Leary, W.P.

Wyndham, C.H.

English

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5 November 1966 S.A. TYDSKRIF VIR LiENEESKU DE(Byvoegsel-Suid-Afrikaanse Tydskrif vir LaboraeoriunJ- ell Kliniekwerk)985LKW 77TABLE Ill. DETERIORATION IN tNDIVIDUAL PERFORMANCE AT 6,000 FT.ALTITUDETable III shows that the performances of a selection ofinternational class athletes in the mile event have all beenbetter by many seconds at sea-level.DISCUSSIONThis analysis indicates that most of the best performancesof middle and long-distance runners in South Africa inthe last 60 years have been recorded at sea-level, whereassprinters recorded better times at medium altitudes wherethe air density is less. Furthermore, the effect of acclimati-zation to altitude is shown in the fact that when themeeting took place at medium altitude nearly all of thebest performances in middle-distance events were recordedby men who lived at these altitudes or by men who hadtravelled to and had trained at that altitude some weeksbefore the event.The deterioration in performance of middle-distancerunners at 6,000 feet is well shown in the poorer times ofa group of international athletes in Johannesburg com-pared with the performances at sea-level.It may be objected that athletic performances aredependent upon many other factors in addition to altitude.Such factors may include the conditions of the track, thewind velocity, the air temperature and humidity, etc. How-ever, it is unlikely that anyone of these factors would beconsistently present in all of the medium altitude athleticmeetings and not at sea-level.NameW. Lueg (Germany)G. ielsen (Denmark)G. Pirie (UK)M. Halberg ( 'Z)D. Lamprecht (SA)AverageYear19551956195819581965Bese coasealperformance4 min. 3 sec.4 min. I sec.4 min. 3 sec.3 min. 57·5 sec.3 min. 58 sec.4 min. 0·5 sec.Performanceae '6,000 ft.4 min. 20 sec·4 min. 10 sec.4 min. 30 sec.4 min. 8 sec.4 min. 8 sec.4 min. 15·2 sec.From this analysis it appears that a number of conclu-sions could be drawn with reference to the performancesof athletes in 1exico City. They are:1. There is a consistent deterioration in performance(of coastal athletes) over middle and long-distanceruns when these are held at medium altitude. Exami-nation of Table 1][ (and of data not et out here)shows that this deterioration ranges from 3~o in thecase of athletes who have undergone a 3 to 4-weekperiod of training at medium altitude to more than10% in those who are unacclimatized.2. Medium altitude will not have any unfavourableeffect on those running in the sprint events and, infact, some small improvement may result.3. It is to be expected that the middle and long-distance events at Mexico City might well be domi-nated by relatively unknown athletes who areaccustomed to living at medium altitudes and havemade a successful adaptation to athletics at thosealtitudes.4. Careful attention should be given by coaches to theproper acclimatization of athletes in the period be-fore the Mexico City Olympic Games. A properbalance will have to be struck between the improvedperformances which occurs over a period of a fewweeks and the eventual deterioration in performancewhich sets in if the period of acclimatization isprolonged too much.To avoid these difficulties, athletic coaches will need toplan the training programme with the help of physiologistswho have experience in exercise physiology.This paper is published with the permission of the Transvaaland Orange Free State Chamber of Mines, Johannesburg.REFERENCESJ. Wyndham. C. H .. Strydom. B .. Morrison. J .. Peter. J .. Williams.G .. Bredel!. G. A. G. and Joffe. A. (963): J. App!. Physio!., 18. 361.2. Leary, W. P. and Wyndham, C. H. (1965): S. Afr. Med. J., 39, 651.PHYSIOLOGICAL PROBLEMS EXPECTED AT THE MEXICO CITY OLYMPIC GAMESC. H. WYNDHAM AND W. P. LEARY, * Human Sciences Laboratory, Transvaal and Orange Free StateChamber of Mines, JohannesburgThere is a growing realization among medical men asso-ciated with athletics and other sports that the physical en-vironment (comprising air temperature, relative humidity,air movement and altitude above sea-level) in whichathletics events are carried out can affect performancesand even constitute a danger to life. Sir AdolpheAbrahams' states that he knows of at least one death fromheat stroke in an athletic event on a very hot and humidday. We have no doubt that if rectal temperatures weremeasured immediately after sudden unexplained deaths insporting events, a much larger number of heat-strokedeaths would have been shown. Recent reports in paperson the deaths from heat stroke of young army recruitscarrying out exercises at a high level of work on very hotdays, lend support to this argument.The next Olympic Games are due to be held in MexicoCity at an altitude of 7,000 feet above sea-level. There is*At present at the Depanmenr of Medicine. University of Natal.much concern in international athletic circles on thepossible effect that this altitude might have on the per-formances of the athletes and, also, as to whether theremight not be some danger to life. With these questions inmind, a Symposium was held in December 1965 atMagglinen in Switzerland on the 'Effects of medium alti-tude on athletic performances' to which exercise-physiolo-gists, including those from this laboratory, were invited.The altitude of Johannesburg is 5,780 feet (1,760 metres)and therefore a study of the physiology of exercise and ofthe performances of athletes at this altitude compared withsea-level will give some information on the limitations im-posed on athletic performances by 'medium' altitudes.In this paper is described the oxygen consumption/ven-tilation (BTPS) relationship during physical activities inJohannesburg and this relationship is compared with thatobtaining at sea-level. The results are also given of studiesof the maximum oxygen intakes and pulmonary ventila-986LCM78S.A. MEDICAL JOURNAL(Supplemenr-Solllh African Journal of Laboratory and Clinical Medicine)5 ovember 1966tions of 10 national and international class athletesstudied in Johannesburg and a comparison of these resultsis made with Astrand's observations on similar gradeathletes studied at sea-level.'The performances of sprinters and distance atWetes atsea-level and at Johannesburg are compared in a separatepaper.'the regression lines of oxygen consumption against work rate,and overlap throughout, so that it can be concluded that thepulmonary ventilations of Caucasians and Bantu during physi-cal effort at an altitude of 6,000 feet are not significantlydifferent. The 'ventilatory equivalent'-the pulmonary ventila-tion (BTPS)/litre per min. of oxygen consumption-is ap-proximately 30 litres.CAUCASIANS--BANTU _ASTRAND ---zg 40-2~~2 3z-0'"U W~ 2~::Jt')>-xo~ ID ~ ~ ~ ~ 00 m 00 ~ ~VENTILATION LITRES I MIN.Fig. 1. See text.Astrand's' regression line for ventilation against oxygen con-sumption at sea-level is also shown in Fig. 1. The ventilatoryequivalent from this regression line is about 20 l./min. It canbe concluded therefore that the ventilatory equivalent at 6,000ft. altitude is about 50% greater than it is at sea-level.Maximum Oxygen [makeCaucasian athletes were significantly taller than the Bantu,with mean heights of 177·9 cm. and 167·7 cm., respectively(Table I). The Caucasians were also significantly heavier, witha mean weight of 67·5 kg. compared with the 58·5 kg. of theBantu (Table I).The mean maximum oxygen intake of the Caucasians was4·13 I./min. and this is significantly greater than the mean ofthe Bantu athletes, 3·69 l.fmin. However, when these figuresare expressed per kg. of body-weight-the correct basis forcomparing samples of different weight-the mean maximumoxygen intakes of Caucasians and Bantu athletes are similar,being 61·1 and 63·2 ml./kg./min. respectively (Table 11).The mean ventilations (BTPS) of the 2 groups at theirrespective maximal levels of exercise are not significantlydifferent.DISCUSSIONIn Fig. 1, it is shown that pulmonary ventilation wasmarkedly increased during physical effort in Johannesburg.RESULTSMETHODSThe procedures used for the measurement of pulmonary ven-tilation and of maximum oxygen intake are described in detailin papers from this laboratory.">" The subjects had physicalcharacteristics as shown in Table I.TABLE I. CA CASIAN AND BANTU ATHLETES COMPARED WITH FITYOUNG MENAge Height WeightCaucasian athletes (years) (cm.) (kg.)I. Richard C. 18 172·1 68·32. John V. 20 176·5 72·33. Wilhelm O. 28 179·0 62·34. Perry L. 24 184·1 67·3Mean 23 177·9 67·5Bantu athletes5. Daniel M. 33 50·56. John Q. 24 167·5 58·97. Benoni M. 23 177·7 69·68. Bennet M. 29 166·8 55·09. Humphrey K. 26 163·2 61·410. Thomas K. 23 163·2 55·2Mean 25 167·7 58-4Fit, young menCaucasian (N = 35) 19 175·9 71·8Bantu ( r = 88) Young adults 165·9 59·1(No registrationof binhs)Pulmonary VentilationThe pulmonary ventilations in I./min. (BTPS) of some 35Caucasians and 88 Bantu who carried out the step test at fourrates, were plotted against oxygen consumptions. Separate re-gression lines were fitted to the data for the Caucasians andthe Bantu and these lines are shown in Fig. 1. The 83% confi-dence limits are relatively wide, compared with those fitted toTABLE n. BANTU A1'.'D CAUCASIAN ATHLETES COMPAREDPulm. vent. Max. oxygenSubjects Max. HR Performance(beats/min.) I./min. BTPS l.fmin. ml./kg.fmin.I. Richard C. 192 140·8 4·07 59·6 Fastest 500 yard swim at6,000 ft. altitude.2. John V. 192 163·2 4·31 59·6 t mile-I min. 53 sec.3. Wilhelm O. 168 143·3 3·97 63·7 I mile---4 min. 8 sec.2 miles-8 min. 53 sec.3 miles-13 min. 38 sec.4. Perry L. 190 152·3 4·16 61·9 I mile---4 min. 11 sec.3 miles-14 min. 28 sec.Mean 186 149·9 4·13 61·25. Daniel M. 190 141·6 3·40 67·3 3 miles-14 min. 11 sec.6 miles-29 min. 23 sec.6. John Q. 192 151·4 3·84 65·2 -\- mile-I min. 52 sec.I mile---4 min. 12 sec.7. Benoni M. 192 160·5 3·90 60·4 -\- mi!e-l min. 48·7 sec.8. Bennet M. 204 142·6 3-37 61·3. i miles-9 min. 14·8 sec.3 miles-14 min. 14·7 sec.9. Humphrey K. 204 163·8 3-46 56·4 ! mile-l min. 48·7 sec.10. Thomas K. 204 135·9 3-80 68·7 2 miles-9 min. 20 sec.3 miles-14 min. 19·8 sec.Mean 198 149·5 3·69 63·25 Tovember 1966 S.A. TYDSKRIF VIR GENEESKU DE(Byvoegsel-Sllid-Afrikaanse Tydskrif Vir Laboratorillm- ell Kliniek"'erk)987LKW 79From this figure it can be estimated that a man running ata maximum oxygen intake of 4·0 I.jmin. at sea-level willhave a pulmonary ventilation of 100 l.fmin. When he runsin Johannesburg the same pulmonary ventilation will givehim an oxygen consumption of only 3·0 l.fmin. This levelof oxygen intake would certainly not be sufficient for himto run his race at the same pace as at sea-level. If he is toincrease his pulmonary ventilation in Johannesburg to givean oxygen consumption of 4·0 l.fmin. (which might beessential to achieve the same time for the event as at sea-level) then he would require a pulmonary ventilation of130 l.fmin. The higher level of pulmonary ventilationmight cause pulmonary distress and force the man to re-duce his speed.It could be argued that the air is less dense at the alti-tude of Johannesburg and that this would allow the manto increase his pulmonary ventilation without the distressthat the same increase would occasion at sea-level. Thishypothesis, however, needs to be tested by experimentation.There is indirect evidence that the increased pulmonaryventilation at medium altitude decreases the maximumoxygen intake. In Johannesburg the mean maximum oxy-gen intake of the athletes was found to be 62·2 ml.jkg.jmin. (mean pulmonary ventilation 149-4 l.fmin.) comparedwith the sea-level value of Astrand's athletes,' a meanmaximum oxygen intake of 72·8 ml.jkg.jmin. (with amean pulmonary ventilation of 119·8 l.jmin).From this evidence it may be concluded that perform-ances at the altitude of Mexico City would be markedlyaffected, but that there is little possibility of danger to life.This paper is published with the permission of the Trans-vaal and Orange Free State Chamber of Mines, Johannesburg.REFERENCES1. Abrahams, Sir A. (1950): Enc}'Ciopaedia of .\1edical Practice, 2nd ed.,pp. 302 - 309. London: Buuerworth.2. Astrand. P. O. (952): Experimental Swdies 0/ Physical lVorking Capa-city in Relation co Sex and Age. Copenhagen: Munksgaard.3. Iden' (1955): Nature (Lond.). 176. 92l.4. Leary. P. W. and Wyndham. C. H. (1965): S. Afr. Med. J .. 39. 651.5. Maritz, J. S., Morrison, J. F., Strydom. '. B., and \Vyndham, C. H.(1961): Ergonomics. 4, 97.6. Wyndham. C. H. and Leary. W. P. (1966): S. Afr. Med. J .. 40. 9 4.7. Wyndham, C. H .. Strydom. N. B., Morrison. J. F. and Maritz, J. S.(1959): J. Appl. Physiol., 14, 927.EXPERIMENTAL BIOLOGY GROUP: SUMMARIES OF SCIE TIFIC PAPERSAbstracts of papers read at the 21st Scientific Meeting of the Experimental Biology Group (EBG) held at the Karl BremerHospital on 16 September 1966:NUS AL I TRACYTOPLASMIC INCLUSIONS FO D IN FOETAL LAM B KID fEY CELL C LTU RESINFECTED WITH WESSELSBRON VIRUSJ. PARKER A 'D L STANNARD, CSIR Virus Research Unit, University of Cape TOII'/1An electron-microscopic study of ultra-thin sections of foetallamb kidney cells infected with Wesselsbron virus (an arbo-virus) revealed unusual intracytoplasmic inclusions. Infectedcells showed distinct changes 40 - 48 hours after infection, atwhich stage many orderly-patterned inclusions in 'crystalline-like' array were seen in the cytoplasm of a very high propor-tion of the cells. They were intimately associated with theendoplasmic reticulum which showed gross vesiculation in thevicinity of the arrays. The 'crystalline-like' inclusions consistof electron-translucent sub-units which, by their hexagonal andrhombic shapes, suggest an arrangement of short hexagonalcylinders.Four days after infection the orderly-patterned inclusionswere no longer apparent in the infected cells but characteristicareas of dense aggregates were visible in the cytoplasm incomparable numbers and situations similar to those of theprior arrays from which they are presumed to have originated.It is presumed that these intracytoplasmic inclusions are asso-ciated with viral multiplication and represent structures in-volved in or required for the assembly of virus particles. Virusparticles were occasionally observed in the cisterns of the en-doplasmic reticulum.Thin sections of foetal lamb kidney cells infected with anallenuated STrain of Wesselsbron virus showed intracytoplasmicinclusions with irregular array. Numerous virus particles.measuring 34 m!' in diameter, were found in clusters in thecytoplasm.THE IODINE AND PROTEINS IN CONGENITAL GOITRE OF CATTLEANDRIES VAN ZYL, DAVID PA 'SEGRO W, BE VA DER WALT, CHRIS THERON A.iD KEYZER VAN DER WALT,* CSfR IodineMetabolism Research Unit, Department of Pharmacology, University of StellenboschA congenital goitre occurring in an inbred herd of Afrikander tyrosines whereas none of the fractions obtained from normalcattle' has been shown to contain an excess of deiodinase' and calf thyroid hydrolysed the "'I-labelled thyroglobulin to anyan abnormal thyroglobulin which comprises most of the goitre appreciable extent during the same period of incubation.iodine.' The abnormal thyroglobulin contains thyroxine.' I/N ratios in the mitochondrial and microsomal fractionsAfter the administration of radioactive iodine ("'I), 48°1c of ob!ained from normal thyroid homogenates were 5·24 and 6·22the radioactivity of the goitre was located in the insoluble frac- whereas those of the goitre were only 0·53 and 0·52 respec-tion whereas only 18°o of the normal thyroid radio-iodine was tively. A similar difference was found in the 1/ r ratios of theinsoluble. nuclear and soluble fractions of the normal thyroid which wereGoitre and normal thyroid tissue were homoaenized in 0·25 both approximately 2, whereas in the goitre they were bothM sucrose from which nuclear, mitochondrial, microsomal, 0·093.and soluble fractions were prepared by differential ultracentri- In view of the heterogeneity of the abnormal thyroglobulinfugation. These fractions were analysed for their enzyme in the goitre,' attempts were made to separate its components(deiodinase and protease) activities and for their iodine: nitro- by gel-filtration through columns of Sephadex G-IOO, granu-gen ratios (,ug. I/mg. ). lated 7°~ agar gel and 3°0 agarose beads. With no~e of the~eTodotyrosine deiodinase activities were only observed in the columns was resolutIOn of the thyroglobulin-like IOdoproteinmitochondrial and microsomal fractions and were higher in the achIeved, although the malO .lOdoprotem could partly befractions obtained from the goitre than in those prepared from separated from the serum protems.normal bovine thyroids: Incubation of all fo~,r fractions with I. Schulz. K. C. A. (1962): Proceedings 01 the Seco/ld CO/lgress 01 the"'I-labelled thyroglobulin caused release of I-labelled IOdo- Genetic Society, p. 90.2. Van Zyl. A.. Schulz. K., Wilson. B. and Pansegrouw. D. (1965): Endo-.Present address: Department of Medicine, Ondersrepoort Veterinary crinology. 76, 353.Research lnstitute. University of Pretoria. 3. Robbins. J .. Van Zyl. A. and Van der Wait. K. (1966): Ibid., 78. 1213IIIIIII

Physiological problems expected at the Mexico City olympic games

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Physiological problems expected at the Mexico City olympic games

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