Preliminary Evidence of the Accuracy of Self-reported Weight, Height and Body Mass Index among Regular Exercisers in Fitness Centers

Abstract

The present study examined the accuracy of self-reported weight, height and the consequent BMI, among people who exercised in Greek fitness centers. One hundred and ten individuals (88 males and 22 females) aged 19 to 61 years old voluntarily participated in the study. Weight and height were self-reported without knowledge that these variables would be subsequently measured. Comparison between self-reported and measured data showed that participants tended to under-report their weight, over-report their height resulting in significant BMI bias. Despite however the significant results, calculation of the effect sizes showed that these differences (0.58 kg for weight, 0.86 cm for height and 0.44 points of BMI) were in fact trivial (Cohen's d ranged from .04 to .13). It was concluded that self-reported weight and height from individuals involving in physical exercise can be trusted to reliably estimate BMI.