 The heart rate formula most often used for the Bruce is the Karvonen formula (below).A more accurate formula, offered in a study published in the journal, Medicine & Science in Sports & Exercise, is 206.9 - (0.67 x age) which can also be used to more accurately determine VO2 Max, but may produce significantly different results.A diagnostician (e.g., physical therapist, personal trainer, doctor, athletic trainer, nurse, medical professional, dietitian, etc.)