Hyperthermia and maximal oxygen uptake in men and women

To compare the effect of hyperthermia on maximal oxygen uptake (O_2max) in men and women, O_2max was measured in 11 male and 11 female runners under seven conditions involving various ambient temperatures (T_a at 50% RH) and preheating designed to manipulate the esophageal (T_es) and mean skin temperatures at O_2max. The conditions were: 25°C, no preheating (control); 25, 35, 40, and 45°C, with exercise-induced preheating by a 20-min walk at ~33% of control O_2max; 45°C, no preheating; and 45°C, with passive preheating during which T_es and were increased to the same degree as at the end of the 20-min walk at 45°C. Compared to O_2max (l·min^–1) in the control condition (4.52±0.46 in men, 3.01±0.45 in women), O_2max in men and women was reduced with exercise-induced or passive preheating and increased T_a, ~4% at 35°C, ~9% at 40°C and ~18% at 45°C. Percentage reductions (7–36%) in physical performance (treadmill test time to exhaustion) were strongly related to reductions in O_2max (r=0.82–0.84). The effects of hyperthermia on O_2max and physical performance in men and women were almost identical. We conclude that men and women do not differ in their thermal responses to maximal exercise, or in the relationship of hyperthermia to reductions in O_2max and physical performance at high temperature. Data are reported as mean (SD) unless otherwise stated.     

Exercise improves biomarkers of health and stress in animals fed ad libitum

Voluntary and forced exercise decrease morbidity and mortality in laboratory animals. Caloric restriction has similar effects on health and unique benefits on life span. Nonetheless, in most experiments, animals do not have access to physical activity and are fed ad libitum (AL). We hypothesized that with regular access to either unlimited running wheel exercise (EX) or limited physical activity (PA), key biomarkers of health would be enhanced enough to counter some consequences of a sedentary AL lifestyle. This 16-month study compared body weight, tumor number and size, tissue lesions, oxidative stress, and reactive stress in (1) sedentary animals with no access to physical activity (SED); (2) animals with access to hour-long, twice weekly activity in a large box (PA); and (3) animals with access every other day to a running wheel (EX). At the end of the study, EX body weight was 8-9% lower than PA and SED. In addition, EX had no kidney lesions versus 50% in PA and SED, and had smaller tumor size (10+/-2 vs. 14+/-4 and 30+/-4 mm). Exhaustive exercise lowered glutathione/oxidized glutathione ratio in EX and PA, but in SED, the ratio was depressed even in resting animals. In all treatments, prolactin (PRL) levels were lower in resting animals than in acutely exercised animals. In conclusion, EX had the most favorable health biomarkers while SED had the least. PA did not confer gross health benefits different than the SED group, but was biochemically more similar to EX animals.     

身心因素与肠易激综合征患者生活质量的相关研究

目的调查肠易激综合征(IBS)患者生活质量状况并评估躯体及心理因素对它的影响。方法采用肠易激综合征生活质量量表(IBS-QOL)、临床症状问卷、艾森克人格问卷简式(EPQ-RSC)、简明心境问卷简式(POMS-SF)、医学应对问卷(MCMQ)对120例IBS患者进行测查,将IBS患者的心理健康水平(人格、情绪、应对)及躯体症状(肠道症状、肠外症状、睡眠障碍)与IBS患者生活质量进行相关分析。结果IBS患者IBS-QOL的8个因子和总分均显著降低(P<0.05),其中健康忧虑和饮食限制降低最为明显,除IBS症状外,肠外症状、睡眠障碍、精神心理异常在IBS患者中也很常见。心理因素中EPQ-RSC神经质(N)分、POMS中焦虑、抑郁等多项因子分及总分、MCMQ屈服积分与IBS-QOL总分呈负相关;躯体因素中IBS症状、肠外症状、睡眠障碍积分与IBS-QOL总分呈负相关。结论肠易激综合征患者的生活质量明显降低,除躯体症状外,心理功能失调也是决定患者生活质量的重要因素。     

Effects of training at simulated altitude on performance and muscle metabolic capacity in competitive road cyclists

Summary Differences between the effects of training at sea level and at simulated altitude on performance and muscle structural and biochemical properties were investigated in 8 competitive cyclists who trained for 3–4 weeks, 4–5 sessions/week, each session consisting of cycling for 60–90 min continuously and 45–60 min intermittently. Four subjects, the altitude group (AG), trained in a hypobaric chamber (574 torr=2300 m above sea level), and the other four at sea level (SLG). Before and after training work capacity was tested both at simulated altitude (574 torr) and at sea level, by an incremental cycle ergometer test until exhaustion. Work capacity was expressed as total amount of work performed. Venous blood samples were taken during the tests. Leg muscle biopsies were taken at rest before and after the training period. AG exhibited an increase of 33% in both sea level and altitude performance, while SLG increased 22% at sea level and 14% at altitude. Blood lactate concentration at a given submaximal load at altitude was significantly more reduced by training in AG than SLG. Muscle phosphofructokinase (PFK) activity decreased with training in AG but increased in SLG. All AG subjects showed increases in capillary density. In conclusion, work capacity at altitude was increased more by training at altitude than at sea level. Work capacity at sea level was at least as much improved by altitude as by sea level training. The improved work capacity by training at altitude was paralleled by decreased exercise blood lactate concentration, increased capillarization and decreased glycolytic capacity in leg muscle.     

Policemen's physical fitness in relation to the frequency of leisure-time physical excercise

Summary Ninety to ninety-five men (aged 27 to 46 years) from the police academy were the study subjects. Their prior habits of physical excercise, estimated aerobic capacity ( ), muscular performance, and thickness of subcutaneous fat were determined. The policemen were taller (181 cm vs 175 cm) and heavier (84 kg vs 74 kg) than the average 20- to 40-year-old Finnish man, and their (1 · min^–1) was higher (3.41 1 · min^–1 vs 2.96 1 min^–1 The frequency of prior physical exercise significantly correlated with most of the variables studied. Those policemen who did not exercise at all (n = 12) were inferior to the average 20- to 40-year-old Finnish man on all the physical fitness tests, whereas the results of the most active policemen (n = 23) were clearly higher. The results indicate that the selection of heavier and taller men for police training guarantees a certain absolute level of physical performance capacity. However, the physical activity involved in police work is insufficient to maintain a high level of physical fitness, which must be achieved through participation in regular and effective physical training.     

Weight change adjusted equations for assessing resting metabolic rate in overweight and obese adults

BackgroundAlthough over one hundred equations have been developed to predict the energy expenditure of individuals, none are sensitive to weight change in assessment of resting metabolic rate (RMR) before and after weight loss.ObjectiveTo formulate adjusted equations for overweight and obese individuals and to compare their accuracy with existing prediction RMR equations before and after weight loss.Subjects/materialsThis is historical prospective study. Participants included 39 overweight and obese men and women before and after losing 10–20% from baseline weight on a diet and physical activity regimen for at least three months. Pre and post weight loss measured RMR results were compared to estimated RMR using several existing prediction equations: Harris and Benedict, Ravussin and Bogardus, and Mifflin et al. To improve the accuracy of these prediction equations, we suggest new equations adjusted for weight loss, based on measured RMR and evaluated their accuracy.ResultsPre and post weight loss data indicated: significant fat reduction in both genders; reduction in free-fat mass only in men, and a significant decrease in measured RMR only in women. Our suggested equations were the most accurate and closest to measured RMR in both genders, in comparison to the Harris and Benedict, Ravussin and Bogardus, and Mifflin et al equation results. Estimated RMR using the latter equations was significantly lower than measured RMR in both genders at pre and post weight loss (P < 0.01).ConclusionsThis study highlights the need for adjusting RMR equations before and after weight loss in overweight and obese individuals. Further research is needed to validate our suggested equations.     

Sleep following intense physical exercise stabilizes motor learning in typically developing boys

There is compelling evidence that sleep (N2, REM sleep, but also N3) supports the consolidation of motor memory in adults. Although children express higher levels of REM sleep and N3, it is still not understood why sleep does not benefit the consolidation of motor memory in children as in adults. Here, we aimed to manipulate sleep by daytime physical exercise in typically developing boys (N = 12; range 9–12 yrs) to test the impact on sleep and motor learning. The manipulation consisted of 1 h of intense ergometer exercise during the daytime before a night of restorative sleep. In a rest control condition, children were seated comfortably and listened to an audio drama. Motor learning was assessed with a visuomotor finger sequence tapping task; in both conditions learning took place before either exercise or rest. Prior to sleep in the sleep laboratory, motor memory was assessed as a baseline. Motor memory was again collected in the morning after a night of sleep in the lab. While there was no change in N3, we found prolonged REM sleep latency after physical activity compared to rest, corresponding to a prolonged first sleep cycle. With respect to motor learning, we found superior accuracy of motor performance after physical exercise compared to rest. Our findings suggest that physical exercise during the daytime stabilizes sleep-dependent motor learning.     

Routine participation in sports and fitness activities among out-patients with psychotic disorders: A multi-site cross-sectional survey in England

BackgroundSedentary lifestyle is a significant contributor to poor outcomes in people with psychotic disorders. However, little is known about the extent of routine participation in specific sports and fitness activities among those who do take part. We investigated the frequency, intensity, time and type of sports and fitness activities (“fitness”) completed by people with psychotic disorders in their daily life and explored correlates associated with fitness participation.MethodsWe conducted a cross-sectional survey among out-patients with psychotic disorders (n = 529) recruited from six different NHS sites in England. Subjective participation in fitness activities during the previous week was assessed by an adaptation of the UK Time Use Survey. The main outcome was whether participants met the minimum World Health Organization recommendations for moderate intensity physical activity (≥150 min/week) through fitness. Poisson regression models with robust error variance were used to examine associations of this outcome with participant variables.ResultsIn total, 267 (52.2%) participants reported taking part in routine fitness activities in the previous week, many of whom did so alone (n = 163, 59.1%). Only 21.5% (n = 114) completed ≥150 min of fitness activities in the previous week. The likelihood of attaining these recommendations was lower among participants who were female, older in age, in a relationship, unemployed and with fewer social contacts.ConclusionMental health services promoting physical activity interventions among people with psychotic disorders may need to modify their approaches based on previous patient preference and increase their focus on sub-groups of patients who are less likely to routinely engage in fitness activities.     

Physical activity and motor skill outcomes of a 10-week intervention for children with intellectual and developmental disabilities ages 4–13: A pilot study

BackgroundChildren with intellectual and developmental disabilities (IDD) often experience increased barriers to engaging in physical activity (PA) which can stem from lack of gross motor function (GMF) development. Intervening on GMF at an early age can create better opportunities for children with IDD to engage in regular PA. In turn, increased PA can improve health outcomes and increase social skills.ObjectiveThe primary objective of this pilot study was to explore the effectiveness of a community-based GMF-focused PA intervention for improving overall motor skills and PA for children with IDD.MethodsAll study participants (n = 24) engaged in 10 weeks of programming for 1 h each week. A convenience sample was utilized.ResultsResults indicated no statistically significant changes pre to post for motor skill scores. However, a visual analysis of mean changes showed a consistent pattern of increased scores from pre to post on most skills. Additionally, we found that a change in participant locomotor skills significantly predicted change in Moderate to Vigorous Physical Activity (MVPA), F (1,11) = 5.16, Adj R² = .26, p = .04.ConclusionsThese results suggest individualized attention on GMF may help to increase motor skills for children with IDD. This study adds to the small but growing amount of research examining the efficacy of community based adapted PA interventions. Further, study results should support continued exploration of effective approaches to address the motor delays experienced by children with IDD.     

Mental health and socioeconomic status impact adherence to youth activity and dietary programs: a meta-analysis

PurposeSubstantial efforts have gone into reducing the physiological and psychological harm of obesity in youth, but few studies have reviewed the factors contributing to adherence to pediatric weight management programs. The attrition rates to programs offering multiple components to address BMI improvement and healthy lifestyle change among youth are quite high. The purpose of this study is to review the literature for factors contributing to adherence to these programs among children and youth with obesity and determine pooled effect of these factors.MethodsA systematic literature search and meta-analysis was conducted through the PubMed database on pediatric weight management interventions offering at least physical activity and dietary support for obese youth aged 10–17 years, where variables contributing to adherence were reported. Only those studies achieving a threshold of methodological rigour were included.ResultsAltogether, seven studies were included in the analysis. There was a pooled RR of lower socioeconomic status on non-adherence of 1.34 [95% confidence intervals 1.19–1.52] and poorer mental health on non-adherence of 1.12 [95% confidence intervals 1.08–1.17].ConclusionIt is important to address barriers related to lower socioeconomic status in pediatric weight management programs to increase adherence. Further, addressing supports for those with poorer mental health can reduce the risk of non-adherence in multi-disciplinary programs targeting youth with obesity.