Low energy availability in recreational high-intensity functional training athletes: associations with health and performance outcomes
- 1Athletic Training Research Lab, Department of Exercise Science, University of South Carolina, Columbia, SC, United States
- 2Department of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC, United States
Abstract
IntroductionLow energy availability (LEA) is the primary etiological factor underlying Relative Energy Deficiency in Sport (RED-S), yet limited research has examined LEA risk and associated health and performance outcomes in recreational high-intensity functional training (HIFT) athletes. The purpose of this study was to evaluate energy availability (EA) and physiological outcomes aligned with the RED-S Health and Performance Models in a recreational HIFT cohort.MethodsThirty participants (females: n = 18, males: n = 12; 31.2 ± 8.2 years) completed a two-week prospective observational study with repeated measures of energy intake, exercise energy expenditure, and associated health and performance-related measures. Energy intake was assessed via dietary logs, exercise energy expenditure was estimated using a wearable armband, and EA was calculated relative to dual-energy X-ray absorptiometry–derived fat-free mass. Participants were classified as LEA if EA was <30 kcal·kg−1 FFM·day−1. Performance-related outcomes included rating of perceived exertion (RPE), perceived recovery status (PRS), and total quality recovery (TQR). Health-related outcomes included sleep duration, Pittsburgh Sleep Quality Index (PSQI), and bone mineral density (BMD) (reported by Z-Score).ResultsMean EA was 24.9 ± 9.7 kcal·kg−1 FFM·day−1, with 80% (n = 24) of participants demonstrating EA below the LEA classification threshold. The high prevalence of LEA should be interpreted cautiously given the potential for underreporting dietary intake. LEA status was not associated with differences in recovery, sleep quality, or BMD (p > 0.05), and EA was not significantly correlated with performance or health outcomes. In an exploratory analysis, sleep duration was moderately positively associated with TQR (ρ = 0.46, p = 0.01); however, this finding should be interpreted cautiously given the number of comparisons performed.DiscussionDespite the high prevalence of LEA, associated health and performance impairments were not detected, suggesting that measurable consequences of LEA may not be evident over a short observation period in recreational HIFT athletes. These findings support ongoing monitoring of EA, fueling practices, and recovery behaviors to reduce the potential long-term consequences associated with RED-S.
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BibTeX
@article{vlattas2026energy,
title = {{Low energy availability in recreational high-intensity functional training athletes: associations with health and performance outcomes}},
author = {Gabriella Vlattas and Xuewen Wang and Andrew Ortaglia and Siqi Hong and Toni Torres-McGehee},
journal = {Frontiers in Nutrition},
year = {2026},
month = oct,
doi = {10.3389/fnut.2026.1953641},
url = {https://doi.org/10.3389/fnut.2026.1953641},
note = {CC BY},
}
RIS
TY - JOUR
TI - Low energy availability in recreational high-intensity functional training athletes: associations with health and performance outcomes
AU - Gabriella Vlattas
AU - Xuewen Wang
AU - Andrew Ortaglia
AU - Siqi Hong
AU - Toni Torres-McGehee
PY - 2026
DA - 2026/10/23
JO - Frontiers in Nutrition
DO - 10.3389/fnut.2026.1953641
UR - https://doi.org/10.3389/fnut.2026.1953641
AB - IntroductionLow energy availability (LEA) is the primary etiological factor underlying Relative Energy Deficiency in Sport (RED-S), yet limited research has examined LEA risk and associated health and performance outcomes in recreational high-intensity functional training (HIFT) athletes. The purpose of this study was to evaluate energy availability (EA) and physiological outcomes aligned with the RED-S Health and Performance Models in a recreational HIFT cohort.MethodsThirty participants (females: n = 18, males: n = 12; 31.2 ± 8.2 years) completed a two-week prospective observational study with repeated measures of energy intake, exercise energy expenditure, and associated health and performance-related measures. Energy intake was assessed via dietary logs, exercise energy expenditure was estimated using a wearable armband, and EA was calculated relative to dual-energy X-ray absorptiometry–derived fat-free mass. Participants were classified as LEA if EA was <30 kcal·kg−1 FFM·day−1. Performance-related outcomes included rating of perceived exertion (RPE), perceived recovery status (PRS), and total quality recovery (TQR). Health-related outcomes included sleep duration, Pittsburgh Sleep Quality Index (PSQI), and bone mineral density (BMD) (reported by Z-Score).ResultsMean EA was 24.9 ± 9.7 kcal·kg−1 FFM·day−1, with 80% (n = 24) of participants demonstrating EA below the LEA classification threshold. The high prevalence of LEA should be interpreted cautiously given the potential for underreporting dietary intake. LEA status was not associated with differences in recovery, sleep quality, or BMD (p > 0.05), and EA was not significantly correlated with performance or health outcomes. In an exploratory analysis, sleep duration was moderately positively associated with TQR (ρ = 0.46, p = 0.01); however, this finding should be interpreted cautiously given the number of comparisons performed.DiscussionDespite the high prevalence of LEA, associated health and performance impairments were not detected, suggesting that measurable consequences of LEA may not be evident over a short observation period in recreational HIFT athletes. These findings support ongoing monitoring of EA, fueling practices, and recovery behaviors to reduce the potential long-term consequences associated with RED-S.
SN - 2296-861X
ER -