Dose-response relationship between intensity of exercise and cognitive performance in individuals with Down syndrome: A preliminary study

Background: Cognitive performance has been shown to be relevant to the early onset of Alzheimer's disease in individuals with Down syndrome. This study was aimed at investigating the dose-response relationship between acute exercise intensity and cognitive performance in this population. Methods: In the current study, we measured information processing speed and two aspects of executive function (i.e. attention shifting and inhibitory control). Participants were assigned to high-intensity exercise (i.e. 75-85% of predicted maximum heart rate) (N=6), moderate-intensity exercise (i.e. 50-75% of predicted maximum heart rate) (N=6) or attentional control (N=6) groups. Two exercise groups walked on a treadmill using an incremental intensity walking protocol, and the attentional control group watched a video for 20 min. Measures of information processing speed and executive function were tested pre-intervention and post-intervention. Results: Our results indicated that the performance in choice reaction time test was impaired in the high-intensity exercise, whereas improved performance was observed in the moderate-intensity exercise. However, moderate-intensity and high-intensity exercises were beneficial for inhibitory control aspect of executive function. Further, inconsistent with previous studies, a quadric trend was seen in information processing speed, and a liner trend was evident in inhibitory control. Conclusions: Future research is needed to examine with a larger sample size, and more physiological measures are necessary to explore the underlying mechanisms in the relationship between exercise intensity and cognitive performance in individuals with Down syndrome.