From Strenuous Migration to Dormancy and Arousal: How Physical (In)Activity Affects Oxidative Status

Physical effort requires a number of energetic, metabolic, hormonal, and cardiovascular responses that can be highly costly for the organism to sustain. Even physical inactivity, typical of animals during hibernation or aestivation, requires several physiological adjustments of the metabolic machinery, which have also to prepare the organism for the reoxygenation and increased metabolic activity that will characterise the phase of arousal. A number of studies described the many ways in which animals regulate their oxidative status during different phases of physical (in)activity, such as strenuous migratory flight, dormancy, or arousal. Many authors also pointed to a role of exercise-induced reactive oxygen species in mediating hormetic responses to physical effort. In this chapter, I have examined the role of oxidative stress induced by physical effort as cost of and constraint on migration strategies and sibling competition. I have also analysed the oxidative challenges that animals face during periods of inactivity, and the transition from dormancy to arousal due to tissue reoxygenation and consequent burst of reactive oxygen species generation in body tissues.