Dysfunction of Nutritive Blood Flow as a Determinant of Anabolic Resistance in Older People

With age, muscles tend to waste at 0.5-1% per year, so that an 80 year old may have only 70% of the muscle possessed at 50. Muscle loss makes it harder to carry out tasks that require strength, keep the body balanced and continue activity for a prolonged period, which together may contribute to a loss of independence and an increased risk of falls. The cause of some of this muscle loss with ageing appears to be a reduction in muscle building in response to food. The known decreased limb blood flow in ageing muscle may go some way to explain this as there may be less nutrient delivery to the muscles. The investigators want to test if the known decrease in limb blood flow with age is matched with a decrease in the proportion of blood being delivered directly to the muscles, rather than fat and connective tissue. If so the investigators expect to see an improvement in the ability of muscles to maintain themselves via better capture of amino acids into protein. The investigators also want to test if 20 weeks resistance exercise training or drinking a cocktail of mixture of high flavanol cocoa (which can increase blood flow) and vitamin C can improve limb blood flow to older muscles and help reduce muscle wasting.