Oxidative stress and metabolism at rest and during exercise in persons with Down syndrome

Measurement protocols and determinants of peak oxygen consumption in adults with Down syndrome: a systematic review

This systematic review aimed to provide an overview of test protocols used to measure peak oxygen uptake (VO2peak) in adults with Down syndrome (DS) and to determine how generalisable the outcomes are for the entire population of adults with DS by describing the sample characteristics of these studies and their impact on VO2peak. A literature search (PROSPERO CRD42022309560) was performed (18 July 2023) using the following databases: PubMed, CINAHL, APA PsycINFO, Web of Science, Embase and SPORTDiscus. For articles to be included, they had to be peer-reviewed pubications, reporting VO2peak or VO2max for individuals with DS separately, with a sample of n ≥ 5 and a mean age ≥18 years. Systematic reviews and meta-analyses were excluded but their reference lists were searched for additional papers to include. Studies were evaluated for risk of bias following the guidelines of Kmet et al. The results were summarised with frequency statistics. Forty-three studies were included in this systematic review. Sample sizes of included adults with DS ranged from n = 4-226, with a total of n = 1498 adults with DS being included. Most studies (29/43) used the same standardised maximal exercise treadmill protocol to measure VO2peak in adults with DS, and 33 out of 43 studies used at least one objective criterion to determine a valid maximal effort. Participants were predominantly male, under 40 years old, and overweight or obese. Additionally, the diversity of study samples was lacking or not reported. The most widely used, standardised, maximal exercise test treadmill protocol is recommended for future use in research and practice, including objective criteria to determine valid maximal effort. The current study samples are not representative of the population of adults with DS in terms of sex, age and diverse backgrounds and therefore likely overestimate VO2peak of this population.

Exercise-Induced Transient Oxidative Stress Is Mitigated in Down Syndrome: Insights About Redox Balance and Muscle Strength

ABSTRACT

Reis, AL, Deus, LA, Neves, RVP, Corrêa, HL Reis, TL, Aguiar, LS Honorato, FS, Barbosa, JMS, Araújo, TB, Palmeira, TRC, Simões, HG, Prestes, J, Sousa, CV, Ide, BN, and Rosa, TdS. Exercise-induced transient oxidative stress is mitigated in Down syndrome: insights about redox balance and muscle strength. J Strength Cond Res 38(3): e125-e34, 2024-This study aimed to evaluate the acute effects of a session of resistance exercise (RE) performed with elastic tubes on the redox balance and inflammatory profile in individuals with Down syndrome (DS). Subjects ( n = 23) were allocated into 2 groups: individuals with DS (DS; n = 11) and individuals without DS (WDS; n = 12), who performed an acute RE session. Diagnostic assessment included medical history, anthropometric measures (body height, body mass, body mass index, and body composition assessment), biological collections, muscle strength assessments (handgrip and maximal voluntary isometric contraction tests), and exercises. The redox balance and inflammatory profile were assessed in urine and saliva samples before and after an acute RE session. There were no differences between WDS and DS groups for body composition ( p > 0.05). The DS group presented higher values pre and post an acute RE session with elastic tubes for oxidative and proinflammatory markers compared with WDS ( p < 0.05). Uric acid values increased from pre-acute RE session to post-acute RE session for WDS ( p < 0.0001). No differences were identified within groups for the delta analysis ( p > 0.05). Inverse correlations were found between total force and F2-isoprostane, 8OHdG, uric acid, allantoin, IL-6, TNF-α, and the TNF-α:IL-10 ratio. A positive correlation was found between IL-10 and total force. The DS group presented increased peak force in the knee extension and elbow flexion exercises (∼25 and 12%, respectively) but decreases in handgrip strength of ∼7%. The WDS group showed higher peak force values for knee extension, elbow flexion, and handgrip (∼16, 10, and 14%, respectively). The DS group had lower transient elevation of oxidative stress after an acute RE session compared with WDS. Oxidative stress and inflammation responses of DS to an acute RE session with elastic tubes may be insufficient to induce health adaptations for the same relative load compared with WDS.

Prescription and Effects of Cardiorespiratory Training in Individuals with Intellectual Disability: A Systematic Review

This study aims to systematize effects of cardiorespiratory training (CT) programs in individuals with intellectual disability (ID) and identifying the fundamental and structuring aspects for the prescription of CT. This systematic review was carried out through four databases (Pubmed, Web of Science, Scopus, and SPORTDiscus), considering data from the period between 2013 and 2022. From 257 studies, 12 studies were included in this systematic review. Three studies used interval CT, while seven used continuous CT. Seven were carried out in the population with Down syndrome, while only three were carried out with participants with ID. The CT programs had the following characteristics: duration of 8 to 12 weeks, weekly frequency of three sessions, for 20 to 60 min, the intensity of 50% to 80% of maximal heart rate or 70% to 80% of peak oxygen consumption, using an ergometer cycle or an outdoor walking. The studies reported improvements in cardiorespiratory function, lipid, hemodynamic and metabolic profile, body composition, and neuromuscular and cognitive capacity. This review presents characteristics and recommendations that technicians can follow when structuring, prescribing, and implementing CT programs to individuals with ID.

Pediatric Population with Down Syndrome: Obesity and the Risk of Cardiovascular Disease and Their Assessment Using Omics Techniques-Review

People with Down syndrome (PWDS) are more at risk for developing obesity, oxidative stress disorders, metabolic disorders, and lipid and carbohydrate profile disorders than the general population. The presence of an additional copy of genes on chromosome 21 (i.e., the superoxide dismutase 1 gene (SOD1) and gene coding for the cystathionine β-synthase (CBS) enzyme) raises the risk for cardiovascular disease (CVD). As a result of disorders in metabolic processes and biochemical pathways, theoretically protective factors (low homocysteine level, high SOD1 level) do not fulfil their original functions. Overexpression of the CBS gene leads to the accumulation of homocysteine-a CVD risk factor. An excessive amount of protective SOD1, in the case of a lack of compensatory increase in the activity of catalase and peroxidase, leads to intensifying free radical processes. The occurrence of metabolic disorders and the amplified effect of oxidative stress carries higher risk of exposure of people with DS to CVD. At present, classic predispositions are known, but it is necessary to identify early risk factors in order to be able to employ CVD and obesity prophylaxis. Detailed determination of the metabolic and lipid profile may provide insight into the molecular mechanisms underlying CVD.

Resistance training and Down Syndrome: A narrative review on considerations for exercise prescription and safety

The current manuscript reviews the literature on the health effects of resistance training (RT) for individuals with Down syndrome (DS), focusing on this training modality’s methodology, application, and safety. The literature has mentioned that early aging in this population is associated with loss of muscle strength, lower lean and bone mass, and increased obesity. It is necessary to propose non-pharmacological measures for prevention and health promotion. Thus, this review suggests a current research-based RT guide for individuals with DS. This review is divided into three sections: Section 2 briefly reviews DS and the effects on structural and functional decline and how exercise and physical activity can influence health aspects in this population; Section 3 summarizes the evidence for RT prescription; Section 4 briefly reviews the health and potential benefits of RT in individuals with DS. The findings from this review suggest that most individuals with DS should engage in moderate-intensity RT at least 2 days a week and perform RT on the major muscle groups and include balance training. The RT program should be modified and adapted according to individuals’ characteristics and limitations. RT promotes positive, health-related benefits such as increasing strength, improving body composition, improving functional capacity and balance, reducing inflammatory status and oxidative stress, and improving the immune system. The RT protocols summarized in this current review provide guidance, critical conclusions, and novel research settings, which could be useful to coaches, clinicians, and researchers to effectively design RT program for individuals with DS.

Therapeutic exercise to improve motor function among children with Down Syndrome aged 0 to 3 years: a systematic literature review and meta‑analysis

The effects and the prescription parameters of therapeutic exercise are not clear. For this reason, is needed to determine the effect of therapeutic exercises on the motor function of children with Down Syndrome (DS) aged 0 to 3 years. The present study is systematic review and meta-analysis of effectiveness outcomes in this population: gait, balance, motor development, fine motor skills, and executive functions. The databases of PubMed, PEDro, EMBASE, SCIELO, Lilacs, Cochrane library were searched from January to December 2019. We recruited Randomized Controlled Trials (RCTs) which met the inclusion criteria in our study. Six studies and 151 participants were included. Two types of therapeutic exercises, aerobic and neuromuscular, were identified. Both types of exercise were effective in improving outcomes. There were no differences between the modes of application of the exercise. No differences were identified between the treadmill and the physiotherapy plan for the reduction of the time to reach independent walking, Mean Difference (MD) 46.79, 95% Confidence Interval (IC) (- 32.60, 126.19), nor for the increase in walking speed MD 0.10 IC (- 0.02, 0.21) m/s. This study suggests that aerobic exercise therapy has a potentially effective role to promote the gait and motor development of children with DS aged 0 to 3 years when it is applied using a treadmill with a frequency of 5 days, a duration of 6-8 min, and an intensity of between 0.2 and 0.5 m/s. Studies with less heterogeneity and larger sample sizes are required.

The Acute Effect of Maximal Exercise on Arterial Stiffness in Adults with and without Intellectual and Developmental Disabilities

PURPOSE

We compared central and peripheral arterial stiffness response patterns between persons with and without intellectual and developmental disabilities (IDD) of different age groups at rest and following a cardiopulmonary exercise test (CPET).

METHODS

15 young adults with and without IDD, and 15 middle-aged adults without IDD performed a CPET. Central and peripheral arterial stiffness were measured at rest and following CPET using estimates of carotid-femoral (cfPWV), carotid-radial (crPWV), and carotid-ankle (cdPWV) pulse wave velocity derived from piezoelectric mechano-transducers.

RESULTS

cfPWV remained unchanged following CPET in adults with and without IDD but increased in middle-aged adults (d= 0.85; 95% CI: 0.27 to 1.42 m.s-1, p= 0.005), whereas cdPWV was similarly reduced (d= -0.77; 95% CI: -1.06 to -0.48 m.s-1, p< 0.001) in all groups. crPWV remained unchanged in all groups. These results were independent of exercise-related changes in mean arterial pressure. Overall group differences suggested that persons with IDD (d = - 1.78; 95% CI: -3.20 to -0.37 m.s-1, p= 0.009) and without IDD (d = -1.84; 95% CI: -3.26 to -0.43 m.s-1, p= 0.007) had lower cfPWV than middle-aged adults.

CONCLUSION

We found no evidence of early vascular aging and diminished vascular reserve following CPET in adults with IDD.

Effects of Resistance Training in Muscle Mass and Markers of Muscle Damage in Adults with Down Syndrome

Recent studies have emphasized that regular exercise should be encouraged as a key part of care and support for people with Down syndrome (DS). However, muscle hypotonia has traditionally been considered a major barrier to resistance training (RT) in people with DS. The main objective of this study was to analyze the impact of circuit RT on markers of muscle damage. The secondary objective was to assess the influence of a RT program on body composition and work task performance. Thirty-six men with DS were recruited and randomly assigned to perform a circuit RT program with six stations 3 days/week for 12 weeks (n = 18) or to a control group (n = 18). Body composition was assessed by bioelectrical impedance analysis. Serum markers of muscle damage (creatine kinase, myoglobin, and lactate dehydrogenase) were determined at baseline and at the end of training weeks 1, 6, and 12. Work task performance was assessed using the weighted pail-carry test. RT did not induce significant changes in markers of muscle damage during the intervention. Furthermore, muscle mass and work task performance were significantly improved in the exercise group. These findings suggest that circuit RT can be used safely to increase muscle mass and work task performance in young adults with DS. Muscle hypotonia should not be considered a major barrier to exercise in people with DS, provided that qualified staff design and supervise all training sessions.

Peripheral Oxidation Markers in Down Syndrome Patients: The Better and the Worse

Oxidative stress plays an important role in Down syndrome (DS) pathology since the gene dose effect leads to abnormal levels of certain enzymes and metabolites. In this review, we focused on relatively easy-to-obtain, peripheral markers of oxidative stress and inflammation, in order to compare the levels of these markers in DS patients and chromosomally healthy persons. Studies taking into account age- and sex-matched control groups were of particular interest in this context. We analyzed the factors that influence the levels of said markers in both groups (i.e., the usefulness of the markers), including the age of DS patients, occurrence of regular trisomy 21 or mosaicism, physical activity of patients, and the onset of Alzheimer's disease in DS. This paper was conceived as a handbook-to help for selecting suitable, easy-to-obtain markers for monitoring of the health status of DS patients (e.g., in nutritional studies and during dietary supplementation).

The health benefits of exercise therapy for patients with Down syndrome: A systematic review

Background

Many patients with Down syndrome (PWDS) have poor cardiometabolic risk profiles, aerobic capacities and weak hypotonic muscles, primarily because of physical inactivity and poor diet.

Objectives

This study discusses the benefits of exercise therapy on body composition, aerobic capacity, muscle strength, proprioception and cardiometabolic profiles of PWDS.

Methods

A literature review using the Crossref metadatabase, following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), focusing on the period 2007-2018, was undertaken. Each record was judged adopting the modified Downs and Black Appraisal Scale. The literature investigation identified 15 701 records. Records were excluded if they were published before 2007, pertained to the impact of exercise on intellectual disabilities beyond Down syndrome or the impact of medical, pharmaceutical, nutrition and psychological interventions among PWDS and were published in languages besides English. Nineteen articles were synthesised into this commentary.

Results

PWDS have a heightened cardiometabolic risk profile and high oxidative stress associated with elevated insulin resistance, poor insulin sensitivity, atherosclerosis and hypertension. PWDS have low aerobic capacity (VO_2max), peak heart rates, muscle strength, agility and balance. Regular physical activity is beneficial to improve their VO_2max and muscle strength. Moreover, regular physical activity reduces lipid peroxidation and arterial cell wall damage, the pathogenesis of atheroma is limited.

Conclusion

Exercise therapy compliance seems to have a positive impact on the cardiometabolic risk profile, muscle strength and aerobic work capacity of PWDS. Nonetheless, additional vigorous experimental investigations are necessary to better understand the effect of exercise therapy on the aerobic, strength, proprioception and cardiometabolic risk profile of PWDS.

Regulator of Calcineurin 1 helps coordinate whole-body metabolism and thermogenesis

Increasing non-shivering thermogenesis (NST), which expends calories as heat rather than storing them as fat, is championed as an effective way to combat obesity and metabolic disease. Innate mechanisms constraining the capacity for NST present a fundamental limitation to this approach, yet are not well understood. Here, we provide evidence that Regulator of Calcineurin 1 (RCAN1), a feedback inhibitor of the calcium-activated protein phosphatase calcineurin (CN), acts to suppress two distinctly different mechanisms of non-shivering thermogenesis (NST): one involving the activation of UCP1 expression in white adipose tissue, the other mediated by sarcolipin (SLN) in skeletal muscle. UCP1 generates heat at the expense of reducing ATP production, whereas SLN increases ATP consumption to generate heat. Gene expression profiles demonstrate a high correlation between Rcan1 expression and metabolic syndrome. On an evolutionary timescale, in the context of limited food resources, systemic suppression of prolonged NST by RCAN1 might have been beneficial; however, in the face of caloric abundance, RCAN1-mediated suppression of these adaptive avenues of energy expenditure may now contribute to the growing epidemic of obesity.

What effect does regular exercise have on oxidative stress in people with Down syndrome? A systematic review with meta-analyses

OBJECTIVE

What effect does regular exercise have on oxidative stress in people with Down syndrome?

DESIGN

Systematic review with meta-analyses.

METHODS

A systematic review with meta-analyses was conducted. Six databases were searched from inception until August 2017. Studies where included if participants with Down syndrome (any age) had completed an exercise program of at least 6 weeks duration and at least one biomarker measured the generation or removal of reactive oxidative species. Data were extracted using a customised form. Risk of bias was assessed using the Cochrane Collaboration's Risk of Bias assessment tool. Effect sizes were calculated and meta-analyses completed for clinically homogeneous data using a random effects model.

RESULTS

Seven studies (11 articles) involving 144 inactive participants investigated the effect of moderate intensity aerobic exercise. No pattern emerged for how most biomarkers responded with non-significant pooled effect sizes and high levels of heterogeneity observed. The exception was catalase which increased significantly after exercise (standardised mean difference 0.39, 95%CI 0.04-0.75; I² 15%). Available studies were at high risk of bias. Two of five studies that measured more than one biomarker reported a decrease in oxidative stress with increased antioxidant activity after exercise but the other three (including one small randomised controlled trial) reported increased oxidative stress with variable change in antioxidant activity.

CONCLUSIONS

There remains uncertainty about the effect of exercise on oxidative stress in people with Down syndrome.

REVIEW REGISTRATION

PROSPERO CRD42016048492.

The Fragile X proteins Fmrp and Fxr2p cooperate to regulate glucose metabolism in mice

Fragile X syndrome results from loss of FMR1 expression. Individuals with the disorder exhibit not only intellectual disability, but also an array of physical and behavioral abnormalities, including sleep difficulties. Studies in mice demonstrated that Fmr1, along with its paralog Fxr2, regulate circadian behavior, and that their absence disrupts expression and cycling of essential clock mRNAs in the liver. Recent reports have identified circadian genes to be essential for normal metabolism. Here we describe the metabolic defects that arise in mice mutated for both Fmr1 and Fxr2. These mice have reduced fat deposits compared with age- and weight-matched controls. Several metabolic markers show either low levels in plasma or abnormal circadian cycling (or both). Insulin levels are consistently low regardless of light exposure and feeding conditions, and the animals are extremely sensitive to injected insulin. Glucose production from introduced pyruvate and glucagon is impaired and the mice quickly clear injected glucose. These mice also have higher food intake and higher VO2 and VCO2 levels. We analyzed liver expression of genes involved in glucose homeostasis and found several that are expressed differentially in the mutant mice. These results point to the involvement of Fmr1 and Fxr2 in maintaining the normal metabolic state in mice.

Effects of aerobic, resistance and balance training in adults with intellectual disabilities

Adults with intellectual disability (ID) have decreased cardiovascular fitness and strength present with lower rates of physical activity (PA), and often have balance and functional impairments. The purpose of this study was to investigate the effect of a combined PA program (CPAP) utilizing aerobic, strength and balance training on cardiovascular fitness, strength, balance and functional measures in a controlled clinical trial. Adults with mild to moderate ID were assigned into either the intervention group (IG; n=37) or the control group (CG; n=29). The IG trained 3 day/week, 1 h/day over 14 weeks, while the CG did not participate in any exercise program. Cardiovascular fitness, strength, balance, flexibility and functional ability were assessed pre-post training. The IG increased cardiovascular fitness (26.8 vs. 29.3 ml kg(-1) min(-1)), handgrip strength (19.2 vs. 21.9 kg), leg strength, and balance following the training period (p<.05). Body weight (70.1 vs. 68.1 kg) and body mass index (27.4 vs. 26.6 kg m(-2)) decreased (p<.05) in the IG group. The CG showed no changes in any parameter. These data suggest a combined aerobic, strength and balance exercise training program is beneficial among individuals with ID.

Assessment protocols of maximum oxygen consumption in young people with Down syndrome--a review

Maximum oxygen consumption is considered the gold standard measure of cardiorespiratory fitness. Young people with Down syndrome (DS) present low values of this indicator compared to their peers without disabilities and to young people with an intellectual disability but without DS. The use of reliable and valid assessment methods provides more reliable results for the diagnosis of cardiorespiratory fitness and the response of this variable to exercise. The aim of the present study was to review the literature on the assessment protocols used to measure maximum oxygen consumption in children and adolescents with Down syndrome giving emphasis to the protocols used, the validation process and their feasibility. The search was carried out in eight electronic databases--Scopus, Medline-Pubmed, Web of science, SportDiscus, Cinhal, Academic Search Premier, Scielo, and Lilacs. The inclusion criteria were: (a) articles which assessed VO2peak and/or VO2max (independent of the validation method), (b) samples composed of children and/or adolescents with Down syndrome, (c) participants of up to 20 years old, and (d) studies performed after 1990. Fifteen studies were selected and, of these, 11 measured the VO2peak using tests performed in a laboratory, 2 used field tests and the remaining 2 used both laboratory and field tests. The majority of the selected studies used maximal tests and conducted familiarization sessions. All the studies took into account the clinical conditions that could hamper testing or endanger the individuals. However, a large number of studies used tests which had not been specifically validated for the evaluated population. Finally, the search emphasized the small number of studies which use field tests to evaluate oxygen consumption.

Assessment of salivary total antioxidant levels and oral health status in children with Down syndrome

Down syndrome (DS) is an autosomal chromosomal disorder caused by trisomy of all or a critical part of chromosome 21. Individuals with DS have high levels of oxidative stress throughout their lifespan. It has been suggested that levels of antioxidants could be altered in response to an infection or disease.

AIM

To assess the total antioxidant capacity (TAC), nitric oxide (NO), and sialic acid (SA) of saliva in children with DS and its relation to their oral health status.

MATERIALS AND METHODS

Thirty-four noninstitutionalized children in the age group of 7-12 years having DS formed the study group. The control group consisted of 34 normal, healthy children. The W.H.O. criteria were used for diagnosis and recording of dental caries. Oral hygiene status was assessed using the simplified oral hygiene index. Estimation of TAC, NO, and SA levels in saliva was done. Data obtained were subjected to statistical analysis.

RESULTS

In comparison to normal children, DS children showed significantly lower TAC of saliva and significantly higher salivary SA levels. In both groups of children, dental caries was higher in primary dentition when compared to their permanent dentition.

The influence of sprint interval training on body composition, physical and metabolic fitness in adolescents and young adults with intellectual disability: a randomized controlled trial

OBJECTIVE

In this study we evaluated the effect of sprint interval training on metabolic and physical fitness in adolescents and young adults with intellectual disabilities when compared with continuous aerobic training and no training (control).

METHODS

Fifty-four persons with intellectual disabilities (age: 17 (3.0), body mass index: 27.7 (3.7), intelligence quotient: 59 (8.6)) were matched based on age, gender and intelligence quotient between sprint interval training (n = 17), continuous aerobic training (n = 15) and control (n = 14). Sprint interval training was composed of three blocks of 10 minutes at ventilatory threshold (blocks 1 and 3: 10 sprint bouts of 15 seconds, followed by 45 seconds relative rest; block 2: continuous training) twice a week for 15 weeks. Continuous aerobic training was composed of three blocks of 10 minutes continuous training. After eight weeks, intensity was increased to 110% of ventilatory threshold. The control group did not participate in supervised exercise training. Before and after the training period, body composition, physical and metabolic fitness were evaluated.

RESULTS

Sprint interval training showed a significant positive evolution for waist circumference, fat%, systolic blood pressure, lipid profile, fasting insulin, homeostasis model assessment of insulin resistance, peak VO2, peak Watt, ventilatory threshold, 6-minute walk distance and muscle fatigue resistance when compared with no training (P < 0.01). The sprint interval training group demonstrated significant improvements for fat%, systolic blood pressure, low-density lipoprotein, fasting insulin, peak VO2 and peak power and ventilatory threshold (P < 0.01) when compared with continuous aerobic training.

CONCLUSION

In this study we could observe that sprint interval training has stronger beneficial effects on body composition, physical fitness and metabolic fitness compared with control. Compared with continuous aerobic training, sprint interval training seems to result in better outcome.

Leptin, insulin and thyroid hormones in a cohort of Egyptian obese Down syndrome children: a comparative study

BACKGROUND

Obesity is a major worldwide health problem. It is commonly observed in Down syndrome individuals than in the general population. The reason for increased risk of obesity in DS is unclear.The current study was designed to clarify differences in some obesity- related hormones in a group of prepubertal Down syndrome children.

METHODS

Thirty six Egyptian children with Down syndrome were enrolled in this study, divided according to their body mass index (BMI) into 23 obese and13 non obese. Another group of 43 non Down children were recruited, they were divided according to their BMI into 20 patients having simple obesity and 23 non obese, as control groups. Fasting blood samples were collected for estimation of fasting blood glucose (FBG), insulin, leptin, free thyroxin (FT4), thyroid stimulating hormones (TSH) and creatine kinase (CK). Insulin resistance was assessed by Homeostasis Model Assessment method (HOMA-IR). The ratio of leptin to BMI (LEP/BMI) was used as an index of leptin resistance.

RESULTS

Median values of FBG, insulin, and HOMA-IR were significantly higher in Down versus non Down groups, while median values of leptin and leptin resistance were non-significantly different among Down versus non Down groups. Median TSH values were non- significantly different between obese Down and obese non Down. Although the median values of TSH and FT4 were within normal range in Down groups, four cases of subclinical hypothyroidism were encountered. Leptin levels were correlated with insulin and IR but not with TSH in Down groups.

CONCLUSION

Increased circulating leptin, a marker of leptin resistance in obese children with Down syndrome seems to be similar to that in children with simple obesity. Elevated FBG and insulin in obese Down children highlights the presence of early IR. Associated myopathy evidenced by mildly elevated CK levels could be an added factor for obesity in such group of patients.

Reproducibility, validity and predictors of six-minute walk test in overweight and obese adolescents with intellectual disability

OBJECTIVES

To assess the reproducibility and validity of the six-minute walk test (6MWT) and predictors of the six-minute walk distance (6MWD) in adolescents with overweight or obesity and intellectual disability (ID).

STUDY DESIGN

Sixty-one adolescents with overweight or obesity and mild-to-moderate ID (intelligent quotient [IQ] 40-70; age 14-22 years) participated in this study. To test reproducibility, 39 of the participants performed the 6MWT twice with an interval of 1 week. To test validity (n = 39), peak oxygen uptake (peak VO(2)) was measured on a bicycle ergometer. For the predictor study (n = 61), weight, height, peak VO(2) and quadriceps strength were measured, and IQ and orthopedic conditions were collected from the participants' medical records.

RESULTS

There was no significant difference between the means of the two 6MWTs (571.3 vs. 576.5 m; p = 0.452). The intraclass correlation coefficient was 0.82, indicating good reliability. The smallest real difference was 82.6 m. 6MWD correlated significantly with relative peak VO(2) (β = 0.69) indicating validity. Relative peak VO(2), height, IQ, body mass index (BMI) and quadriceps strength are predictors of the 6MWD in this population.

CONCLUSION

6MWT is a reliable and valid test in adolescents with overweight or obesity and ID. Low IQ, overweight/obesity and low physical fitness contribute to the outcome of the 6MWT.

Effect of combined exercise training on physical and metabolic fitness in adults with intellectual disability: a controlled trial

OBJECTIVE

Investigating the effect of combined aerobic and strength training on metabolic and physical fitness in adults with intellectual disabilities compared to endurance training and no training.

DESIGN

A controlled trial with patients receiving either combined (COM), endurance (END) or no training (C).

SETTING

Two centres for intellectual disabilities (Sterrenhuis, Brasschaat and Emiliani, Lokeren, Belgium).

SUBJECTS

Forty-five adults with intellectual disabilities (mean age: 42 (9,2), mean body mass index (BMI): 24 (3,9), mean IQ: 56 (5,6)).

INTERVENTION

Combined exercise training (n = 15) and endurance training (n = 15) twice a week for 70  minutes per session for 20 weeks and no training (n = 15). Groups were matched for age, sex and intellectual disability.

MAIN MEASURES

Lipid profile, physical fitness (primary); blood pressure and body composition.

RESULTS

Compared to no training, combined exercise training has significant positive effects on total cholesterol levels, aerobic capacity, muscle strength and resting systolic blood pressure, while endurance exercise training has significant effects on aerobic capacity and resting systolic blood pressure. Compared to endurance training, combined exercise training resulted in a significant better evolution of total cholesterol (mean differences: -18 versus -3 mg/dl), 1RM upper (+6 versus +1  kg) and lower limb (+25 versus +8  kg) and abdominal muscles (+15 versus +1  kg), hand grip strength (+9 versus +2  kg), muscle fatigue resistance (+11 versus +5  sec), sit-to-stand (+5 versus +2/30   sec) and systolic blood pressure (-15 versus -10 mmHg).

CONCLUSION

This study revealed a tendency towards more beneficial effects of combined exercise training in adults with intellectual disability.

Aerobic exercise training programmes for improving physical and psychosocial health in adults with Down syndrome

BACKGROUND

Although physical fitness has been suggested to improve physical and psychosocial health for a variety of population profiles, there is a lack of information about the safety and effectiveness of aerobic exercise for adults with Down syndrome.

OBJECTIVES

To evaluate the effectiveness and safety of aerobic exercise training programmes for physiological and psychosocial outcomes in adults with Down syndrome.

SEARCH STRATEGY

The following electronic databases were searched: The Cochrane Central Register of Controlled Trials (CENTRAL) (2009, Issue 1); MEDLINE (1966 to August 2009); EMBASE (1980 to August 2009); CINAHL (1982 to August 2009); LILACS (1982 to August 2009); PsycINFO (1887 to August 2009); ERIC (1966 to August 2009); Current Controlled Trials (August 2009); and Campbell Collaboration's Social, Psychological, Educational and Criminological Register (C2- SPECTR) (to August 2009). Information about ongoing clinical trials was sought by searching ClinicalTrials.gov (http://clinicaltrials.gov) (accessed August 2009), and the National Research Register (NRR) (2009 Issue 1).

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials using supervised aerobic exercise training programmes with behavioral components accepted as co-interventions.

DATA COLLECTION AND ANALYSIS

Two reviewers selected relevant trials, assessed methodological quality and extracted data. Where appropriate, data were pooled using meta-analysis with a random-effects model. Positive values favour the intervention group, while negative values favour the control group.

MAIN RESULTS

Three studies included in this systematic review used different kinds of aerobic activity: walking/jogging and rowing training and included participants with a broad age range (17 to 65 years). They were conducted in the USA, Portugal and Israel. In the meta-analyses, only maximal treadmill grade was improved after aerobic exercise training programmes (4.26 grades (%) [95% CI 2.06, 6.45]). Other variables relative to work performance that could not be combined in a meta-analysis were also improved in the intervention group (maximal test time P=0.0003), total turns of fan wheel (P=0.02), resistance of ergometer (p=0.003), power knee extension and flexion (p<0.00001), and timed up and go test (p=0.008). Thirty other outcomes measured in this review including, oxidative stress and body composition variables, could not be combined in the meta-analysis. Apart from work performance, trials reported no statistically significant improvements.

AUTHORS' CONCLUSIONS

There is insufficient evidence to demonstrate that there is improvement in physical or psychosocial outcomes of aerobic exercise in adults with Down syndrome. Although evidence exists to support improvements in physiological and psychological aspects from strategies using mixed physical activity programmes, well-conducted research examining long-term physical outcomes, adverse effects, psychosocial outcomes and costs is required before informed practice decisions can be made.

Aerobic exercise reduced oxidative stress in saliva of persons with Down syndrome

The aim of this investigation was to examine the effect of aerobic exercise (AE) on uric acid (UA), total antioxidant activity (TAA), oxidative stress (OS) and nitrite a stable nitric oxide (NO) metabolite in saliva from persons with Down syndrome (DS). Stimulated saliva was sampled from 12 participants 1 hour before and immediately after a 1,600-meter walking test. Uric acid (UA) was assayed by enzymatic method, TAA by ABTS method, lipid hydroperoxides (OS marker) by the ferrous iron/xylenol orange (FOX) method and nitrite concentration by the Griess reaction. Aerobic exercise (AE) caused a decrease in salivary lipid hydroperoxides in persons with DS (p = 0.001). Aerobic exercise (AE), however, did not affect salivary UA, TAA, and nitrite. This result suggested that AE can be considered as a way to reduce the OS in persons with DS, particularly in the mouth cavity.

The influence of combined exercise training on indices of obesity, physical fitness and lipid profile in overweight and obese adolescents with mental retardation

INTRODUCTION

This study investigated the effect of combined exercise training on indices of body composition, physical fitness and lipid profile in adolescents with mental retardation.

MATERIALS AND METHODS

Thirty adolescents with mental retardation (total IQ, 45-70) received exercise training (n = 15) or no training (n = 15). Groups were matched for age, sex and mental retardation. Before and after the intervention period, indices of body composition, physical fitness and lipid profile were measured.

RESULTS

In comparison with the control group, weight, body mass index, waist and fat mass decreased significantly, while relative fat-free mass increased. The level of triglycerides, total cholesterol and low-density lipoprotein decreased significantly, while high-density lipoprotein increased. Muscle strength, muscle fatigue resistance and sit-to-stand were ameliorated. PeakVO2/peak power decreased significantly. The distance covered in the 6-min walk test (6MWT) increased with 50 m.

CONCLUSION

In conclusion, combined exercise training has a positive effect on indices of obesity, physical fitness and lipid profile in adolescents with mental retardation.

The exercise redox paradigm in the Down's syndrome: improvements in motor function and increases in blood oxidative status in young adults

Considerable evidence has indicated a pro-oxidant status in the brain of people with Down's syndrome (DS), which may contribute to motor and cognitive impairments verified in this condition. On the other hand, previous studies addressing the role of physical exercise on oxidative stress and antioxidant status in DS have indicated conflicting results. Here, we investigated the effects of a supervised judo training of controlled intensity and monitored on the basis of lactate threshold on the blood oxidative stress status and motor coordination in 21 young adults with DS. The training extended over a period of 16 weeks and consisted of three sessions per week. The exercise improved the motor function and significantly decreased lactate production in the DS subjects. However, blood markers of oxidative damage to lipids (TBARS and lipid peroxides) and proteins (carbonyls) were increased by the judo training. Moreover, superoxide dismutase and catalase activity also increased, while glutathione peroxidase activity remained unaltered after exercise. These results reinforce the notion that physical exercise can improve motor disabilities in people with DS. More importantly, our findings demonstrate that the beneficial effects are accompanied by some degree of oxidative stress, suggesting that young adults with DS may be more susceptible to physical training-induced oxidative stress than adolescents with DS, which should be taken into account in physical training programs for this population.