HOME HYGIENELIBRARY CATALOG CHAPTER 18
"Those who think they have not time for bodily exercise
will sooner or later have to find time for illness."
Edward Stanley, Earl of Derby
(from Conduct of Life, address to Liverpool College, 20 December, 1873)
We are seeking perfect health--a fit, active, vigorous bodywith a highly efficient cardiovascular system, keen faculties, strong sex drive,disease-free, resistant to effects of heat and cold, stress, germs and viruses, withgood digestion, elimination and stamina, and which will stay in that condition fora hundred years or so.
Some people, despite a sedentary lifestyle, have lived healthy,long and productive lives, having maintained the integrity of their bodies' tissuesand vital organs by prudent eating and other sensible lifestyle habits. Others toohave lived long, healthy and productive lives despite poor dietary habits, the integrityof their bodies having been maintained pretty well by a lifetime of regular physicalactivity. The longest lived people studied in the world are usually found to be thosewhose way of life has provided them with simple food, regular outdoor exercise, andfreedom from stress.
While it is now common knowledge that physical exercise cannotprevent artery disease, and indeed may even precipitate a heart attack in those withblocked arteries, there is no doubt that regular exercise, by improving the circulationof the heart and the rest of the body, and by improving the general metabolism, particularlythe metabolism of blood fats, will enhance health and provide strong protectionagainst all disease.
The desired standard of physical fitness is brought about bywhat is called the "Training Effect" and the body is said to be "incondition". While some people's day-to-day activity maintains this standard,most will need to deliberately increase their physical activity in order to achieveit.
Types of exercise and exercise programs
There are different ways in which a person can exercise, whichare given specific names.
The type and level of activity you should undertake dependson your physical condition at the outset. There are a number of books on the subjectand as with books on diet, they vary considerably in their advice. The reason thatthey vary is because the authors have different conceptions of what fitness is. Hereis one definition:
"Fitness is a condition of the body (and mind) which enablesit to perform its assignments efficiently without undue strain or fatigue, with adequatereserves."
What are the assignments? What do we want? Some people thinkfitness is having a lean body. A lot of nutrition-minded people think that way. Othersconsider a well-proportioned muscular body as fitness. Reasonable diet and isometricexercise for a few minutes a day can achieve this. To others a further requirementis a certain degree of agility and skill. Isotonics will produce this. A furtherrequirement again may be sprinting or jumping ability--anaerobics.
We are getting closer, but read again the opening paragraphsof this chapter. That is what we desire, and the surest way of achieving such a highlevel of fitness is a program Of regular fairly extended exercise--aerobic or enduranceexercise.
In 1958 the Canadian Air Force produced the famous 5BX exerciseprogram. It is based mainly on calisthenics which when performed together with stationaryrunning in an eleven-minute time limit will improve the fitness of a sedentary personto a reasonable standard. Done property it becomes aerobic exercise and three timesper week is claimed to be sufficient.
My brother, at age 42, said 5BX was wonderful as it enabledhim to surf three hours straight, several times a week. I pointed out to him hissurfing activity was aerobics and in itself produced his high fitness level. He dropped5BX and surfs and walks instead, still fit at 70.
A recent bestseller, Total Fitness in 30 Minutes a Week(1975) by Professor L. Morehouse, Professor of Exercise Physiology and Founding Directorof the Human Performance Laboratory, University of California, claims that three10-minute sessions per week of not very vigorous exercise will achieve fitness. Theopening page says:
"Our thanks to those men and women who voluntarily exercisedto exhaustion in physiology laboratories to establish that a desirable level of fitnesscan be achieved without strain or sweat."
That sounds pretty good, but what is a desirable level? ProfessorMorehouse says we need a certain amount of muscle strength and endurance in orderto live well and carry out our daily activities effectively and without fatigue.A good definition?
Yes, but is it good enough?
The standard of physical fitness described by Professor Morehousein his book as being desirable may be high compared to the average level among thepopulation, but is not up to the standard we are seeking.
The proof of any pudding is in the eating. The only proof inthe world in the field of longevity is to be seen by the study of those centenariansaround the world still enjoying happy and vigorous life. There are many of them andmost follow a lifestyle containing two common denominators:
"Fitness is a desirable state for anyone who wants to leada zestful and productive life and realize his full potential." So says Lt. GeneralR. L. Bohannon (USAF ret.) in the introduction to Kenneth Coopers' Aerobics,first published in 1968 with many reprints since.
Aerobics (the word means sustaining life by the burningof oxygen) describes the relationship of endurance exercise with fitness and freedomfrom disease. In that book Cooper coined the term "Training Effect".
Copper, while in the US Air Force, was the first to scientificallyevaluate the effects of aerobic exercise on over 15,000 people. Leaving the Air Forcehe established a clinic and research center at Dallas, where he has since evaluatedand instructed many thousands more.
The physical training must be regular (at least four times aweek), sustained and reasonably vigorous. We must burn oxygen with our effort, requiringthe lungs and heart to maintain a high output. The heart deepens its stroke and increasesits rate, blood and lymph circulation is boosted. Long vigorous walks, jogging, cycling,swimming or other such endurance exercise, preferably daily, are best. It shouldbe carefully graduated initially because not only may the heart overload, but creakingknees and ankles must be strengthened as well.
It is the extended processing of oxygen for muscular energyand the rate of oxygen consumption which produce the training effect.
Major (later Colonel) Cooper devised a point system based onevaluating oxygen consumption with different forms of exercise related to time. Itis all in the book. Thirty points a week are required to maintain a good standardand those points can be picked up in any number of combinations of different exercises.For instance, 1 mile walked or run in under 14.5 minutes gets 2 points, in under12 minutes gets 3 points, in under 10 minutes, 4 points and so on. By comparison,swimming 500 yards in under 12.5 minutes gets 4 points. A popular workout for joggersis to run 1.5 miles in 12 minutes or less for 7.5 points. Four times a week give30 points in 48 minutes total running time. Incidentally, 1.5 miles in 12 minutesis the pass rate in the Air Force test.
Less is demanded of women (1.35 miles) and less with age. After50 a man passes with 1.25 miles and a woman with 1.05 miles in 12 minutes. Thereare lots of men over 50 who can make 1.75 miles, the excellent rating for young men.When you get into shape you will find at 12 minutes you are just warming up.
Nathan Pritikin called his exercise system "roving".Roving is essentially aerobic or endurance exercise but it is not done on a strictlycalculated basis. You walk or run as you feel, starting perhaps with a couple ofblocks, and with improved condition, extend to 6-10 miles. Many patients at the LongevityCenter who at first could walk only a few yards, have improved over a four week periodto accomplish 10 miles a day. It is never too late to start.
The 10 fundamentals of roving are.
Thus, the roving program is not very demanding, it is strictlyon the safe side having been designed around people in pretty poor condition.
Heart recovery rate
After exercise the heart rate gradually slows down to its normalrate. The quicker it returns to its resting rate, the better is the fitness level.If the rate remains elevated too long it indicates the exercise has been too strenuous.You can check your heart recovery quite simply.
At the completion of the exercise--
A count of 100 indicates a good level of fitness.
For "high risk" patients, jogging is not recommendedbecause of the possibility of plaque breaking loose within an artery. This is possiblewith jarring or exaggerated movement and is thought to have precipitated Bing Crosby'sheart attack while playing golf.
The roving program suggests working up the distance to 6 miles.If you took 1 hour 50 minutes for 6 miles which is very easy walking, you earn 6aerobic points. So if you did that 5 times a week you would get 30 points and itwould take a total of 9 hours.
The two systems seem to agree, and their results are thoroughlyproven. They are based on facts documented years ago by physiologists such as DrWilhem Raab in his book The Prevention of Ischemic Heart Disease (Chas. Thomas,Springfield, Illinois, 1966) and by Professor Thomas Cureton, University of IllinoisPhysical Fitness Research Laboratory, in his book The Physiological Effects ofExercise Programs on Adults (Chas. Thomas, Springfield, Illinois, 1969).
When the physiological effects of exercise are understood, itcan be seen that the main advantage of the training effect is that fat metabolismis more efficient both at rest as well as when exercising.
Even when not actively exercising, a fit person burns more fatin his body and his basal metabolism is high compared to an unfit person. Such peoplerequire less clothing to keep warm even though they have less body fat. Kenneth Cooper,while in the Air Force, conducted an experiment with two groups of men, one groupphysically trained, the other untrained, to observe their metabolism of fat. Allthe men consumed 1.5 pints of cream for breakfast, nothing else, and through theday blood tests were made. All the men's blood became infested with fat dropletsbut the trained men's blood cleared in four hours whereas the blood of the unconditionedmen took up to 10 hours to clear.
On the other hand, vegetarians, without the high levels of fatand cholesterol in their blood do not need to the same extent, the protection ofthe training effect.
This then raises the point--what is the ideal amount of exercise?
Our object is to achieve optimum health through optimum bodychemistry. We want our body cells perfectly nourished and cleansed, because it isat that level that health is determined. With healthy nourished cells supplied withlots of oxygen, there can be no disease.
This ideal condition can only be achieved with a pure, healthybloodstream. This is the vital factor.
A low fat, vegetarian diet achieves this pretty well by avoidingtoxins and high fat levels to begin with. Aerobic exercise helps to achieve thisby burning excess blood fats for fuel.
Live cells can be kept in glass jars in laboratories in healthycondition providing the fluid medium in which they reside is kept pure and providesthe cells with all their nutritional requirements, oxygen, and freedom from toxins.It is feasible then that a diet may be possible allowing perfect body chemistry withoutmuch exercise but it is very obvious that the more "improper" a person'sliving habits may be, the more vital physical exercise becomes.
Assuming you are a typical American or European having alwaysconsumed a Western type diet, your arteries will not be in good condition, so notonly do you have to clean your blood, you must clean the linings of your arteriesas well. The more carefully graduated endurance exercise you get, in conjunctionwith a low fat/cholesterol diet, the faster will this be accomplished. In the absenceof excess fat in the blood, the fatty atheroma choking the artery walls is graduallyreabsorbed and used as fuel.
It should be remembered too, that the incidence of cancer amongathletes is only one-seventh that of the general population.
So the answer to what is the ideal amount of exercise couldvary greatly, depending on a person's overall lifestyle. It will be recalled thatsome of the centenarians studied by Dr de Lacy Evans had sedentary lives. The author,who spends most of his life reading and writing, maintains a good level of fitnessby long hours of outdoor manual work on his steep Mountainside fruit orchard. Thisis in contrast to the 40 miles a week I used to run, and which for my purposes wasprobably excessive. The fittest I have ever felt has been on the occasions in mylife when I have indulged in extended periods of hard manual outdoor work.
What we do know is that many people suffer from a lack of exerciseand that rarely do people suffer from an excess of it.
Perhaps hours of "roving" may be the ideal if youhave the time and the inclination, but on the other hand the more vigorous Cooperaerobic system works very well for those with less time to spare.
Physiology of exercise
Energy for muscular exercise is supplied by fat and carbohydrateoxidized in the muscle tissues. Fat is stored throughout the body in convenient placesand in body cells as well, whereas carbohydrate is stored in the liver and muscletissues as glycogen derived from blood sugar (glucose). Fat is a much more compactfuel than glycogen as it contains twice the amount of potential energy as glycogen.
Thus body fat is the main form of stored energy, and for levelsof normal activity it supplies the bulk of the body's muscular energy, together withsome carbohydrate. So much energy is contained in fat that even lean people havesufficient for days of activity even when deprived of food.
Blood sugar contributes to energy production by the musclesand continually enters the bloodstream from the intestines while there is food beingdigested. That which is excess to normal blood levels is stored by the liver, andwhat cannot be stored converts to fat. The primary use of blood glucose is for fuelingthe cells of the brain and nervous system, which use glucose exclusively, and relyentirely on the level available in the blood. When glucose is not available fromthe digestion of food, the liver maintains the correct level in the blood by convertingglycogen back to glucose and releasing it.
The ratio of fat and carbohydrate used by the muscles varieswith the intensity and duration of the exercise performed.
The purpose of muscle glycogen stores is--
Thus for our purpose of achieving a clean bloodstream and cleanarteries and optimum health, it can be seen that moderate aerobic exercise is idealbecause we are concerned with fat metabolism, particularly if not maintaining properdietary habits.
Two well-built people can stand side by side, both in apparentlygood physical condition, and yet one may be dreadfully unfit and the other capableof running a marathon. Somewhere inside their bodies they are very different, andrecent findings from several Scandinavian sources explain what this difference is.
Dr J. P. Clauson and Dr Bengt Saltin took physically untrainedsubjects and on each one selectively trained different limbs, leaving other limbsuntrained. When tested for cardiovascular function, the subjects revealed impressiveimprovement when the test involved the use of the trained limbs, and little improvementif the test involved use of untrained limbs.
Thus it was shown that most of the improvement in general metabolicfunction, i.e. training effect, is specific to those muscles which have been exercisedby the training.
Two other experimenters, Dr P. Anderson and Dr Henriksson, demonstratedthat the muscle tissue changes with training. Biopsies taken after eight weeks trainingshowed in the muscle tissue an increased level of enzymes which play a part in theutilization of substrates and the release of energy. At the same time, the contentof energy substrates in the muscle cells and the density of the capillaries supplyingthe muscles with blood had increased.
Comparison of the responses when testing a subject with one"trained" leg and the other "untrained", demonstrated some ofthe metabolic consequences of training. At rest or when exercising there is an increasein the amount of fat oxidized by the trained muscles and a corresponding reductionin the amount of carbohydrate oxidized. Thus glycogen is conserved and exercise potentialincreased. The untrained muscles release lactic acid which indicates incomplete combustiondue to insufficient oxygen, and are more prone to discomfort or pain.
Thus the primary changes in training are improvements in thechemistry of the muscle cells and in the capillarity of the vascular bed--the bloodsupply--of the muscle. These adaptations ensure that the cells of trained musclescan extract oxygen from the circulating blood more completely--removing say, two-thirdsto the available oxygen instead of half. These metabolic improvements also reducethe local concentration of certain intermediary metabolites. It is this concentrationwhich determines the calibre of the blood vessels supplying the muscles and hencethe volume of blood they receive. Accordingly, the muscles need and receive a smallerblood flow than before training, and therefore place less demand upon the heart.
The main aspect which affects a person's muscular endurancefor vigorous exercise is the amount of glycogen (carbohydrate) stored in the muscletissue. This varies not only with training but is greatly dependent on diet. It wasdescribed in Chapter 15 how athletes on a high complex carbohydrate diet displayedthree times the endurance as athletes on a high protein and fat diet. All championathletes of the present day require the high natural carbohydrate diet to attaintheir performance.
Although fat alone provides energy, when a runner's leg musclesrun out of glycogen he can no longer run. Similarly, when a boxer's arms run outof glycogen he may scarcely be able to raise them although his legs are still okay.
Sometimes an athlete will run out of liver-stored glycogen aswell, resulting in an immediate drop in blood sugar and consequent irrational behavior.The blood sugar level can be almost immediately restored by eating some food, butthe glycogen stores may take hours and several meals to replenish. Depleted muscleglycogen stores may take from 10 hours to several days to replenish.
Exhaustion of glycogen stores occurs only when exercise is takento extreme limits and rarely happens to ordinary people on a reasonable fitness program.
In summary then, the training effect--:
This information explains a few anomalies. Such as why a swimmerwith a high degree of cardiovascular fitness may not indicate that degree of fitnessif tested by the 12-minute running test or a treadmill test. It explains why somethin and wiry people are stronger than others with bulging muscles. Also explainedis how Cooper's trained men metabolized the heavy cream in four hours. The lowerblood pressure of trained individuals results not only by virtue of better circulationand lower blood viscosity but also because less blood flow is required.
It becomes apparent that for optimum fitness, all muscles shouldbe trained, for instance swimming and running may be better than just one or theother.
Sometimes physical training causes false symptoms of disease:
Overtraining by zealous athletes can be highly stressful andoccasionally cause debility and fatigue and they become susceptible to infection.On rarer occasions runners collapse and sometimes die of cardiac fibrillation whenattempting strenuous feats of endurance. They are usually men approaching middleage subsequently found to have cardiovascular disease. Such men have the misapprehensionthat strenuous exercise conveys. Immunity to heart attacks, whereas a correct dietand a much less strenuous exercise program would have achieves their purpose.
Neither 5BX nor Total Fitness in 30 Minutes a Week mentiondiet and its relationship to heart disease.
Professor Morehouse includes a chapter titled "Why CardiologistsExercise", In the first paragraph he says: "cardiologists theorize thata well conditioned heart will have more capillaries to take over if and when there'sa stoppage of blood vessel". I would like to point out that this is not a theory.Collateral circulation has been shown over and over again to develop as a resultof exercise. It will develop without exercise to some extent to help a blocking artery,but exercise brings about a vast improvement.
To what extent a person living all his life on a low fat, vegetariandiet needs to exercise for best results I do not know. We do know that the fittestoldest people in the world eat simple food and exercise a lot.
Whereas, in our civilization, women outlive men on the averageby about five years (due probably to the more debilitating lifestyles of our mengenerally), in Hunza and among the primitive Eskimos, the men (who are more physicallyactive) outlive the women by about five years.
Getting back to ordinary folk. Regardless of what they haveappreciated from the chapter on nutrition, I somehow doubt that many people, unlessthey have been frightened already, will at once relinquish their favorite foods.That is their business, but it should be registered very clearly that aerobic exerciseis the second line of defense against degenerative diseases, and therefore shouldnot be skimped. I think it is a rule of life that you get a reward only commensuratewith your effort in the long run.
Quoting from Aerobics Major Cooper says:
"This program has been tested to exhaustion, by the mostmodern means available, both in the field, and in the laboratory. And it has beenproven several thousand times over in the only place it really counts--in the humanbody. There's only one problem remaining. I can give you the program, but I can'tdo it for you. You have to do the rest. It isn't easy, but it works. Keep this inmind whenever you think about quitting: it's medically sound and it works."
It works all right, as anyone who has seriously tried it knows.The writer checked his medical records back to 1945 and sure enough with passingyears the blood pressure figures showed the "normal" increase. From thecommencement of training in 1969 the trend reversed and blood pressure soon fellto 114/70, resting pulse rate 42, same as at age 2 1.
There are many intent people who mistakenly consider themselvesin good shape but are nowhere near it, and confusion arises when occasionally oneof them keels over. Sometimes it may be someone jogging or playing squash, Unlessa good standard has been attained and a prudent diet followed, such exercise couldbe dangerous. Playing squash requires a high fitness level, and the amount of squashplayed by most people is insufficient to achieve or maintain such a level.
Gadgets, weightlifting, touching toes, social tennis, golf,sailing and gardening may make you look fit on the outside, are beneficial to someextent, as indulged in by most people, but they may not achieve the desired trainingeffect.
Side benefits of exercise accrue gradually too. Toned up posturalmuscles prevent back strain and "slipped discs" and many common ailmentsaccepted by most people as normal, just do not happen any more, eg. indigestion,constipation, colds, fatigue etc. and although exercise may take up an average sayof 30 minutes a day, fit people have more spare time because they need only six orseven hours' sleep.
Cooper also described many more dramatic recoveries from diseasesuch as ulcers, glaucoma and emphysema achieved by endurance training--one USAF fighterpilot who was finally reinstated to operational flying status, having been groundedwith heart trouble.
There are many recorded cases of recovery from heart troubleachieved by physical training. The most spectacular, in Australia anyway, must bethat of Norman Cutter of Adelaide, who suffered a severe coronary attack at age 47,and who, completely fed up with being a permanent invalid, embarked on his own trainingprogram. Some years later he demonstrated his renewed self in a non-stop ascent (bystairs) of the AMP Building in Sydney, and later in a non-stop ascent of the EmpireState Building in New York. At the age of 59, he raced a 21-year-old Adelaide footballplayer up the tallest building there (22 floors), beat him by one floor. He saysit is a good idea to avoid heart attacks; they are not much fun.
The effect of training on heart and circulation and its importance in preventive cardiologySystolic blood pressure in or, average population as compared with that of well-trained sportsmen (5) (Courtesy of Dr D. Steinkopff, Darmstadt, 1956)
Exercise, training and cardiac stroke forceThree series of ball istocardiograms consecutively recorded: (1) from 10 untrained students aged 18 to 2 1; (2) from 10 NCAA championship finalists in middle and long distance races in Austin Texas, 1958; and (3) from 10 middle-aged ex-athletes who eight and more years ago had performed on a level comparable to that of the men whose tracings are shown in (2).
Note: the rapid weak action of the students' hearts compared withthe slow powerful action of the athletes'. The heart action of the middle-aged ex-athletesshown here is extremely poor, but nevertheless, by graduated training, good heartcondition can be restored to such people (see reference Norman Currer). Do not confusethis ballistocardiogram with electrocardiogram.
Results--one year later
Death rate by degree of exercise and age group during period of approximately one year after last survey. For example, in the age group 60-64, 1 per cent (1/100) of the men in the heavy exercise category died,whereas 5 per cent of those in the no-exercise group died during the follow-up year. (Adapted from Hammond )
In September 1974, the University of NSW Medical Foundationheld a seminar on Executive Health. Dr Cooper presented two lectures--clear cut data,not speculation. His data clearly demonstrates the direct beneficial effects of fitnesson each of the following factors:
Depression, hypochondria, absenteeism, obesity, ulcers, pulmonarydisease, general susceptibility, arrhythmia, abnormal ECG, work performance, efficiency,body shape, ability to handle stress, vital capacity, condition of heart tissuesand blood supply, resting heart rate, maximal heart rate, blood pressure, blood cholesteroland triglycerides, fasting blood sugar, recovery from heart disease.
For those loafers who derive comfort having read occasionalreports of joggers dropping dead, check this one paragraph out of 31 close-typedfoolscap pages of his lectures. An evaluation of 13,763 Austrian (not Australian)men (aged 29-30 years) versus 6,712 American men (aged 19-20). The Austrians hadover 80% pass in the 1.5 mile in 12-minute test as against the American 39%, andthe American subjects were 10 years younger, only 19-20!
Compare Austria and USA in this statistic--death from heartattacks in different countries, young men per 100,000 population. Japan 18.5, Austria36.2, Australia 66.3, USA 90.6--young men.
On the brighter side, rehabilitation: 25 heart attack patientsof Dr J. Scaff, cardiologist, Honolulu, competed in the Rimner Pacific Marathon,15 December, 1974. A marathon is 26 miles. In 1973 and 1974 there were 13 people,ex-heart-attack patients, who finished in the famous Boston Marathon. Ever sincethen recovered heart patients have become commonplace as marathon competitors.
For someone embarking on a fitness program they would be welladvised to start with walking. Do not undertake a program beyond your actual standardand never force yourself to extremes, as this is where the only danger lies. Manyelderly Longevity Center patients comfortably manage 10 miles a day by the end ofthe four-week session at the Pritikin Center, usually split up into two or threeseparate walks.
It is a good idea to have a proper check-up first to note allthe figures, basal pulse rate, blood pressure, weight, cholesterol, triglycerides,blood chemistry etc, and then observe the improvements as you progress.
Elaborate "gear" is unnecessary. Those flash tracksuitsare only to keep you warm while you are loafing. Sweating is not the object, it isjust a byproduct, and is only a temporary loss of water while the body is tryingto cool itself. Overheating can be dangerous, resulting in fainting, even suddendeath. To lose fat you must burn it as fuel by activity.
If running, at the completion of each session walk for aboutfive minutes as most of the blood will have been circulating in the lower part ofthe body, and walking will keep assisting its return upwards until circulation isrearranged. Running on grass or firm sand, barefooted, is less strain on feet andankles and shins. They are painful enough at first.
Having read of the wonderful benefits of endurance exerciseyou can see it would be easy to accept aerobics as a "cure all". By improvingoxygen transport, it benefits all functions and the improvements are rapidly felt;they are measurable and impressive--BUT--
Remember heart attacks may occur during strenuous exercise andit is important to ensure adequate circulation by first lowering the blood viscosity.This can only be accomplished after several days on a very lowfat, low-cholesterol,low-sugar diet. And remember too that unless such a diet is permanently adopted,atherosclerosis will not reverse but will continue to increase relentlessly.
In case any misconceptions still remain, remember:
The faculties of keen eyesight, good hearing, clear thinking,efficient body functions and so on, can only be gained with completely clear bloodvessels. And until runners ensure the freedom of their arteries, the occasions where,now and again, some of them are stricken with fibrillation, will continue. The "carteblanche" for superbly fit people to eat and drink as they please, and whichmade me smug for years, never existed. Remember too, that if exercise is discontinued,the training effect will be lost in a few weeks.
This recent statement by Dr Dintenfas correlates perfectly."Studies of athletes, normal individuals and patients with cardiac and renaldiseases show a progression from a low blood viscosity with a high flow velocityamong athletes, to an elevated viscosity and low flow velocity among patients. Furthermore,my colleagues and I have found time and again an elevation of blood viscosity amongapparently healthy individuals who later developed symptoms of heart disease andcancer."
In a nutshell, that means physically fit people have free-flowingblood, and with free-flowing blood they are strongly insured against degenerativediseases.
By chase our fathers earned their food,
Toil strung their hearts and purified their blood,
But we their sons, a pampered race of men,
Are dwindled down to three-score years and ten,
Better to hunt in fields for health unbought,
Than fee the doctor for a nauseous draught,
The wise for cure on exercise depend,
God never made his work for man to mend.
John Dryden, 1680