Feasibility of a school-based exercise intervention for children with intellectual disability to reduce cardio-metabolic risk.

BACKGROUND: People with intellectual disabilities (ID) are at increased risk of secondary health conditions, reduced quality of life and life expectancy. Children with ID demonstrate low levels of physical activity in association with a higher prevalence of obesity, a modifiable risk factor associated with secondary health conditions including type 2 diabetes and cardiovascular disease. Despite this, physical activity interventions addressing weight and weight-related complications in this population are limited. This study aimed to establish the feasibility of a school-based group exercise intervention for children with moderate to severe ID. METHODS: A single-arm intervention study was used to establish the feasibility of a 16-week exercise intervention. Children attending a School for Specific Purposes in Sydney, Australia, participated in two 30-min exercise sessions per week across the intervention period in addition to their regular physical education class. Each exercise session was 60% aerobically based, 20% strength based and 20% targeted towards fundamental movement skill development. We used two facilitation strategies to assist the delivery of the intervention, including the implementation of a variety of communication resources and promotion of social interaction. Feasibility was assessed through recruitment rates, program retention, adverse effects, attendance, group size feasibility and non-compliance. Anthropometric measures included height (m), weight (kg) and waist circumference (cm; umbilicus), with body mass index (BMI) and waist-to-height ratios (WtHR) used to determine cardio-metabolic risk. Aerobic capacity was assessed using the submaximal 6-min walk test (6-MWT). Intensity of physical activity sessions was measured through the use of tri-axial accelerometers and compared to physical activity recommendations. RESULTS: Ten children aged between 9 and 13 years completed the 16-week intervention, with a 55% recruitment rate, 91% program retention, 86% attendance and with no adverse effects reported. Sessions commenced as 1:1 supervisor to child ratios before progressing to established small groups of 2:7 (supervisor : child). Children spent 38.4% (11.5 min) of each session in moderate to vigorous physical activity (MVPA), equating to 20% of their MVPA recommended daily physical activity levels (twice per week). There was a significant change in weight across the intervention period, with a trend towards increased weight between mid-intervention and 3-month follow-up time points. There were no significant changes in child BMI, WtHR or aerobic capacity. CONCLUSIONS: A school-based group exercise intervention for children with moderate to severe ID is feasible and safe, with high retention rates and physical activity participation. No significant improvements in body composition or aerobic capacity were determined. The present study demonstrates that engaging children with moderate-severe ID in school-based group exercise is feasible to assist in physical activity participation.

Leucine improves glucose and lipid status in offspring from obese dams, dependent on diet type, but not caloric intake.

Previously, we showed that offspring from obese rat dams were hyperphagic, with increased adiposity, hyperlipidaemia and glucose intolerance associated with increased orexigenic neuropeptide expression after fasting. Mammalian target of rapamycin (mTOR) can inhibit food intake through a hypothalamic action. As we previously showed that maternal obesity down-regulated hypothalamic mTOR, in the present study, we hypothesised that dietary leucine supplementation would activate hypothalamic mTOR to reduce food intake, thus limiting metabolic disorders in offspring from obese dams, regardless of postweaning diet. Obesity was induced in Sprague-Dawley females by high-fat diet (HFD) for 5 weeks before mating, throughout gestation and lactation. Male pups from HFD-fed mothers were weaned onto chow or HFD; within each dietary group, half were supplied with leucine via drinking water (1.5%) versus water control for 10 weeks. Those from chow-fed mothers were fed chow and water. Maternal obesity led to increased adiposity in chow-fed offspring. Postweaning HFD consumption exaggerated adiposity, hyperglycaemia, hyperinsulinaemia and hyperlipidaemia. Supplementation with leucine doubled leucine intake and increased hypothalamic mTOR activation; however, appetite regulation was not affected. A reduction in blood lipid levels was observed in offspring regardless of diet, as well as improved glucose tolerance in HFD-fed rats. In HFD-fed rats, up-regulated carnitine palmitoyl-transferase-1 and peroxisome-proliferator-activated receptor-γ coactivator-1α in muscle and glucose transporter 4 in fat suggested that leucine improved peripheral fat oxidation and glucose transport. Leucine is able to improve peripheral glucose and lipid metabolism independent of appetite and weight regulation, suggesting its potential application in the management of metabolic disorders.

Effect of an 8-weeks aerobic training program in elderly on oxidative stress and HSP72 expression in leukocytes during antioxidant supplementation.

OBJECTIVE: To investigate the effect of aerobic training in the context of antioxidant supplementation on systemic oxidative stress and leukocytes heat shock protein (Hsp)72 expression in the elderly. DESIGN: Sixteen septuagenarians (8 males and 8 females, mean age 74.6) were supplemented with Vitamin C and E (respectively 500 and 100mg per day) and randomly assigned either to sedentary (AS) or individualized aerobically trained (AT) group for 8 weeks. METHODS: Plasma Vitamin C and E concentrations and aerobic fitness, as well as resting and post graded exercise (GXT) Hsp72 expression in leukocytes, plasma levels of thiobarbituric acid reactive substances (TBARS) and advanced oxidation protein product (AOPP) were measured pre and post training / supplementation. RESULTS: At the end of the intervention, the two groups showed a significant increase in resting plasma vitamin C and E (approximately 50 and 20% increase respectively) and a significant decrease in both resting and post GXT plasma TBARS and AOPP (approximately 25 and 20% decrease respectively). These changes were of similar magnitude in the two groups. The reduced oxidative stress was concomitant with a 15% decreased expression of Hsp72 in monocytes and granulocytes in both groups. CONCLUSION: This study provides evidence that in elderly, increased concentration of antioxidant vitamins C and E is associated with a reduction in oxidative stress and leukocytes Hsp72. In this context, 8 weeks of aerobic training has no impact on oxidative stress or leukocytes Hsp72 expression in elderly people.

Interaction between maternal obesity and post-natal over-nutrition on skeletal muscle metabolism.

BACKGROUND AND AIMS: Maternal obesity and post-natal over-nutrition play an important role in programming glucose and lipid metabolism later in life. The aim of this study was to decipher the contributions of maternal obesity and post-natal over-nutrition on glucose and lipid metabolism in skeletal muscle. METHOD AND RESULTS: Male offspring of Sprague Dawley rat mothers fed either chow or high fat diet (HFD) for 5 weeks prior to mating were subsequently fed either chow or HFD until 18 weeks of age. Collection of plasma and skeletal muscle was performed at weaning (20 days) and 18 weeks. At weaning, offspring from obese mothers showed increased body weight, plasma insulin and lactate concentrations associated with reduced skeletal muscle glucose transporter 4 (GLUT4) and increased monocarboxylate transporter 1 (MCT1) protein. In 18-week old offspring, post-weaning HFD further exacerbated the elevated body weight caused by maternal obesity. Surprisingly this additive effect on body weight was not reflected in plasma glucose, insulin, lactate and MCT1; these markers were only increased by post-weaning HFD consumption. However, an additive effect of maternal obesity and post-weaning HFD led to decreased muscle GLUT4 levels, as well as mRNA levels of carnitine palmitoyl transferase-1, myogenic differentiation protein and myogenin. CONCLUSION: Post-weaning HFD exerted an additive effect to that of maternal obesity on body weight and skeletal muscle markers of glucose and lipid metabolism but not on plasma glucose and insulin levels, suggesting that maternal obesity and post-natal over-nutrition impair skeletal muscle function via different mechanisms.

Basal plasma leptin levels in healthy elderly males are related to physical fitness without impact on bone metabolism.

AIM: Investigated the relationship between leptin levels or bone remodelling and physical fitness level in healthy elderly participants. METHODS: Twenty women and 18 men (mean age 72.7 years, range 59-90) performed a maximal incremental exercise test to evaluate their maximal oxygen uptake (VOmax). Basal blood concentrations of bone biochemical markers (BM) and leptin were analysed. RESULTS: Women presented higher values of leptin than men (+34.7%, P=0.024), but no difference related to gender was observed for the other biological parameters. Leptin levels were positively correlated with Body Mass Index (BMI) in both genders. Whether adjusted or not for BMI, leptin was negatively correlated with VOmax only in men (r=-0.55, P=0.02 and r=-0.57, P=0.01, respectively). No relationship between VOmax or leptin and BM was observed, except for leptin and osteocalcin in men (r=-0.66, P=0.015). CONCLUSION: Our data suggest that neither physical fitness nor leptin level seems to have a noticeable effect in the regulation of bone cell activity in healthy elderly participants. In this specific population, physical fitness plays a crucial role on leptin secretion, independently of BMI variation, and this action appears to be sex-dependent.

Response of calciotropic hormones and bone turnover to brisk walking according to age and fitness level.

Ageing is associated with a gradual bone loss and physical activity has been suggested as practical strategy for a non-pharmacological prevention of osteoporosis. However, until now, the specific mechanism by which physical activity affects bone tissue is not thoroughly understood. The aim of this study was to evaluate the effect of strenuous exercise on bone metabolism as a function of age and fitness level. Eighteen physically highly active elderly participants (mean age 71.7+/-7.3 years, HAcEl group), 18 moderately active elderly participants (mean age 71.9+/-8.6 years, ModEl group) and 9 young physically active participants (mean age 25.8+/-2.3 years, AcYo) participated in this study. Concentrations of plasma ionised calcium (iCa), serum parathyroid hormone (iPTH), 25-hydroxy-vitamin D [25(OH)D], and 1,25-dihydroxy-vitamin D3 [1,25(OH)(2)D3] as well as the bone biochemical markers type-I collagen C-telopeptide (CTX) for bone resorption and osteocalcin (OC) and bone alkaline phosphatase (B-ALP) for bone formation, were analyzed before and after a maximal incremental exercise test. In all groups, iCa decreased significantly (p<0.05 for ModEl and AcYo and p<0.001 for HAcEl) while iPTH increased significantly (p<0.01 for ModEl and HAcEl and p<0.001 for AcYo) after exercise. The levels of 1,25(OH)(2)D3, OC and CTX remained unchanged, while 25(OH)D decreased only in HAcEl group while B-ALP increased in ModEl group. In conclusion, strenuous exercise disturbed calcium homeostasis, mainly the iCa/iPTH equilibrium independently of gender, age or fitness level of the participants while no immediate effect on bone turnover was observed.

Response of bone metabolism related hormones to a single session of strenuous exercise in active elderly subjects.

OBJECTIVE: To evaluate the effect of strenuous exercise on bone metabolism and related hormones in elderly subjects. METHODS: Twenty one active elderly subjects (11 men and 10 women; mean age 73.3 years) showing a mean theoretical Vo2max of 151.4% participated. Concentrations of plasma ionised calcium (iCa), serum intact parathyroid hormone (iPTH), 25-hydroxyvitamin D (25(OH)D), and 1.25-dihydroxy-vitamin D3 (1.25(OH)2D3), as well as the bone biochemical markers type I collagen C-telopeptide for bone resorption and osteocalcin and bone alkaline phosphatase for bone formation, were analysed before and after a maximal incremental exercise test. RESULTS: At basal level, iPTH was positively correlated with age (r = 0.56, p < 0.01) and negatively correlated with 25(OH)D (r = -0.50; p < 0.01) and 1.25(OH)2D3 (r = -0.47; p < 0.05). Moreover, 25(OH)D and 1.25(OH)2D3 levels were negatively correlated with age (r = -0.50, p < 0.01 and r = -0.53, p < 0.01, respectively). After exercise, iCa and 25(OH)D decreased (p < 0.001 and p = 0.01, respectively) while iPTH increased (p < 0.001). The levels of 1.25(OH)2D3, bone biochemical markers, haematocrit, and haemoglobin were unchanged. The variations in iCa and 25(OH)D were not related to age and/or sex. The iPTH variation was directly related to basal iPTH levels (p < 0.01) and indirectly related to age. CONCLUSIONS: In active elderly subjects, strenuous exercise disturbed calcium homeostasis and bone related hormones without immediate measurable effect on bone turnover. Although an increase in iPTH could have an anabolic action on bone tissue, our findings from our short term study did not allow us to conclude that such action occurred.

Aerobic and functional capacities in a selected active population of European octogenarians.

Master athletes are often considered to represent the ideal rate of decline of aerobic function; however, most of the studies interested in active elderly people are often limited to people younger than 75. We aimed to determine the physiological adaptations and aerobic fitness in a selected European population of active octogenarians during maximal and submaximal exercise tests. Aerobic capacity was measured during maximal incremental tests on treadmill (TR) and cycle-ergometer (CE) and functional capacity during a 6-minute walk test (6-MWT) in 17 subjects aged 81.2 +/- 0.8 years. Pulmonary gas exchange and heart rate (HR) were continuously measured during the different exercise tests. Maximal oxygen consumption (V.O (2max)) on TR and CE was significantly higher than predicted values (TR: 28.7 +/- 1.2 vs. 17 +/- 0.5 ml . kg (-1) . min (-1); CE: 23 +/- 1.2 vs. 16 +/- 0.6 ml . kg (-1) . min (-1) for measured and predicted values respectively). V.O (2max) and HR (max), as well as V.O (2) and HR at the ventilatory threshold (V.O (2)T (V.E) and HR T (V.E)) were significantly higher on TR than on CE (HR (max): 144 +/- 4 vs. 138 +/- 4 bpm; V.O (2)T (V.E): 22.5 +/- 0.8 vs. 17.7 +/- 0.9 ml . kg (-1) . min (-1) for TR and CE respectively). V.O (2)T (V.E) and HR T (V.E) on TR were equivalent to V.O (2) and HR measured during the 6-MWT. HR T (V.E) on TR and mean HR during the 6-MWT were strongly correlated (R = 0.82, p < 0.01). Maintenance of regular physical activity provides high aerobic fitness, in octogenarians, as was shown by the higher values of our subjects in comparison to predicted values. Moreover, the close relation between the intensity developed at T (V.E) on TR and 6-MWT could support the idea that a walk test is a submaximal test performed at high intensity that could provide a basis for exercise prescription in an individualized manner in active elderly people.