Part 1: Proteins - The Role In Exercise

Current understanding of protein dynamics in exercise comes from study that determines protein breakdown through urea excretion.

As exercise progresses, the concentration of blood urea also increase coupled with increase in nitrogen excretion (from protein breakdown) in sweat.

With low carbohydrate (depleted state) intake the amount of nitrogen excreted in sweat is much higher compared to an with high carbohydrate loaded state. Thus carbohydrate is an important protein sparer in exercise as if there is inadequate carbohydrate, the body will breakdown the protein into glucose.

Athletes in protracted and intense training should conserve adequate carbohydrate to conserve muscle protein.

The RDA for protein intake in adults is 0.83g per kg of body mass.

A continuing area of controversy concerns whether the initial increased protein demand when training commences creates a true long-term increase in protein requirement above RDA. A definitive answer is elusive, but protein breakdown above resting levels does occur during intense weights and cardio training to a greater degree than previously thought.It may be only slighly more than sedentary people.

It is recommend that people who train intensely consume between 1.2 and 1.8g of protein per kg of body weight daily. For most there is no need for protein supplements.