Prevalence of Surrogate Markers of Relative Energy Deficiency in Male Norwegian Olympic-Level Athletes

Abstract

The syndrome of Relative Energy Deficiency in Sport (RED-S) includes wide-ranging effects on physiological and psychological functioning, performance, and general health. However, RED-S is understudied among male athletes at the highest performance levels. This cross-sectional study aimed to investigate surrogate RED-S markers prevalence in Norwegian male Olympic-level athletes. Athletes (n = 44) aged 24.7 ± 3.8 years, body mass 81.3 ± 15.9 kg, body fat 13.7% ± 5.8%, and training volume 76.1 ± 22.9 hr/month were included. Assessed parameters included resting metabolic rate (RMR), body composition, and bone mineral density by dual-energy X-ray absorptiometry and venous blood variables (testosterone, free triiodothyronine, cortisol, and lipids). Seven athletes (16%) grouped by the presence of low RMR (RMRratio < 0.90) (0.81 ± 0.07 vs. 1.04 ± 0.09, p < .001, effect size 2.6), also showed lower testosterone (12.9 ± 5.3 vs. 19.0 ± 5.3 nmol/L, p = .020) than in normal RMR group. In low RMRratio individuals, prevalence of other RED-S markers (—subclinical—low testosterone, low free triiodothyronine, high cortisol, and elevated low-density lipoprotein) was (N/number of markers): 2/0, 2/1, 2/2, 1/3. Low bone mineral density (z-score < −1) was found in 16% of the athletes, all with normal RMR. Subclinical low testosterone and free triiodothyronine levels were found in nine (25%) and two (5%) athletes, respectively. Subclinical high cortisol was found in 23% of athletes while 34% had elevated low-density lipoprotein cholesterol levels. Seven of 12 athletes with two or more RED-S markers had normal RMR. In conclusion, this study found that multiple RED-S markers also exist in male Olympic-level athletes. This highlights the importance of regular screening of male elite athletes, to ensure early detection and treatment of RED-S.

Dietary Intake, Serum Hormone Concentrations, Amenorrhea and Bone Mineral Density of Physique Athletes and Active Gym Enthusiasts

“…We also found that most of the hormone levels in all individuals were within reference values, and no difference was found in estradiol, testosterone, IGF-1, insulin, leptin, TSH, T4, T3, or cortisol concentrations between physique athletes and gym enthusiasts within sexes. In 10–16% of female athletes, the concentrations of the mentioned hormones were below, while almost 50% had cortisol concentrations above the reference range which, although being higher, agrees with the previous studies in athletes who often have high serum cortisol [ 22 ]. This may be in part due to early sample collection in this study (often at 7–8 am) as serum cortisol is highest in the morning 20–45 min after waking up [ 23 ].…”

Energy expenditure, dietary intake and energy availability in female professional football players

“…This was possible as players completed RMR measurements during the data collection, following the best practice guidelines for RMR measurements,26 as part of a larger project 27. A more thorough methodological description is available elsewhere 28…”

“…27 A more thorough methodological description is available elsewhere. 28 Energy availability EA on match and training days were calculated using the estimated EEE derived by the GPS using the formula (EA = [EI -EEE] / FFM (Fat-free mass)). 29 The estimation of the average EA during the 14 days was calculated using the method described by Morehen et al 11 Specifically, the thermic effect of food (TEF) was assumed to be 10% across individuals, 30 estimating activity EE (AEE) possible through the formula (AEE=TDEE -[RMR+TEF]) and subsequently EA (EA=EI -[AEE/FFM]).…”

Signs of low energy availability in elite male volleyball athletes but no association with risk of bone stress injury and patellar tendinopathy

“…Surrogate markers of LEA were BMD (≤ −1 z ‐score) (Mountjoy et al, 2018), measured:predicted RMR (m:pRMR) (<0.9) (Staal et al, 2018) or measured RMR (≤ 29.0 kcal/kg FFM) (Thompson et al, 1993), LDL cholesterol (>3.0 mmol/L) (Stenqvist et al, 2021), subclinical low fT3 (<3.4 pmol/L), low total‐ (<16.3 nmol/L) or free‐ (<306 pmol/L) testosterone (TES), defined as within the lowest quartile of clinical range, and subclinical high cortisol (>437 nmol/L), defined as within the highest quartile of the clinical range defined by the laboratory. A player with both low total‐ and free‐TES or both low m:pRMR and measured RMR was interpreted as having one surrogate marker to prevent the risk of double counting and over‐estimating the total number of LEA surrogate markers per athlete.…”

“…LEA has been reported in Olympic‐level male athletes competing in endurance, lean and weight‐category sports (Heikura et al, 2018; Stenqvist et al, 2021). However, there is a paucity of information on athletes playing elite team sports.…”