S ep tem ber, 1962 P H Y S I O T H E R A P Y Page 3 THE SIGNIFICANCE OF PHYSICAL EDUCATION IN HUMAN HEALTH AND FITNESS By PRIV .-D O Z. D r . M ED . W. H O L L M A N , Leiter des Institutes fur Kreislausforschung und Sportmedizin, Med. Unv.—K linik, K oln West. Germany. Sacharzt siir [nnere K rankheiten. Address given at the Congress for Physical Fitness, Pretoria, 1961. Published by Vigor, M arch, 1962. We are living in an age o f technology. This is a mixed blessing, since it has brou gh t advantages as well as dis­ advantages. A m ongst the latter, there are the diseases arising from lack o f exercise. They have been given the medical term o f “ hypokinetosis” . As a result o f o u r com fortable mode o f living, o u r bodies are n o t subjected to sufficient physical strain. Hence, trophic processes m ay develop which, at first, may mean no m ore th an a reduction o f physical capacity. L ater on, however, functional and regulatory disturbances will result, which finally will lead to perm anent damage to the organs. There is no m ethod o f prophylaxis other than to restore norm al physical activity. This is also true likewise for functional disturbances and reduction o f capacity. These conditions m ay be cured by occupational therapy and by rehabilitation. A t present, internal medicine is faced w ith tw o m ajor problems: the struggle against cancer, and against the diseases o f the h eart and circulation. In the western civilisa­ tion, cardiac and circulatory diseases have become Public Enemy N um ber One. It is no t the inflam m atory conditions which are p re ­ dom inant in this field, as was the case only 30 years ago, but the functional disturbances which, a t a later period, lead to organic diseases. W hen once organic damage has devel­ oped, the physician can do no m ore than give sym ptom atic treatm ent. As yet, there are no drugs by means o f which organic damage may be cured. F o r this reason, prophylaxis is the aim o f internal medicine, i.e., the endeavour to avoid, from the beginning, the developm ent o f cardiac and circu­ latory disturbances. This m ay be achieved only by indivi­ dually prescribed occupational therapy. I t is the task o f sports medicine to make a detailed investigation o f occu­ pational therapy and establish the laws accordingly. Sports medicine, therefore, can be regarded as prophylaxis or preventative medicine, the latter being one o f the two pillars o f internal medicine. Physical Training W hat form o f physical training is required for this p u r­ pose? H ere we m ust distinguish between three form s of training: (1) Speed training; (2) Strength tra in in g ; (3) Endurance training. From a medical po in t of view, speed training is o f lesser im portance as it only dem ands co-ordination between the muscular and nervous systems as well as strength in the particular muscle groups. By speed training, we understand sprint training. The factors limiting the achievement in a 100 metre dash, fo r instance, are the trunk-lim b leverage, the co-ordination o f the nervous system and the musculature, the viscosity of the nerve fibres, and the m uscular strength. This training however, does n o t affect the internal organs. Thus, for example, even an Olympic cham pion in sprinting like H ary, shows a h eart volum e barely equal to th a t o f the average trained individual. Strength training, from the medical point o f view, is more interesting, even though its effect is o f no im portance on the internal organs. T he cross-section o f the individual muscle fibre is increased by strength training. However, there is no increase in the number o f muscle fibres. A lthough there is an enlargement o f the muscle fibres, it is im portant to rem em ber th at the blood supply rem ains practically u n ­ changed. T here is no increase in the num ber o f capillaries, and these are the only area o f metabolic exchange. Thus, the passage o f the diffusion o f oxygen on its tran s­ p o rt to each individual muscle fibre is lengthened. The increase in the circumference o f the individual muscle fibre consequently m akes the blood-supply more difficult. This explains the difference in achievement between endurance and strength athletes. T he endurance o f a muscle is p ro p o r­ tionate to its blood supply. T he m ore blood per unit o f time, th at can be supplied to the active muscle, the m ore oxygen thus offered to the cells, the higher the endurance capacity o f the muscle will be. I should like to quote an example: a few years ago, a so-called “ M ister-W orld- com petition” was held at M unich. T he so-called best devel­ oped man in the world was to be elected. The persons chosen were men with exceptionally large muscles, but they could hardly execute norm al movements. I had the opportunity, subsequent to the election, o f examining the first three prize­ winners. They were able to w ork a turn-m ill with a load o f 700 to 800 w att for a period o f one m inute. A well-trained physical education student can, for instance, m anage 300 to 350 w att. These muscle-men, however, were n o t able to endure a load o f 120 w att over a period o f 10 minutes, which can easily be accom plished by any well-trained fem ale student o f physical education. The reason for this discrep­ ancy lies in the fact th a t in strength training, the individual muscle fibres will gain in size, whereas the supplying blood vessels, an d particularly the capillaries, will n o t increase. Such strength training has no effect on the internal organs, and particularly none on the heart. T he size o f this organ rem ains unchanged. A n action which lasts for one m inute only can be perform ed on pure m uscular strength. But when an action lasts longer than three minutes, the limiting factor lies in the heart and blood circulation. This is the reason why the muscle men could perform the extraordinary feat o f strength o f 800 w att p er m inute, bu t were unable to perform the relatively easy work of 120 w atts in 10 minutes. They adm it th a t they exercise each muscle individually. These men can, therefore, be com pared with a m otor-car with too heavy body-w ork. The cylinder-capacity o f its m o to r and the cross section o f its petrol pipes are too small. T he car, therefore, will only develop a m inor capacity. These relations are the sam e in the hum an being. The small cylinder capacity is the heart which has rem ained small, the too narrow petrol pipes are the capillaries which likewise have n o t developed. T heir capacity, therefore, is no t sufficient for offering the necessary am ount o f oxygen to th e w orking muscle. Endurance Training The Heart From a medical p oint o f view, it is only the endurance training which is o f particular interest. Its influence spreads to the most im portant internal organs. First o f all, the heart m ust be mentioned. I t is a well and long-known fact, that in the course of time, large athletic endurance achievements leads to an enlargement o f the heart. In the medical litera­ R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. ) Page 4 P H Y S I O T H E R A P Y September, 1962 ture, this condition has been called the “ athletic heart” or the “ sport h eart” . U ntil only a few years ago, the athletic heart was considered to be a condition with a bad prognosis. It was said to be the result o f a pathological process o f adaptation o f the m yocardium to excessive strain. T he persons concerned were said to have a decreased life expec­ tation. In the last years, however, exam inations using the most m odern scientific methods have taught us th a t th e athletic heart is a completely healthy heart. In an athlete who is working his way up to the world-class in endurance achieve­ ment, a heart o f this size is a basic organic prerequisite. It is com parable to a m otor the piston displacement o f which has been increased, and the capacity thereby has been improved. The developm ent o f the large athletic h eart is brought ab o u t by tw o factors: the increase in the heart muscle, and the increase in the volume o f the heart cavities. The studies conducted by L IN ZB A C H has shown th at the growth o f the heart muscle is a harm onious process. T he individual heart muscle fibres gain both in length and in width. H ow ­ ever, the so-called “ Critical weight” o f 500 gram s o f the heart is never exceeded. The critical weight o f the heart is based on the following conditional factors: for anatom ico- physical reasons which can be m athem atically proved a healthy hum an heart may grow to a weight o f 500 grams w ithout any im pairm ent o f its blood supply. W hen this critical threshold is exceeded, disturbance o f the blood flow autom atically occurs. F o r now, the growth o f the capillaries can no longer keep in step with the growth o f the myo­ cardial fibres. In the past 20 years, we have learned from the autoptic findings in athletes who had been killed in acci­ dents, th at the critical heart weight had never been reached, n o t even in the largest athletic hearts. The average heart- weights ranged from 430 to 450 grams. Moreover, the electrocardiogram s o f star athletes w ith large athletic hearts have never shown sym ptom s suggestive of disturbance in the blood supply. If the contrary were true, these hearts certainly would n o t be able to accomplish such high achieve­ ments. F o r a long tim e, the enlargem ent o f th e heart cavities has been considered as a pathological change. The enlarge­ m ent may arise from a pathological increase o f the pressure w ithin the heart, this is the co-called tonogenic dilatation, o r by a failure o f the heart muscle, this is the so-called myogenic dilatation. By heart-catheterization in star athletes under strain, we have been able to dem onstrate th at neither a tonogenic n o r a myogenic dilatation is present in the athletic heart. Completely norm al pressure values were noted right up to the limit o f physical capacity. Therefore, pathological dilatation o f the heart cavities could reliably be excluded. R E IN D E L L and D E L IU S m ention a regulative form o f dilatation. In all probability, this is a decrease o f physio­ logical n atu re in th e tone o f the heart muscle which gives rise to an enlargem ent o f the interior space o f the heart. T he increase in th e m uscular volume and the enlargement o f the heart cavities enable a large athletic h eart to prom ote a large o u tp u t even against high pressure w ithout having to fall back on its physical reserves. D ue to the large am ount o f blood which can be supplied with each beat, the athletic h eart is able to w ork at a lower rate. The studies conducted by G O L L W IT Z E R M E IE R and American authors, m ore­ over, have shown th a t the oxygen requirem ent o f the m yo­ cardium grows in pro p o rtio n to the beating rate, ap art from the pressure. Thus, a slower beating h eart will work m ore economically. By means o f experiments using h eart catheteri­ zation, we have actually established a m arkedly lower oxygen-requirem ent in the athletic heart. This fact reduces th e danger o f nutritional disturbances occurring under stress. Thus, th e oxygen requirem ent in the athletic heart is reduced by th e bradycardiac action and th e economical regulation. The so-called arteriovenous oxygen difference, i.e., th e difference in the oxygen levels in the arterial and in the venous blood, gives inform ation on the extent o f oxygen utilization. In the resting heart muscle, and under physical strain with a rise o f 12 to 14 volume per cent, the arterio­ venous oxygen difference rem ains alm ost unchanged. If however, in the accom plishm ent o f a certain achievement, the h eart muscle requires less oxygen, a larger oxygen reserve will result. Thus, the so-called coronary reserve increases. Since, according to the investigations carried out by SABISTON and G R E G G , th e blood flow in the myo­ cardium only travels in the diastolic phase, an d since, in the slow-beating trained h eart the diastole is prolonged, there will result in an im provem ent in the blood flow in the trained heart muscle. By means o f the m odern m ethod o f interval training, it is possible to achieve an optim al enlargem ent o f the heart within a period no longer th an six weeks. W hen a trained athlete is put to bed for a fortnight, however, he will loss 200 to 300 ml o f his form er heart volume during this period. The S keletal M uscle System E ndurance training likewise has an effect on the skeletal muscle system. H ere, it is especially capillarization which is im proved. This means a n increase in the num ber and ini the calibre o f the capillaries. An im provem ent in the blood supply, and thus in the oxygen supply o f the muscles will be the result. This is a most im portant factor. H eart, circu­ lation, and respiration are n o t m ore than the servants of metabolism , and it is their task to satisfy the metabolic requirem ents. If, however, th e muscle, due to the improved capillary distribution, is able to withdraw m ore oxygen from the blood stream ing by, this will bring ab o u t a decrease in the dem and on th e heart. Please, let me quote a practical exam ple: in an untrained person, the resting arterio-venous oxygen difference on an average am ounts to 5 per cent, in a trained person, it will am ount to ab o u t 7 to 8 per cent, thus perm itting a reduction o f th e o u tp u t p er m inute o f the heart. The resting o u tp u t per m inute o f the h eart o f an untrained person actually am ounts to 5 litres, as com pared with an o u tp u t o f 3 to 4 litres in an endurance trained athlete. This can be illustrated by the following calculation: the resting h eart o f a poorly trained m an in his thirties has to perform an achievement o f approxim ately 10,300 mkg w ithin 24 hours. W ithin th e same period, the achievement o f the h eart o f an endurance-trained athlete is no m ore than 5,500 to 6,000 mkg. Even if a daily training period o f 2 hours, and an expenditure per hour o f 1,500 mkg is taken as a base, th e perform ance o f the trained heart at work is still lower than th at o f the resting untrained heart. E ndurance training improves th e capillarization b o th o f the skeletal muscles and the m yocardium . This has been clearly dem onstrated by E C K S T E IN in experiments on dogs. Thus, prophylaxis o f myocardial infarction may be exercised by adequate training. The Blood Endurance training likewise m arkedly influences the blood. T he total am o u n t o f blood increases. The maximum increase in the blood hitherto reported in th e medical litera­ tu re is from 5 to 7 litres. A t th e sam e time, there is a rise in the haem oglobin level. The highest rise in haem oglobin hitherto reported was 240 grams. Even m ore significant th an these tw o factors is an o th er sym ptom . D uring physical stress, the blood coagulation time decreases to an extent o f 300 to 400 per cent. W hen pathological alterations o f the walls o f the vessels are present, the form ation o f throm bi m ay easily occur. In an athlete trained fo r endurance, the clotting time is reduced to a much lesser extent. Thus, there will be much less danger o f throm bus form ation under physical stress. H ere, a “ practical anticoagulant therapy” m ay be spoken of. Respiration T he effect o f endurance training on respiration, to o , is clearly dem onstrable. R espiration may be subdivided into three m ain functions: ventilation; diffusion and perfusion. R ep ro du ce d by S ab in et G at ew ay u nd er li ce nc e gr an te d by th e P ub lis he r (d at ed 2 01 3. )