The Science of Canoeing By Richard Cox

More sophisticated electronic devices now exist which can also be used to measure the maximum amount of air
which a subject can ventilate in a unit of time (1)
The blood which passes through the capillaries surrounding the alveoli is forced round the pulmonary
circulatory system by the pumping action of the heart. The heart is divided into two halves, which are separated
by a thick muscular wall. In each side of the heart there is an upper and lower chamber; the top one is called the
atrium and the bottom one the ventricle. Between the atrium and the ventricle there is a valve which ensures that
when the heart muscles contract, blood can only pass in one direction. Blood from the body's general and
systematic
circulatory system enters the right atrium depleted of oxygen. The blood in the right atrium is pushed down into
the right ventricle and in turn is forced round the pulmonary system as the heart contracts and squeezes blood
out of the right ventricle. As the blood passes over the lungs, carbon dioxide is off-loaded (by diffusing through
the alveoli wall) and
(1) Unfortunately, little research has been carried out to determine the vital capacaties of sprint and marathon
paddlers. Sidney and Shephard (1973), however, discovered that there was a significant correlation between
vital capacity and performance in white water racing which one suspects might also be the case in the other
disciplines