The aim of this observational study was to compare head motion and prefrontal haemodynamics during exercise using three commercial cycling ergometers. Participants (n = 12) completed an incremental exercise test to exhaustion during upright, recumbent and semi-recumbent cycling. Head motion (using accelerometry), physiological data (oxygen uptake, end-tidal carbon dioxide [PETCO2] and heart rate) and changes in prefrontal haemodynamics (oxygenation, deoxygenation and blood volume using near infrared spectroscopy [NIRS]) were recorded. Despite no difference in oxygen uptake and heart rate, head motion was higher and PETCO2 was lower during upright cycling at maximal exercise (P<0˙05). Analyses of covariance (covariates: head motion P>0˙05; PETCO2, P<0˙01) revealed that prefrontal oxygenation was higher during semi-recumbent than recumbent cycling and deoxygenation and blood volume were higher during upright than recumbent and semi-recumbent cycling (respectively; P<0˙05). This work highlights the robustness of the utility of NIRS to head motion and describes the potential postural effects upon the prefrontal haemodynamic response during upright and recumbent cycling exercise.