LAUSR

Introduction/Background Exercise therapy is a core component of rehabilitation for patients with cardiopulmonary disease and diabetes. A recent study showed that cognitive function improved after a single episode of moderate-intensity exercise. However, the laterality of cortical oxyhemoglobin (O2Hb) increases during exercise is unknown. We aimed to evaluate the laterality of O2Hb changes in the prefrontal cortex (PFC) during 20 min of moderate-intensity cycling exercise. Material and method Twelve healthy volunteers (9 women) participated. After a 3 min of rest, 20 min of exercise was performed at a workload of 50% VO2peak, followed by 15 min of post-exercise rest. The O2Hb levels in the right (R-PFC) and left (L-PFC) prefrontal cortices were measured using a 34-channel, near-infrared spectrometry system. The O2Hb levels in each area were expressed as changes from the mean pre-exercise rest phase values. The O2Hb values in the last 5 min of the 20-min exercise period were averaged in both regions. The laterality index (LI) was calculated using the formula (L-PFC O2Hb–R-PFC O2Hb)/(L-PFC O2Hb + R-PFC O2Hb). A positive LI indicated that the increase in O2Hb in the L-PFC was larger than in the R-PFC; a negative LI indicated the opposite. Results O2Hb levels increased during the first 10 min and were maintained over the latter half of the exercise period in both R-PFC and L-PFC. The average O2Hb values in the last 5 min were 0.066 ± 0.013 mM·cm in the R-PFC and 0.085 ± 0.015 mM·cm in the L-PFC. The average LI of the PFC was 0.16 ± 0.10. Conclusion L-PFC-dominant O2Hb increases were observed during 20 min of moderate-intensity cycling exercises. The L-PFC plays an important role in executive functions and verbal working memory, which might be promoted by 20 min of exercise.