There are two forms of scleroderma: localized scleroderma (primarily affects the skin, most common form found in children) and systemic sclerosis (a chronic, degenerative disease rarely seen in children). Linear scleroderma is a progressive loss of subcutaneous fat with pigment changes in the skin.
We assume that the person described here starts the work period eagerly, using stored glycogen at the beginning of the work session. Muscle glycogen remains is the major source of energy during the first half-hour. After this period we see that fatty acids and blood glucose takes over as important energy sources.
During exercise, the body will then utilize the individual sugar molecules in the carbohydrates to provide energy for your muscles and brain. Once you run out of sugar (or the form that humans store it in, glycogen) your body turns to the other fuel sources, namely, protein and fat.