An understanding of exercise physiology basics is necessary for all RDNs interested in sports nutrition to understand the sports nutrition specific guidelines and their effects on performance.
Exercise results in increased skeletal muscle ATP demand, and the cardiovascular and respiratory systems work in a coordinated fashion to deliver oxygen and nutrients to the working skeletal muscle.
The key nutrients providing energy during exercise are carbohydrate and fat. Carbohydrate can provide ATP via both anaerobic and aerobic metabolism, but fat can only be fully oxidized aerobically.
At all times, the body is using a mixture of carbohydrate and fat. As exercise intensity increases, there is an increased reliance on carbohydrate for fuel (crossover concept). Carbohydrate is a more oxygen-efficient fuel and can produce ATP quickly.
Short-term or metabolic fatigue is a result of reliance on anaerobic metabolism under high exercise intensities. Long-term or substrate fatigue is a result of glycogen depletion.
Sound training results in physiological adaptations that improve performance. There are several principles of training that should be considered.
RDNs should include physical activity in their use of the Nutrition Care Process.
All RDNs interested in sports nutrition should be comfortable discussing the health benefits of exercise and the key principles presented in the federal Physical Activity Guidelines for Americans.
An RDN may or may not have the education and training to conduct fitness assessments and develop exercise prescriptions. If not, the RDN must refer to a qualified exercise professional.