This study observed Systems 1 (heuristic) and Systems 2 (cognitively effortful) decision making styles in individuals undergoing high and low intensity exercise versus a no exercise control group. The attraction effect and delay discounting were measured to test the hypothesis that post exercise hyperglycaemia can reduce heuristic-based decision making and increase cognitively effortful decisions. Individual differences in decision making traits were also assessed using the General Decision Making Styles questionnaire. Results showed that high-intensity exercise can induce elevation in blood glucose; however this effect was observed only in half the sample. Participants in the high intensity exercise condition were significantly more likely than those in the low intensity exercise condition to elicit post exercise hyperglycaemia. Additionally, results from this study show that higher blood glucose is associated with a greater probability of choosing the non-heuristic option in the apartment task; thus signifying less reliance on heuristic based System 1 decision making. Furthermore, in the delay discounting task, exploratory analyses suggest that high-intensity exercise-induced hyperglycaemia may rescue optimal decision-making for individuals who tend to make more intuitive decisions (i.e., are more reliant on System 1). Further studies with larger sample sizes are needed to further elucidate the effects of exercise on decision making, taking into account blood glucose changes and individual difference profiles.
