Dogs are some of nature’s most capable athletes. When blessed with the appropriate anatomic form to facilitate exercise and the appropriate environment and opportunity for conditioning, they can perform exercise far in excess of all other domestic animals. A well-trained dog may have an aerobic capacity 4-5 times greater than an elite human athlete, and a dog’s endurance capacity (when quantified as sustained caloric expenditure) may also be 4-5 fold greater than an elite human endurance athlete. Unsurprisingly, their specific exercise physiology is iconoclastic relative to other lesser athletes such as humans – a dog’s superlative exercise capacity is in many instances due to having developed metabolic strategies that circumvent the “rules” that limit human performance. Probably the most unexpected finding is that despite years of belief that dogs were fat-adapted (excelled at burning fat to support their exercise), recent work has demonstrated precisely the opposite: a well-conditioned dog is highly dependent on carbohydrates to fuel their exercise, and their extensive physiological responses to improve exercise capacity are directed towards increasing the availability of glucose for skeletal muscle uptake. These responses not only include the expected increase in insulin- and contraction-sensitive glucose transporters (GLUT4), but also a 2.5 fold increase in the expression of constitutively-active glucose transporters (GLUT1). This corresponds to the 2.5 fold increase in insulin-independent glucose clearance previously reported in well-conditioned athletic dogs and illustrates the extent to which exercising dogs convert their basic metabolic machinery to consider exercise performance as their basal metabolic state.