Fitness professionals rely on four basic measurements — Body Mass Index (BMI), Blood Pressure (BP), Resting Heart Rate (RHR), and Waist-to-Hip Ratio (WHR) — to broadly assess an individual's health and risk for metabolic complications. These simple metrics provide essential starting points for a training program and offer clear data on the effectiveness of lifestyle changes over time.

Body Mass Index (BMI) is an inexpensive and easy screening tool used to determine a healthy body weight by calculating the ratio of weight (in kilograms) to height (in meters squared). While a basic measure with an ideal range of 18.5 to 24.9, BMI has limitations because it does not measure body composition and may inaccurately classify highly muscular athletes as overweight or obese.