Measuring the Exercise Component of Energy Availability during Arduous Training in Women

INTRODUCTIONLow energy availability (EA) may impede adaptation to exercise, suppressing reproductive function and bone turnover. Exercise energy expenditure (EEE) measurements lack definition and consistency. This study aimed to compare EA measured from moderate and vigorous physical activity from accelerometry (EEEmpva) with EA from total physical activity (EEEtpa) from doubly-labelled water in women. The secondary aim was to determine the relationship of EA with physical fitness, body composition by DXA, heartrate variability (HRV) and eating behavior (brief eating disorder in athletes-questionnaire, BEDA-Q). METHODSProspective, repeated measures study, assessing EA measures and training adaptation during 11-month basic military training. 47 women (23.9 ±2.6 years) completed 3 consecutive 10-d assessments of EEEmvpa, EEEtpa and energy intake (EI). EA measures were compared using linear regression and Bland-Altman analyses; relationships of EA with fat mass, heartrate variability, 1.5-mile run times and BEDA-Q were evaluated using partial correlations. RESULTSEA from EEEmvpa demonstrated strong agreement with EA from EEEtpa across the measurement range (R=0.76, r=0.87, p