Effect of SunGold Kiwifruit and Vitamin C Consumption on Ameliorating Exercise-Induced Stress Response in Women.

Abstract

Markers of oxidative and psychological stress are elevated during high-intensity exercise. Additionally, when energy intake does not match expenditure, women who actively participate in sports and exercise are at risk of developing menstrual dysfunction, infertility, and osteoporosis. Vitamin C is known to reduce exercise-induced stress. Here, this study investigates the efficacy of consuming vitamin C from SunGold kiwifruit compared to in isolation, in ameliorating exercise-induced stress in recreationally active women. Ten eumenorrheic women are recruited in this crossover study and attended three exercise and one rest trial. In the exercise trials, participants consumed 300mg vitamin C from kiwifruit or drink, or have a placebo drink, followed by 30-min exercise on a cycle ergometer at 60% power. During rest visit, participants sat quietly and consumed a placebo drink. Salivary uric acid (oxidative stress) and cortisol (psychological stress) are measured before and immediately after exercise for 2 h. Both vitamin C and kiwifruit reduced exercise-induced uric acid, immediately after exercise. Vitamin C drink continued to decrease uric acid for a further 30 min and slightly attenuated exercise-induced cortisol. Consuming liquid vitamin C prior to high-intensity cycling appears more effective than eating kiwifruit, in ameliorating exercise-induced stress in recreationally active women of reproductive age.