Oxygen insufficiency (hypoxia) is a condition prevalent amongst a range of diseased populations. Furthering our understanding of hypoxic acclimation and of potential methods to alleviate hypoxic stress is thus highly clinically relevant. A controversial aspect of acclimation is skeletal muscle metabolic remodelling, a process that may be aided by nitrate supplementation. Mechanisms of nitrate action have been shown to involve interaction with a master regulator of fat metabolism, peroxisome proliferator-activated receptor alpha (PPARα) [1]. In this study, the potential for nitrate to aid hypoxic acclimatisation in skeletal muscle (soleus) and the role of PPARα in this process were investigated. Wild type (WT) (n=42) and PPARα knockout (KO) (n=42) mice from a SVEV129 genetic background received either nitrate or chloride supplementation via drinking water for a week prior to and during exposure to either 4 weeks of hypoxia (10% oxygen) or normoxia. Mice were then killed by dislocation of the neck and mitochondrial respiration was subsequently assessed in permeabilised soleus muscle using a Clark-Type oxygen electrode. Data was analysed using a three way ANOVA in order to assess effects of all 3 parameters (hypoxia, nitrate, PPARα), with significant interactions between parameters being investigated further using a post hoc Tukeys test. Hypoxia induced a suppression of mitochondrial function, including a decrease in mass corrected fatty acid LEAK state respiration (no addition of ATP, a non-phosphorylating resting state, normoxic chloride vs hypoxic chloride WT: 22.9+3.5 vs.15.1+4 pmolsO2/sec/mg, +SD, P<0.001) and carbohydrate oxidative phosphorylation (OXPHOS) capacity (with addition of ATP, normoxic chloride vs. hypoxic chloride WT: 50.6+4.2 vs. 35.9+8.3 pmolsO2/sec/mg). These significant decreases were lost in nitrate supplemented mice, indicating a nitrate dependent recovery of mitochondrial function. A nitrate effect was observed in both WT and KO, suggesting it can act independently of any effects on PPARα. Nitrate supplementation failed to recover hypoxic induced suppression of fatty acid or mitochondrial complex 2 OXPHOS capacity. Our results confirm previous reports of hypoxia suppressing skeletal muscle mitochondrial function [2]. In addition, they support the notion that nitrate supplementation may aid hypoxic acclimation by partially recovering this suppression. In conclusion, our results indicate that nitrate can exert effects upon skeletal muscle metabolism in hypoxia independently of PPARα. Although mechanisms remain unclear, this effect may occur though improvements in skeletal muscle blood flow and/or activation of PPARβ/δ.