88 Fisioterapie, Desember 1983, deeI 39, no 4 excessively high tem peratures. Once this stage is reached, sweating becomes ineffective, the body tem perature rises rapidly and uncontrollably to levels in excess of 42°C, soon the patient becomes confused, loses consciousness, suffers circulatory collapse and dies. P r e m o n ito r y signs in c lu d e in c o h e r e n t sp e e c h , disorientation, an altered gait and staggering. A nhydrosis, i.e. absence o f sweating, is classically described, BUT TH IS M UST NOT BE R ELIED ON TO D IST IN G U ISH HEAT STROKE FROM TH E LESS SE R IO U S HEAT INJURY, HEAT EXHAUSTION, as mild sweating may be present. The blood pressure is m oderately to severely reduced with a tachycardia (pulse 120-140/min) but it may be slower in highly trained athletes. Treatment The body tem perature must be lowered to below 40°C as soon as possible. Massage with wet towels packed with ice is very effective. Once below 40°C cooling may be more passive. Fluid therapy should include glucose and electrolyte solutions, but excessive adm inistration should be avoided to prevent circulatory overload and cerebral oedema. Serum levels o f glucose and electrolytes must be m easured early and thereafter patient closely m onitored in hospital for at least 36 hours. M arathon running D uring steady state exercise at 75% o f m axim um physical work capacity, heat production may reach 1200 K /c a l/h and corresponding rectal tem peratures o f 39 - 41°C. These tem peratures apparently cause no harm . The critical m axim um tem perature appears to be in the vicinity of 42°C M ost cases o f heat stroke occur in novice, overweight undertrained runners taking in too little fluid in long runs such as m arathons. It is, however, vital to realize th at heat stroke may also occur in well trained athletes running relatively short distances such as 5 km when dehydration and fluid replenishm ent play a minimal role. In fact, it is the elite ru n n er running at nearly m axim um energy expenditure who is at greatest risk as his rate o f heat production is so high. H eat stroke may occur w ithin minutes as has been reported in runners who, near the end o f a m arathon (which generally tends to be m id-m orning when the am bient tem perature has started rising), suddenly start speeding up for a fast finish and exceed the capacity o f their bodies to cope with the extra heat produced. Prevention G uidelines for conducting exercise in hot w eather such as m axim um tem peratures an d hum idity permissible, have been established and must be firm ly adhered to. As im portant should be the aw areness by all persons of all the factors involved in exercise in a warm environm ent and the prevention, diagnosis and m anagem ent o f heat injury. PHYSICAL ACTIVITY AND AGING* T. D. N OA K ES M.B. Ch.B. M.D. SUMMARY The effects of exercise on aging are discussed under 4 headings viz. whether there is evidence th a t e x e rc is e m ig h t d e la y a g in g , the physiological and biochemical factors that alter with age, how exercise training influences these factors and ends with advice on how to start exercising at an older age. The author concludes that regular exercise is of great benefit to preserve physical well-being into old age. M etropolitan Sport Science C entre, ! D epartm ent o f Physiology, University o f C ape Town Medical School O bservatory, 7935 •B ased on a lecture delivered at the U C T Summ er School Symposium on The aged in modern society, Jan u ary , 1982. OPSOM MING D ie u itw e fk in g s van o e fe n in g op d ie verouderingsproses word onder 4 hoofde bespreek nl. of oefening die verouderingsproses mag vertraag, die flsiologiese en biochemiese faktore wat met Ouderdom verander, hoe oefening hierdie faktore bei'nvloed en ten sJotte word daar raad gegee hoe om op 'n gevorderde oudenJom met oefening te begin. D ie skrywer kom tot die gevolgtrekkingdatgereelde oefening tot op 'n hoe ouderdom van groot baat sal wees. IN TRO D U C TIO N There are tw o ways to look at aging: T he C anadian hum orist, Stephen Leacock said “ A bout the only thing you can say ab o u t it (age) is, it’s better than being d ead ” . On turning 61, the A m erican Philosopher R alph Waldo Em erson wrote; “ W ithin, I d o not find wrinkles or a used heart, but unspent y o u th ” . 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. ) physiotherapy, D ecem ber 1983, vo! 39, no 4 89 In the context o f physical activity and aging, we believe hat Emerson’s interpretation is the more valuable. F o r there s now good evidence th a t a significant pro p o rtio n o f the ' eing process is not that we wear out (E m erson’s wrinkles or a used heart), but that we m ay be exercising too little (Emerson’s unspent youth). In discussing this topic, consideration will be given to four m ain questions:— 1 Is there any evidence th a t exercise might delay those processes th at cause physical work capacity to deteriorate with age? 2 What are the physiological an d biochemical, factors that alter with age and which explain why our physical abilities deteriorate as we age? 3 How does exercise training influence these factors? 4, How might one start exercising particularly at an older age? 1 E V ID E N C E T H A T R E G U L A R E X E R C IS E REDUCES TH E EFFEC T O F AGE ON PHYSICAL WORK CAPACITY. I Everyone is aw are th at the ability to perform physical work decreases with age. P art o f this deterioration is unquestionably due to the aging process. Yet there is another component o f this process which is usually ignored. F or as people age, they also become less active. Thus at least p a rt of the age-related fall in physical work capacity could be related to inactivity. Evidence for this possibility comes from studies of world long distance running records which show that, RUNNING SPEED AND ENDURANCE DECREASE WITH AGE AGE D.H. Moore, 1975 Fig. I This figure shows the influence o f age on the speeds o f the S m anc* ^ *cm M arathon records. The d ata for the 1975 curve comes from M oore. With age, there is a steady decline in the speed at which either distance can be run. N ote, however, the dram atic improvements th at have occurred in both events in the past 7 years for runners older than 40. These im provem ents can ath1|° St certain|y t>e traced to the rapid grow th o f competitive a hletic opportunities for M aster (over 40) runners which has increased the incentive for older runners to train harder and 0 remain active for longer. over the past five to ten years, the rate o f im provem ent o f the runners 40 years and older greatly exceeds th at o f the younger runners aged between 20 and 30 years (Figure 1). The explanation for this unlikely phenom enon must simply be th a t the grow th o f the Masters athletic movem ent, particularly in the U nited States which provides serious athletic com petition for athletes over 40 years o f age has provided these “ older” runners with an irresistible incentive to perform better. Thus they train h a rd e r and their perform ances must im prove more rapidly than those o f the younger runners who are already trained to their limits. Table I 42 KM MARATHON R unner Age Time Hrs:M in % Fall-off % Fall-off per decade A lberto Salazar 23 2:08 __ __ Jack Foster 40 2:11 2 1 D r. Alex Ratelle 56 2:30 17 6 Clive Davies 62 2:42 27 6 Table 1 shows th at the perform ance o f the w orld’s best 40- year old m arathon ru n n er is less than 2% worse than the worlds best 23 year old runner, and is equivalent to a perform ance d eterioration o f a b o u t 1% per decade. The perform ances o f Dr. Ratelle (56 years old) and Clive Davies (62 years old) suggest th at perform ance then falls off at about 6% per decade. However, it is probable th at this rate of perform ance deterioration exceeds the true rate of biological deterioration because:— 1. The older athletes probably still do not train as hard as they could. N or do they enjoy the financial incentives available to the younger “ a m ateu r” runners. 2. The three top older athletes (Foster, Ratelle and Davies) only began running late in life and their perform ances are probably not equivalent to those th at might have been achieved by athletes who were w orld-record holders in their youth and who continued to com pete until old age. Thus we can safely assume th at the maximum rate of perform ance d eterioration in active persons is a b o u t 6% per decade after age 20. To put this into context, a person able to run 10 miles in 60 m inutes a t age 20, would be able to run the same distance in under 75 m inutes up to his 70th birthday. (It is of interest th at this long-term deterioration over 50 years is of equal m agnitude to th at which would occur in a young athlete who stopped training for a few m onths. T hat is, a 20 year old who runs 10 miles in 60 m inutes when fully-trained would probably run 75 minutes when he had not trained for some m onths. This shows th at the physical deterioration that occurs with age is really not all th a t dram atic). We have th e re fo re e stab lish ed th a t p e rfo rm an ce deteriorates with age, th a t the extent of this deterioration is much less than is generally accepted, an d th a t it is almost certainly reduced by a program m e o f regular exercise th at is m aintained for life. 2. ALTERATIONS IN W H IC H PH Y SIO L O G IC A L AND B IO C H E M IC A L FACTORS CAUSE PHYSICAL WORK CAPACITY TO DETERIORATE WITH AGE 1. Endurance exercise The ability to m aintain a high energy o u tp u t (work rate) for a prolonged period is know n as endurance. E ndurance athletes are those who participate in activities which 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. ) 90 Fisioterapie, Desember 1983, deel 39, no 4 continue fo r prolonged periods o f time (long distance runners, cyclists, rowers, swimmers, etc). The ability to perform endurance-type activities is closely related to the ability to tran sp o rt oxygen via the blood-stream to the working muscles. In the laboratory, we can m easure the maximum ability of the body to tran sp o rt oxygen. This is know n scientifically as the maximum oxygen utilization capacity o r, in scientific sh o rth an d , the V 0 2 max. V 0 2 max is a m easure o f the h e a rt’s ability to pum p sufficient blood_ to the muscles. Top-class endurance athletes have very high V 0 2 max values, which are largely determ ined by genetic factors. H owever V 0 2 max does fall with age (Figure 2) and this probably explains some o f the reduction in endurance capacity that occurs with age (Figure 1). The fall in V 0 2 max probably reflects d eterioration in peak heart function with age. The aged heart has a reduced maxim um heart rate, and a reduced pum ping capacity possibly due to a reduced activity o f the myocardial enzyme myosin A TPase, the enzyme that correlates best with peak heart function. 2. Speed/Strength Reference to Figure 1 shows th at o f the 1975 curves, the upper curve, (the curve describing the relationship between the speed o f the 200 metres world running records and age), falls more steeply with age than does the lower curve (which describes the same relationship, but for the 42-km standard m arathon distance). This suggests that running speed deteriorates more rapidly with age than does endurance. (N ote however th at the 1981 curve fo r the 200 m etres’ records shows a great im provem ent over the 1975 curve so th at the gradient o f fall with age is reduced. This indicates th at once the oldies, like w orld-record holder D r. Fred Reid from Johannesburg, get out and do some training, the true potential of the hum an body becomes apparent!) MAXIMUM OXYGEN UPTAKE DECREASES WITH AGE c E Q) ro Q. c Q) D) > Xo E E xro 10 20 30 40 50 60 Age in years Fig. 2 This figure shows th at maximum oxygen uptake decreases with age. N ote also that females have lower V 0 2 max values than males, A fter M cC ardle, Katch and K atch2. We believe th at speed is determ ined by the type o f fibre th at constitutes the m ajor p ortion o f the appropriate muscles. Muscles are made o f 2 principle fibre types — the red and white muscle fibres. The white fibre has the ability to c ontract rapidly, so they have been called th e fa s t twitch (FT) fibres. The red fibre, on the o th er hand, is a slow twitch (ST) fibre. It is found th at athletes who excel in p articu lar sports have predictable muscle fibre com positions (T able 2) — in general, the faster the athlete, the more fast-tw itch fibres he has. Endurance athletes have a predom inance o f slow-twitch fibres because the ST fibre is designed for endurance, not for speed. Table 2 M U SC LE FIBRE C O M P O S IT IO N O F ATHLETES S port Sprinters S p rin ters/Ju m p ers Weightlifters M iddle distance runners Elite long distance runners Cross-country skiers F rom : N oakes (1979) F T Fibres % ST Fibres 74 61-63 51-56 45-52 12-21 11-18 26 39-37 49-44 55-48 88-79 79-72 Again, it is believed that muscle fibre com position is largely determ ined by hereditary (genetic) factors. Thus, one is born to run fast o r slowly. Age causes a gradual decline in the % and size o f the fast-twitch fibres and this is likely to be the m ajor explanation for the fall o f maximum speed with age. But, again, regular training probably reduces the rate at which this d eterioration occurs (see example of D r. Fred Reid in Figure 1). A nother facto r which may explain why speed falls with age, is th at aging causes a reduction in the rate at which a response is initiated to an incom ing stim ulus. Thus, the aged sprinter responds more slowly to the crack o f the sta rte r’s pistol, and therefore takes longer to get o u t o f his starting blocks! Body com position also tends to alter with age. As we age, we tend to get heavier, and this is solely due to the deposition o f body fat (Figure 3). A final aging problem is th a t recovery from severe exercise or training definitely takes longer as one ages. Thus many athletes com plain th at even in their early 30’s they are unable to recover as quickly after hard training o r com petition, as they had in their twenties. 3. H O W D O E S REGULAR EXERCISE IN FLUENCE T H E SE FACTORS? Exercise has been shown to influence the following aging process:— ix. The rate of training. F urtherm ore V 0 2 max can be dram atically im proved, at any age, by the ap p ro p riate training program m e. P ro fesso r H e rb e rt De V ries3 fro m C alifo rn ia persuaded 112, 70 year old male inm ates o f a “ leisure w orld” retirem ent com m unity, to stop watching television, playing cards and generally acting old, and to s ta rt an exercise program m e. After 12-15 m onths’ exercise, these form er bench-w arm ers had im proved their V 0 2 max values by 20%, an im provem ent equivalent to th at which w ould be expected in untrained 20-year olds. Thus even at 70, the body retains the ability to a d a p t to an exercise program m e. 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. ) physiotherapy, D ecem ber 1983, vol 39, no 4 91 PERCENTAGE BODY FAT INCREASES WITH AGE 30 a>S’ 20H CD C o o 5 CL 10- f t 1— I I l” “ l I I I— I , 1 . 1 _ I— I— I— I— I— 1 ,£> ^ /?> rvO . 0 , 0 fc0 A0 AGE Fig. 3 Percentage body fat increases with age. Note th at females are fatter than males at all ages, and that body fat increases rapidly after age 20 - 30, in both sexes. It is o f interest that most people stop doing meaningful exercise in their twenties. Thus the increase in body fat may be due to too little exercise, rather than too much age. A fter M cA rdle, K atch and K atch2. 2. Body com position. Exercise training probably prevents the accum ulation o f body fat th at norm ally occurs with age (Figure 3). Persons who exercise fo r life m aintain low body fat levels and exercise is one o f the m ost effective ways to lose body fat at any age.4 3. Reaction time. Training improves the reaction time o f the elderly5. 4. De-calcification o f bones. With age, the bones lose their calcium. Regular exercise dram atically reduces the rate o f this calcium loss.6 This is an exceptionally im p o rtan t consideration in view o f the high rate o f bone fractures particularly of the fem oral neck, in the elderly. It is a reasonable assum ption that regular exercise should reduce the likelihood o f age- related fractures in the elderly. 5. Longevity. From a study o f 1712 persons who had lived more than 100 years, E aston7 concluded th a t “ it is no t the rich and great nor those who depend on medicine who become old: but such as use much exercise. F o r an idler never attains a great age.” O ther studies* o f centurions have lead to similar advice. “ To be as much as possible in the open air, and especially in the sunshine, and to take plenty o f exercise, taking special care to breathe deeply and regularly” . These studies only suggest, they do not prove, that regular lifelong exercise may increase longevity. 6. Psychological benefits. Professor H erbert De Vries’s studies,3 noted earlier, also found that when his 70 year old benchw arm ers became athletes, their psychological status im proved as did their interest in life. Readers interested in the psychological benefits that have been ascribed to exercise training are referred elsewhere.9 4. HOW M IG H T ONE START EXERCISING AT AN O LD ER AGE? We have therefore established that exercise is beneficial for virtually all people. But how does one start? A more detailed description, is available elsewhere,10 here only the im p o rtan t principles will be discussed. (a) There are two form s of exercise — dynam ic and static. Dynamic exercise (walking, running, swim ming, cycling, rowing, skipping, squash) improves endurance, whereas static exercise (weight-lifting) improves muscle strength. A lthough endurance training is by far the more im portant, gentle strength training should not be ignored, particularly in the elderly. (b) T raining program m e. To achieve a training effect, the training program m e must be o f the correct intensity, frequency and du ratio n . It must also be specific. (i) Intensity. The exercise intensity can be assessed by measuring heart rate o r by the technique o f perceived exertion . The correct intensity is one at which you are able to hold a conversation (the talk test) and at which you feel completely com fortable. Remem ber th at the key is to train, not to strain. (ii) Frequency. Exercise should be undertaken 3 - 5 times a week. (iii) D uration. This should be for up to 30 minutes a session. The addictive dose is som ew hat longer than 30 minutes. Therefore, to become addicted to exercise one will need to exercise for m ore than 30 minutes at each session. (iv) Specificity. Fitness is specific. R unning makes one fit fo r running, swimming for swimming, and so on. There is little transference of fitness from one sport to another. T hus it is im p o rtan t to choose the appropriate exercise. Finally, it is appropriate to ask w hether there are any dangers. Yes, there are. If the exercise program m e is unnecessarily enthusiastic, musculo-skeletal injury or som ething more serious, including precipitation o f heart attack may very rarely occur. All these problem s are prevented by starting easily and progressing slowly, “ listening to your bod y ” and reporting any sym ptom s th at may develop. M ost older people are wise enough to follow this advice naturally. It is usually only the im petuous middle-aged who ignore such wisdom and get into trouble. A CO N C LU D IN G VIEW The words o f Paavo Nurmi, Olympic cham pion and one o f the greatest athletes o f all time: “ Standing w ater and a man who does not move are the same as death. You have to move. Otherwise, you are bound for the grave!” References 1. M oore, D H . A study o f age group track and field records to relate age and running speed. Nature, 1975; 253: 264-265. 2. M cArdle, W D , K atch, FI. Katch VL. Exercise Physiology (Philadelphia:) Lea and Febiger, 1981. 3. de Vries, HA. Physiological effects o f an exercise training regimen upon men aged 52 to 88. J Geronton 1970; 25: 325-336. 4. Pollock, ML, Miller, HS, Ribisl, PM. Effect o f fitness on aging. Physcn Sports M ed 1978: 6: 45-48. 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. ) 92 Fisioterapie, Desember 1983, deeI 39, no 4 5. Sherw ood, DE. Selder, D J. C ardiorespiratory health, reaction time and aging. M ed S ci Sports 1979: 11: 186- 189. 6. Smith, EL. R eddan, W. Smith, PE. Physical activity and calcium m odalities for bone m ineral increase in aged women. M ed Sci Sports 1981: 13: 60-64. 7. Easton, J. Human Longevity. (L ondon) Salisbury, 1979. 8. L orand, A. Old age deferred. (Philadelphia:) FA Davis, 1911. 9. N oakes, T D . The risks and benefits of jogging. A scientific appraisal. Trans. Coll. M ed SA 1982; 25 (suppl): 176-186. 10. Noakes, T D . Enjoy life through exercise and physical fitness. (Cape Town) M etropolitan Homes T rust Life, 1980. 11. N oakes, T D . Skeletal m uscular ad ap ta tio n to training. In: (The South African Textbook o f Sports Medicine). THE SOUTH AFRICAN SOCIETY OF PHYSIOTHERAPY DIE SUID-AFRIKAANSE FISIOTERAPIE- VERENIGING REPORT N A T IO N A L E X E C U T IV E C O M M IT T E E This C om m ittee has m et twice since the N ational Council Meeting, and will be meeting once more before the end of 1983. Several m atters were referred to the Professional Board for Physiotherapy, which met on 9 A ugust 1983. These m atters were referred by the B oard to the South African Medical and D ental Council, which had not yet m et a t the time at which this report was w ritten. We are still, therefore, aw aiting confirm ation of further adjustm ents to the tariff of fees, as well as answers to queries raised at the N ational Council Meeting. These queries included the allocation of registration fees, the possibility o f inspecting hospitals and o th er clinical facilities, the possibility of altering the name o f the S.A. Medical and D ental Council and several m atters related to physiotherapy assistants. C areer and salary structure The conditions o f the new dispensation are regarded as being far from satisfactory, especially when consideration is given to the salary scales for certain allied professions with sim ilar or even lesser educational qualifications. The N ational Executive C omm ittee is now generating a two­ pronged approach. Firstly a new m em orandum is being prepared, which will have been subm itted by the time this report is published. Secondly an investigation has been initiated in o rd er to establish the long-term physiotherapy needs throughout the Republic. W hen this has been com pleted, a m em orandum stressing the inadequacy of present physiotherapy services will be draw n up. The newly form ed R em uneration C om m ittee, established by Council, will play an im portant role in com piling both these docum ents. The N ational Executive C om m ittee is o f the opinion that th e C o m m iss io n f o r A d m in is tr a tio n has g ro s sly underestim ated the opportunities for physiotherapists in the private sector and that the Comm ission has thus been mislead into offering non-com petitive scales and conditions of service. Objectives of the Society At the 15th N ational Council M eeting two m otions were passed requiring the Society to delineate its objectives fo r the future with a view to long-term planning. It is hoped that the Branches and Special G roups/A ssociations will rise to this challenge and subm it their ideas. The future o f the Society is | the concern o f each one of its m em bers, not only the mem bers of the N ational Executive Com m ittee. The scope of physiotherapy This is being revised and updated, and once again contributions have been requested from the Branches and the Special G roups/A ssociations. It is disturbing to note th at the Scope of the C hiropractors as gazetted in G overnm ent G azette No. 1745 o f 12 A ugust 1983, reflects com prehensive overlap with both traditional and modern physiotherapeutic modalities. Post-registration courses The Society is negotiating with several specialist practitioners from overseas countries, to run courses on such wide-ranging subjects as neuro-developm ental therapy, fu n c tio n a l a n a to m y and the new er e le c tro th e ra p y modalities. These courses will be advertised as soon as details are finalised. 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. )