The effects of acute nicotinamide riboside supplementation on substrate utilisation and 5km time-trial performance

Nicotinamide Riboside (NR) administration has been shown to increase fat oxidation and improve endurance performance in rodents, whilst recent research has proven it is safe for human consumption. The present study aimed to investigate the influence of acute NR supplementation on substrate utilisation and exercise performance in humans. In this counter-balanced, crossover design study, eleven recreationally-active males performed a 60-minute bout of cycling at 55% VO\\(_2\\)\\(_m\\)\\(_a\\)\\(_x\\), followed by a 5km time-trial. Participants completed this twice during visits separated by at least one week, once following the consumption of 1000mg NR, and the other following placebo consumption. The contribution of fat oxidation to total substrate utilisation was not significantly different between the NR and placebo conditions during steady-state exercise (22.3±9.0% and 19.6±7.3%, respectively; p < 0.05). Similarly, there were no significant differences shown between 5km time-trial performance with NR (823.4±250.0 seconds) and placebo (819.5±239.8 seconds). To conclude, a single dose of NR does not influence substrate utilisation during moderate-intensity exercise, nor does it enhance exercise performance. Future research should investigate the effects of chronic NR supplementation, or the coupling of this with exercise training to further test the capacity of NR in humans during exercise.