Measures

To measure changes in cognitive performance participants completed a Go/NoGo task modelled on one developed by Pontifex et al. (2009) and previously used by Moore et al. (2012). The task used in the present study was a RT paradigm during which subjects performed a binary decision on each stimulus. One of the outcomes required subjects to make a motor response (go), whereas the other required subjects to withhold a response (no-go). The Go/NoGo task is considered a measure of response inhibition and is generally used to assess the ability to inhibit the “prepotent” response. Specifically, the test required participants to respond quickly and accurately to a circle of 5.5 cm diameter that occurred on 20% of the trials and not to respond to a non-target circle of 3.0 cm diameter that occurred on 80% of the trials. The cognitive task consisted of one unique block of 100 trials performed during the last 2 min of exercise once the target intensity (high-intensity exercise at 90% of HRR or moderate-intensity at 70% of HRR) had been reached. Stimuli were presented for 300 ms with a 1000 ms interstimulus interval via open source experiment software (Mathôt et al., 2012) at the centre of a computer monitor located on the treadmill in front of the participant.

For each trial, participants were asked to press a trigger button with their dominant hand when the target stimulus was presented. This trigger button process enabled participants to complete the Go/NoGo task during exercise, thereby addressing key criticism of prior research that studied the effects of exercise on cognitive performance (Lambourne and Tomporowski, 2010) pre and post exercise. Participant’s performance on the Go/NoGo task was calculated and comprised of three measures. Two error rates were calculated, one for omission errors relating to instances where the stimulus was presented and the trigger not pressed, and another for decision errors, relating to instances when the non-target stimulus was presented and the trigger was pressed. RTs (ms) were also calculated for target stimulus trials indicating the time taken to respond when the target stimulus was presented.

A resting heart rate (HR_rest) was also obtained from each participant by getting them to lie down in a prone position for 10 min while wearing a heart rate monitor (Polar RS400, Polar Electro Oy, Kempele, Finland), in a quiet room void of visual or auditory distractions. A maximum heart rate (HR_max) was estimated as 220 minus the participant’s age. Both the HR_rest and HR_max were then recorded and used to calculate 70% and 90% of heart rate reserve (HRR) (Karvonen et al., 1957).