How specific foods reshape oxidative stress responses during and after high-intensity training

By Dr. Sanchari Sinha Dutta, Ph.D.Reviewed by Lauren HardakerDec 11 2025

A new randomized trial reveals how simple food choices before and after fasted HIIT can shift the body’s oxidative stress and recovery patterns, offering practical guidance for tailoring nutrient timing to support training goals.

Study: Acute Impact of Polyphenol-Rich vs. Carbohydrate-Rich Foods and Beverages on Exercise-Induced ROS and FRAP in Healthy Sedentary Female Adults - A Randomized Controlled Trial. Image Credit: Improvisor / Shutterstock

University of Vienna researchers recently conducted a randomized controlled trial to compare the efficacy of polyphenol-rich foods and carbohydrate-rich foods in mitigating oxidative stress during exercise. The findings, published in the journal Antioxidants, highlighted the benefits of carbohydrates during exercise and of polyphenols during recovery under fasted, high-intensity conditions, and in a sedentary female population.

ROS Dynamics During Intense Exercise

Exercise-induced oxidative stress is a well-established condition in sports. Reactive oxygen species (ROS) produced during exercise have both beneficial and detrimental effects, depending on their concentration and timing.

Excessive ROS production is associated with impaired muscle contraction, poor recovery, and muscle soreness. Chronic exposure to ROS increases the risk of various diseases, including cardiovascular disease, diabetes, and age-related pathologies.

Physiological levels of ROS, on the other hand, play vital roles in strengthening muscle and improving antioxidant defense mechanisms. This dual role of ROS highlights the existence of an optimal physiological state in which moderate levels of oxidative stress and inflammation optimize exercise performance and recovery.

Diet plays an essential role in modulating exercise-induced oxidative stress. Carbohydrates may attenuate oxidative stress by reducing physiological stress and inflammatory responses rather than directly scavenging ROS in vivo, although glucose and sucrose have shown radical-scavenging properties in vitro.

Polyphenols, a diverse group of plant-derived compounds, have gained significant attention in medical science due to their potent antioxidant and anti-inflammatory properties. Polyphenol-enriched whole foods have shown significantly greater physiological relevance in mitigating oxidative stress than conventional high-dose vitamin supplements, as vitamins at higher concentrations have been found to suppress the body’s internal antioxidant defense system.

To provide a comprehensive overview of the impact of dietary interventions on exercise-induced oxidative stress, researchers at the University of Vienna designed a randomized controlled trial to investigate the efficacy of carbohydrate- and polyphenol-rich foods in mitigating oxidative stress during resistance-circuit high-intensity interval training.

Randomized Trial Design and Protocol

This randomized controlled trial initially randomized 45 women, of whom 30 completed the full protocol, comprising healthy, sedentary females aged 19 to 33 years. Four types of foods were analyzed in the study, including two polyphenol-rich foods (pomegranate juice and blueberries) and two carbohydrate-rich foods (whole-grain bread and bread roll).

The participants were randomly assigned to two study arms: one included blueberries, whole-grain bread, and bread rolls, and the other included pomegranate juice. Within each study arm, participants randomly consumed each of the included foods after a 12-hour fast, with a washout period of at least seven days between intervention days. In both study arms, water intake served as a control condition.

On each intervention day, participants performed the resistance training, and blood samples were collected at baseline, immediately before training, immediately after training, and 15 minutes after training. The samples were analyzed to measure ROS (electron paramagnetic resonance spectroscopy) and total antioxidant capacity (ferric reducing ability of plasma assay, FRAP).

Carbohydrates Reduce Acute Oxidative Stress

The analysis of control group participants (water intake) revealed a clear induction in ROS levels and total antioxidant capacity following the training session. However, the magnitude of these changes was modest and subject to inter-individual variability, indicating a considerable physiological stress response.

The analysis of intervention group participants revealed that intake of carbohydrate-rich foods significantly attenuated the training-induced elevation in total antioxidant capacity and showed a non-significant trend toward attenuating the training-induced elevation in ROS levels, compared with intake of polyphenol-rich foods or water. These observations highlight a protective role of carbohydrates against oxidative stress, primarily through effects on FRAP rather than consistent significant effects on ROS.

Regarding the intake of polyphenol-rich foods, the study found significant efficacy in enhancing recovery after training. Compared with carbohydrate intake, polyphenol intake significantly reduced ROS levels during the post-exercise recovery period, although no significant differences relative to water were observed.

Regarding total antioxidant capacity, a continuous increase was observed during the recovery period, reflecting the impact of high-intensity training sessions, with no significant differences between the intervention foods during recovery and with changes reflecting redox-system kinetics rather than enhanced antioxidant capacity.

Nutritional Strategies for Exercise Recovery

The study highlights the protective efficacy of carbohydrates against exercise-induced oxidative stress and the efficacy of polyphenols in accelerating post-exercise normalization of ROS levels.

The observed benefit of polyphenol intake is particularly significant, as chronic exposure to oxidative stress is associated with impaired recovery, reduced muscle function, and increased risk of tissue damage.

The observed benefit of carbohydrate intake may reflect the fact that sufficient carbohydrate availability reduces exercise-induced oxidative stress by lowering reliance on fat oxidation and minimizing mitochondrial ROS production.

These effects are particularly relevant during endurance exercise, where carbohydrates mitigate cumulative oxidative stress responses from repeated sessions and sustain performance. However, over-suppression of ROS production may impair training adaptations such as muscle strengthening, highlighting the importance of dosage in carbohydrate strategies.

Overall, this study provides valuable information for both athletes and coaches to optimize their performance and training adaptations through nutrition, although the findings should be interpreted cautiously, given that the study population consisted of sedentary young women, the intervention assessed acute, single-session effects, and the fasted-state high-intensity interval training (HIIT) protocol does not fully reflect typical training environments.

Given the findings, researchers suggest integrating polyphenol-rich foods in meals consumed before and after training sessions. Regarding carbohydrate-rich foods, they emphasize personalized approaches based on training intensity, duration, and energy demands, while acknowledging that performance impacts were not directly measured in this trial.