Objectives. This study investigated the effect of 7 days’ supplementation with New Zealand blackcurrant extract on thermoregulation and substrate metabolism during running in the heat. Design. Randomized, double-blind, cross-over study. Methods. Twelve men and six women (mean ± SD: Age 27 ± 6 years, height 1.76 ± 0.10 m, mass 74 ± 12 kg, V˙ O2max 53.4 ± 7.0 mL kg−1 min−1) completed one assessment of maximal aerobic capacity and one familiarisation trial (18 ◦C, 40% relative humidity, RH), before ingesting 2 × 300 mg day−1 capsules of CurraNZTM (each containing 105 mg anthocyanin) or a visually matched placebo (2 × 300 mg microcrystalline cellulose M102) for 7days (washout 14 days). On day 7 of each supplementation period, participants completed 60 min of fasted running at 65% V˙ O2max in hot ambient conditions (34 ◦C and 40% relative humidity). Results: Carbohydrate oxidation was decreased in the NZBC trial [by 0.24 g min−1 (95% CI: 0.21–0.27 g min-1)] compared to placebo (p = 0.014, d = 0.46), and fat oxidation was increased in the NZBC trial [by 0.12 g min−1 (95% CI: 0.10 to 0.15 g min−1)], compared to placebo (p = 0.008, d = 0.57). NZBC did not influence heart rate (p = 0.963), rectal temperature (p = 0.380), skin temperature (p = 0.955), body temperature (p = 0.214) or physiological strain index (p = 0.705) during exercise. Conclusions. Seven-days intake of 600 mg NZBC extract increased fat oxidation without influencing cardiorespiratory or thermoregulatory variables during prolonged moderate intensity running in hot conditions.
Hiles, Ania M.Flood, Tessa R.Lee, Ben J.Wheeler, Lucy E.V.Costello, Rianne Walker, Ella F.Ashdown, Kimberly M.Kuennen, Matthew R.Willems, Mark E.T.
Department of Sport, Health Sciences and Social Work
Year of publication: 2020Date of RADAR deposit: 2020-04-03