A Collaborative Resource
We have developed a systematic approach to understand the extremes of both health and exercise capacity that is prospective, hypothesis-based, and underwritten by fundamental ideas from evolution and non-equilibrium thermodynamics.
To achieve this goal we have developed (via artificial selection) two rat model systems that contrast for the extremes of intrinsic (inherent) and that acquired by adaptation to training. These rats are maintained as a National and International Collaborative Resource by the Department of Anesthesiology at the University of Michigan and the National Institutes of Health (Division of Comparative Medicine).
Low Capacity Runners (LCR) and High Capacity Runners (HCR)
The association between low exercise capacity and all-cause morbidity and mortality is strong statistically yet mechanistically unresolved. By connecting clinical observation with a theoretical base, we developed a working hypothesis that: variation in capacity for energy transfer is the central mechanistic determinant between disease and health (energy transfer hypothesis). As an unbiased test of this hypothesis, we show that two-way artificial selective breeding of rats for low and high intrinsic endurance exercise capacity also produces rats that differ for numerous disease risks, including the metabolic syndrome, premature aging, reduced longevity, fatty liver disease, obesity, and Alzheimer’s degeneration.
Low Response Trainers (LRT) and High Response Trainers
Besides intrinsic, one’s current exercise capacity is also a result of adaptation to all aspects of physical activity. To capture this biology we have also selectively bred rats for low and high response to 8 weeks of treadmill running exercise. Thus, we have models that represent the 4 “corners” of exercise capacity.