Prevalence of relative energy deficiency in sport among well-trained male Norwegian cyclists and long-distance runners

Abstract

Introduction Relative Energy Deficiency in Sport (RED-S) links low and reduced energy availability (EA) with negative health and performance consequences, though not well investigated in male endurance athletes. The aim of this study was to investigate the prevalence of RED-S and associated health consequences in well-trained male endurance athletes. Methods Forty-one subjects, cyclists (n=21) and runners (n=20) [age: 40 (31-45) years; BMI: 23.5 (21.4-24.0) kg/m2; body-fat: 14.0% (10.0-16.5%); training volume: 12 (9-16) h/week presented as median + interquartile range] were recruited. Protocol included assessment of bone health, body composition, resting metabolic rate (RMR), blood pressure, energy intake, energy expenditure, hormonal biomarkers, blood glucose and lipids. 27 subjects were included in the final analysis. Results Eighteen subjects had reduced EA (<40kcal/kgFFM/day) and showed a trend of lower RMR ratio compared to the optimal EA group (0.83 vs. 0.86, P=0.026). Six subjects had low bone mineral density (BMD), but not related to EA status. The reduced EA group showed a trend of higher BMD in femur (P=0.037), hip (P=0.057), lumbar spine (P=0.01) and total body (P=0.035). No associations between groups were observed in hormonal biomarkers, blood glucose or blood lipids. Conclusion We found high prevalence of reduced EA accompanied by metabolic alterations in this group of well-trained athletes. However, no differences were observed between EA groups in either anthropometric, hormonal biomarkers, blood glucose, blood lipids or BMD. This may indicate that well-trained male endurance athletes are better protected against associations to negative health consequences in combination with reduced EA, compared to female endurance athletes. Keywords Athlete health, bone health, energy availability, hormonal biomarkers, male endurance athletes, resting metabolic rate Due to word limitations in the master thesis, the following will only be present in the article (part 2); results, discussion regarding results and conclusion