The nausea caused by exhaustive sprinting is associated with high lactate ([La-]) and hydrogen ion concentrations ([H+]) and fall in blood pCO2, thus raising the issue of whether there is a causal link between nausea and these variables. For this reason, this study aimed to determine if interspersing repeated sprints (RS) with periods of active, compared to passive, recovery results in lower levels of both nausea and changes in [La-], [H+] and pCO2.
Twelve male participants completed two separate sessions comprising four 30-sec sprints separated by 20-min of either active (AR; cycling at 40% V[Combining Dot Above]O2peak) or passive recovery (PR). At 6 and 18-min of each recovery period, nausea was assessed via a visual analogue scale (VAS), and blood samples were obtained to measure [La-], [H+] and pCO2.
RS significantly increased VAS score in both AR (P<0.001) and PR (P<0.01). Following the first sprint, VAS was higher than pre-exercise in only AR (P<0.01). AR was associated with lower VAS, [La-], [H+] and higher pCO2 (all P=0.001) compared to PR following sprints 2-4. Linear mixed modelling indicated that each of the variables significantly predict VAS scores (P<0.0001). Repeated measures correlation (rrm2) indicated that [La-] had the closest association with VAS (rrm2=0.22, P<0.0001).
The lower levels of both nausea and changes in [La-], [H+] and pCO2 in response to AR suggests that nausea associated with repeated sprints may be causally related with these variables. However, the absence of a close relationship between these variables following the first sprint and the findings that [La-], [H+] and pCO2 only account for 13-22% of the variation in VAS indicate that other mechanisms may also mediate nausea.