Infinity Functional Performance | Patient & Athlete Education Series

Why we test instead of guess​

Every training program, every nutrition plan, and every recovery protocol makes assumptions about one thing: your metabolism. How many calories you burn at rest. What fuel — fat or carbohydrate — you rely on. How efficiently your heart, lungs, and cells move oxygen. Where your true "fat‑burning" heart‑rate lives, and where anaerobic stress begins.

Most gyms and clinics estimate those numbers using population equations such as Harris‑Benedict or Mifflin‑St Jeor. Those equations are useful, but they carry meaningful error at the individual level — group‑level accuracy is only around 60–80%, and individual predictions frequently miss measured resting metabolic rate by ≥10%, sometimes by hundreds of calories per day (Frankenfield et al., 2005 — J Am Diet Assoc; Achamrah et al., 2016 — J Acad Nutr Diet). A 300 kcal/day error is the difference between weight loss and a stubborn plateau — or between healthy fueling and unintended under‑eating.

At Infinity Functional Performance we replace estimation with measurement. Our platform is PNOĒ, a portable breath‑by‑breath metabolic analyzer that has been validated head‑to‑head against the laboratory gold‑standard COSMED Quark CPET, with near‑perfect agreement (r ≈ 0.98 for VO₂, VCO₂, and ventilation, and test‑retest reliability ICC ≈ 0.98) (Tsekouras et al., 2019 — Front Sports Act Living).

We offer two tests:

• RMR (Resting Metabolic Rate) test — a short quiet‑breathing test that measures the calories and fuel mix your body uses at rest.
• AMR (Active Metabolic Rate) / CPET‑style ramp test — a graded exercise test that measures VO₂peak, ventilatory thresholds, personalized heart‑rate zones, calorie and fat/carb burn per zone, biological age, and recovery capacity.

Together, these two tests build what we call a Metabolic Blueprint — an individualized map for training, nutrition, and recovery. Here's what each one delivers.