Waist circumference

Waist circumference is a tape measurement around the torso used as a proxy for visceral and abdominal fat and obesity-related health risk.^{1Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 180.},^{2Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 181.} Fat carried on the trunk raises the risk of hypertension, metabolic syndrome, type 2 diabetes, cardiovascular disease and premature death more than fat on the hips and thighs.^{3Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 179.} Waist circumference is reported to be better than BMI as a gauge of obesity-related health risk and can flag increased risk even in clients of normal weight.^{2Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 181.},^{4Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 178.}

For clients with a BMI of 25 to 34.9, a waist above 102 cm (40 in) in men or 88 cm (35 in) in women signals an increased risk of type 2 diabetes, dyslipidemia, hypertension and cardiovascular disease.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 533.} Above a BMI of 35 these cutoffs add little, because nearly everyone exceeds them.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 533.}

In practice

• Measure at the same site every time: protocols and risk tables use different sites, so consistency matters for follow-ups.^{6Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 182.} ACSM’s standard waist site is the narrowest part of the torso, above the navel and below the bottom of the breastbone.^{1Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 180.}
• Use a flexible tape that doesn’t stretch, without compressing the skin.^{1Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 180.} Take two measurements and retest if they differ by more than 5 mm.^{1Ozemek et al., ACSM’s Guidelines for Exercise Testing and Prescription, 12th ed., p. 180.}
• For clients with obesity, use waist and BMI instead of skinfolds, which can be hard to take and embarrassing for the client.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 533.} Seeing inches come off can also help adherence.^{5Schoenfeld and Snarr (eds.), NSCA’s Essentials of Personal Training, 3rd ed., p. 533.}