Catecholamine response to exercise in children with attention deficit hyperactivity disorder

The effect of methylphenidate on the dopamine and growth hormone response to exercise in children with attention-deficit hyperactivity disorder

PURPOSE

To assess the growth hormone (GH) and Dopamine (DA) response to exercise in children with attention-deficit hyperactivity disorder (ADHD) with and without methylphenidate (MP). We hypothesized that the GH and DA response to the exercise with MP would be siginicantly lower.

METHODS

Twenty children participated in the study (12 males and 8 females, age range 9-13 years). Ten with ADHD and 10 controls. Participants with ADHD performed an exercise test twice, with and without MP while controls performed one exercise test. Blood samples for GH and DA were collected before, at peak, 30 and 60 min after the end of exercise.

RESULTS

Compared to controls, children with ADHD with and without MP, had a significantly lower GH (P < .002) and DA (P < .01) responses to exercise. In participants with ADHD, a significantly greater GH response (p < .04) to exercise was found when MP administered to the children before exercise, yet this response was still significantly lower than controls.

CONCLUSIONS

GH and DA excretion after an exercise challenge in children with ADHD is impaired. MP slightly attenuates the GH blunted response. This may link ADHD with growth impairment in some children and explain previous findings indicating that the final adult height is usually not compromised in children with ADHD treated with MP. The combined exercise and stimulant treatment therapeutic effects needs to be further explored.

TRIAL REGISTRATION NUMBER

NCT00945971.

Comparative effectiveness of various physical exercise interventions on executive functions and related symptoms in children and adolescents with attention deficit hyperactivity disorder: A systematic review and network meta-analysis

Background

Physical exercise has been recommended as an important nonpharmacological therapeutic strategy for managing attention deficit hyperactivity disorder (ADHD). We conducted a network meta-analysis (NMA) to assess the comparative impact of different physical exercise modalities on enhancing executive functions (EFs) and alleviating symptoms in children and adolescents with ADHD.

Methods

We searched Web of Science, PubMed, Embase, Cochrane Central Register of Controlled Trials, SPORTDiscus, PsycINFO, CNKI, and clinical trials databases from inception to October 20, 2022. Randomized controlled trials (RCTs) and quasi-experimental studies investigating physical exercise for ADHD-related symptoms of hyperactivity/impulsivity and inattention, and executive functions were included. The frequentist random-effect NMA method was applied to pool the results.

Results

A total of 59 studies (including 39 RCTs, 5 quasi-RCTs, and 15 self-controlled trials) published between 1983 and 2022 were incorporated into the systematic review, of which 44 studies with 1757 participants were eligible for meta-analysis. All types of physical exercise were effective in improving EFs (SMD = 1.15, 95% CI: 0.83 to 1.46), and open-skill activities which require participants to react in a dynamically changing and externally paced environment induced the most incredible benefits for executive functions (SUCRA = 98.0%, SMD = 1.96, and 95% CI: 1.15 to 2.77). Subgroup analyses for EFs revealed varied findings that open-skill activities were the most promising physical exercise type for improving inhibitory control (SUCRA = 99.1%, SMD = 1.94, and 95% CI: 1.24 to 2.64), and closed-skill activities dominated by aerobic exercises had a slightly higher probability of being the most promising physical exercise intervention for working memory (SUCRA = 75.9%, SMD = 1.21, and 95% CI: -0.22 to 2.65), and multicomponent physical exercise tended to be the most effective in cognitive flexibility (SUCRA = 70.3%, SMD = 1.44, and 95% CI: -0.19 to 3.07). Regarding ADHD-related symptoms, closed-skill activities dominated by aerobic exercises might be more advantageous for hyperactivity/impulsivity (SUCRA = 72.5%, SMD = -1.60, and 95% CI: -3.02 to -0.19) and inattention (SUCRA = 96.3%, SMD = -1.51, and 95% CI: -2.33 to -0.69) improvement.

Conclusion

Physical exercise can significantly help to alleviate the symptoms of ADHD and improve executive functions in children and adolescents with ADHD. Most of all, to promote adherence to treatment, they should be encouraged to perform the physical exercises that they enjoy most.

Meta-analysis and systematic review of physical activity on neurodevelopment disorders, depression, and obesity among children and adolescents

Background

No consensus on whether physical activity (PA) is related to physical and mental health among pediatric population remains has been reached to date. To further explore their association, our study assessed the effect of PA on physical and mental health of children and adolescents through a systematic review and meta-analysis of randomized controlled studies (RCTs).

Methods

Several databases(Web of science, PubMed, Embase, Cochrane Central register of controlled trials, CINAHL) were searched from inception to 1st, December 2020 without language restrictions.

Results

38,236 records were identified primitively and 31 included studies with 1,255 participants eventually met our inclusion criteria, all of which exhibited a relatively low-moderate risk of bias of overall quality. In regard to mental health, the administration of PA, compared with the control group, led to moderate improvements in Autism Spectrum Disorder(ASD)[Standard mean difference (SMD) = -0.50, Confidence interval(CI): -0.87, -0.14)] and depression(SMD = -0.68, CI: -0.98, -0.38) among children and adolescents. Similarly, significant result was observed in obesity (SMD = -0.58, CI: -0.80, -0.36). No significant differences were observed in Attention deficit hyperactivity disorder (ADHD) (SMD = -0.29, CI: -0.59, 0.01).

Conclusion

Altogether, PA may have a beneficial effect on children and adolescents with ASD, depression and obesity; nevertheless, there is insufficient evidence to confirm its efficacy in ADHD. More large-scale population based randomized controlled trials are needed to explore more reliable evidence between them.

Reduced exercise-induced growth hormone secretion among children with attention-deficit hyperactivity disorder

PURPOSE

Attention-deficit/hyperactivity disorder (ADHD) is typically a chronic, often lifelong condition. Data suggest that ADHD itself and its treatment may be associated with dysregulated growth, including height and BMI. The reason for this association is yet unknown. The objective of this study was to examine differences in growth hormone (GH) response to exercise between children who had received a diagnosis of ADHD and age- and gender-matched controls. We reasoned that the normal increase in circulating GH seen in response to exercise would be blunted in children with ADHD.

METHODS

We recruited 13 treatment-naïve children with newly diagnosed ADHD and 14 age-matched controls (all male) and measured GH response to an exercise test in which the work was scaled to each subject's physical capability.

RESULTS

There was no difference in the peak heart rate achieved during exercise between controls and ADHD participants (196.6 ± 1.5 vs. 196.5 ± 2.1 bpm, respectively) and lactate response to exercise (53.8 ± 5.0 vs. 47.9 ± 3.8 mg/dl, respectively). After exercise, GH increased significantly in the control subjects (p < 0.005), while GH responses were substantially blunted in the ADHD group (p = NS) even though the work performed did not differ from controls.

CONCLUSIONS

Our data suggest that GH excretion after exercise challenge in children with ADHD is impaired. This can be detected using a minimally invasive, nonpharmacologic challenge and may link ADHD with growth impairment in some children.

TRIAL REGISTRATION NUMBER

NCT00945971.

Device-Based Movement Behaviors, Executive Function, and Academic Skills among African American Children with ADHD and Disruptive Behavior Disorders

Background: Physical activity (PA) has been identified as a promising intervention to improve executive function (EF) and reduce ADHD symptoms in children. Few African American children with ADHD and Disruptive Behavior Disorders (DBDs) from families with low incomes are represented in this literature. The purpose of this study is to test the relationships between PA and sedentary time (ST), and EF and academic skills among African American children with ADHD and DBD from low-income families. Methods: Children (n = 23, 6–13 years old) wore an ActiGraph for one week to measure PA and ST. EF was measured through parent report and direct neuropsychological tests. Academic skills were measured with the Curriculum-Based Measurement System. Bivariate correlations tested relationships between PA, ST, EF, and academic skills. Results: A significant correlation was observed between vigorous PA time and parent reported EF (r = −0.46, p = 0.040). Light PA and moderate PA were not related to EF or academic skills, and neither was ST. Conclusions: Vigorous PA may prove useful as an adjunct treatment to improve EF in African American children with ADHD and DBD in low-income neighborhoods. Research using experimental and longitudinal designs, and examining qualitative features of PA experiences, will be critical for understanding relationships between PA, academic skills, and EF in this population.

The relationship between internalizing problems and acute exercise duration in children with attention-deficit/hyperactivity disorder: The role of frontal alpha asymmetry

BACKGROUND

Frontal alpha asymmetry (FAA) has been associated with the regulation of certain types of internalizing psychopathologies, and is affected by acute aerobic exercise (AE). However, no previous studies have examined the association between FAA and internalizing problems or the effects of acute exercise on FAA in children with ADHD.

AIMS

This study had two objectives. First, it aimed to examine the relationship between FAA and internalizing behaviors in children with ADHD. Second, it sought to investigate the differential effects of acute AE (30 and 50 min) on FAA.

METHOD

Participants were assigned to one of the following three groups: 50 min of AE, 30 min of AE, and a control group. Resting electroencephalogram (EEG) data were recorded before and after their respective treatments. EEG data from 43 participants were analyzed to investigate the association between pre-test FAA and internalizing problems as assessed by Child Behavior Checklist scores. Additionally, EEG data from 46 participants were analyzed to examine the effects of acute AE on post-test FAA while controlling for pre-test FAA.

RESULTS

Pre-test FAA was found to be significantly negatively associated with internalizing problems, with both hemispheres contributing to this association. Regarding the effects of acute exercise, the 50-minute AE group had highest post-test FAA, reflected by the increased relative left-side frontal activity.

CONCLUSIONS

These findings suggest that FAA is a biological marker of internalizing symptoms in children with ADHD, and a 50-minute session of AE can effectively modulate FAA.

Effectiveness of Physical Activity Intervention on ADHD Symptoms: A Systematic Review and Meta-Analysis

Objective: To assess the effectiveness of physical activity (PA) intervention on attention-deficit/hyperactivity disorder (ADHD)-related symptoms. Method: Studies that investigated PA intervention for ADHD-related symptoms were identified through searching PubMed, Web of Science, Cochrane Library, and Embase databases from inception through June 2021. Standardized mean difference (SMD) with 95% confidence interval (CI) was used to assess the effectiveness of PA intervention on improving ADHD-related symptoms. The meta-analyses were conducted using fixed-effect or random-effect models according to the heterogeneity of the studies. Results: Nine before-after studies (232 participants) and 14 two-group control studies (162 participants/141 controls) were included in this meta-analysis. Combined results for before-after studies indicated significant improvements on all studied ADHD-related symptoms (inattention: SMD = 0.604, 95% CI: 0.374-0.834, p < 0.001; hyperactivity/impulsivity: SMD = 0.676, 95% CI: 0.401-0.950, p < 0.001; emotional problems: SMD = 0.416, 95% CI: 0.283-0.549, p < 0.001; behavioral problems: SMD = 0.347, 95% CI: 0.202-0.492, p < 0.001). Meta-analyses for two-group control studies further confirmed that PA intervention significantly improved the inattentive symptom (SMD = 0.715, 95% CI: 0.105, 1.325, p = 0.022). Subgroup analyses suggested significant beneficial effect on inattention symptoms in children. Moreover, closed motor skills were beneficial for hyperactive/impulsive problems (SMD = 0.671, p < 0.001), while open motor skills were beneficial for attention problems (SMD = 0.455, p = 0.049). When excluding studies with combined medication, the studies in unmedicated participants in before-after studies still showed significant results in all studied ADHD-related symptoms as in the overall analysis. Given the limited sample size, the best frequency and intensity of PA intervention need further investigation. Conclusion: Our results suggested that PA intervention could possibly improve ADHD-related symptoms, especially inattention symptoms. Closed-skill and open-skill activities could be beneficial for hyperactivity/impulsivity and inattention symptoms, respectively. Further high-quality randomized clinical trials with large sample size are needed.

Updates in technology-based interventions for attention deficit hyperactivity disorder

PURPOSE OF REVIEW

Technological advancement has led to the development of novel treatment approaches for attention deficit hyperactivity disorder (ADHD). This review aims to review recent studies which employ the use of technology to treat ADHD, with particular focus on studies published during a 1-year period from February 2019 to February 2020.

RECENT FINDINGS

Most recent studies involved children aged 12 years and below. Interventions included cognitive training through games, neurofeedback and a combination of several approaches. More novel approaches included trigeminal nerve stimulation and brain-computer interface, and studies had utilized technology such as X-box Kinect and eye tracker. There was a shift towards delivering intervention at home and in school, enabled by technology. The study outcomes were variable and mainly included executive functioning measures and clinical ratings. These interventions were generally safe with few reported adverse events.

SUMMARY

Technology has enabled interventions to be delivered outside of the clinic setting and presented an opportunity for increased access to care and early intervention. Better quality studies are needed to inform on the efficacy of these interventions.

Relationship between Health-Related Quality of Life and Physical Activity in Children with Hyperactivity

The main purpose of this paper was to evaluate the relationship between health-related quality of life (HRQoL) and the frequency of physical activity in Spanish children aged 8 to 14 years with attention deficit hyperactivity disorder (ADHD). Sample selection was performed using the data obtained from the children’s questionnaire of the National Health Survey of Spain 2017 that is carried out with the children’s parents, and that had an initial size of 6106 participants. After the application of the inclusion and exclusion criteria, the sample size was reduced to 496 subjects. Results show significant differences between the different levels of physical activity frequency, as well as a positive correlation of the average between HRQoL and ADHD. In conclusion, the practice of physical activity may contribute to the improvement of HRQoL in children with ADHD, possibly achieving greater benefits at higher levels of physical activity practice.

Physical exercise in attention deficit hyperactivity disorder - evidence and implications for the treatment of borderline personality disorder

A growing body of literature indicates a potential role for physical exercise in the treatment of attention deficit hyperactivity disorder (ADHD). Suggested effects include the reduction of ADHD core symptoms as well as improvements in executive functions. In the current review, we provide a short overview on the neurophysiological mechanisms assumed to underlie the beneficial effects of exercise. Further, we review the current evidence from experimental studies regarding both acute exercise and long-term interventions in ADHD. While the positive effects observed after acute aerobic exercise are promising, very few well-designed long-term intervention studies have been conducted yet. Moreover, although exercise effects have not yet been studied in borderline personality disorder (BPD), in the end of this paper we derive hypotheses why exercise could also be beneficial for this patient population.

Enhancing Children's Motor Memory Retention Through Acute Intense Exercise: Effects of Different Exercise Durations

Physical exercise has been proposed as a viable means to stimulate motor learning. Exercise characteristics, including intensity and duration, may play a role in modulating the exercise effect on motor learning. While some evidence exists regarding the benefits of intense and relatively long exercise, little is known about the effect of short exercise bouts on motor learning, especially in children. This study aimed to assess the effect of long versus short intense exercise bouts on the adaptation and consolidation of a rotational visuomotor adaptation task. The participants were 71 healthy children from two sites divided into three groups: long exercise bout (LONG), short exercise bout (SHORT), and no exercise (CON). Children performed a rotated (clockwise 60° rotation) motor task on four different occasions: an adaptation set and 1 h, 24 h, and 7 days delayed retention sets. Exercise bouts were performed prior to the adaptation set. Results showed a group effect during motor adaptation [F(2,68) = 3.160; p = 0.049; η p 2 = 0.087], but no statistical differences were found between groups. Regarding retention tests, both exercise groups (LONG and SHORT) showed superior retention compared to CON group [F(2,68) = 7.102; p = 0.002; η p 2 = 0.175]. No differences were found between exercise groups, indicating similar benefits for the two exercise interventions. Overall, whether the exercise duration was long or short, exercise improved motor memory retention as an estimate of memory consolidation process. The use of short exercise bouts may be suitable to improve children's motor memory consolidation in environments where time constraints exist.

Interventions Based on Mind-Body Therapies for the Improvement of Attention-Deficit/Hyperactivity Disorder Symptoms in Youth: A Systematic Review

Background and objectives: Attention-deficit/hyperactivity disorder (ADHD) is one of the most common psychiatric disorders in children and adolescents. Mind–body therapies (MBTs) seem to be effective for improving health in different populations; however, whether a positive effect occurs in children and adolescents with ADHD is still controversial. The main aim of this systematic review was to analyse the interventions based on MBT aimed to improve the main ADHD symptoms in children and adolescents. Materials and Methods: A systematic review was conducted following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines to identify MBT studies on children and adolescents (4–18 years) with a clinical diagnosis of ADHD. Study quality was evaluated by the NIH quality tool (U.S. National Institute of Health). Results: There were positive results in eleven out of twelve included studies regarding the effect of the MBT interventions on ADHD symptoms. With respect to ADHD symptoms, we observed differences across studies. In relation to the studies’ quality, eleven studies were rated “poor” and one was rated as “fair”. Conclusions: MBTs, such as yoga or mindfulness, could be positive strategies to mitigate ADHD symptoms in children and adolescents. However, further research with high-quality designs, with randomization, greater sample sizes, and more intensive supervised practice programs are needed.

Effects of Exercise on Cognitive Performance in Children and Adolescents with ADHD: Potential Mechanisms and Evidence-based Recommendations

Attention Deficit Hyperactivity Disorder (ADHD) is a neurodevelopmental disorder with a complex symptomatology, and core symptoms as well as functional impairment often persist into adulthood. Recent investigations estimate the worldwide prevalence of ADHD in children and adolescents to be ~7%, which is a substantial increase compared to a decade ago. Conventional treatment most often includes pharmacotherapy with central nervous stimulants, but the number of non-responders and adverse effects call for treatment alternatives. Exercise has been suggested as a safe and low-cost adjunctive therapy for ADHD and is reported to be accompanied by positive effects on several aspects of cognitive functions in the general child population. Here we review existing evidence that exercise affects cognitive functions in children with and without ADHD and present likely neurophysiological mechanisms of action. We find well-described associations between physical activity and ADHD, as well as causal evidence in the form of small to moderate beneficial effects following acute aerobic exercise on executive functions in children with ADHD. Despite large heterogeneity, meta-analyses find small positive effects of exercise in population-based control (PBC) children, and our extracted effect sizes from long-term interventions suggest consistent positive effects in children and adolescents with ADHD. Paucity of studies probing the effect of different exercise parameters impedes finite conclusions in this regard. Large-scale clinical trials with appropriately timed exercise are needed. In summary, the existing preliminary evidence suggests that exercise can improve cognitive performance intimately linked to ADHD presentations in children with and without an ADHD diagnosis. Based on the findings from both PBC and ADHD children, we cautiously provide recommendations for parameters of exercise.

Exercise Interventions in Children and Adolescents With ADHD: A Systematic Review

OBJECTIVE

Exercise has attracted attention as a potential helpful intervention in children with ADHD. Effects are emphasized on cognition, social-emotional, and motor development.

METHOD

A systematic literature search was conducted using the electronic databases Web of Science, PubMed, Scopus, and ERIC to analyze the efficacy of different types of exercise interventions in children and adolescents with ADHD. Seven studies examining the acute and 14 studies examining the long-term effects were included.

RESULTS

The largest effects were reported for mixed exercise programs on ADHD symptomatology and fine motor precision. However, because of the large differences in the study designs, the comparability is limited.

CONCLUSION

At this time, no evidence-based recommendation can be formulated regarding frequency, intensity, or duration of exercise. Nevertheless, some first trends regarding the effects of certain types of exercise can be identified. When focusing on long-term health benefits in children and adolescents with ADHD, qualitative exercise characteristics might play an important role.

Effect of Taekwondo Practice on Cognitive Function in Adolescents with Attention Deficit Hyperactivity Disorder

Attention Deficit Hyperactivity Disorder (ADHD) is one of the most common neuro-developmental/behavioral disorders among adolescents. Sport and physical activity seem to play a major role in the development of cognition, memory, selective attention and motor reaction time, especially among adolescents with ADHD. In this context, the objective of this study was to investigate the effects of a one-and-a-half-year-long Taekwondo (TKD) intervention on cognitive function in adolescents with ADHD. Two cognitive instruments, namely the Stroop and the Ruff 2 and 7 tests, were administered to assess attentional inhibitory control and sustained and selective visual attention, respectively. Comparisons between the TKD and control groups at baseline did not reveal significant differences. For post-test scores, there were statistically significant differences on the Stroop color block test (large effect size or ES = 1.26 [95% confidence interval or CI 0.30⁻2.22]), the color-word interference test (large ES = 2.16 [95% CI 1.10⁻3.26]), the interference test (large ES = 1.63 [95% CI 0.62⁻2.64]) and error (large ES = -2.20 [95% CI -3.31 to -1.10]). Similar trends were reported for the Ruff 2 and 7 automated detection trials (large ES = 2.78 [95% CI 1.55⁻4.01]), controlled search trials (large ES = 2.56 [95% CI 1.38⁻3.75]) and total speed (large ES = -2.90 [95% CI -4.15 to -1.64]). In conclusion, TKD practice increased selective attention in adolescents with ADHD. Practitioners should implement martial art programs in their general plans to favorably influence attention and health in adolescents with ADHD.

Salivary cortisol and alpha-amylase diurnal profiles and stress reactivity in children with Attention Deficit Hyperactivity Disorder

There is growing evidence for dysregulation of the stress system in individuals with Attention Deficit Hyperactivity Disorder (ADHD). The stress system includes neuroanatomical and functional components that function in concert to maintain homeostasis and its main effectors are the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic/adrenomedullary nervous system (SNS). As stress system activity demonstrates a distinct circadian variation, we aimed to describe simultaneously, diurnal rhythms of both the HPA axis and the SNS in children with ADHD and a comparison group. Moreover, we attempted to investigate stress responses to a physical stressor, venipuncture, in both groups. Sixty-two prepubertal children with ADHD combined (ADHD-C) or inattentive (ADHD-I) type and 40 typically developing children provided saliva samples at six specific time points during a day, as well as before and 10 min after a scheduled morning venipuncture. Salivary cortisol and α- amylase were selected as reliable noninvasive biomarkers for HPA axis and SNS function and were measured in the samples obtained. Results revealed that children with ADHD-C had lower mean cortisol values both 30 min after awakening and at 18:00 h than controls (p = 0.002 and p = 0.018 respectively), as well as lower mean Cortisol Awakening Response (CAR) and Area Under the Curve for "wake to bed" period (AUC_i) values of cortisol (p = 0.004 and p = 0.001, respectively). Also, mean CAR and cortisol AUC_i were lower in children with ADHD-I than the control group (p = 0.034 and p = 0.038 respectively). Alpha-amylase measurements showed an increase over time (p < 0.001), which was similar in all three groups. Interestingly, α-amylase changes over time were correlated with the corresponding cortisol changes (p < 0.001). Venipuncture, elicited a significant increase only in α-amylase levels and more so in the control group (p = 0.003). These findings suggest a partial hypofunction of the stress system in children with ADHD.

Bright light therapy versus physical exercise to prevent co-morbid depression and obesity in adolescents and young adults with attention-deficit / hyperactivity disorder: study protocol for a randomized controlled trial

BACKGROUND

The risk for major depression and obesity is increased in adolescents and adults with attention-deficit / hyperactivity disorder (ADHD) and adolescent ADHD predicts adult depression and obesity. Non-pharmacological interventions to treat and prevent these co-morbidities are urgently needed. Bright light therapy (BLT) improves day-night rhythm and is an emerging therapy for major depression. Exercise intervention (EI) reduces obesity and improves depressive symptoms. To date, no randomized controlled trial (RCT) has been performed to establish feasibility and efficacy of these interventions targeting the prevention of co-morbid depression and obesity in ADHD. We hypothesize that the two manualized interventions in combination with mobile health-based monitoring and reinforcement will result in less depressive symptoms and obesity compared to treatment as usual in adolescents and young adults with ADHD.

METHODS

This trial is a prospective, pilot phase-IIa, parallel-group RCT with three arms (two add-on treatment groups [BLT, EI] and one treatment as usual [TAU] control group). The primary outcome variable is change in the Inventory of Depressive Symptomatology total score (observer-blinded assessment) between baseline and ten weeks of intervention. This variable is analyzed with a mixed model for repeated measures approach investigating the treatment effect with respect to all three groups. A total of 330 participants with ADHD, aged 14 - < 30 years, will be screened at the four study centers. To establish effect sizes, the sample size was planned at the liberal significance level of α = 0.10 (two-sided) and the power of 1-β = 80% in order to find medium effects. Secondary outcomes measures including change in obesity, ADHD symptoms, general psychopathology, health-related quality of life, neurocognitive function, chronotype, and physical fitness are explored after the end of the intervention and at the 12-week follow-up.

DISCUSSION

This is the first pilot RCT on the use of BLT and EI in combination with mobile health-based monitoring and reinforcement targeting the prevention of co-morbid depression and obesity in adolescents and young adults with ADHD. If at least medium effects can be established with regard to the prevention of depressive symptoms and obesity, a larger scale confirmatory phase-III trial may be warranted.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00011666. Registered on 9 February 2017. ClinicalTrials.gov, NCT03371810. Registered on 13 December 2017.

Managing childhood and adolescent attention-deficit/hyperactivity disorder (ADHD) with exercise: A systematic review

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders affecting some 8-10% of children worldwide. Increasing research has shed light on the life course of the disorder, suggesting that majority of children with ADHD will continue to have persistent symptoms into adulthood. The mainstay of ADHD management has been pharmacologic and behavioural/psychological interventions, with little attention paid to exercise as a potential management strategy. A systematic review, examining both the short-term and long-term effects of exercise on children with ADHD, is timely and necessary to guide further research in this area.

METHODS

Using the keywords [exercise OR physical OR activity OR sport] AND [attention deficit hyperactivity disorder OR ADHD OR ADDH], a preliminary search on the PubMed and Ovid database yielded 613 papers published in English between 1-Jan-1980 and 1-July-2016. Full articles were also reviewed for references of interest.

RESULTS

A total of 30 studies were included in this systematic review. Both short-term and long-term studies support the clinical benefits of physical activity for individuals with ADHD. Cognitive, behavioural and physical symptoms of ADHD were alleviated in most instances, and the largest intervention effects were reported for mixed exercise programs. No adverse effects arising from physical exercise were reported in any of the studies, suggesting that exercise is a well-tolerated intervention.

CONCLUSION

Physical activity, in particular moderate-to-intense aerobic exercise, is a beneficial and well-tolerated intervention for children and adolescents with ADHD. Future research should include more adequately-powered trials and investigate the ideal exercise prescription.

Sweat it out? The effects of physical exercise on cognition and behavior in children and adults with ADHD: a systematic literature review

As attention-deficit/hyperactivity disorder (ADHD) is one of the most frequently diagnosed developmental disorders in childhood, effective yet safe treatment options are highly important. Recent research introduced physical exercise as a potential treatment option, particularly for children with ADHD. The aim of this review was to systematically analyze potential acute and chronic effects of cardio and non-cardio exercise on a broad range of functions in children with ADHD and to explore this in adults as well. Literature on physical exercise in patients with ADHD was systematically reviewed based on categorizations for exercise type (cardio versus non-cardio), effect type (acute versus chronic), and outcome measure (cognitive, behavioral/socio-emotional, and physical/(neuro)physiological). Furthermore, the methodological quality of the reviewed papers was addressed. Cardio exercise seems acutely beneficial regarding various executive functions (e.g., impulsivity), response time and several physical measures. Beneficial chronic effects of cardio exercise were found on various functions as well, including executive functions, attention and behavior. The acute and chronic effects of non-cardio exercise remain more questionable but seem predominantly positive too. Research provides evidence that physical exercise represents a promising alternative or additional treatment option for patients with ADHD. Acute and chronic beneficial effects of especially cardio exercise were reported with regard to several cognitive, behavioral, and socio-emotional functions. Although physical exercise may therefore represent an effective treatment option that could be combined with other treatment approaches of ADHD, more well-controlled studies on this topic, in both children and adults, are needed.

Enhanced Physical Activity Improves Selected Outcomes in Children With ADHD: Systematic Review

This review examines associations between physical activity (PA) and cognitive, behavioral, and physiological outcomes in children with attention-deficit/hyperactivity disorder (ADHD). We reviewed studies on participants ≤18 years old, published in English between January 1998 and December 2014, in PubMed, CINAHL, PsycINFO, and Cochrane Reviews. Twenty-six studies were grouped into two categories: those that did and did not account for effects of ADHD medications. The first category showed lower levels of PA and improved cognitive and behavioral outcomes in youth whose ADHD was treated with medications. The second category showed a positive association between PA levels and cognitive and behavioral outcomes in youth whose ADHD was not treated with medications. For both categories of studies, results were inconclusive regarding physiological outcomes. Randomized controlled trials are needed to better clarify the relationship between PA and outcomes in youth with ADHD, and particularly to understand the impact of ADHD medications on that relationship.

The effects of physical exercise in children with attention deficit hyperactivity disorder: a systematic review and meta-analysis of randomized control trials

OBJECTIVE

The aim of this systematic review and meta-analysis was to examine the evidence for the effectiveness of exercise interventions on attention deficit hyperactivity disorder (ADHD)-related symptoms such as inattention, hyperactivity/impulsivity, anxiety and cognitive functions in children and adolescents.

METHOD

Five databases covering the period up to November 2014 (PubMed, Scopus, EMBASE, EBSCO [E-journal, CINAHL, SportDiscus] and The Cochrane Library) were searched. Methodological quality was assessed using the Cochrane tool of bias. Standardized mean differences (SMD) and 95% confidence intervals were calculated, and the heterogeneity of the studies was estimated using Cochran's Q-statistic.

RESULTS

Eight randomized controlled trials (n = 249) satisfied the inclusion criteria. The studies were grouped according to the intervention programme: aerobic and yoga exercise. The meta-analysis suggests that aerobic exercise had a moderate to large effect on core symptoms such as attention (SMD = 0.84), hyperactivity (SMD = 0.56) and impulsivity (SMD = 0.56) and related symptoms such as anxiety (SMD = 0.66), executive function (SMD = 0.58) and social disorders (SMD = 0.59) in children with ADHD. Yoga exercise suggests an improvement in the core symptoms of ADHD.

CONCLUSIONS

The main cumulative evidence indicates that short-term aerobic exercise, based on several aerobic intervention formats, seems to be effective for mitigating symptoms such as attention, hyperactivity, impulsivity, anxiety, executive function and social disorders in children with ADHD.

Effects of combined exercise on physical fitness and neurotransmitters in children with ADHD: a pilot randomized controlled study

[Purpose] The purpose of the present study was to determine the effect of a jump rope and ball combined exercise program on the physical fitness the neurotransmitter (epinephrine, serotonin) levels of children with attention-deficit hyperactivity disorder. [Subjects and Methods] The subjects were 12 boys attending elementary school, whose grade levels ranged from 1-4. The block randomization method was used to distribute the participants between the combined exercise group (n = 6) and control group (n = 6). The program consisted of a 60-min exercise (10-min warm-up, 40-min main exercise, and 10-min cool down) performed three times a week, for a total of 12 weeks. [Results] The exercise group showed a significant improvement in cardiorespiratory endurance, muscle strength, muscle endurance and flexibility after 12 weeks. A significant increase in the epinephrine level was observed in the exercise group. [Conclusion] The 12-week combined exercise program in the current study (jump rope and ball exercises) had a positive effect on overall fitness level, and neurotransmission in children with attention-deficit hyperactivity disorder.

Equine-Assisted Activities and Therapy for Treating Children with Attention-Deficit/Hyperactivity Disorder

OBJECTIVE

To investigate clinical effects of equine-assisted activities and therapy (EAA/T) for treating attention-deficit/hyperactivity disorder (ADHD) in children age 6-13 years.

METHODS

This 12-week, prospective, open-label trial included 24 sessions of EAA/T. Twenty participants (19 boys and 1 girl) completed 12 weeks of EAA/T. Various clinical tests were administered at baseline and after EAA/T. Assessments included the investigator-administered ADHD-Rating Scale (ARS-I), Clinical Global Impressions (CGI)-Severity Scale, Clinical Global Impressions-Improvement Scale (CGI-I), Gordon Diagnostic System, Korea-Child Behavior Checklist (K-CBCL), Self-Esteem Scale, second edition of the Bruininks-Oseretsky test of motor proficiency (BOT-2), and quantitative electroencephalography. The primary efficacy measure was the response rate.

RESULTS

The response rate was 90% based on a 30% or greater decline in the ARS-I score or 85% based on CGI-I scores of 1 or 2. The mean±standard deviation ARS-I score decreased from 33.65±6.42 at baseline to 16.80±6.86 after 12 weeks of EAA/T (p<0.001, paired t-test). EAA/T also resulted in significant improvement in the social problems subscale of the K-CBCL and in the manual dexterity, bilateral coordination, and total motor composite subscales of the BOT-2. The theta/beta ratio on electroencephalography was decreased significantly at the Pz electrode after 12 weeks of EAA/T.

CONCLUSION

This is the first study demonstrating that EAA/T is effective for improving core ADHD symptoms. On the basis of these results, EAA/T could be a viable treatment strategy as a part of a multimodal therapy for children with ADHD.

Exercise outcomes in prevalent users of stimulant medications

BACKGROUND

To compare users of stimulant medications with matched nonusers on exercise outcomes during a maximal treadmill exercise test.

METHODS

A cross-sectional study of a community-based cohort comparing propensity-score-matched stimulant medication users (n = 245) and nonusers (n = 735) who underwent a maximal treadmill exercise test in the Cooper Center Longitudinal Study cohort from January 1, 1995 to December 31, 2013. Main Outcomes were peak systolic blood pressure (SBP), average rise in SBP, peak heart rate (HR), and estimated VO2max during exercise. A linear mixed model analysis was used to evaluate the effect of stimulant exposure on each of the exercise outcomes. In a sensitivity analysis, users were compared against nonusers for risk of chronotropic incompetence. Analyses were adjusted for relevant covariates and multiple testing.

RESULTS

Peak HR during exercise was significantly lower in stimulant medication users (least square mean estimate 170.2 beats/minute) compared to nonusers (174.4 beats/minute; p < 0.0001). Moreover, stimulant medication users had an increased risk of chronotropic incompetence compared to nonusers (adjusted odds ratio 3.28, 95% confidence interval 1.70 to 6.34, p = 0.0008). No significant differences were observed in the outcomes of peak SBP, average SBP rise, and estimated VO2max between matched groups.

CONCLUSIONS

Stimulant medication use was associated with a significant decrease in peak HR and an increased risk of chronotropic incompetence. Further investigation is required to understand the clinical significance of chronotropic incompetence in stimulant medication users. Concerns that stimulant medication use may increase peak SBP and average SBP during exercise were not supported by this study.

Healthy body, healthy mind?: the effectiveness of physical activity to treat ADHD in children

Data from animal studies provide convincing evidence that physical exercise enhances brain development and neurobehavioral functioning in areas believed to be impaired in children with attention-deficit/hyperactivity disorder (ADHD). To a lesser but still compelling extent, results from studies in typically developing children and adults indicate beneficial effects of exercise on many of the neurocognitive functions that have been shown to be impaired in children with ADHD. Together, these data provide a strong rationale for why a program of structured physical exercise might serve as an effective intervention for children with ADHD.

Exercise reduces the symptoms of attention-deficit/hyperactivity disorder and improves social behaviour, motor skills, strength and neuropsychological parameters

This review summarises research studies on the impact and beneficial effects of different types of exercise on childhood attention-deficit/hyperactivity disorder (ADHD) and provides recommendations for the scientific and therapeutic communities.

CONCLUSION

Although the design and the exercise interventions featured in these studies varied considerably, all showed that exercise reduced the symptoms of ADHD and led to improvements in social behaviour, motor skills, strength and neuropsychological parameters.

ADHD and adolescent athletes

Attention-deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder that affects the child and adolescent population. It is characterized by impairment in attention/concentration, hyperactivity, and impulsivity, all of which can impact performance of athletes. ADHD treatment within the athletic population is a unique challenge. The research in this field has been relatively limited. The National Collegiate Athletic Association and International Olympic Committee both regulate the use of psychostimulants for treatment of ADHD due to their performance-enhancing effects. In this article, authors have discussed the screening methods, pharmacological treatment, side effects, and behavioral approaches for the treatment of ADHD in adolescent athletes.

Der Einfluss von Sport auf kognitive Funktionen bei Kindern mit ADHS

Der positive Einfluss sportlicher Aktivitäten auf kognitive und exekutive Funktionen (EF) wurde mittlerweile vielfach aufgezeigt. EF stellen zugleich ein zentrales Defizit bei ADHS dar, weshalb betroffene Kinder und Jugendliche im Besonderen von sportlichen Aktivitäten profitieren könnten. Dieser Überblicksbeitrag verfolgt das Ziel, den aktuellen Forschungsstand zum Einfluss von sportlichen Aktivitäten auf Kognitionen allgemein und im Besonderen auf EF für Kinder und Jugendliche mit ADHS aufzuzeigen sowie auf einer theoretisch-konzeptionellen Ebene Erklärungsansätze zu liefern. Es wird deutlich, dass eine heterogene Befundlage vorliegt, die unter anderem mit einer zu geringen Differenzierung der sportlichen Aktivitäten begründet wird. Interessante sportspezifische Erklärungen stammen aus der aktuellen Kognitionsforschung an gesunden Kindern und Jugendlichen, wo eine physiologische und/oder kognitive Aktivierung durch sportliche Aktivitäten diskutiert wird. Die gewonnenen Erkenntnisse fließen in ein Rahmenmodell von Tomporowski, Lambourne und Okumura (2011) ein, welches für den Anwendungsbereich von ADHS adaptiert wurde, und wo bereits identifizierte Mediatoren und Moderatoren im Sport-Kognitions-Zusammenhang beinhaltet sind.

Protection from genetic diathesis in attention-deficit/hyperactivity disorder: possible complementary roles of exercise

OBJECTIVE

The degree of functional impairment and adverse developmental outcomes in individuals with attention-deficit/hyperactivity disorder (ADHD) likely reflect interplay between genes and environment. To establish whether physical exercise might reduce the level of ADHD symptoms or ADHD-related impairments, we conducted a comprehensive review of the effect of exercise in children with ADHD. Findings on the impact of exercise in animals and typically developing human beings, and an overview of putative mechanisms involved, are also presented to provide the context in which to understand this review.

METHOD

The electronic databases PubMed, OVID, and Web of Knowledge were searched for all studies investigating the effect of exercise in children and adolescents with ADHD, as well as animal models of ADHD behaviors (available in January 2013). Of 2,150 initially identified records, 16 were included.

RESULTS

Animal studies indicate that exercise, especially early in development, may be beneficial for ADHD symptom reduction. The limited research investigating the effect of exercise in children and adolescents with ADHD suggests that exercise may improve executive functioning and behavioral symptoms associated with ADHD. Although animal research suggests that brain-derived neurotrophic factor (BDNF) and catecholamines (CAs) play a role in mediating these effects, the association between BDNF and ADHD remains unclear in human beings.

CONCLUSIONS

The potential protective qualities of exercise with regard to reducing symptoms and impairments commonly associated with ADHD may hold promise for the future. Further research is needed to firmly establish whether there are clinically significant effects of exercise on the severity of ADHD symptoms, impairments, and associated developmental outcomes.

Exercise: applications to childhood ADHD

ADHD is the most common neurobehavioral disorder of childhood, presenting with pervasive and impairing symptoms of inattention, hyperactivity, impulsivity, or a combination. The leading hypothesis of the underlying physiology of this disorder of inattention and/or hyperactivity-impulsivity is based on catecholamine dysfunction. Pharmacotherapy research indicates that psychostimulants, which are catecholamine agonists, show the greatest efficacy for treating the core symptoms of ADHD. Exercise affects the same dopaminergic and noradrenergic systems that stimulant medications target and is a stressor, which elicits measurable physiological changes. The magnitude of these peripheral alterations is posited as a potential biomarker of ADHD. The hypothesis that exercise training alters the underlying physiology present in ADHD and other medical conditions as well as conceptual issues behind its potential clinical utility is reviewed.

Pilot physical activity intervention reduces severity of ADHD symptoms in young children

OBJECTIVE

Physical activity associates with mental health and neurocognitive function, showing potential for addressing ADHD symptoms. As a preliminary assessment of this potential, the authors piloted a before-school physical activity intervention for young children.

METHOD

Seventeen children (Grades K-3) exhibiting four or more hyperactivity/impulsivity symptoms on the Disruptive Behavior Disorders Rating Scale (Pelham, 2002) completed about 26 min of continuous moderate-to-vigorous physical activity daily over eight school weeks. The authors administered cognitive, motor, social, and behavioral functioning measures at pre- and postprogram, assessed response inhibition weekly, and coded negative behaviors daily.

RESULTS

Several measures showed significant or marginally significant change over time (effect size = 0.35-0.96) with additional measures showing meaningful effect size values (≥ 0.20). Response inhibition effects were most consistent. Most participants (64% to 71%) exhibited overall improvement according to postprogram parent, teacher, and program staff ratings.

CONCLUSION

Physical activity shows promise for addressing ADHD symptoms in young children.

The novel use of objective laboratory school tasks to measure stress responses in children with ADHD

OBJECTIVE

To pilot the novel use of 2 existing laboratory school measures--the Permanent Product Measure of Performance (PERMP) and the Grammar Task--as provoking stimuli of stress, and to observe the effects of medication and stress on children with attention-deficit/hyperactivity disorder (ADHD).

METHODS

Children received individually determined optimal doses of an oral methylphenidate stimulant medication on 1 of 2 consecutive modified laboratory school days, which is a setting that is known for being a reliable measure of the exact timing of treatment effects. Blood pressure and heart rate measurements collected after administration of the PERMP, an ability-adjusted math test, were presumed to be stress related when compared with baseline data. In addition, children ranked their stress levels on a stress rating scale and completed the Grammar Task as a measure of academic performance.

RESULTS

Seven subjects enrolled in and completed the study. The results suggest that children with ADHD demonstrate a decreased stress response when medicated, as measured by blood pressure, heart rate, and academic performance.

CONCLUSION

Completion of a more difficult PERMP was associated with an increased stress response. This study supports an expanded use of both the PERMP and Grammar Task. Future controlled studies should include larger samples and other indicants of stress responses, particularly peripherally circulating catecholamine levels.

Biomarkers and attention-deficit/hyperactivity disorder: a systematic review and meta-analyses

OBJECTIVE

To determine whether peripheral biochemical markers (biomarkers) might differentiate patients with attention-deficit/hyperactivity disorder (ADHD) from non-ADHD individuals.

METHOD

We conducted a systematic search and a series of meta-analyses of case-control studies comprising studies from 1969 to 2011.

RESULTS

We identified 210 studies in the following categories: 71 studies of the main metabolites and metabolism enzymes of monoaminergic neurotransmission pathway; 87 studies of environmental risk factors divided into heavy metals (18 studies), substance/chemical exposures (16 studies), and nutritional factors (trace elements: 29 studies; essential fatty acids: 24 studies); 22 studies of the hypothalamic-pituitary-adrenal axis (HPA) pathway; 31 studies indicated with "other". After screening for the availability for meta-analyses of drug naïve/free case-control studies and Bonferroni correction, five comparisons were statistically significant (Norepinephrine [NE], 3-Methoxy-4-hydroxyphenylethylene glycol [MHPG], monoamine oxidase [MAO], Zinc [Zn], cortisol), five of the significant findings found support in studies of response to ADHD medications (NE, MHPG, MAO, b-phenylethylamine [PEA], cortisol), six in studies of symptoms severity (NE, MHPG, MAO, ferritin, Zn, cortisol) and three in studies of neurophysiological or cognitive functioning (lead-ferritin-Zn). No evidence of publication bias was found, whereas significant heterogeneity of effect sizes across studies was found for three of the five biomarkers that differentiated ADHD from control subjects. Suggestive associations were evidenced for neuropeptide Y (NPY), manganese, and dehydroepiandrosterone (DHEA).

CONCLUSIONS

This study provides evidence for several peripheral biomarkers as being associated with ADHD both in diagnosis and in treatment efficacy. Further studies are warranted to replicate these findings, to assess their specificity for ADHD, and to quantify the degree to which they are sufficiently precise to be useful in clinical settings.

The effects of physical activity on attention deficit hyperactivity disorder symptoms: the evidence

Evidence supports the beneficial effects of physical activity (PA) on cognitive performance and suggests that effects might be particularly large for children. However, limited research has explored PA as a means of managing behavioral symptoms and improving cognitive performance of children with attention deficit hyperactivity disorder (ADHD). The etiology of ADHD and the putative mechanisms for the effects of PA on cognitive performance suggest that PA might be especially important for this population.

OBJECTIVE

The purpose of this paper is to review the literature regarding the potential of PA for ADHD symptom management, particularly in regard to behavioral and cognitive symptoms.

METHODS

Literature was reviewed for published and unpublished research specifically examining the effects of PA on cognitive and/or behavioral symptoms of ADHD. Additionally, potential mechanisms were addressed.

RESULTS

Albeit limited, current research generally supports the potential for acute and chronic PA to mitigate ADHD symptoms.

CONCLUSION

Given the generally supportive extant literature and the challenges that face children with ADHD, future research exploring the potential of PA with this population is advocated.

Physical activity as the main therapeutic tool for metabolic syndrome in childhood

Physical activity (PA) and diet directly influence obesity and metabolic syndrome (MS) as important determinants of body composition. Understanding how PA relates to MS in youth is of great importance, and could offer a common strategy for clinical and public health approaches to control this condition. The underlying disorder of MS is a condition of insulin resistance, and a strong relationship between PA level and insulin sensitivity is clearly ascertained. The type, duration, frequency and intensity of PA affect fuel metabolism, in particular carbohydrate and lipid oxidation. The possible modulation of metabolism because of increased fat oxidation by PA is the basis for both prevention and restoration of insulin resistance and MS in obese children. In daily clinical practice, diet followed by pharmacologic treatment are usually the approaches taken, whereas PA is often considered just a suggestion. Although diet and PA have different effects on body composition, with both contributing to fat loss, only PA increases muscle mass and thus has a direct effect on metabolic function, expressed by changes in cardiovascular risk factors. Therefore, it is important to remember their complementary but different targets in daily clinical practice, such as body weight control for diet and metabolic health for PA. In this review, we have summarized the literature on the relationship between PA and MS in pediatrics. Then, we have analyzed the possibility of using PA for MS treatment, as an alternative to drugs, by discussing the results of intervention studies, reasons for low compliance to PA, related benefits, adherence difficulties and costs. Finally, we have tried to suggest recommendations for a multiple-step PA strategy in children and adolescents at risk for MS, by considering PA as the 'key' player in treatment.

The influences of environmental enrichment, cognitive enhancement, and physical exercise on brain development: can we alter the developmental trajectory of ADHD?

Attention-deficit/Hyperactivity Disorder (ADHD) is characterized by a pervasive pattern of developmentally inappropriate inattentive, impulsive and hyperactive behaviors that typically begin during the preschool years and often persist into adulthood. The most effective and widely used treatments for ADHD are medication and behavior modification. These empirically-supported interventions are generally successful in reducing ADHD symptoms, but treatment effects are rarely maintained beyond the active intervention. Because ADHD is now generally thought of as a chronic disorder that is often present well into adolescence and early adulthood, the need for continued treatment throughout the lifetime is both costly and problematic for a number of logistical reasons. Therefore, it would be highly beneficial if treatments would have lasting effects that remain after the intervention is terminated. This review examines the burgeoning literature on the underlying neural determinants of ADHD along with research demonstrating powerful influences of environmental factors on brain development and functioning. Based upon these largely distinct scientific literatures, we propose an approach that employs directed play and physical exercise to promote brain growth which, in turn, could lead to the development of potentially more enduring treatments for the disorder.

Sport participation and anxiety in children with ADHD

OBJECTIVE

Few studies have examined the psychological benefits of physical activity in children with ADHD who may be at higher risk for mood and anxiety problems. This study explores the relationship between participation in physical activity and emotional functioning in children with ADHD.

METHOD

Scores on parent-reported measures of mood and behavior were retrospectively compared among a group of 65 children (ages 6 to 14) diagnosed with ADHD based on their amount of sport participation. A total of 32 children diagnosed with a learning disorder (LD) were used as a comparison group.

RESULTS

Children with ADHD who participated in three or more sports displayed significantly fewer anxiety or depression symptoms than did those who participated in fewer than three sports. These differences were not evident among children with LDs.

CONCLUSION

Results suggest that active sport participation may be associated with a reduced expression of anxiety or depression symptoms in children with ADHD.

Exercise responses in boys with attention deficit/hyperactivity disorder: effects of stimulant medication

OBJECTIVE

The effect of stimulant medication on exercise responses was studied in 14 boys (10.9 +/- 1.1 years) with attention deficit/hyperactivity disorder (ADHD).

METHOD

Exercise, with and without medication, was performed at 25 W, 50 W, and 75 W, followed by a peak exercise test.

RESULT

Submaximal heart rate (HR) was significantly higher by ~8 to 13 b.min(-1) across the three intensities during the medication trial, but oxygen uptake (VO(2)), respiratory exchange ratio (RER), and perceived exertion were similar (p > .05). At peak exercise, VO(2), HR, and work rate were attenuated (p < or = .05) in the absence of medication but not RER or perceived exertion. The decreased peak exercise responses were apparent in 6 of 13 participants.

CONCLUSION

Stimulant medication raises submaximal HR but does not affect other cardiorespiratory measures or perceived exertion. Without medication physiological responses at peak exercise are attenuated in some but not all boys with ADHD.

Patients with classic congenital adrenal hyperplasia have decreased epinephrine reserve and defective glycemic control during prolonged moderate-intensity exercise

CONTEXT

Patients with classic congenital adrenal hyperplasia (CAH) have adrenomedullary dysplasia and hypofunction, and their lack of adrenomedullary reserve has been associated with a defective glucose response to brief high-intensity exercise.

OBJECTIVE

Our objective was to assess hormonal, metabolic, and cardiovascular response to prolonged moderate-intensity exercise comparable to brisk walking in adolescents with classic CAH.

SUBJECTS AND METHODS

We compared six adolescents with classic CAH (16-20 yr old) with seven age-, sex-, and body mass index group-matched controls (16-23 yr old) using a 90-min standardized ergometer test. Metabolic, hormonal, and cardiovascular parameters were studied during exercise and recovery.

RESULTS

Glucose did not change throughout exercise and recovery for controls, whereas CAH patients showed a steady decline in glucose during exercise with an increase in glucose in the postexercise period. Glucose levels were significantly lower in CAH patients at 60 (P = 0.04), 75 (P = 0.01), and 90 (P = 0.03) min of exercise and 15 (P = 0.02) min post exercise, whereas glucose levels were comparable between the two groups early in exercise and at 30 min (P = 0.19) post exercise. As compared with controls, CAH patients had significantly lower epinephrine (P = 0.002) and cortisol (P < or = 0.001) levels throughout the study and similar norepinephrine, glucagon, and GH levels. Patients with CAH and controls had comparable cardiovascular parameters and perceived level of exertion. Despite having lower glucose levels, insulin levels were slightly higher in CAH patients during the testing period (P = 0.17), suggesting insulin insensitivity.

CONCLUSION

CAH patients have defective glycemic control and altered metabolic and hormonal responses during prolonged moderate-intensity exercise comparable to brisk walking.

Effect of prior hyperglycemia on IL-6 responses to exercise in children with type 1 diabetes

The proinflammatory cytokine interleukin-6 (IL-6) may modulate the onset and progression of complications of diabetes. As this cytokine increases after exercise, and many other exercise responses are altered by prior glycemic fluctuations, we hypothesized that prior hyperglycemia might exacerbate the IL-6 response to exercise. Twenty children with type 1 diabetes (12 boys/8 girls, age 12-15 yr) performed 29 exercise studies (30-min intermittent cycling at approximately 80% peak O2 uptake). Children were divided into four groups based on highest morning glycemic reading [blood glucose (BG) < 150, BG 151-200, BG 201-300, or BG > 300 mg/dl]. All exercise studies were performed in the late morning, after hyperglycemia had been corrected and steady-state conditions (plasma glucose < 120 mg/dl, basal insulin infusion) had been maintained for > or = 90 min. Blood samples for IL-6, growth factors, and counterregulatory hormones were drawn at pre-, end-, and 30 min postexercise time points. At all time points, circulating IL-6 was lowest in BG < 150 and progressively higher in the other three groups. The exercise-induced increment also followed a similar dose-response pattern (BG < 150, 0.6 +/- 0.2 ng/ml; BG 151-200, 1.2 +/- 0.8 ng/ml; BG 201-300, 2.1 +/- 1.1 ng/ml; BG > 300, 3.2 +/- 1.4 ng/ml). Other measured variables (growth hormone, IGF-I, glucagon, epinephrine, cortisol) were not influenced by prior hyperglycemia. Recent prior hyperglycemia markedly influenced baseline and exercise-induced levels of IL-6 in a group of peripubertal children with type 1 diabetes. While exercise is widely encouraged and indeed often considered part of diabetic management, our data underscore the necessity to completely understand all adaptive mechanisms associated with physical activity, particularly in the context of the developing diabetic child.

Inflammatory cytokine, growth factor and counterregulatory responses to exercise in children with type 1 diabetes and healthy controls

In children with type 1 diabetes (T1DM), altered adaptive responses to exercise (secretion of growth factors, inflammatory cytokines, and glucoregulatory mediators) may have potential implications in growth and development, early onset of disease complications, and incidence of hypoglycemia. We therefore measured a broad spectrum of exercise responses in 12 children with T1DM (seven males and five females) and 12 controls (six males / six females) aged 11-15 yr, during a 30-min exercise challenge @ 80% VO(2)max. Euglycemia was strictly controlled during exercise, and in diabetic patients a basal rate of i.v. insulin was allowed to maintain baseline insulin concentrations. Throughout the experiment, interleukin-6 (IL-6) concentrations (pg/mL) were markedly higher in T1DM vs. controls (preexercise: 5.0+/-1.3 vs. 1.9+/-0.6, p<0.02; end-exercise 5.3+/-1.2 vs. 2.7+/-1.0, p<0.05; 30-min postexercise: 8.2+/-2.2 vs. 3.9+/-0.8, p<0.05). A similar pattern was also observed with norepinephrine. Growth hormone (GH) concentration was similar in both groups at baseline and end-exercise, but in T1DM the exercise-induced GH remained significantly elevated 30 min after exercise (9.2+/-2.2 vs. 3.1+/-0.9 ng/L, p<0.01). The exercise-induced increase in glucagon elicited by exercise in controls was similar to that previously observed in healthy adults (10+/-3 pg/mL); however, it was significantly blunted in T1DM children (2+/-2 pg/mL, p<0.05). In conclusion, T1DM children displayed significant alterations in multiple aspects of their adaptive response to intense exercise.

Reduced exercise-associated response of the GH-IGF-I axis and catecholamines in obese children and adolescents

Obesity blunts catecholamine and growth hormone (GH) responses to exercise in adults, but the effect of obesity on these exercise-associated hormonal responses in children is unclear. Therefore, the aim of the present study was to asses the effect of childhood obesity on the counterregulatory hormonal response to acute exercise. Twenty-five obese children (Ob; body mass index > 95%), and 25 age, gender, and maturity-matched normal-weight controls (NW) participated in the study. Exercise consisted of ten 2-min bouts of constant-cycle ergometry above the anaerobic threshold, with 1-min rest intervals between each bout. Pre-, post-, and 120-min postexercise blood samples were collected for circulating components of the GH-IGF-I axis and catecholamines. There were no differences in peak exercise heart rate, serum lactate, and peak O2 uptake normalized to lean body mass between the groups. Obesity attenuated the GH response to exercise (8.9 +/- 1.1 vs. 3.4 +/- 0.7 ng/ml in NW and Ob participants, respectively; P < 0.02). No significant differences in the response to exercise were found for other components of the GH-IGF-I axis. Obesity attenuated the catecholamine response to exercise (epinephrine: 52.5 +/- 12.7 vs. 18.7 +/- 3.7 pg/ml, P < 0.02; norepinephrine: 479.5 +/- 109.9 vs. 218.0 +/- 26.0 pg/ml, P < 0.04; dopamine: 17.2 +/- 2.9 vs. 3.5 +/- 1.9 pg/ml, P < 0.006 in NW and Ob, respectively). Insulin levels were significantly higher in the obese children and dropped significantly after exercise in both groups. Despite the elevated insulin levels and the blunted counterregulatory response, none of the participants developed hypoglycemia. Childhood obesity was associated with attenuated GH and catecholamine response to acute exercise. These abnormalities were compensated for, so that exercise was not associated with hypoglycemia, despite increased insulin levels in obese children.

Characterizing the ADHD phenotype for genetic studies

The genetic study of ADHD has made considerable progress. Further developments in the field will be reliant in part on identifying the most appropriate phenotypes for genetic analysis. The use of both categorical and dimensional measures of symptoms related to ADHD has been productive. The use of multiple reporters is a valuable feature of the characterization of psychopathology in children. It is argued that the use of aggregated measures to characterize the ADHD phenotype, particularly to establish its pervasiveness, is desirable. The recognition of the multiple comorbidities of ADHD can help to isolate more specific genetic influences. In relation to both reading disability and conduct disorder there is evidence that genes may be involved in the comorbid condition that are different from pure ADHD. To date, progress with the investigation of endophenotypes for ADHD has been disappointing. It is suggested that extending such studies beyond cognitive underpinnings to include physiological and metabolic markers might facilitate progress.