It is known that the hypoxic response at a cellular level is involved in the longevity induced by calorie restriction, and works like most forms of hormesis - by stimulating cells to greater housekeeping efforts. Here is an open access paper on the subject: "A mild reduction in mitochondrial respiration extends the life span of many species, including C. elegans. We recently showed that hypoxia-inducible factor 1 (HIF-1) is required for the acquisition of a long life span by mutants with reduced respiration in C. elegans. We suggested that increased levels of reactive oxygen species (ROS) produced in the respiration mutants increase HIF-1 activity and lead to this longevity. In this research perspective, we discuss our findings and recent advances regarding the roles of ROS and HIF-1 in aging, focusing on the longevity caused by reduced respiration. ... Many interesting questions remain unanswered. Which tissues and functional target genes are important in the regulation of aging by HIF-1? How can both up-regulation and down-regulation of HIF-1 promote longevity? What is the molecular mechanism by which mitochondrial ROS stimulates HIF-1 activity? ... Since many aging-regulatory processes are conserved between C. elegans and mammals, these studies may also provide insights into the regulatory mechanisms of aging in mammals, including humans. Moreover, in addition to aging, HIF-1 and mitochondrial impairment have been implicated in various human diseases such as cancer, diabetes, and neurodegenerative diseases. Thus, we believe that these future studies will help us better understand the pathophysiology of these diseases."