurring in this specific population. This sub-optimal hydration status could be a cause for concern in terms of overall performance. Efforts should be made to integrate hydration interventions and daily monitoring to minimize hypohydration in players.

Resumen Propósito: Se ha demostrado que la hidratación juega un papel fundamental en el deporte. El fútbol es un deporte de equipo en el que la integridad de todos los jugadores es vital para su rendimiento; por lo tanto, el estado de hidratación de cada jugador es importante. El objetivo principal de este estudio fue investigar el estado de hidratación de las jugadoras universitarias de fútbol durante la temporada regular. Métodos: Dieciséis jugadoras universitarias de fútbol (edad: 20.4 ± 0.8 años; estatura: 163.6 ± 6.9 cm; peso: 65.3 ± 12 kg) proporcionaron muestras de orina durante 9 días para controlar su estado de hidratación, la cual se determinó por la gravedad específica de la orina (Usg). La Usg se analizó en la mañana (AM) y en la tarde antes del entrenamiento o el juego (PM). Resultados: Las 16 jugadoras estaban al menos mínimamente hipohidratadas (Usg > 1.010) en la AM en 5 de los 9 días medidos. Las jugadoras tuvieron valores Usg significativamente más altos en AM en comparación con PM (F (1,250) = 23.09; p < 0.0001); sin embargo, no hubo interacción significativa de tiempo * día (F(1,250) = 1.98; p = 0.16). Conclusión: los datos muestran una alta prevalencia de hipohidratación en esta población específica. Este estado de hidratación subóptimo podría ser motivo de preocupación en términos de rendimiento general. Se deberían hacer esfuerzos para integrar las intervenciones de hidratación y el monitoreo diario para reducir al mínimo la hipohidratación en las jugadoras.

Resumo Objetivo: Foi demonstrado que a hidratação desempenha um papel fundamental no esporte. O futebol é um esporte coletivo no qual a integridade de todos os jogadores é vital para o desempenho da equipe; portanto, o estado de hidratação de cada jogador é importante. O objetivo principal deste estudo foi investigar o estado de hidratação de universitárias jogadoras de futebol do sexo feminino durante a temporada regular. Métodos: Dezesseis universitárias jogadoras de futebol (idade: 20,4 ± 0,8 anos; altura: 163,6 ± 6,9 cm; peso: 65,3 ± 12 kg) forneceram amostras de urina por 9 dias para monitorar seu estado de hidratação. A hidratação foi determinada pela gravidade específica da urina Usg. Sua Usg foi analisado pela manhã (matutino) e à tarde (vespertino) antes do treino ou jogo. Resultados: As 16 jogadoras estavam minimamente hipohidratadas (Usg > 1.010) no período matutino em 5 dos 9 dias medidos. As jogadoras apresentaram valores de Usg significativamente maiores no período matutino em comparação ao vespertino (F (1.250) = 23,09; p <0,0001); no entanto, não houve interação tempo * dia significativa (F (1.250) = 1,98; p = 0,16). Conclusão: os dados mostram uma alta prevalência de hipohidratação nesta população específica. Este estado de hidratação abaixo do ideal pode ser uma preocupação em termos de desempenho geral. Devem ser feitos esforços para integrar intervenções de hidratação e monitoramento diário para minimizar a hipohidratação em jogadoras.

Fluid Loss in Recreational Surfers.

Surfing offers unique challenges to thermoregulation and hydration. The purpose of this study was to quantify fluid loss in recreational surfers, and to analyze the effects of water temperature, air temperature, exercise intensity, duration, and garment thickness on the total amount of fluid lost during a surf session. A total of 254 male and 52 female recreational surfers were recruited from San Diego, Costa Rica, and Australia to participate in the study. Participants' hydration status was assessed by comparing nude body mass pre- and post-surf session. Heart rate (HR), used as an index of exercise intensity, was measured throughout the session. Environmental conditions and surf characteristics were recorded. The difference between average pre-mass (73.11 ± 11.88 kg) and average post-mass (72.51 ± 11.78) was statistically significant (0.60 ± 0.55, p < 0.001). Surfers experienced a 0.82 ± 0.73% reduction in body mass. In multivariable linear regression, session duration and body mass index (BMI) were significantly associated with fluid loss. For every 10-minute increase in session duration, there was a 0.06 kg (SE = 0.001; p < 0.001) increase in fluid loss, and for every two unit increase in BMI, fluid loss increased by 0.05 kg (SE = 0.03; p = 0.02). Results suggest that prolonged surfing at high environmental temperatures in participants with high BMI's resulted in significant body water deficits. Since there is no opportunity to rehydrate during a surf session, surfers must properly pre-hydrate before surfing in order to avoid the detrimental effects of dehydration.

Effect of Fed State on Self-selected Intensity and Affective Responses to Exercise Following Public Health Recommendations.

Nutritional status has numerous effects on exercise metabolism and psychological responses. The effect of fed state on changes in affective valence; however, are unknown. Thus, the present study examined how fed state influenced self-selected exercise intensity, affective responses during exercise, and exercise enjoyment when exercise was completed following physical activity guidelines for public health. In a repeated-measures crossover design, 25 recreationally active men and women (age and BMI = 22.0 ± 2.0 yr and 24.3 ± 3.3 kg/m2) performed a single 30 min session of treadmill exercise at a Rating of Perceived Exertion (RPE) equal to 13 on the Borg 6-20 scale following an overnight fast (FAST) or 30 minutes after a small meal (FED). Affective valence was recorded every 3 minutes during exercise. Heart rate and gas exchange data were measured continuously using a metabolic cart, blood glucose and blood lactate concentration were measured pre/post-exercise, and enjoyment was measured 15 minutes post-exercise. There was no effect of condition on affective valence, enjoyment, or self-selected intensity (all p>0.05). However, pre-exercise blood glucose was higher in FED pre-exercise, but higher post-exercise in FAST (p<0.05). Blood lactate concentration was also higher in FAST (p<0.05). Our results reveal minimal effects of a small, high-carbohydrate pre-exercise meal on in-task and post-task affective responses, exercise enjoyment, and self-selected intensity. These data suggest that an overnight fast does not alter affective valence or reduce enjoyment of continuous exercise.

Energy balance dynamics during short-term high-intensity functional training.

CrossFit (CF; CrossFit Inc., Washington, DC, USA) is a form of high-intensity functional training that focuses on training across the entire spectrum of physical fitness. CF has been shown to improve a number of indicators of health but little information assessing energy balance exists. The purpose of the present study was to investigate energy balance during 1 week of CF training. Men and women (n = 21; mean ± SD; age, 43.5 ± 8.4 years; body mass index, 27.8 ± 4.9 kg·m-2), with ≥3 months CF experience, had body composition assessed via air displacement plethysmography before and after 1 week of CF training. Participants wore ActiHeart monitors to assess total energy expenditure (TEE), activity energy expenditure, and CF energy expenditure (CF EE). Energy intake was assessed from TEE and Δ body composition. CF EE averaged 605 ± 219 kcal per 72 ± 10 min session. Weekly CF EE was 2723 ± 986 kcal. Participants were in an energy deficit (TEE: 3674 ± 855 kcal·day-1; energy intake: 3167 ± 1401 kcal·day-1). Results of the present study indicate that CF training can account for a significant portion of daily activity energy expenditure. The weekly expenditure is within levels shown to induce clinically meaningful weight loss in overweight/obese populations.

Reliability and validity of various laboratory methods of body composition assessment in young adults.

Accurate measures of body composition (BC) are essential for performance and health. In addition to accuracy, BC measures should be practical and be minimally invasive to maximize their utility. The purpose of the present study was to compare the day-to-day variability and validity of four common laboratory-based body composition assessments to a criterion four-compartment model. Dual x-ray absorptiometry (DXA), air displacement plethysmography (BP), multi-frequency bioelectrical impedance (MF-BIA) and underwater weighing (UWW) were performed twice in a sample of 32 young men and women. Participants were assessed in a fasted, euhydrated state 2-7 days apart. All methods were compared to a criterion four-compartment model using BP-derived body volume, DXA-derived bone mineral content and MF-BIA-derived total body water (4CBP ). Additional four-compartment models using UWW- and DXA-derived body volume were also examined (4CUWW ) and (4CDXA ). Validity results were conducted with paired t-tests and Bland-Altman analysis. Reliability was determined using intraclass correlations (ICC), coefficients of variation (CV) and standard error of the measurement (SEM). Validity analysis revealed that all methods overestimated per cent body fat and fat mass, and underestimated fat-free mass when compared with 4CBP , but only DXA and BP were significantly different (P<0·008). All measures were highly reliable across days (ICCs > 0·9, CVs < 12%). Results of the present study indicate that typical laboratory-based methods of body composition are valid and reliable. However, we caution that results should not be translated between methods and assessments should be performed with the same instrument when the goal is to monitor changes in body composition over time.

The Polar ® OH1 Optical Heart Rate Sensor is Valid during Moderate-Vigorous Exercise.

PURPOSE: Traditional heart-rate monitoring through the use of electrocardiograms or chest-worn heart rate sensors can be challenging in certain sports or in field settings. New technologies, such as photoplethysmography (PPG), have enabled heart-rate monitoring at alternate sites. However, to date, the accuracy and validity of various PPG sensors has not been examined in detail. The purpose of the present investigation was to determine the validity of an arm-worn PPG sensor during yoga sequences. METHODS: Fifteen college-aged men and women participated in a ~45 min power vinyasa yoga class. During the class, participants wore Polar ® H7 chest straps and RCX3 receivers (criterion) and Polar ® OH1 arm bands on their upper right arm (practical). Mean differences were compared via a paired t -test, heart rate during yoga using a time*device repeated measures ANOVA, and agreement assessed with Bland-Altman analysis. RESULTS: Mean heart rates during yoga were not different (mean difference=0.76, 95% CI: -0.54 to 2.06; p =0.229). Yoga created a main effect of time on heart rate ( p <0.0001), but there was no difference between devices ( p =0.86) or interaction ( p =0.90). Mean bias±95% limits of agreement was 0.76±1.30 bpm, with a typical error of 2.42±1.49 bpm and a coefficient of variation of 1.8±1.5%. CONCLUSIONS: Results of the present investigation revealed that the Polar ® OH1 is a valid measure of heart rate during moderate-vigorous exercise. Future validation studies should consider other exercise modes and participant characteristics.

Heart rate and thermal responses to power yoga.

BACKGROUND: and Purpose: Yoga has grown in popularity and may offer a viable alternative form of physical activity. The purpose of this study was to examine heart rate, hydration, and thermal responses to a power yoga sequence. MATERIALS AND METHODS: Twenty-seven men and women (n = 4/23; Mean ±â€¯SD age = 23.3 ±â€¯3.3 years; BMI = 23 ±â€¯3 kg m-2) underwent ∼45 min of power yoga. Heart rate and skin temperature were recorded. Mass was measured before and after exercise to estimate fluid loss. Time spent in light, moderate, and vigorous heart rate zones was calculated. RESULTS: Heart rate and skin temperature increased (p < 0.0001). Participants spent more time in moderate and vigorous heart rate zones than in light intensity (p < 0.0001). There was a reduction in body mass (-0.28 ±â€¯0.13 kg, p < 0.0001). CONCLUSION: Power yoga may be considered moderate-vigorous intensity exercise, based on heart-rate.

Changes in fat oxidation in response to various regimes of high intensity interval training (HIIT).

Increased whole-body fat oxidation (FOx) has been consistently demonstrated in response to moderate intensity continuous exercise training. Completion of high intensity interval training (HIIT) and its more intense form, sprint interval training (SIT), has also been reported to increase FOx in different populations. An explanation for this increase in FOx is primarily peripheral adaptations via improvements in mitochondrial content and function. However, studies examining changes in FOx are less common in response to HIIT or SIT than those determining increases in maximal oxygen uptake which is concerning, considering that FOx has been identified as a predictor of weight gain and glycemic control. In this review, we explored physiological and methodological issues underpinning existing literature concerning changes in FOx in response to HIIT and SIT. Our results show that completion of interval training increases FOx in approximately 50% of studies, with the frequency of increased FOx higher in response to studies using HIIT compared to SIT. Significant increases in ß-HAD, citrate synthase, fatty acid binding protein, or FAT/CD36 are likely responsible for the greater FOx seen in these studies. We encourage scientists to adopt strict methodological procedures to attenuate day-to-day variability in FOx, which is dramatic, and develop standardized procedures for assessing FOx, which may improve detection of changes in FOx in response to HIIT.

Effect of periodized high intensity interval training (HIIT) on body composition and attitudes towards hunger in active men and women.

BACKGROUND: High intensity interval training (HIIT) increases maximal oxygen uptake similar to aerobic exercise. However, changes in body composition are equivocal in response to HIIT. We examined changes in body composition and dietary restraint in response to 20 sessions of HIIT varying in structure. METHODS: Thirty nine active men and women (age and VO2max=22.5±4.4 years and 40.1±5.6 mL/kg/min) were randomized to one of three periodized HIIT regimes performed on a cycle ergometer. Before and after training, body composition was assessed using skinfolds (SKF), circumference measures, and Bioelectrical Impedance Analysis (BIA) following standardized procedures. Hunger, restraint, and disinhibition were also measured using the 3-Factor Eating Questionnaire and Power of Food Survey. Control participants (N.=32, age and VO2max=25.6±4.4 years and 40.6±4.9 mL/kg/min) matched for age and fitness level underwent all testing but did not complete HIIT. RESULTS: There was no change (P>0.05) in body mass, circumferences, or BIA-derived body fat in response to HIIT. However, SKF-derived body fat declined (P=0.04) with HIIT, and gender x time (P=0.03) and gender x time x regimen interactions (P=0.04) were shown in that women but not men exhibited significant reductions in body fat. Hunger was reduced from baseline to post-training (P=0.028), but this response was not different in response to HIIT compared to controls. CONCLUSIONS: Twenty sessions of low-volume HIIT reduce body fat in women but not men, but do not alter perceptions of hunger.

Energy compensation after sprint- and high-intensity interval training.

BACKGROUND: Many individuals lose less weight than expected in response to exercise interventions when considering the increased energy expenditure of exercise (ExEE). This is due to energy compensation in response to ExEE, which may include increases in energy intake (EI) and decreases in non-exercise physical activity (NEPA). We examined the degree of energy compensation in healthy young men and women in response to interval training. METHODS: Data were examined from a prior study in which 24 participants (mean age, BMI, & VO2max = 28 yrs, 27.7 kg•m-2, and 32 mL∙kg-1∙min-1) completed either 4 weeks of sprint-interval training or high-intensity interval training. Energy compensation was calculated from changes in body composition (air displacement plethysmography) and exercise energy expenditure was calculated from mean heart rate based on the heart rate-VO2 relationship. Differences between high (≥ 100%) and low (< 100%) levels of energy compensation were assessed. Linear regressions were utilized to determine associations between energy compensation and ΔVO2max, ΔEI, ΔNEPA, and Δresting metabolic rate. RESULTS: Very large individual differences in energy compensation were noted. In comparison to individuals with low levels of compensation, individuals with high levels of energy compensation gained fat mass, lost fat-free mass, and had lower change scores for VO2max and NEPA. Linear regression results indicated that lower levels of energy compensation were associated with increases in ΔVO2max (p < 0.001) and ΔNEPA (p < 0.001). CONCLUSIONS: Considerable variation exists in response to short-term, low dose interval training. In agreement with prior work, increases in ΔVO2max and ΔNEPA were associated with lower energy compensation. Future studies should focus on identifying if a dose-response relationship for energy compensation exists in response to interval training, and what underlying mechanisms and participant traits contribute to the large variation between individuals.

Impact of 4 weeks of interval training on resting metabolic rate, fitness, and health-related outcomes.

Resting metabolic rate (RMR) and substrate oxidation (respiratory exchange ratio; RER) are important indicators of health. The effects of interval training on RMR have not been thoroughly investigated, which was the purpose of the present study. Thirty men and women (mean ± SD age and maximal oxygen uptake: 28.8 ± 7.6 years and 33.0 ± 8.3 mL·kg-1·min-1) completed 4 weeks of Wingate-based sprint interval training (SIT), repeated 1-min high-intensity intervals (HIIT), or served as controls. Before and after training, RMR, resting RER, maximal oxygen uptake, body composition, physical activity, and energy intake were recorded. Data were analyzed using a repeated-measures ANOVA. RMR increased in response to 4 weeks of SIT training (1789 ± 293 to 1855 ± 320 kcal·day-1; p = 0.003) but did not increase after HIIT (1670 ± 324 to 1704 ± 329 kcal·day-1; p = 0.06). While SIT increased RMR by ∼2× the magnitude of HIIT, the difference was not significant (p = 0.5). Fasting substrate oxidation and RER did not change (p > 0.05). Maximal oxygen uptake increased, and small changes were also observed in percent body fat and fat mass (p < 0.05 for all). In conclusion, SIT provided a time-efficient stimulus to increase RMR after 4 weeks in healthy adults. However, the clinical relevance of the changes observed in this study remains to be determined. Further studies should be conducted in obese individuals and those with diabetes or insulin resistance to examine if interval training (≥4 weeks) influences resting metabolic rate in magnitudes similar to that reported here.

Caffeine, coffee, and appetite control: a review.

Coffee and caffeine consumption has global popularity. However, evidence for the potential of these dietary constituents to influence energy intake, gut physiology, and appetite perceptions remains unclear. The purpose of this review was to examine the evidence regarding coffee and caffeine's influence on energy intake and appetite control. The literature was examined for studies that assessed the effects of caffeine and coffee on energy intake, gastric emptying, appetite-related hormones, and perceptual measures of appetite. The literature review indicated that coffee administered 3-4.5 h before a meal had minimal influence on food and macronutrient intake, while caffeine ingested 0.5-4 h before a meal may suppress acute energy intake. Evidence regarding the influence of caffeine and coffee on gastric emptying, appetite hormones, and appetite perceptions was equivocal. The influence of covariates such as genetics of caffeine metabolism and bitter taste phenotype remain unknown; longer controlled studies are needed.

Exercise volume and aerobic fitness in young adults: the Midwest Exercise Trial-2.

To examine the effect of exercise volume at a fixed intensity on changes in aerobic fitness. Ninety-two overweight/obese individuals (BMI 25-40 kg m(2)), age 18-30 years, 50 % women, completed a 10 mo, 5 d wk(-1) supervised exercise intervention at 2 levels of exercise energy expenditure (400 or 600 kcal session(-1)) at 70-80 % heart rate (HR) max. Exercise consisted primarily of walking/jogging on motor-driven treadmills. The duration and intensity of all exercise sessions were verified by a downloadable HR monitor set to collect HR in 1-min epochs. All participants were instructed to continue their typical patterns of non-exercise physical activity and dietary intake over the duration of the 10 mo intervention. Maximal aerobic capacity (indirect calorimetry) was assessed on a motor-driven treadmill using a modified Balke protocol at baseline, mid-point (5 mo), and following completion of the 10 mo intervention. VO2 max (L min(-1)) increased significantly in both the 400 (11.3 %) and 600 kcal session(-1) groups (14 %) compared to control (-2.0 %; p < 0.001); however, the differences between exercise groups were not significant. Similar results were noted for change in relative VO2 max (mL kg(-1) min(-1)); however, the magnitude of change was greater than for absolute VO2 max (L min(-1)) (400 group = 18.3 %; 600 group = 20.2 %) due to loss of body weight over the 10-mo intervention in both exercise groups. Our results indicate that exercise volume was not associated with change in aerobic fitness in a sample of previously sedentary, overweight and obese young adults.

Breakfast Intake and Composition Is Associated with Superior Academic Achievement in Elementary Schoolchildren.

OBJECTIVE: To determine whether breakfast consumption or content affects academic achievement measured by standardized tests. METHODS: Baseline data were collected in fall of 2011 from 698 students (50.5% female, age = 7.5 ± 0.6 years) living in the state of Kansas. Academic achievement was assessed using 3 components from the Wechsler Individual Achievement Test (WIAT-III). Prior to taking the WIAT-III, participants completed a breakfast recall of all foods and drinks consumed that morning, which was analyzed using Nutrition Data System for Research (NDS-R). WIAT-III scores were compared between breakfast and non-breakfast consumers in a sample (n = 162) matched for age, sex, race, education level of both parents, household income, body mass index (BMI), and cardiovascular fitness, and Pearson correlations were calculated from all breakfast eaters (n = 617) between test performance and components of the breakfast. RESULTS: When compared to non-breakfast consumers, the breakfast consumers had significantly higher scores in all 3 WIAT-III components (all p < 0.05). In breakfast consumers, servings of fruit juice were negatively correlated with reading comprehension and fluency standard score and mathematics standard score (both p < 0.0001), and greater servings of whole grains were significantly related to higher scores in reading comprehension and fluency and mathematics (both p < 0.05). CONCLUSION: Both breakfast consumption and the content may be associated with improved standardized test performance in elementary school students.

Perceptual Changes in Response to Two Regimens of Interval Training in Sedentary Women.

This study examined acute and chronic changes in perceptual measures (rating of perceived exertion [RPE], affect, and arousal) in response to 2 regimens of high-intensity interval training (HIIT). Twenty-three healthy sedentary women (mean ± SD age and V[Combining Dot Above]O2max = 23.0 ± 5.7 years and 30.1 ± 4.4 ml·kg·min, respectively) were randomized to complete 12 weeks of one of 2 HIIT regimes, whereas an additional 7 women served as sedentary controls. Training was performed 3 days per week on a cycle ergometer and consisted of up to ten 1-minute bouts at moderate (60-80%Wmax = moderate intensity [MOD]) or more intense (80-90%Wmax = HI) workloads separated by active recovery. At baseline and every 3 weeks, RPE, affect, and arousal were measured during training using validated scales. Repeated measures analysis of variance was used to examine acute and chronic changes in these variables to HIIT. Data revealed significant (p < 0.001) increases in RPE and arousal and decreases (p < 0.001) in affect during acute HIIT, with RPE responses differing (p ≤ 0.05) between HI and MOD. However, acute changes in affect and arousal were similar in HI and MOD. Training led to a significant reduction in RPE, whereas both affect and arousal were unchanged (p > 0.05) after HIIT. Completion of moderate or more intense interval training reduces perceptions of RPE during training yet does not alter arousal or affect. RPE was reduced via training, yet large dependence on anaerobic metabolism during HIIT may minimize training-induced changes in affect.

Acute exercise and gastric emptying: a meta-analysis and implications for appetite control.

BACKGROUND: Gastric emptying (GE) could influence exercise-induced changes in appetite and energy intake. GE also could contribute to changes in gastric symptoms and the availability of nutrients during exercise, which will subsequently affect performance. OBJECTIVE: The objective of this review was to determine the effects of acute exercise on GE using a systematic review and meta-analysis. The most common parameters to determine GE were selected, consisting of half-emptying time and volume emptied. Oral-caecal transit time (OCTT) was also examined. DATA SOURCES: Research databases (PubMed, Scopus, Google Scholar, EBSCOhost, SPORTDiscus) were searched through November 2013 for original studies, abstracts, theses and dissertations that examined the influence of acute exercise on GE. STUDY SELECTION: Studies were included if they evaluated GE or OCTT during and/or after exercise and involved a resting control trial. STUDY APPRAISAL AND SYNTHESIS: Initially, 195 studies were identified. After evaluation of study characteristics and quality and validity, data from 20 studies (35 trials) involving 221 participants (157 men; 52 women; 12 unknown) were extracted for meta-analysis. Random-effects meta-analyses were utilised for the three main outcome variables, and effect sizes (ES) are reported as Hedge's g due to numerous small sample sizes. RESULTS: Random-effects modelling revealed non-significant and small/null main effect sizes for volume emptied (ES = 0.195; 95% CI -0.25 to 0.64), half-time (ES = -0.109, 95% CI -0.66 to 0.44) and OCTT (ES = 0.089; 95% CI -0.64 to 0.82). All analyses exhibited significant heterogeneity and numerous variables moderated the results. There was a dose response of exercise intensity; at lower intensities GE was faster, and at high exercise intensities GE was slower. Walking was associated with faster GE and cycling with slower GE. Greater volume of meal/fluid ingested, higher osmolality of beverage and longer exercise duration were also associated with slower GE with exercise. LIMITATIONS: The major limitation is that the majority of studies utilised a liquid bolus administered pre-exercise to determine GE; the relationship to post-exercise appetite and energy intake remains unknown. Study populations were also generally active or trained individuals. Furthermore, our review was limited to English language studies and studies that utilised resting control conditions. CONCLUSIONS: These results suggest that exercise intensity, mode, duration and the nature of meal/fluid ingested all influence GE during and after acute exercise. The relationship of GE parameters with appetite regulation after exercise remains largely unexplored. Further integrative studies combining GE and alterations in gut hormones, as well as in populations such as overweight and obese individuals are needed.

A review of the bioactivity of coffee, caffeine and key coffee constituents on inflammatory responses linked to depression.

Coffee is a widely consumed beverage containing numerous biologically active constituents predominantly belonging to the polyphenol and alkaloid classes. It has been established that coffee has a beneficial effect on numerous disease states including depression. A number of prospective and retrospective cohort studies have assessed the effects of coffee consumption on the relative risk of developing major depressive disorder in humans. These studies have identified an inverse relationship between the consumption of caffeinated coffee and the risk of developing depression. Caffeine, chlorogenic acid, ferulic acid and caffeic acid, all important constituents of coffee, have been shown to possess biological activities that highlight a possible mechanistic link to the pathology of depression. This review aims to assess the evidence from the biological evaluation of these constituents of coffee on markers of inflammation associated with depression in in vitro and in vivo models of inflammation, neuroinflammation and depression. The ability of bioactive coffee constituents to modulate the parameters of neuroinflammation has been shown with caffeine having strong antioxidant properties in vitro, chlorogenic acid and caffeic acid having strong anti-inflammatory and antioxidant properties in vitro and ferulic acid having activities in in vivo animal models of depression.

Coffee for morning hunger pangs. An examination of coffee and caffeine on appetite, gastric emptying, and energy intake.

Coffee is one of the most widely consumed beverages in the world and has a number of potential health benefits. Coffee may influence energy expenditure and energy intake, which in turn may affect body weight. However, the influence of coffee and its constituents - particularly caffeine - on appetite remains largely unexplored. The objective of this study was to examine the impact of coffee consumption (with and without caffeine) on appetite sensations, energy intake, gastric emptying, and plasma glucose between breakfast and lunch meals. In a double-blind, randomised crossover design. Participants (n = 12, 9 women; Mean ± SD age and BMI: 26.3 ± 6.3 y and 22.7 ± 2.2 kg•m⁻²) completed 4 trials: placebo (PLA), decaffeinated coffee (DECAF), caffeine (CAF), and caffeine with decaffeinated coffee (COF). Participants were given a standardised breakfast labelled with ¹³C-octanoic acid and 225 mL of treatment beverage and a capsule containing either caffeine or placebo. Two hours later, another 225 mL of the treatment beverage and capsule was administered. Four and a half hours after breakfast, participants were given access to an ad libitum meal for determination of energy intake. Between meals, participants provided exhaled breath samples for determination of gastric emptying; venous blood and appetite sensations. Energy intake was not significantly different between the trials (Means ± SD, p> 0.05; Placebo: 2118 ± 663 kJ; Decaf: 2128 ± 739 kJ; Caffeine: 2287 ± 649 kJ; Coffee: 2016 ± 750 kJ); Other than main effects of time (p <0.05), no significant differences were detected for appetite sensations or plasma glucose between treatments (p > 0.05). Gastric emptying was not significantly different across trials (p > 0.05). No significant effects of decaffeinated coffee, caffeine or their combination were detected. However, the consumption of caffeine and/or coffee for regulation of energy balance over longer periods of time warrant further investigation.