Physical training for an Ironman provides physiological and metabolic adaptations to complete 3.8 km swimming, 180 km cycling and 42.2 km running. PURPOSE: We examined effects of acute intake of New Zealand blackcurrant extract (420 mg anthocyanins) on physiological and metabolic responses during 4 hours of cycling in a male amateur Ironman athlete (age: 49 yrs, BMI: 24.3 kg·m-2, body fat%: 13.5%, V ̇O2max: 58.6 mL·kg-1·min-1, maximal aerobic power: 400 W, OBLA (4 mmol·L-1): 289 W, history: 14 Ironmans in 16 years) three weeks before competition. METHODS: Indirect calorimetry was used and heart rate recorded at 30-min intervals during 4 hours indoor (~22.4°C, relative humidity: ~55%) constant power (165 W) cycling on a Trek Speed Concept connected to a Kickr smart trainer. Blood lactate and RPE were taken at 60-min intervals. Study was single-blind placebo-controlled with a breakfast 3 hours and capsules taken 2 hours before cycling. Participant was allowed water ad libitum and had consumption of gels [8 of which 3 with caffeine (100 mg)], two bananas and electrolyte (sodium and potassium) capsules. RESULTS: With NZBC extract, during 4 hours of cycling (mean of 8 measurements), minute ventilation was 8% lower (PL: 60.0±4.1, NZBC: 55.2±1.6 L·min-1, P<0.001). There was no difference for oxygen uptake (PL: 2.54±0.07, NZBC: 2.49±0.08 L·min-1, P=0.111). Carbon dioxide production was 4% lower (PL: 2.24±0.07, NZBC: 2.15±0.07 L·min-1, P=0.027). Heart rate was 10 beats·min-1 lower (PL: 140±11, NZBC: 130±6 beats·min-1, P=0.001). Lactate was 40% different with lower lactate at 2, 3 and 4 hours. RPE was lower at 2, 3 and 4 hours. Carbohydrate oxidation was 11% lower (PL: 2.04±0.17, NZBC: 1.80±0.13 g·min-1, P=0.025). Fat oxidation may have been higher by 13% (PL: 0.50±0.06, NZBC: 0.56±0.05 g·min-1, P=0.096). RER was 0.02 units lower (PL: 0.88±0.01, NZBC: 0.86±0.01, P=0.042). CONCLUSION: Acute intake of New Zealand blackcurrant extract (420 mg anthocyanins) provided beneficial physiological and metabolic responses during 4 hours of indoor constant-power cycling in a male Ironman athlete 3 weeks before competition. Future work may address whether acute and chronic dosing strategies with New Zealand blackcurrant provide a nutritional ergogenic effect for Ironman athletes to enhance swimming, cycling and running performance.

Supplements were provided by Health Currancy Ltd (UK). Blackcurrant New Zealand Inc (NZ) and Health Currancy Ltd (UK) provided funding for conference attendance.