TY - JOUR
T1 - The effect of hydration status on the measurement of lean tissue mass by dual-energy X-ray absorptiometry
AU - Toomey, Clodagh M.
AU - McCormack, William G.
AU - Jakeman, Phil
N1 - Publisher Copyright:
© 2017, Springer-Verlag Berlin Heidelberg.
PY - 2017/3/1
Y1 - 2017/3/1
N2 - Purpose: Athletes cycle between exercise and recovery. Exercise invokes changes in total body water from thermal sweating, muscle and hepatic glycogen depletion 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-ray absorptiometry (DXA). The purpose of this study was to determine the effect of exercise and thermal dehydration 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. Participants subsequently underwent a glycogen supercompensation phase, whereby a high carbohydrate 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 dehydration and nutrition regimens that involve carbohydrate 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.
AB - Purpose: Athletes cycle between exercise and recovery. Exercise invokes changes in total body water from thermal sweating, muscle and hepatic glycogen depletion 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-ray absorptiometry (DXA). The purpose of this study was to determine the effect of exercise and thermal dehydration 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. Participants subsequently underwent a glycogen supercompensation phase, whereby a high carbohydrate 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 dehydration and nutrition regimens that involve carbohydrate 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.
KW - Athletes
KW - DXA
KW - Glycogen
KW - Hydration
KW - Lean tissue mass
KW - Measurement
UR - http://www.scopus.com/inward/record.url?scp=85012874830&partnerID=8YFLogxK
U2 - 10.1007/s00421-017-3552-x
DO - 10.1007/s00421-017-3552-x
M3 - Article
C2 - 28204901
AN - SCOPUS:85012874830
SN - 1439-6319
VL - 117
SP - 567
EP - 574
JO - European Journal of Applied Physiology and Occupational Physiology
JF - European Journal of Applied Physiology and Occupational Physiology
IS - 3
ER -