Our thermal cycles induced significant changes in blood lactate and liver glycogen, with minimal differences among thermal regimes. Alterations to the initial metabolic condition when an organism is exposed to increasing (LeBlanc et al., 2011) and diel thermal stress are often short lived (<24 h; Tunnah et al., 2017). In our study, transitory cyclic increases in both blood lactate and glucose occurred in the warm thermal cycles. The modest decreases in liver glycogen we observed with high temperature cycling may be indicative of rapid mobilization of free glucose to surrounding metabolically active tissues resulting in a loss of metabolic capacity (Viant et al., 2003). After 3 days of thermal cycling, no difference in liver glycogen was apparent among treatments suggesting a comparably high energetic demand in all our diel thermal cycles. Our results therefore suggest that salmon metabolically manage diel cycles in an equivalent manner, regardless of nighttime temperature, refuting the notion that warmer thermal minima are most strenuous (see DFO, 2012). Wilkie et al. (1997) exposed exercised Atlantic salmon to stable recovery temperatures and determined fish were able to recover to a pre-stress metabolic status faster at warmer temperatures (23°C vs. 12 and 18°C). There is some field evidence for the preference of warm recovery temperatures during periods of thermal stress. For example, juvenile salmonids have been observed dispersing from aggregations formed at cool water sources at nightfall despite temperatures remaining above the species’ thermal optima (Belchik et al., 2004; Corey et al., unpublished data). Although it is implied that this behavior is driven by a thermal cue, our results indicate that this response may not be directly associated with a metabolic or cellular advantage to a particular Tmin, but may be an effort to minimize the magnitude of temperature change experienced by the fish.