title: Effect of scalp and facial hair on air displacement plethysmography estimates of percentage of body fat.
abstract: OBJECTIVE
  The objective of this study was to determine the effect of body hair (scalp and facial) on air displacement plethysmography (BOD POD) estimates of percentage of body fat.
  
  
  METHODS
  A total of 25 men (31.4 +/- 8.0 years, 83.4 +/- 12.2 kg, 181.8 +/- 6.9 cm) agreed to grow a beard for 3 weeks to participate in the study. Total body density (g/cm(3)) and percentage of body fat were evaluated by BOD POD. To observe the effect of trapped isothermal air in body hair, BOD POD measures were performed in four conditions: criterion method (the beard was shaven and a swimcap was worn), facial hair and swimcap, facial hair and no swimcap, and no facial hair and no swimcap(.)
  
  
  RESULTS
  The presence of only a beard (facial hair and swimcap) resulted in a significant underestimation of percentage of body fat (16.2%, 1.0618 g/cm(3)) vs. the criterion method (17.1%, 1.0597 g/cm(3), p < 0.001). The effect of scalp hair (no swim cap worn) resulted in a significant underestimation in percentage of body fat relative to the criterion method, either with facial hair (facial hair and no swimcap; 14.8%, 1.0649 g/cm(3)) or without facial hair (no facial hair and no swimcap; 14.8%, 1.0650 g/cm(3), p < 0.001 for both).
  
  
  CONCLUSIONS
  A significant underestimation of percentage of body fat was observed with the presence of facial hair ( approximately 1%) and scalp hair ( approximately 2.3%). This underestimation in percentage of body fat may be caused by the effect of trapped isothermal air in body hair on body-volume estimates. Thus, excess facial hair should be kept to a minimum and a swimcap should be worn at all times to ensure accurate estimates of body fat when using the BOD POD.
authors.affiliation: Division of Physiology and Metabolism, Department of Nutrition Sciences, University of Alabama at Birmingham, 35294-3360, USA.
authors.forename: P B
authors.initials: PB
authors.lastname: Higgins
authors.forename: D A
authors.initials: DA
authors.lastname: Fields
authors.forename: G R
authors.initials: GR
authors.lastname: Hunter
authors.forename: B A
authors.initials: BA
authors.lastname: Gower
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology*; D000328:Adult; D000388:Air; D001823:Body Composition; D005145:Face; D006197:Hair; D006801:Humans; D008297:Male; D010991:Plethysmography / Q000379:methods*; D012535:Scalp