Here is an experimental methodology that I haven't seen advocated recently, though it bears on some of the theorizing regarding the evolutionary origins of naked mole rat longevity, since they live in comparatively oxygen-poor tunnel environments.
The negative relation between metabolism and life span is a fundamental gerontological discovery well documented in a variety of ontogenetic and phylogenetic models. But how do the long-lived species and populations sustain lower metabolic rate and, in more general terms, what is the efficient way to decline the metabolism?
The suggested 'pull and push back' hypothesis assumes that decreased O2 (hypoxia) and/or increased CO2 (hypercapnia) may create preconditions for the declined metabolic and aging rates. However, wider implementation of such ideas is compromised because of little advances in modification of the metabolic rate. Artificial atmosphere with controlled O2 and CO2 levels could be a promising approach because of the minimal external invasions and involvement of the backward and forward loops ensuring physiological self-regulation of the metabolic perturbations.
General considerations and existing data indicate that manipulations of CO2 levels may be more efficient in life span extension than O2 levels. Thus, maximum life span of mammals positively correlates with the blood CO2 and HCO3- but not with O2 levels. Yet, proportional decease of the body O2 and increase of CO2 seems the most optimal regime ensuring lower losses of the energy equivalents. Furthermore, especially rewarding results could be expected when such changes are modeled without major external invasions using the animals' inner capacity to consume O2 and generate CO2, as it is typical for the extreme longevity.