For females this would usually be finished in about 1 hour 15minutes. For males this would be finished in about 1 hour. Olympic distance triathlon (1500m / 40m bike / 10km run) For females this would take about 2 hours 25mins. For males this would take about 2 hours. Half Ironman (1.9km swim / 90km bike / 21km run) Females usually take about 5 hours 30mins.
Zinc. Night blindness may also be the result of a zinc deficiency which reduces the activity of an enzyme that helps the body produce vitamin A (retinol dehydrogenase). Research has shown that taking a zinc supplement is helpful. Healthcare providers often recommend 15 - 30 mg of zinc daily for vision.
Prevalence of vitamin A deficiency. Vitamin A deficiency (VAD) is a lack of vitamin A in humans. It is common in poorer countries but rarely seen in more developed countries. Nyctalopia (night blindness) is one of the first signs of VAD.pproximately 250,000 to 500,000 malnourished children in the developing world go blind each year from a deficiency of vitamin A, approximately half of whom die within a year of becoming blind. The United Nations Special Session on Children in 2002 set a goal of the elimination of VAD by 2010.