Fig. 4.

Skeletal muscle intracellular Nrf2 and Keap1 signalling in response to incremental exercise to exhaustion in normoxia and severe hypoxia and the application of immediate ischaemic or non-ischaemic recovery. Protein expression levels of pSer⁴⁰ Nrf2 (A), Nrf2 total (B), pSer⁴⁰ Nrf2/Nrf2 total ratio (C), Keap1 (D), Nrf2 Total/Keap1 ratio (E). Nx; test performed in normoxia (F_IO₂ = 0.21, P_IO₂: 143 mmHg), Hyp; test performed in severe acute normobaric hypoxia (F_IO₂ = 0.104, P_IO₂: 73 mmHg); Pre, before exercise; Post, 10 s after the end of exercise with ischaemic recovery; Oc1m, 60 s after the end of exercise with ischaemic recovery; FC1m, 60 s after the end of exercise in the leg recovering without occlusion (free circulation). A detailed description of the experimental phases is explained in Fig. 1. The statistical analysis was performed with logarithmically transformed data for all proteins except for Keap1. The values shown are means ± standard errors and expressed in arbitrary units (a.u.). n = 11 in all conditions except for Oc1m Nx (n = 9), Post Hyp (n = 10), and Oc1m Hyp (n = 10). †p < 0.05 vs Pre Nx; *p < 0.05 vs Pre Hyp; ^#p < 0.05 vs Post Hyp; ^§p < 0.05 vs Oc1m Hyp.