title: Active women before/after an intervention designed to restore menstrual function: resting metabolic rate and comparison of four methods to quantify energy expenditure and energy availability.
abstract: It is hypothesized that exercise-related menstrual dysfunction (ExMD) results from low energy availability (EA), defined as energy intake (EI)--exercise energy expenditure (EEE). When EI is too low, resting metabolic rate (RMR) may be reduced to conserve energy.
  
  
  OBJECTIVE
  To measure changes in RMR and EA, using four methods to quantify EEE, before/after a 6-month diet intervention aimed at restoring menses in women with ExMD; eumenorrheic (Eumen) active controls (n = 9) were also measured.
  
  
  METHODS
  Active women with ExMD (n = 8) consumed +360 kcal/d (supplement) for 6 months; RMR was measured 2 times at 0 months/6 months. EI and total energy expenditure (TEE) were estimated using 7-day diet/activity records, with EA assessed using four methods to quantify EEE.
  
  
  RESULTS
  At baseline, groups did not differ for age, gynecological age, body weight, lean/fat mass, VO₂max, EI and EA, but mean TEE was higher in ExMD (58.3 ± 4.4 kcal/ kgFFM/d; Eumen = 50.6 ± 2.4; p < .001) and energy balance (EB) more negative (-10.3 ± 6.9 kcal/kgFFM/d; Eumen=-3.0 ± 9.7; p = .049). RMR was higher in ExMD (31.3 ± 1.8 kcal/kgFFM/d) vs. Eumen (29.1 ± 1.9; p < .02). The intervention increased weight (1.6 ± 2.0 kg; p = .029), but there were no significant changes in EA (0-month range = 28.2-36.7 kcal/kgFFM/d; 6-month range = 30.0-45.4; p > .05), EB (6 months = -0.7 ± 15.1 kcal/kgFFM/d) or RMR (0 months = 1515 ± 142; 6 months = 1522 ± 134 kcal/d). Assessment of EA varied dramatically (~30%) by method used.
  
  
  CONCLUSIONS
  For the ExMD group, EI and weight increased with +360 kcal/d for 6 months, but there were no significant changes in EB, EA or RMR. No threshold EA value was associated with ExMD. Future research should include TEE, EB and clearly quantifying EEE (e.g.,>4 MET) if EA is measured.
authors.affiliation: School of Biological and Population Health Sciences, Oregon State University, Corvallis, OR.
authors.forename: Charlotte P
authors.initials: CP
authors.lastname: Guebels
authors.forename: Lynn C
authors.initials: LC
authors.lastname: Kam
authors.forename: Gianni F
authors.initials: GF
authors.lastname: Maddalozzo
authors.forename: Melinda M
authors.initials: MM
authors.lastname: Manore
mesh_terms: D000328:Adult; D001481:Basal Metabolism; D001835:Body Weight; D015930:Diet Records; D002149:Energy Intake; D004734:Energy Metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008598:Menstruation; D008599:Menstruation Disturbances / Q000178:diet therapy / Q000209:etiology; D055815:Young Adult