“The Heart is not a Machine”

At one of the GS forums I came across a link (http://www.roller.ru/content/cat-181/article-1495.html) with the discussion of an interesting book by Victor Seluyanov. The title of the book in question is “Preparation of Middle Distance Runner”. The author is a serious PhD coach with more than 100 publications in peer reviewed journals. Mathematical modeling is one of author’s interests, and one chapter of his book is devoted to the discussion of processes that happen in the heart during training. The link refers to the discussion of the book between two commentators, a doctor and a cross-country skier, and covers many topics, such as training regimes for different muscle fibers, assessing muscle composition and other complicated stuff. This post borrows the title from the part of the discussion that is dedicated to the adaptation processes in the hearts of middle runners. I am going to summarize it here.

What is happening to the heart during training? It is important to understand that the heart is not a mechanical machine and it is relatively easy to damage it by training incorrectly. The main effect of training on the heart is the increase in minute volume, the amount of blood the heart is able to pump in a minute. The heart gets larger, or develops hypertrophy. There are two types of cardiac hypertrophy: L-type, when the heart muscle stretches, its muscle fibers get longer and the volume of the heart increases; and D-type, when the thickness of the heart wall increases, therefore increasing the strength of contraction.

In order to increase the volume of the heart they use training at heart rates corresponding to the maximal stroke volume. Just as the reminder, stroke volume is the volume of blood expelled by the heart during one contraction. Usually stroke volume sharply increases at HR of 100/min, at 120 increases more and in some individuals still increases until HR of 150. Prolonged training at maximal stroke volume is, figuratively speaking, “stretching exercise” for the heart. Muscles pump the blood, and the heart get stretched by the increased flow. As the consequence the heart dilates. It is possible to double its size, and 30-40% is almost a guarantee. That’s what is meant by coaches when they say “building the base”; it is, in fact, stretching of the heart.

D-type hypertrophy is stimulated by the work at heart rates close to maximal – 180.min and higher. Again, a little reminder of physiology. The heart is the muscle and therefore needs the blood in order to contract. The blood is delivered to it mostly during diastole, or relaxation phase. When working at maximal heart rate, the heart does not fully relax, and the blood supply is impaired to some degree. What follows is the accumulation of acidic substances leading to acidosis which, in turn, stimulates growth of the heart muscle. This is typical interval training, the rave of the fitness crowd in recent years. The problem starts when this kind of training is done too often. If the heart does not relax, its blood supply is impaired, the delivery of oxygen becomes inadequate and anaerobic glycolysis starts. As the results lactic acid is produced and leads to the acidosis inside the cell. If it lasts long enough, some cellular structures die. And if it lasts some more, the whole myocardiocytes – heart muscle cells – can die. This is microinfarction. If the training of this intensity is repeated again and again, more cells die and are replaced with the connective tissue which, in turn, is poorly distensible and does not properly conduct electric impulses necessary for adequate cardiac contraction. Apparently this has been confirmed by autopsies of athletes who suddenly died during physical activity.

That is why it is important to first build the base – dilate the heart – and only then increase intensity. Working at heart rates close to maximal must be introduced gradually and done infrequently, especially at the early stages of training.

This also brings us to the topic of recovery and frequency of training. If your muscles are sore after a workout, you take a day or two off and allow them to recover, to heal. Why should the heart be different? Adaptation takes days and the heart muscle needs rest in order for these processes to take place.

This is not just a theory. Every year you hear of a few athletes dying as the result of sports activity, both professional and amateur. This year a 27 year old man died during City to Surf race in Sydney, the run only 14 km long. Did he have some undiagnosed cardiac condition? It is possible. But it is also possible that his heart was damaged by overzealous training.

Does any of this apply to GS? I think it does. GS is primarily an endurance activity with the intensity on top of it, and its effects are very demanding on the recovery ability of the body. Both snatches and jerks done at high tempo for prolonged period of time shoots the heart rate close to the maximum. I am not aware of any studies on the volume of the heart in gireviks, but would expect them to have hypertrophy of various degrees. So it would make sense to regularly do some aerobic activity: running, swimming, cycling, playing soccer etc., just as Russians recommend. Also, as it follows from the earlier post, intensity is the amount of weight lifted per minute. If you agree with this statement you would also agree that doing longer sets means increasing intensity. Higher intensity leads to higher heart rate. From the info above it would follow that doing it too often is “ne harasho”, not good.

It was suggested by Andrey at IGX that monitoring the heart rate may be useful in order to gauge the intensity. After reading the discussion above it seems like a good idea. For some of us five minute set of 2 x 24 kg jerks is no big deal, whereas for some it is, and heart rate can give an indication of the relative intensity. Of course, as pointed out by some, wearing heart rate monitor during the set of snatches or jerks is impractical. But at least it can be checked at the end of the set in order to make sure that it does not go too high too often.