The mitochondrial (UPR^mt) and the endoplasmic reticulum (UPR^ER) unfolded protein responses are important for cellular homeostasis during stimulus-induced increases in protein synthesis. Exercise triggers the synthesis of mitochondrial proteins, regulated in part by PGC-1 . To investigate the role of the UPR in exercise-induced adaptations, we subjected rats to 3-hrs of chronic contractile activity (CCA) for 1, 2, 3, 5 or 7 days, followed by 3-hrs recovery. Mitochondrial biogenesis signaling, through PGC-1 mRNA, increased 14-fold after 1 day of CCA. This resulted in 10-32% increases in COX activity, indicative of mitochondrial content, between days 3-7, as well as increases in the autophagic degradation of p62 and LC3-II protein. Preceding these adaptations, UPR^ER transcripts ATF4, XBP1s, and BiP were elevated (1.3-3.8-fold) from 1-3 days, while CHOP and chaperones BiP and HSP70 were elevated at both mRNA and protein levels (1.5-3.9-fold) from 1-7 days of CCA. Mitochondrial chaperones CPN10, HSP60, and mtHSP70, protease ClpP, and regulatory protein SirT3 of the UPR^mt were concurrently induced 10-80% between 1-7 days. To test the role of the UPR in CCA-induced remodeling, we treated animals with the ER stress suppressor TUDCA and subjected them to 2 or 7 days of CCA. TUDCA attenuated CHOP and HSP70 protein induction, however this failed to impact mitochondrial remodeling. Our data indicate that signaling to the UPR is rapidly activated following acute contractile activity, that this is attenuated with repeated bouts, and that the UPR is involved in chronic adaptations to CCA, however this appears to be independent of CHOP signaling.