. 2021 Jun 15;12:670977. doi: 10.3389/fphys.2021.670977

Table 1.

Acid–base balance before and after 30 km time trial in normoxia (N) and hypoxia (H).

Variables	Conditions	Rest	Max
pH	N	7.41 ± 0.01	7.30 ± 0.06^***
pH	H	7.40 ± 0.02	7.25 ± 0.07^***
LA (mmol/l)	N	2.34 ± 0.54	11.99 ± 2.49^***
LA (mmol/l)	H	2.23 ± 0.54	13.70 ± 2.99^***
H⁺ (nmol/l)	N	39.02 ± 1.07	50.89 ± 7.03^***
H⁺ (nmol/l)	H	39.81 ± 2.09	57.13 ± 9.15^***
${HCO}_{3}^{-}$ (mmol/l)	N	24.56 ± 1.23	15.16 ± 2.83^***
${HCO}_{3}^{-}$ (mmol/l)	H	25.10 ± 1.09	13.22 ± 3.01^***
tCO₂ (mmol/l)	N	25.78 ± 1.28	16.11 ± 2.90^***
tCO₂ (mmol/l)	H	26.36 ± 1.12	14.14 ± 3.07^***
BE (mmol/l)	N	0.01 ± 1.08	−9.95 ± 3.48^***
BE (mmol/l)	H	0.29 ± 1.12	−12.38 ± 4.03^***

All values shown as mean ± SD; rest – before time trial; max – immediately after time trial. pH, blood pH; LA, blood lactate concentration; H⁺, hydrogen ion concentration; ${HCO}_{3}^{-},$ bicarbonate concentration; tCO₂, total carbon dioxide concentration; and BE, base excess.

^***

p < 0.001 – significant differences between rest and max.