Aerobic Interval Training Impacts Muscle and Brain Oxygenation Responses to Incremental Exercise

Kevin Caen; Kobe Vermeire; Silvia Pogliaghi; Annelies Moerman; Victor Niemeijer; Jan Gustaaf Bourgois; Jan Boone

doi:10.3389/fphys.2019.01195

Aerobic Interval Training Impacts Muscle and Brain Oxygenation Responses to Incremental Exercise

Front Physiol. 2019 Sep 20:10:1195. doi: 10.3389/fphys.2019.01195. eCollection 2019.

Authors

Kevin Caen¹, Kobe Vermeire¹, Silvia Pogliaghi², Annelies Moerman³, Victor Niemeijer⁴, Jan Gustaaf Bourgois¹, Jan Boone¹

Affiliations

¹ Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
² Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
³ Department of Anesthesiology, Ghent University Hospital, Ghent, Belgium.
⁴ Department of Sports Medicine, Elkerliek Hospital, Helmond, Netherlands.

Abstract

The purpose of the present study was to assess the effects of aerobic interval training on muscle and brain oxygenation to incremental ramp exercise. Eleven physically active subjects performed a 6-week interval training period, proceeded and followed by an incremental ramp exercise to exhaustion (25 W min^-1). Throughout the tests pulmonary gas exchange and muscle (Vastus Lateralis) and brain (prefrontal cortex) oxygenation [concentration of deoxygenated and oxygenated hemoglobin, HHb and O₂Hb, and tissue oxygenation index (TOI)] were continuously recorded. Following the training intervention $\dot{V} O_{2}$ _peak had increased with 7.8 ± 5.0% (P < 0.001). The slope of the decrease in muscle TOI had decreased (P = 0.017) 16.6 ± 6.4% and the amplitude of muscle HHb and totHb had increased (P < 0.001) 40.4 ± 15.8 and 125.3 ± 43.1%, respectively. The amplitude of brain O₂Hb and totHb had increased (P < 0.05) 40.1 ± 18.7 and 26.8 ± 13.6%, respectively. The training intervention shifted breakpoints in muscle HHb, totHb and TOI, and brain O₂Hb, HHb, totHb and TOI to a higher absolute work rate and $\dot{V} O_{2}$ (P < 0.05). The relative (in %) change in $\dot{V} O_{2}$ _peak was significantly correlated to relative (in %) change slope of muscle TOI (r = 0.69, P = 0.011) and amplitude of muscle HHb (r = 0.72, P = 0.003) and totHb (r = 0.52, P = 0.021), but not to changes in brain oxygenation. These results indicate that interval training affects both muscle and brain oxygenation, coinciding with an increase in aerobic fitness (i.e., $\dot{V} O_{2}$ _peak). The relation between the change in $\dot{V} O_{2}$ _peak and muscle but not brain oxygenation suggests that brain oxygenation per se is not a primary factor limiting exercise tolerance during incremental exercise.

Keywords: cerebral oxygenation; incremental ramp exercise; interval training; limiting factors; muscle oxygenation.