Document Type : Research Paper I Open Access I Released under (CC BY-NC) license
Authors
Department of Sport Sciences and Wellness, Tarbiat Modares University, Faculty of Humanities, Tarbiat Modares University
Abstract
Objective: To examine the effect of acute NZBC supplementation on FATox during submaximal running and identify individual response patterns.
Methodology: Twenty-one trained male endurance runners (age: 34±7 years; V̇O₂max: 51.6±8.0 mL·kg⁻¹·min⁻¹) participated in a randomized, double-blind, crossover study. Participants completed four separate sessions with 4–8 days between visits, consuming either 1200 mg NZBC (containing 420 mg anthocyanins) or placebo 2 h before each session, with each participant completing two NZBC and two placebo sessions. In each session, following a warm-up, participants ran at 50% of vV̇O₂max on treadmill, and respiratory gases, FATox, and carbohydrate oxidation were measured via indirect calorimetry. Group-level outcomes were analyzed using two-way repeated-measures ANOVA, and individual-level outcomes were assessed using the smallest worthwhile change (SWC).
Results: Group-level analysis revealed that acute NZBC supplementation did not significantly alter any respiratory variable, heart rate, rating of perceived exertion, FATox, or carbohydrate oxidation compared to placebo (p>0.05). Pooled mean FATox was 0.34±0.11 and 0.35±0.10 g·min⁻¹ in the NZBC and placebo conditions, respectively (p=0.14). Nevertheless, considerable inter-individual variability was observed: FATox increased in both trials in 23.81% of participants (responders), decreased in both trials in 28.57% (negative responders), and 47.62% showed an inconsistent response between trials and were classified as non-responders.
Conclusion: Acute NZBC supplementation did not significantly alter FATox during submaximal running at the group level; however, substantial individual variability in FATox response was observed. Future studies should identify predictive factors to lay the groundwork for personalized approaches to NZBC supplementation.
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