This study aims to investigate whether physical activity intervention would be effective to improve sleep quality in children with ASD, and investigate how physical activity impacts on sleep in children with ASD through melatonin-mediated mechanism model. A parallel-group randomized controlled trial comparing a 12-week jogging intervention and a control group receiving standard care in 32 children with ASD will be conducted. This study will monitor the changes of four sleep parameters (sleep onset latency; sleep efficiency, wake after sleep onset and sleep duration) through objective actigraphic assessment and parental sleep logs.

Sleep disturbance is commonly found in children with autism spectrum disorder (ASD) and is often accompanied with family distress. Disturbed sleep may exacerbate the core symptoms of ASD including stereotypic behaviors, social interactions, and health problems. Therefore, it is important to develop effective intervention strategies to ameliorate the sleep disturbance in children with ASD. Traditionally, behavioral interventions and supplemental melatonin medication are used to improve their sleep quality. However, poor sustainability of behavioral intervention effects and use of other medications (e.g. antidepressants and stimulants) that metabolize melatonin may degrade the effectiveness of these interventions. Alternatively, previous research supported physical activity intervention as an effective treatment on sleep disturbance for typically developing children who suffered from sleep disturbance. It is therefore natural to extend the study to examine whether such intervention is also effective in children with ASD. This study aims to investigate whether physical activity intervention would be effective to improve sleep quality in children with ASD. Moreover, how physical activity impacts on sleep in children with ASD through melatonin-mediated mechanism model will also be investigated. According to this mechanism model, it is suggested that physical activity could affect circadian rhythm through altering melatonin level. Melatonin is generally lower in ASD children than in their typically developing counterparts and supplemental melatonin medication is often used to treat the sleep disturbance in this population. This study is a parallel-group randomized controlled trial comparing a 12-week jogging intervention and a control group receiving standard care in 32 children with ASD. The changes of four sleep parameters (sleep onset latency; sleep efficiency, wake after sleep onset and sleep duration) through objective actigraphic assessment and parental sleep logs will be monitored. To measure melatonin level, all participants will be instructed to collect a 24-h urinary sample. 6-sulfatoxymelatonin, a creatinine-adjusted morning urinary melatonin and representative for melatonin level, will be measured from the collected urine sample. All the assessments will be carried out before the intervention (T1), immediately after the 12 weeks of physical activity intervention or regular treatment (T2), and 12 weeks after post-intervention (T3) for examination of sustained intervention effect. The findings of this proposed study can provide information on the mechanism pathway that physical activity impacts on sleep in children with ASD, which will contribute to the design of an effective intervention to improve sleep quality for children with ASD.

Inclusion Criteria:

• pre-puberty or early puberty as indicated by Tanner stage I or II ;
• ASD diagnosis from a physician based on Diagnostic and Statistical Manual of Mental Disorders, 5th edition, (DSM-V)[42]
• non-verbal IQ over 40
• the ability to follow instructions;
• physically able to participate in the intervention
• no additional regular participation in physical exercise other than school physical education classes for at least 6 months prior to the study
• no concurrent medication for at least 6 months before the study or any prior melatonin treatment;
• have sleep difficulties, including sleep onset insomnia and frequent and prolonged nightwaking and/or early morning awakenings reported by parents

Exclusion Criteria:

• with one or co-morbid psychiatric disorders as established by a structured interview based on DSM-V
• with other medical conditions that limit their physical activity capacities (e.g., asthma, seizure, cardiac disease);
• with a complex neurologic disorder (e.g., epilepsy, phenylketonuria, fragile X syndrome, tuberous sclerosis)