Temporal and Dose-response Effects of Nicotinamide Riboside Supplementation on Metabolic Flexibility During Zone 2 Training in Adults: A Double-blinded, Randomized, Controlled, Crossover Trial

What this Trial Is About

Researchers are investigating how nicotinamide riboside (NR) supplementation affects metabolic flexibility and exercise performance during Zone 2 cycling training in healthy adults. Zone 2 training is a low-intensity endurance exercise performed near the first ventilatory threshold that improves aerobic capacity, fat metabolism, and mitochondrial efficiency. This study seeks to clarify potential interactions between NR, a dietary supplement involved in cellular energy metabolism, and this type of endurance training. Participants will undergo a double-blinded, randomized, controlled, crossover trial comparing different doses of NR supplementation—600 mg, 300 mg, and no supplementation—during Zone 2 cycling training. The intervention lasts four weeks, focusing on the temporal and dose-dependent effects of NR combined with exercise. The study evaluates how NR supplementation influences substrate utilization, energy production, and fatigue resistance during low-intensity endurance training. Throughout the trial, researchers will monitor participants' substrate use (carbohydrate and fat oxidation rates), oxygen consumption, heart rate, blood glucose and lactate levels, peak and mean power output, perceived exertion, muscle pain, and muscle fatigue from enrollment through the four-week treatment. This comprehensive assessment aims to measure metabolic flexibility and exercise performance changes related to NR supplementation and Zone 2 training in adults aged 18 to 80 years.

Effects of NR Supplementation on Metabolic Flexibility in Zone 2 Training