01Why measure metabolism during exercise
At rest, indirect calorimetry reports baseline metabolic rate and fuel use. Under graded exercise, the same measurements reveal aerobic capacity, the intensity at which fuel use shifts from fat toward carbohydrate, and endurance — read-outs central to exercise physiology, cardiovascular, and metabolic-disease models.
02Designing a graded exercise test
A graded exercise test increases workload in defined steps — programming a sequence of speed and slope stages, each held while gas exchange is recorded continuously.
- Warm-up — a low-speed stage to stabilise gait and baseline VO₂.
- Incremental stages — speed and/or slope step up at set intervals.
- Stopping criteria — a VO₂ plateau despite rising workload, or a humane time-on-stimulus limit, ends the test.
03Reading VO₂max
VO₂max is the maximal rate of oxygen consumption — the point where VO₂ plateaus even as workload climbs. It is the canonical index of aerobic capacity, normalised to body (or lean) mass. A clean VO₂max needs per-second sampling so the plateau is resolved rather than averaged away.
04The substrate shift with intensity
As intensity rises, the respiratory exchange ratio climbs from fat-dominant toward carbohydrate-dominant values — a measurable marker of the fat-to-carbohydrate crossover. Tracking RER across stages quantifies how an intervention, genotype, or training state changes fuel selection under load.
05Endurance & energy cost
Beyond peak capacity, the same run yields time-to-fatigue, distance, and the energy cost of locomotion at each workload — by pairing per-lane treadmill data with synchronized VO₂/VCO₂.
06One timeline, hardware + software
ConductMetabolism ships with the Rodent Metabolic Treadmill and is fully integrated with it: program speed and acceleration steps, capture VO₂/VCO₂ while the animal runs, and correlate energy expenditure to workload on a single timeline, with per-animal results exported for analysis.
