PURPOSE: Athletes cycle between exercise and recovery. Exercise invokes changes in total body water from thermal sweating, muscle and @entity99 and metabolic water loss. Recovery from exercise results in rehydration, substrate repletion, and possible glycogen supercompensation. Such changes may corrupt the measurement of hydrated tissues, such as lean tissue mass (LTM), by dual-energy X- @entity16039 absorptiometry (DXA). The purpose of this study was to determine the effect of exercise and thermal @entity2700 and subsequent glycogen supercompensation on DXA-based measurement of body composition. METHODS: Twelve active adult (18-29  years) males exercised at 70% VO2max on a cycle ergometer in a thermal environment (30     C) to induce a 2.5% reduction in body mass. @entity1 subsequently underwent a glycogen supercompensation phase, whereby a high @entity1735 diet (8-12  g/kg body mass/day) was consumed for a 48-h period. Whole-body DXA measurement was performed at baseline, following exercise and supercompensation. RESULTS: Following exercise, mean body mass decreased by -1.93  kg (95% CI -2.3, -1.5), while total LTM decreased by -1.69  kg (-2.4, -1.0). Supercompensation induced a mean body mass increase of 2.53  kg (2.0, 3.1) and a total LTM increase of 2.36  kg (1.8, 2.9). No change in total fat mass or bone mineral content was observed at any timepoint. CONCLUSIONS: Training regimens that typically induce @entity2700 and nutrition regimens that involve @entity1735 loading can result in apparent changes to LTM measurement by DXA. Accurate measurement of LTM in athletes requires strict observation of hydration and glycogen status to prevent manipulation of results.

The effect of hydration status on the measurement of lean tissue mass by dual-energy X- XXXX absorptiometry.

@entity1 :: ('9606', 'Species') :: ['Participants'] @entity2700 :: ('MESH:D003681', 'Disease') :: ['dehydration'] @entity16039 :: ('255564', 'Species') :: ['ray'] @entity1735 :: ('CHEBI:16646', 'Chemical') :: ['carbohydrate'] @entity99 :: ('MESH:D056486', 'Disease') :: ['hepatic glycogen depletion']
@entity16039 :: (255564,Species) :: ['ray']
