AI Article Synopsis

  • The study assessed the impact of 14 days of Low Energy Availability (LEA) versus Optimal Energy Availability (OEA) on trained female endurance athletes, focusing on their metabolism, insulin sensitivity, and exercise performance.
  • Participants followed a controlled diet with specific calorie intakes and maintained their regular training, revealing that LEA negatively impacted a 20-minute endurance performance by about 7.8% while increasing fat utilization.
  • Despite changes in fat metabolism, LEA did not significantly affect glucose control or skeletal muscle oxidative capacity, indicating a need for further research on its long-term effects on training quality and recovery.

Article Abstract

This study investigated the effects of 14 days low energy availability (LEA) versus optimal energy availability (OEA) in endurance-trained females on substrate utilization, insulin sensitivity, and skeletal muscle mitochondrial oxidative capacity; and the impact of metabolic changes on exercise performance. Twelve endurance-trained females (V̇O 55.2 ± 5.1 mL × min × kg) completed two 14-day randomized, blinded, cross-over, controlled dietary interventions: (1) OEA (51.9 ± 2.0 kcal × kg fat-free mass (FFM) × day) and (2) LEA (22.3 ± 1.5 kcal × kg FFM × day), followed by 3 days OEA. Participants maintained their exercise training volume during both interventions (approx. 8 h × week at 79% heart rate max). Skeletal muscle mitochondrial respiratory capacity, glycogen, and maximal activity of CS, HAD, and PFK were unaltered with LEA. 20-min time trial endurance performance was impaired by 7.8% (Δ -16.8 W, 95% CI: -23.3 to -10.4, p < .001) which persisted following 3 days refueling post-LEA (p < .001). Fat utilization was increased post-LEA as evidenced by: (1) 99.4% (p < .001) increase in resting plasma free fatty acids (FFA); (2) 270% (p = .007) larger reduction in FFA in response to acute exercise; and (3) 28.2% (p = .015) increase in resting fat oxidation which persisted during submaximal exercise (p < .001). These responses were reversed with 3 days refueling. Daily glucose control (via CGM), HOMA-IR, HOMA-β, were unaffected by LEA. Skeletal muscle O utilization and carbohydrate availability were not limiting factors for aerobic exercise capacity and performance; therefore, whether LEA per se affects aspects of training quality/recovery requires investigation.

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Source
http://dx.doi.org/10.1096/fj.202401780RDOI Listing

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