TY - JOUR
T1 - Menstrual Disruption with Exercise Is Not Linked to an Energy Availability Threshold
AU - Lieberman, Jay L.
AU - De Souza, Mary Jane
AU - Wagstaff, David A.
AU - Williams, Nancy I.
N1 - Funding Information:
This study was supported by National Institutes of Health Grants: RO1-HD-39245-01 and M01-RR-10732, and the Department of Kinesiology, Women's Health and Exercise Laboratory, Penn State University. The authors declare no conflict of interest and that the results of the study are presented clearly, honestly, and without fabrication, falsification, or inappropriate data manipulation. The results of the present study do not constitute endorsement by ACSM.
Publisher Copyright:
© 2017 by the American College of Sports Medicine.
PY - 2018/3/1
Y1 - 2018/3/1
N2 - Introduction Chronic reductions in energy availability (EA) suppress reproductive function. A particular calculation of EA quantifies the dietary energy remaining after exercise for all physiological functions. Reductions in luteinizing hormone pulse frequency have been demonstrated when EA using this calculation is <30 kcal·kg -1 ·fat-free mass (ffm)·d -1. Purpose We determined whether menstrual disturbances (MD) are induced when EA is <30 kcal·kg -1 ffm·d -1. Methods Thirty-five sedentary, ovulatory women age 18 to 24 yr (weight, 59.0 ± 0.8 kg; body mass index, 21.8 ± 0.4 kg·m -2) completed a diet and exercise intervention over three menstrual cycles. Participants were randomized to groups that varied in the magnitude of negative energy balance created by the combination of exercise and energy restriction. Menstrual disturbances were determined using daily urinary estrone-1-glucuronide and pregnanediol glucuronide, midcycle luteinizing hormone, and menstrual calendars. In a secondary analysis, we calculated EA from energy balance data and tested the association of EA with MD. Results A generalized linear mixed-effects model showed that the likelihood of a MD decreased by 9% for each unit increase in EA (odds ratio, 0.91; 95% confidence interval, 0.84-0.98; P = 0.010). No specific value of EA emerged as a threshold below which MD were induced. When participants were partitioned into EA tertile groups (low EA, 23.4-34.1; n = 11; moderate EA, 34.9-40.7; n = 12, and high EA, 41.2-50.1; n = 12 [kcal·kg -1 ffm·d -1 ]), estrone-1-glucuronide (P < 0.001), pregnanediol glucuronide (P < 0.001), and luteal phase length (P = 0.031) decreased significantly, independent of tertile. Conclusions These findings do not support that a threshold of EA exists below which MD are induced but do suggest that MD increase linearly as EA decreases. Menstrual disturbances can likely be prevented by monitoring EA using a simplified assessment of metabolic status.
AB - Introduction Chronic reductions in energy availability (EA) suppress reproductive function. A particular calculation of EA quantifies the dietary energy remaining after exercise for all physiological functions. Reductions in luteinizing hormone pulse frequency have been demonstrated when EA using this calculation is <30 kcal·kg -1 ·fat-free mass (ffm)·d -1. Purpose We determined whether menstrual disturbances (MD) are induced when EA is <30 kcal·kg -1 ffm·d -1. Methods Thirty-five sedentary, ovulatory women age 18 to 24 yr (weight, 59.0 ± 0.8 kg; body mass index, 21.8 ± 0.4 kg·m -2) completed a diet and exercise intervention over three menstrual cycles. Participants were randomized to groups that varied in the magnitude of negative energy balance created by the combination of exercise and energy restriction. Menstrual disturbances were determined using daily urinary estrone-1-glucuronide and pregnanediol glucuronide, midcycle luteinizing hormone, and menstrual calendars. In a secondary analysis, we calculated EA from energy balance data and tested the association of EA with MD. Results A generalized linear mixed-effects model showed that the likelihood of a MD decreased by 9% for each unit increase in EA (odds ratio, 0.91; 95% confidence interval, 0.84-0.98; P = 0.010). No specific value of EA emerged as a threshold below which MD were induced. When participants were partitioned into EA tertile groups (low EA, 23.4-34.1; n = 11; moderate EA, 34.9-40.7; n = 12, and high EA, 41.2-50.1; n = 12 [kcal·kg -1 ffm·d -1 ]), estrone-1-glucuronide (P < 0.001), pregnanediol glucuronide (P < 0.001), and luteal phase length (P = 0.031) decreased significantly, independent of tertile. Conclusions These findings do not support that a threshold of EA exists below which MD are induced but do suggest that MD increase linearly as EA decreases. Menstrual disturbances can likely be prevented by monitoring EA using a simplified assessment of metabolic status.
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U2 - 10.1249/MSS.0000000000001451
DO - 10.1249/MSS.0000000000001451
M3 - Article
C2 - 29023359
AN - SCOPUS:85042365452
SN - 0195-9131
VL - 50
SP - 551
EP - 561
JO - Medicine and science in sports and exercise
JF - Medicine and science in sports and exercise
IS - 3
ER -