Effect of high-intensity interval training in adolescents with asthma:The eXercise for Asthma with Commando Joe’s^(■)(X4ACJ)trial

Background:Higher levels of cardiorespiratory fitness are associated with reduced asthma severity and increased quality of life in those with asthma.Therefore,the purpose of this study was to evaluate the effectiveness of a 6-month high-intensity interval training(HIIT)intervention in adolescents with and without asthma.Methods:A total of 616 adolescents(334 boys;13.0±1.1 years,1.57±0.10 m,52.6±12.9 kg,mean±SD),including 155 with asthma(78 boys),were recruited as part of a randomized controlled trial from 5 schools(4 control and 1 intervention).The 221 intervention participants(116 boys;47 asthma)completed 6 months of school-based HIIT(30 min,3 times per week,10-30 s bouts at>90%age-predicted maximum heart rate with equal rest).At baseline,mid-intervention,post-intervention,and 3-month follow-up,measurements for 20-m shuttle run,body mass index(BMI),lung function,Pediatric Quality of Life Inventory,Paediatric Asthma Quality of Life Questionnaire,and Asthma Control Questionnaire were collected.Additionally,69 adolescents(39 boys(of the 36 with asthma there were 21 boys))also completed an incremental ramp test.For analysis,each group’s data(intervention and control)were divided into those with and without asthma.Results:Participants with asthma did not differ from their peers in any parameter of aerobic fitness,at any time-point,but were characterized by a greater BMI.The intervention elicited a significant improvement in maximal aerobic fitness but no change in sub-maximal parameters of aerobic fitness,lung function,or quality of life irrespective of asthma status.Those in the intervention group maintained their BMI,whereas BMI significantly increased in the control group throughout the 6-month period.Conclusion:HIIT represents an effective tool for improving aerobic fitness and maintaining BMI in adolescents,irrespective of asthma status.HIIT was well-tolerated by those with asthma,who evidenced a similar aerobic fitness to their healthy peers and responded equally well to a HIIT program.

Back to school after lockdown: The effect of COVID-19 restrictions on children’s device-based physical activity metrics

Background:The coronavirus disease-2019(COVID-19) pandemic and national lockdowns took away opportunities for children to be physically active.This study aimed to determine the effect of the COVID-19 lockdown on accelerometer-assessed physical activity(PA) in children in Wales.Methods:Eight hundred participants(8-18 years old),stratified by sex,age,and socio-economic status,wore Axivity AX3 accelerometers for7 days in February 2021,during the lockdown,and in May 2021,while in school.Raw accelerometer data were processed in R-package GGIR,and cut-point data,average acceleration(AvAcc),intensity gradient,and the acceleration above which the most active X minutes are accumulated(MX) metrics were extracted.Linear mixed models were used to assess the influence of time-point,sex,age,and socioeconomic status(SES) on PA.Results:During lockdown,moderate-to-vigorous PA was 38.4±24.3 min/day;sedentary time was 849.4±196.6 min/day;mean± SD.PA levels increased significantly upon return to school(all variables p <0.001).While there were no sex differences during lockdown(p=0.233),girls engaged in significantly less moderate-to-vigorous PA than boys once back in school(p <0.001).Furthermore,boys had more favorable intensity profiles than girls(intensity gradient:p <0.001),regardless of time-point.PA levels decreased with age at both time-points;upper secondary school girls were the least active group,with an average M30 of 195.2 mg(while in school).Conclusion:The lockdown affected boys more than girls,as reflected by the disappearance of the typical sex difference in PA levels during lockdown,although these were re-established on return to school.Upper secondary school(especially girls) might need specific COVID-recovery intervention.