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Reading #12

physical activity, health and aging

Introduction

Aside from the positive effects of exercise in maintaining physiologic function, regular physical activity protects against the ravages of this nation’s greatest killer, coronary heart disease (CHD). Individuals in physically active occupations have a two- to threefold lower risk of heart attack than individuals in sedentary jobs. Furthermore, chances of surviving a heart attack increase substantially for those with a physically demanding job or lifestyle. Physical activity also favorably modifies important CHD risk factors. Regular aerobic exercise lowers elevated blood pressure, reduces excess body fat, and improves the blood lipid profile. The blood clotting mechanism can normalize with exercise training, which reduces the chances of a blood clot forming on the roughened surface of a coronary artery. Regular exercise may also improve myocardial blood flow. This adaptation could retard the progression of heart disease, or at least maintain adequate blood supply to the heart muscle to compensate for coronary arteries narrowed by fatty deposits within their walls.

The Graying of America

Elderly persons make up the fastest growing segment of American society. Thirty years ago, age 65 represented the onset of old age. Now gerontologists mark 85 as the demarcation of “oldest-old” and age 75 as the “young old.” Currently, nearly 12% of all Americans (about 35 million) exceed age 65 and by the year 2030, 70 million Americans will exceed age 85. Some demographers project that one-half of the girls and one-third of the boys born in developed countries near the end of the 20th century actually will live in three centuries. In the short term, disease prevention, health care, and more effective treatment of age-related diseases like heart disease and osteoporosis continue the advances in longevity. Far fewer people now die from infectious childhood diseases, so those with the genetic potential actualize their proclivity for longevity.

Centenarians currently represent proportionately the fastest growing age group in the United States. Numbers range between 30,000 and 50,000, up from the estimate of 15,000 in 1980 and almost none at beginning of the 20th century. No longer viewed as a quirk of nature, 1 in 10,000 Americans live to the age of 100. Demographers project that by the middle of the next century more than 800,000 Americans will exceed age 100, with many of these men and women remaining in relatively good health. Old-age mortality actually appears on the decline in that the death rate (number of people per 100 in a specific age group) levels off in the 90-year-old age category (approximately 11 per 100) and decreases to 8 per 100 after age 100! On a disturbing front, the Centers for Disease Control and Prevention reports that nearly one in ten Americans over age 70 needs help with daily activities such as bathing and four in ten use assistive devices such as walkers or hearing aides. In addition, about one-half of men and two-thirds of women older than age 70 have arthritis; one-third of all Americans in this age group also have high blood pressure and 11% have diabetes. Of all seniors, women over age 85 are the most likely to need everyday help, with 23% requiring assistance with at least one basic activity (e.g., dressing or going to the toilet).

The New Gerontology

Genes exert strong influence over life span, patterns of aging, and susceptibility to disease. Yet scientists know little why humans live five times longer than cats, cats five times longer than mice, mice outlive fruit flies by a factor of 25, or why the onset of different diseases (e.g., Alzheimer’s disease) often differ by many years in identical twins.

The contribution of genetics to the unprecedented increase in human life expectancy remains unanswered. In the early 1900s, for example, 4% of the U.S. population exceeded 65 years of age. By 1998, that percentage increased to 13%. A citizen’s average life expectancy has increased from 47 years in 1900 to 76 years today, and should reach 83 years by the year 2050. Sixty-three percent of today’s 65-year-olds will achieve their 85th birthday, and 24% will celebrate age 95. Researchers now believe that the average child born today may readily live healthfully to age 95 or 100, with the limit of human life span currently estimated at 130 years.

Improved overall health accompanies extended life span. The prevalence of chronic disorders (e.g., arthritis, dementia, hypertension, stroke, and emphysema) continues to decline. Eighty-nine percent of Americans age 65 to 74 years reports no disability; even after 85 years of age, 4% remain fully functional. A decline in the population of elders living in nursing homes (6.3% in 1982 to 5.2% in 1998) accompanies the upgraded functional status of the elderly. Concurrently, a “new gerontology” expands the focus on aging from preoccupation with disease and frailty to a more positive, notion of “successful aging.”

The Concept of “Healthspan” and “Successful Aging”

The aging process, including the development of physical frailty towards the last decade of life, traditionally has been viewed as physiologically inevitable. The typical “aging syndrome” includes a constellation of chronological age-related and/or lifestyle-dependent deleterious changes in blood pressure, bone mass, body composition and body fat distribution, insulin sensitivity, and homocysteine levels that convey increased health risk, dysfunction, or actual disease. This traditional view has changed dramatically; it now seems evident that chronological aging does not conform to a grim stereotype of unalterable decline and loss of body structure and functional capacity. As more people reach that “ripe old age,” the concept of successful aging encompasses more than just the avoidance or delay of disease. Successful aging entails maintenance and even enhancement of physical and cognitive functions. It requires full engagement in life, including productive activities and interpersonal relations.

To a large extent, lifestyle changes that include sound nutrition and diverse forms of exercise substantially blunt the decline in function and increased disease risk with aging. The lack of muscle strength often limits an increasing number of the healthy elderly’s chances to live a full, independent, and productive life into the ninth and tenth decade. In a study of 100 frail nursing home residents (average age 87 years), resistance training for only 45 minutes, three times weekly for ten weeks doubled muscular strength and improved gait and stair climbing. Such findings demonstrate the substantial responsiveness of the healthy human body at any age to regular exercise.

Many gerontologists maintain that research on aging must focus not simply on increasing lifespan but rather improving “healthspan,” the total number of years a person remains in excellent health. Researchers now view much of the physiologic deterioration previously considered as “normal aging” as dependent on lifestyle and environmental influences subject to significant modification with proper diet and exercise. For those achieving older age, poor muscular strength, cardiovascular function, and joint range of motion as well as sleep disturbances link directly to functional limitations regardless of disease status.

Physical Activity Epidemiology

Epidemiology involves quantifying factors that influence the occurrence of illness to ultimately better understand, modify, and/or control a disease pattern in the general population. The specific field of physical activity epidemiology applies the general research strategies of epidemiology to study the association of physical activity as a health-related behavior with disease and other outcomes.38

Terminology

Physical activity epidemiology applies specific definitions to characterize behavioral patterns and outcomes of the groups under investigation. Examples of relevant terminology include:

• Physical activity: Body movement produced by muscle action that increases energy expenditure.

• Exercise: Planned, structured, repetitive, and purposeful physical activity.

• Physical fitness: Attributes related to one’s ability to perform physical activity.

• Health: Physical, mental, and social well being, not simply the absence of disease.

• Health-related physical fitness: Components of physical fitness associated with some aspect of good health and/or disease prevention include cardiovascular fitness, abdominal muscular strength and endurance, optimal body composition, flexibility of the lower back and hamstrings.

• Longevity: Length of life.

Within this framework, physical activity becomes a generic term and exercise comprises the major component. Similarly, the definition of health focuses on the broad spectrum of well being that ranges from the complete absence of health (death) to the highest levels of physiological function. Such definitions often challenge our ability to objectively measure and quantify. However, they do provide the broad frame of reference to study the role of physical activity and exercise in health and disease.

Surgeon General’s Report On Physical Activity and Health

The Surgeon General of the United States acknowledged the importance of physical activity in 1996 in a wide-ranging report summarizing the benefits of physical activity in disease prevention. The conclusions and recommendations of this hallmark report apply to all individuals interested in health improvement. In essence, the Surgeon General proposed a national agenda that urges the nation to adopt and maintain a physically active lifestyle to combat the increasing number of physical ailments associated with the country’s generally low level of energy expenditure. Hopefully, this document will generate as great an impact as the 1964 Surgeon General’s Report on the hazards of smoking.

The Report focuses on three objectives:

1. Summarize existing literature relating regular physical activity to disease prevention

2. Evaluate current status of physical activity in the population

3. Stimulate increased physical activity among Americans of all ages.

Concerning benefits of regular physical activity, the Report concludes

1. Almost everyone derives overall health benefits from participation in regular physical activity

2. Significant health and quality of life benefits emerge with only moderate, daily physical activity (e.g., 30 minutes brisk walking or raking leaves, 15 minutes running, or 45 minutes playing volleyball)

|For Your Information |

|Physical Activity Levels of Adults and Children in the USA |

|Adults |

|•• 15% of adults engage in regular vigorous physical activity |•• 22%of adults engage regularly in light-to-moderate |

|during leisure time (3/wk for at least 20 min) |physical activity during leisure time (5/wk for at least 30 |

| |min) |

|•• More than 60% of American adults do not engage regularly in|•• Physical inactivity occurs more among women than men, |

|physical activity; 25% lead sedentary lives |blacks and Hispanics than whites, older than younger adults, |

| |and less affluent than wealthier persons |

|•• Walking, gardening, and yard work represent the most |•• Participation in fitness activities declines with age. A |

|popular leisure-time activities for adults |large number of older citizens have such poor functional |

| |capacity that they cannot raise from a chair or bed, walk to |

| |the bathroom, or climb stairs without assistance |

|Children and Teenagers |

|•• Nearly one-half between ages 12 and 21 yrs do not |•• 25% engage in light to moderate physical activity nearly |

|vigorously exercise on a regular basis; a sharp decline in |every day (e.g., walk or bicycle) |

|physical activity occurs during adolescence | |

|•• 14% report no recent physical activity (more prevalent |•• More males participate in vigorous physical activity, |

|among females, particularly black) |strengthening activities, and walking or bicycling than |

| |females |

|•• Participation in all types of physical activity declines |•• Daily attendance in school physical education programs |

|strikingly as age and school grade increase |declined from 42% in early 1990 to only 25% in 1996 |

|•• 19% of high school students report being physically active | |

|for at least 20 min in daily physical education classes | |

People who maintain regular vigorous activity of longer duration obtain the greatest health benefits

Regular physical activity reduces general premature mortality risk, and specific risks of coronary heart disease, hypertension, osteoporosis, colon cancer, and adult-onset diabetes. It also enhances overall mental well being, and contributes to optimal neuromuscular-skeletal functioning.

Safety of Exercising

PEOPLE HAVE QUESTIONED THE SAFETY OF EXERCISE BECAUSE OF SEVERAL WELL-PUBLICIZED REPORTS OF SUDDEN DEATH DURING PHYSICAL ACTIVITY. ACTUALLY, SUDDEN DEATH RATES DURING EXERCISE HAVE DECLINED OVER THE PAST 20 YEARS DESPITE AN OVERALL INCREASE IN EXERCISE PARTICIPATION. IN ONE REPORT OF CARDIOVASCULAR EPISODES OVER A FIVE-YEAR PERIOD, 2935 EXERCISERS RECORDED 374,798 EXERCISE HOURS THAT INCLUDED 2,726,272 KM (1.7 MILLION MILES) OF RUNNING AND WALKING. NO DEATHS OCCURRED DURING THIS TIME (WITH ONLY TWO NONFATAL CARDIOVASCULAR COMPLICATIONS). CERTAINLY, A SMALL INCREASED RISK OF A CARDIOVASCULAR EPISODE DURING EXERCISE EXISTS COMPARED TO RESTING. HOWEVER, THE TOTAL REDUCTION IN HEART DISEASE RISK FROM REGULAR PHYSICAL ACTIVITY (COMPARED WITH REMAINING SEDENTARY) FAR OUTWEIGHS ANY SLIGHT INCREASE IN RISK DURING THE ACTUAL EXERCISE.

PERHAPS NOT SURPRISINGLY, MUSCULOSKELETAL INJURY REPRESENTS THE MOST PREVALENT EXERCISE COMPLICATIONS. FOR 351 PARTICIPANTS AND 60 INSTRUCTORS AT SIX AEROBIC DANCE FACILITIES, 327 MEDICAL COMPLAINTS WERE REPORTED DURING NEARLY 30,000 HOURS OF ACTIVITY. EIGHTY-FOUR OF THE INJURIES CAUSED DISABILITY (2.8 PER 1000 PERSON-HOURS OF PARTICIPATION), AND ONLY 2.1% OF THE INJURIES REQUIRED MEDICAL ATTENTION. THE GREATEST ORTHOPEDIC INJURY POTENTIAL FOR JOGGING AND RUNNING ACTIVITIES EXISTS AMONG INDIVIDUALS WHO EXERCISE FOR EXTENDED DURATIONS: MORE IS CERTAINLY NOT BETTER.

AGING AND BODILY FUNCTION

FIGURE 1 SHOWS THAT VARIOUS BODILY FUNCTIONS GENERALLY IMPROVE RAPIDLY DURING CHILDHOOD TO REACH A MAXIMUM BETWEEN AGE 20 AND 30 YEARS; THEREAFTER, A GENERAL DECLINE IN FUNCTIONAL CAPACITY OCCURS WITH ADVANCING AGE. ALTHOUGH A SIMILAR AGE TREND EXISTS FOR THE PHYSICALLY ACTIVE, PHYSIOLOGIC FUNCTION AVERAGES ABOUT 25% HIGHER COMPARED WITH THE SEDENTARY AT EACH AGE CATEGORY (AN ACTIVE 50-YEAR OLD MAN OR WOMAN OFTEN MAINTAINS THE FUNCTIONAL LEVEL OF A 30-YEAR-OLD). ALTHOUGH ALL PHYSIOLOGICAL MEASURES EVENTUALLY DECLINE WITH AGE, NOT ALL DECREASE AT THE SAME RATE. CONSIDERABLE VARIATION EXISTS FROM PERSON-TO-PERSON, AND FROM BIOLOGIC SYSTEM-TO-BIOLOGIC SYSTEM WITHIN THE SAME PERSON.

NERVE CONDUCTION VELOCITY, FOR EXAMPLE, DECLINES ONLY 10 TO 15% FROM 30 TO 80 YEARS OF AGE, WHEREAS RESTING CARDIAC INDEX (RATIO OF CARDIAC OUTPUT TO SURFACE AREA) AND JOINT FLEXIBILITY DECLINE 20 TO 30%; MAXIMUM BREATHING CAPACITY AT AGE 80 AVERAGES 40% OF VALUES FOR A 30-YEAR-OLD. BRAIN CELLS DIE AT A FAIRLY CONSTANT RATE UNTIL AGE 60, WHILE LIVER AND KIDNEYS LOSE 40 TO 50% OF THEIR FUNCTION BETWEEN AGES 30 AND 70. BY THE SEVENTH DECADE, THE AVERAGE FEMALE HAS LOST 30% OF BONE MASS, WHILE MEN ONLY 15%. GERONTOLOGISTS HAVE OFTEN CONSIDERED THESE AGING PATTERNS TO REPRESENT THE “NORMAL” AND “EXPECTED” DECREASES IN STRUCTURE AND FUNCTION.

AGING AND MUSCULAR STRENGTH

MEN AND WOMEN GENERALLY ACHIEVE MAXIMUM STRENGTH BETWEEN AGES 20 TO 30 YEARS, WHEN MUSCULAR CROSS-SECTIONAL AREA ACHIEVES MAXIMUM SIZE. THEREAFTER, STRENGTH PROGRESSIVELY DECLINES FOR MOST MUSCLE GROUPS, SO BY AGE 70 A 30% DECREMENT OCCURS IN OVERALL STRENGTH.

DECREASE IN MUSCLE MASS

REDUCED MUSCLE MASS REPRESENTS THE PRIMARY FACTOR RESPONSIBLE FOR AGE-ASSOCIATED STRENGTH DECREASES. THE SMALLER MUSCLE MASS REFLECTS A LOSS OF TOTAL MUSCLE PROTEIN INDUCED BY INACTIVITY, AGING, OR THE COMBINED EFFECTS OF BOTH. SOME LOSS IN MUSCLE FIBER NUMBER ALSO TAKES PLACE WITH AGING. FOR EXAMPLE, THE BICEPS MUSCLE OF A NEWBORN CONTAINS ABOUT 500,000 INDIVIDUAL FIBERS, WHILE THE SAME MUSCLE FOR A MAN AGE 80 HAS 300,000 FIBERS OR 40% LESS.

MUSCLE TRAINABILITY AMONG THE ELDERLY

REGULAR EXERCISE TRAINING FACILITATES PROTEIN RETENTION AND BLUNTS THE LOSS OF MUSCLE MASS AND STRENGTH WITH AGING. HEALTHY MEN BETWEEN AGE 60 AND 72 YEARS WHO PARTICIPATED IN A 12-WEEK STANDARD RESISTANCE TRAINING PROGRAM SHOWED THAT MUSCLE STRENGTH INCREASED PROGRESSIVELY THROUGHOUT THE PROGRAM, AVERAGING ABOUT 5% EACH EXERCISE SESSION – A TRAINING RESPONSE SIMILAR TO YOUNG ADULTS. MANY EXERCISE SPECIALISTS WHO WORK WITH THE ELDERLY MAINTAIN THAT IMPROVING STRENGTH REPRESENTS A HIGHLY EFFECTIVE WAY TO MAINTAIN MUSCLE MASS, INCREASE MOBILITY, AND REDUCE INJURY INCIDENCE.

AGING AND JOINT FLEXIBILITY

WITH ADVANCING AGE, CONNECTIVE TISSUE (CARTILAGE, LIGAMENTS, AND TENDONS) BECOMES STIFFER AND MORE RIGID, WHICH REDUCES JOINT FLEXIBILITY. IT REMAINS UNCERTAIN WHETHER THESE CHANGES RESULT FROM BIOLOGIC AGING PER SE OR REFLECT THE IMPACT OF CHRONIC DISUSE THROUGH SEDENTARY LIVING AND/OR DEGENERATIVE TISSUE DISEASES OF SPECIFIC JOINTS. REGARDLESS OF THE CAUSE, APPROPRIATE EXERCISES THAT REGULARLY MOVE JOINTS THROUGH THEIR FULL RANGE OF MOTION INCREASE FLEXIBILITY 20 TO 50% IN MEN AND WOMEN AT ALL AGES.

ENDOCRINE CHANGES WITH AGING

PART OF THE AGING PROCESS RELATES ALTERED ENDOCRINE FUNCTION, PARTICULARLY THE PITUITARY, PANCREAS, ADRENAL, AND THYROID GLANDS. ABOUT 40% OF INDIVIDUALS AGED 65 AND 75 YEARS, AND 50% OF THOSE OLDER THAN AGE 80, HAVE IMPAIRED GLUCOSE TOLERANCE LEADING TO NON-INSULIN DEPENDENT DIABETES (ADULT-ONSET OR TYPE 2 DIABETES). THIS REPRESENTS THE MOST COMMON FORM OF THE DISEASE AND AFFLICTS 1 IN 17 AMERICANS; NEARLY ONE-HALF OF THESE CASES REMAIN UNDIAGNOSED. IMPAIRED GLUCOSE METABOLISM LEADING TO HIGH BLOOD GLUCOSE LEVELS IN TYPE II DIABETES RESULTS FROM:

DECREASED EFFECT OF INSULIN ON PERIPHERAL TISSUE (INSULIN RESISTANCE)

INADEQUATE INSULIN PRODUCTION BY THE PANCREAS TO CONTROL BLOOD SUGAR (RELATIVE INSULIN DEFICIENCY)

COMBINED EFFECT OF THE ABOVE

THESE FACTORS ARE INFLUENCED BY GENETIC PREDISPOSITION, OBESITY, SEDENTARY LIFESTYLE AND AGING.

AGING AND NERVOUS SYSTEM FUNCTION

A 37% DECLINE IN NUMBER OF SPINAL CORD AXONS AND A 10% DECLINE IN NERVE CONDUCTION VELOCITY REFLECT CUMULATIVE EFFECTS OF AGING ON CENTRAL NERVOUS SYSTEM FUNCTION. SUCH CHANGES PARTIALLY EXPLAIN THE AGE-RELATED DECREMENTS IN NEUROMUSCULAR PERFORMANCE. PARTITIONING REACTION TIME INTO CENTRAL PROCESSING TIME AND MUSCLE CONTRACTION TIME INDICATES THAT AGING MOST AFFECTS STIMULUS DETECTION AND INFORMATION PROCESSING TO PRODUCE A RESPONSE.

AGING AND PULMONARY FUNCTION

WHETHER REGULAR EXERCISE THROUGHOUT ONE’S LIFE OVERRIDES PULMONARY SYSTEM “AGING” REMAINS UNKNOWN. CROSS-SECTIONAL STUDIES INDICATE THAT DYNAMIC PULMONARY CAPACITY OF OLDER ENDURANCE-TRAINED ATHLETES EXCEEDS THAT OF SEDENTARY PEERS. ALTHOUGH LONGITUDINAL STUDIES WILL PROVIDE A DEFINITIVE ANSWER, AVAILABLE DATA SUGGESTS THAT REGULAR PHYSICAL ACTIVITY RETARDS PULMONARY FUNCTION DETERIORATION ASSOCIATED WITH AGING.

AGING AND CARDIOVASCULAR FUNCTION

DIFFERENT INDICES OF CARDIOVASCULAR FUNCTION DECLINE WITH AGE. BELOW, WE REVIEW SOME OF THESE CHANGES AND THE EFFECTS OF EXERCISE ON ALTERING THE RATE OF DECLINE.

MAXIMAL OXYGEN UPTAKE

MAXIMAL OXYGEN UPTAKE (VO2MAX) DECLINES STEADILY AFTER AGE 20, DECREASING BY 35 TO 40% AT AGE 65 (SLIGHTLY LESS THAN 1% PER YEAR). A SLOWER RATE OF DECLINE OCCURS FOR INDIVIDUALS WHO MAINTAIN AN ACTIVE LIFESTYLE THAT INCLUDES REGULAR AEROBIC TRAINING , WITHOUT A DECLINE IN FAT-FREE BODY MASS. PHYSICAL ACTIVITY, HOWEVER, DOES NOT ENTIRELY PREVENT AGING’S EFFECT ON VO2MAX, EVEN WHEN ADJUSTING FOR A PERSON’S QUANTITY OF MUSCLE.

DETERIORATION IN VO2MAX WITH AGING PROBABLY RESULTS FROM CUMULATIVE EFFECTS INCLUDING AGE-ASSOCIATED LOSS OF MUSCLE MASS, INCREASES IN BODY FAT, AND ALTERED CARDIOVASCULAR AND PULMONARY FUNCTIONS. THE REDUCTIONS IN AEROBIC POWER PER KG OF ACTIVE MUSCLE WITH AGING CAN ONLY REFLECT REDUCED OXYGEN DELIVERY AND/OR REDUCED OXYGEN EXTRACTION AT THE ACTIVE MUSCLE. IN CONTRAST, SKELETAL MUSCLE OXIDATIVE CAPACITY AND CAPILLARIZATION REMAIN SIMILAR IN OLDER AND YOUNGER INDIVIDUALS WITH COMPARABLE PHYSIOLOGIC CHARACTERISTICS AND TRAINING HISTORIES. THE WELL-DOCUMENTED REDUCTION IN CARDIAC OUTPUT (BOTH MAXIMUM HEART RATE AND STROKE VOLUME) REPRESENTS THE MOST LIKELY EXPLANATION FOR THE DECREASE IN VO2MAX PER KG OF ACTIVE MUSCLE ACCOMPANYING AGING.

A SYSTEM RESPONSIVE TO TRAINING AT ANY AGE

AMONG THE HEALTHY ELDERLY, EXERCISE TRAINING ENHANCES THE HEART’S CAPACITY TO PUMP BLOOD AND INCREASES AEROBIC CAPACITY TO THE SAME RELATIVE DEGREE AS YOUNGER ADULTS. NINE TO 12 MONTHS OF ENDURANCE TRAINING IN HEALTHY OLDER ADULTS INCREASED VO2MAX 19% IN MEN AND 22% IN WOMEN. THESE VALUES REPRESENT THE HIGH END OF THE TYPICAL TRAINING RESPONSE FOR YOUNG ADULTS. REGULAR AEROBIC TRAINING FOR MIDDLE-AGED MEN OVER A 20-YEAR PERIOD SIGNIFICANTLY DELAYED THE USUAL 10 TO 15% DECLINE IN EXERCISE CAPACITY AND AEROBIC FITNESS. AT AGE 55, THESE ACTIVE MEN MAINTAINED NEARLY THE SAME VALUES FOR BLOOD PRESSURE, BODY MASS, AND VO2MAX AS AT AGE 35; BY AGE 70, THEIR VO2MAX EQUALED VALUES FOR INDIVIDUALS 25 YEARS YOUNGER! THESE REMARKABLE FINDINGS ATTEST TO THE ADAPTABILITY OF THE AEROBIC SYSTEM TO TRAINING AT ANY AGE.

AGING AND ENDURANCE PERFORMANCE

COMPARING ENDURANCE PERFORMANCE TIMES AMONG INDIVIDUALS OF DIFFERENT AGES POINTS UP THE DRAMATIC EFFECTS OF EXERCISE TRAINING ON PRESERVING CARDIOVASCULAR FUNCTION THROUGHOUT LIFE. FIGURE 2 SHOWS THE WORLD-RECORD MARATHON TIMES FOR MALES AND FEMALES OF DIFFERENT AGES, STARTING AT ABOUT AGE 4 AND INTO THE MID-80S (THE WORLD RECORD WAS JUST SET ON APRIL 1, 2002; 2:05:38, NOT SHOWN HERE.)

THE WORLD RECORD TIME OF 340.2 MINUTES FOR THE 86-YEAR OLD MALE CORRESPONDS TO A 12.9 MIN PER MILE PACE; FOR THE-80 YEAR OLD FEMALE, THE WORLD RECORD TIME EQUALS 328.6 (12.5 MIN PER MILE PACE.) THIS REPRESENTS A REMARKABLE 26.2-MILE AVERAGE RUNNING SPEED FOR MEN AND WOMEN IN THEIR EIGHTH DECADE OF LIFE. PERFORMANCES OF THIS QUALITY ATTEST TO THE TREMENDOUS CARDIOVASCULAR CAPABILITIES OF THE HEALTHY ELDERLY WHO CONTINUE TO TRAIN REGULARLY AS THEY GROW OLDER.

AGING AND BODY COMPOSITION

EXCESS BODY FAT ACCUMULATION USUALLY BEGINS IN CHILDHOOD OR DEVELOPS SLOWLY DURING ADULTHOOD. MIDDLE-AGED MEN AND WOMEN INVARIABLY WEIGH MORE THAN THEIR COLLEGE-AGE COUNTERPARTS OF THE SAME STATURE (WITH DIFFERENCES IN BODY FAT ACCOUNTING FOR THE WEIGHT DIFFERENCE). SCIENTISTS DO NOT KNOW IF GAINS IN BODY FAT DURING ADULTHOOD REPRESENT A NORMAL BIOLOGIC PATTERN. OBSERVATIONS OF PHYSICALLY ACTIVE OLDER INDIVIDUALS SUGGEST THAT, WHILE THE TYPICAL INDIVIDUAL GROWS FATTER WITH AGE, THOSE WHO REMAIN PHYSICALLY ACTIVE COUNTER THE NORMAL LOSS IN FAT-FREE BODY MASS WITHOUT INCREASING BODY FAT PERCENTAGE.

REGULAR EXERCISE: A FOUNTAIN OF YOUTH?

ALTHOUGH EXERCISE MAY NOT NECESSARILY REPRESENT A “FOUNTAIN OF YOUTH,” REGULAR PHYSICAL ACTIVITY NOT ONLY RETARDS THE DECLINE IN FUNCTIONAL CAPACITY ASSOCIATED WITH AGING AND DISUSE, BUT OFTEN REVERSES THE LOSS OF FUNCTION REGARDLESS OF WHEN A PERSON BECOMES ACTIVE.

MEDICAL EXPERTS HAVE DEBATED IF A LIFETIME OF REGULAR EXERCISE CONTRIBUTES TO GOOD HEALTH AND PERHAPS LONGEVITY COMPARED WITH A SEDENTARY “GOOD LIFE.” BECAUSE OLDER FIT INDIVIDUALS EXHIBIT MANY FUNCTIONAL CHARACTERISTICS OF YOUNGER PEOPLE, ONE COULD ARGUE THAT IMPROVED PHYSICAL FITNESS AND A VIGOROUS LIFESTYLE RETARDS BIOLOGICAL AGING AND CONFERS HEALTH BENEFITS LATER IN LIFE.

ONE GROUP OF RESEARCHERS INVESTIGATED THE DISEASES AND LONGEVITY OF FORMER COLLEGE ATHLETES. THIS SEEMED LIKE AN EXCELLENT GROUP WITH WHICH TO STUDY POSSIBLE LINKS BETWEEN EXERCISE AND LONGEVITY, BECAUSE COLLEGIATE ATHLETES USUALLY HAVE LONGER INVOLVEMENT IN HABITUAL PHYSICAL ACTIVITY PRIOR TO ENTERING COLLEGE THAN NONATHLETES, AND THEY MAY REMAIN MORE PHYSICALLY ACTIVE FOLLOWING GRADUATION. THESE AND MORE RECENT FINDINGS SUGGEST THAT PARTICIPATION IN ATHLETICS AS A YOUNG ADULT DOES NOT ASSURE SIGNIFICANT LONGEVITY.

ENHANCED QUALITY TO LONGER LIFE: HARVARD ALUMNI STUDY

RESEARCH CONCERNING CURRENT LIFESTYLES AND EXERCISE HABITS OF 17,000 HARVARD ALUMNI WHO ENTERED COLLEGE BETWEEN 1916 AND 1950 INDICATES THAT ONLY MODERATE AEROBIC EXERCISE, EQUIVALENT TO JOGGING THREE MILES A DAY, PROMOTES GOOD HEALTH AND LONGEVITY. MEN WHO EXPENDED 2000 KCAL WEEKLY HAD UP TO ONE-THIRD LOWER DEATH RATES THAN CLASSMATES WHO DID LITTLE OR NO EXERCISE. TO ACHIEVE A 2000 KCAL ENERGY OUTPUT WEEKLY REQUIRES MODERATE ADDITIONAL PHYSICAL ACTIVITY SUCH AS A DAILY 30 TO 45-MINUTE BRISK WALK, RUN, CYCLE, SWIM, CROSS COUNTRY SKI, OR AEROBIC DANCE. THE FOLLOWING SUMMARIZES THE RESULTS OF THE STUDY OF ALUMNI:

REGULAR EXERCISE COUNTERS THE LIFE-SHORTENING EFFECTS OF CIGARETTE SMOKING AND EXCESS BODY WEIGHT

EVEN FOR PEOPLE WITH HIGH BLOOD PRESSURE (A PRIMARY HEART DISEASE RISK), THOSE WHO EXERCISED REGULARLY REDUCED THEIR DEATH RATE BY ONE-HALF

REGULAR EXERCISE COUNTERED GENETIC TENDENCIES TOWARD AN EARLY DEATH. FOR INDIVIDUALS WHO HAD ONE OR BOTH PARENTS DIE BEFORE AGE 65 (ANOTHER SIGNIFICANT RISK), A LIFESTYLE THAT INCLUDED REGULAR EXERCISE REDUCED THE RISK OF DEATH BY 25%

A 50% REDUCTION IN MORTALITY RATE OCCURRED FOR THOSE WHOSE PARENTS LIVED BEYOND 65 YEARS

FIGURE 4 (PREVIOUS PAGE) SHOWS THAT AMONG PHYSICALLY ACTIVE PEOPLE, A PERSON WHO EXERCISES MORE HAS A REDUCED RISK OF DEATH. FOR EXAMPLE, MEN WHO WALKED 9 OR MORE MILES A WEEK SHOWED A 21% LOWER MORTALITY RATE THAN MEN WHO WALKED 3 MILES OR LESS. EXERCISING IN LIGHT SPORTS ACTIVITIES INCREASED LIFE EXPECTANCY 24% OVER MEN WHO REMAINED SEDENTARY. FROM A PERSPECTIVE OF ENERGY EXPENDITURE, THE LIFE EXPECTANCY OF HARVARD ALUMNI INCREASED STEADILY FROM A WEEKLY EXERCISE ENERGY OUTPUT OF 500 KCAL TO 3500 KCAL, THE EQUIVALENT OF SIX TO EIGHT HOURS OF STRENUOUS WEEKLY EXERCISE. IN ADDITION, ACTIVE MEN LIVED AN AVERAGE OF ONE TO TWO YEARS LONGER THAN SEDENTARY CLASSMATES. (OTHER RESEARCH ESTIMATES A LIFE EXPECTANCY INCREASE OF ABOUT 10 MONTHS WITH REGULAR EXERCISE.)

NO ADDITIONAL HEALTH OR LONGEVITY BENEFITS ACCRUED BEYOND WEEKLY EXERCISE OF 3500 KCAL. MEN WHO PERFORMED EXTREME EXERCISE ACTUALLY HAD HIGHER DEATH RATES THAN LESS ACTIVE COLLEAGUES (ANOTHER EXAMPLE OF WHY MORE DOES NOT NECESSARILY INDICATE BETTER EXERCISE BENEFITS).

IMPROVED FITNESS: A LITTLE GOES A LONG WAY

A STUDY OF MORE THAN 13,000 MEN AND WOMEN OVER AN EIGHT-YEAR INTERVAL INDICATES THAT EVEN MODEST AMOUNTS OF EXERCISE SUBSTANTIALLY REDUCE THE RISK OF DEATH FROM HEART DISEASE, CANCER, AND OTHER CAUSES. THE STUDY EVALUATED FITNESS PERFORMANCE BY DIRECTLY, RATHER THAN RELYING ON VERBAL OR WRITTEN REPORTS OF REGULAR PHYSICAL ACTIVITY HABITS. TO ISOLATE THE EFFECT OF PHYSICAL FITNESS PER SE, THE RESEARCHERS CONSIDERED FACTORS OF SMOKING, CHOLESTEROL AND BLOOD SUGAR LEVELS, BLOOD PRESSURE, AND FAMILY HISTORY OF CORONARY HEART DISEASE. FIGURE 5 (BELOW) BASED ON AGE-ADJUSTED DEATH RATES PER 10,000 PERSON-YEARS, ILLUSTRATES THAT THE LEAST FIT GROUP DIED AT A THREE-TIMES GREATER RATE THAN THE MOST FIT SUBJECTS.

THE MOST STRIKING FINDING WAS THAT THE GROUP RATED JUST ABOVE THE MOST SEDENTARY CATEGORY DERIVED THE GREATEST HEALTH BENEFITS. THE DECREASE IN DEATH RATE FOR MEN FROM THE LEAST FIT TO THE NEXT CATEGORY EQUALED 38 (64.0 VS. 25.5 DEATHS PER 10,000 PERSON-YEAR), WHEREAS THE DECLINE FROM THE SECOND GROUP TO THE MOST FIT CATEGORY EQUALED ONLY SEVEN. WOMEN OBTAINED SIMILAR BENEFITS AS MEN. THE AMOUNT OF EXERCISE REQUIRED TO MOVE FROM THE MOST SEDENTARY CATEGORY TO THE NEXT MORE FIT CATEGORY (THE JUMP SHOWING THE GREATEST HEALTH BENEFITS) OCCURRED FOR MODERATE-INTENSITY EXERCISE LIKE WALKING BRISKLY FOR 30 MINUTES SEVERAL TIMES WEEKLY. ACCORDING TO AVAILABLE EVIDENCE, IF LIFE-EXTENDING BENEFITS OF EXERCISE EXIST, THEY ARE ASSOCIATED MORE WITH PREVENTING EARLY MORTALITY THAN IMPROVING OVERALL LIFE SPAN. WHILE THE MAXIMUM LIFE SPAN MAY NOT EXTEND GREATLY, MORE ACTIVE PEOPLE SURVIVE TO A “RIPE OLD AGE” WITH ONLY MODERATE EXERCISE.

CORONARY HEART DISEASE

1.5 MILLION AMERICANS WILL HAVE A HEART ATTACK THIS YEAR AND ABOUT ONE-THIRD OF THEM WILL DIE. WHILE DEATHS FROM CHD HAVE DECLINED MORE THAN 35% SINCE 1970, HEART DISEASE STILL REMAINS THE LEADING CAUSE OF DEATH IN THE WESTERN WORLD. ALTHOUGH DEATH RATES FOR WOMEN LAG ABOUT 10 YEARS BEHIND MEN, THE GAP HAS CLOSED FAST, PARTICULARLY FOR WOMEN WHO SMOKE. FOR EVERY AMERICAN WHO DIES OF CANCER, NEARLY THREE DIE OF HEART-RELATED DISEASES. THIS HEALTH DISASTER PRODUCES STAGGERING ECONOMIC LOSSES – $130 BILLION IN 1996 FROM MEDICAL COSTS, LOSS OF EARNINGS, AND LOST PRODUCTIVITY. AND THIS DOES NOT INCLUDE THE EMOTIONAL IMPACT OF LOSING A LOVED ONE IN THE PRIME OF LIFE.

A LIFE-LONG PROCESS

ALMOST ALL PEOPLE SHOW SOME EVIDENCE OF CHD, WHICH CAN BE SEVERE IN SEEMINGLY HEALTHY YOUNG ADULTS. THIS DEGENERATIVE PROCESS PROBABLY BEGINS EARLY IN LIFE, AS FATTY STREAKS EMERGE IN THE CORONARY ARTERIES OF CHILDREN AS YOUNG AS AGE FIVE. LITTLE HARM EXISTS FOR MOST PEOPLE UNTIL THE CORONARY ARTERIES BECOME MARKEDLY NARROWED. FIGURE 6 SHOWS THAT ATHEROSCLEROSIS INVOLVES DEGENERATIVE CHANGES IN THE INNER LINING OF THE ARTERIES THAT SUPPLY THE HEART MUSCLE.

THE ACTION AND CHEMICAL MODIFICATION OF VARIOUS COMPOUNDS, INCLUDING OXIDATION OF CHOLESTEROL IN LOW-DENSITY LIPOPROTEINS, INITIATES A COMPLEX PROCESS THAT ULTIMATELY CAUSES BULGING LESIONS IN THE ARTERIAL WALL. THE LESIONS INITIALLY TAKE THE FORM OF FATTY STREAKS. WITH FURTHER DAMAGE AND PROLIFERATION OF UNDERLYING SMOOTH MUSCLE CELLS, VESSELS PROGRESSIVELY CONGEST WITH LIPID-FILLED PLAQUES, FIBROUS SCAR TISSUE, OR BOTH. THIS CHANGE REDUCES THE VESSELS’ CAPACITY FOR FLOOD FLOW, CAUSING THE MYOCARDIUM TO RECEIVE DIMINISHED OXYGEN (ISCHEMIA) FROM INADEQUATE BLOOD FLOW.

THE ROUGHENED, HARDENED LINING OF THE ARTERY FREQUENTLY CAUSES THE SLOWLY FLOWING BLOOD TO CLOT. WHEN A BLOOD CLOT (THROMBUS) FORMS, IT PLUGS ONE OF THE SMALLER CORONARY VESSELS, CAUSING NECROSIS (DEATH) OF A PORTION OF THE MYOCARDIUM. WHEN THIS OCCURS, THE PERSON CAN SUFFER A HEART ATTACK OR MYOCARDIAL INFARCTION. WITH ONLY MODERATE BLOCKAGE (BUT WITH BLOOD FLOW REDUCED BELOW THE HEART’S REQUIREMENT), THE PERSON MAY EXPERIENCE TEMPORARY CHEST PAIN TERMED ANGINA PECTORIS. THE PAINS USUALLY MAGNIFY DURING EXERTION BECAUSE INCREASED PHYSICAL ACTIVITY CAUSES A GREAT DEMAND FOR MYOCARDIAL BLOOD FLOW. ANGINA ATTACKS PROVIDE VIVID EVIDENCE OF THE IMPORTANCE OF ADEQUATE OXYGEN SUPPLY TO THE MYOCARDIUM.

WOMEN AT RISK

WOMEN HAVE INCREASED THEIR RISK FOR DEVELOPING CHD. SINCE 1910, MORE AMERICAN WOMEN HAVE DIED OF HEART DISEASE THAN ANY OTHER CAUSE. BECAUSE WOMEN DEVELOP HEART DISEASE 10 TO 15 YEARS LATER IN LIFE THAN MEN, THEY MORE LIKELY HAVE HEART ATTACKS WHEN PAST MIDDLE AGE. ONLY 1% OF WOMEN UNDER AGE 45 DEVELOP CHD, WHILE 13% ABOVE AGE 75 SHOW CLINICAL HEART DISEASE MANIFESTATIONS. THIS SEX-AGE DIFFERENCE IN HEART DISEASE EPISODES MAKES CHD APPEAR AS A MORE PERVASIVE AND DRAMATIC PROBLEM IN MEN; A HEART ATTACK FOR A 75-YEAR-OLD WOMAN SEEMS LESS SHOCKING THAN FOR A MALE “WAGE EARNER” WHO SUFFERS AN ATTACK IN THE PRIME OF LIFE. INCREASED CHD FOR WOMEN IN LATER YEARS PARTLY RELATES TO LOSS OF PROTECTION OFFERED BY ESTROGEN, WHICH DECLINES MARKEDLY AFTER MENOPAUSE. DESPITE LIMITED HEART DISEASE RESEARCH ON WOMEN, AVAILABLE EVIDENCE INDICATES THAT DISEASE SYMPTOMS, PROGRESSION, AND OUTCOME DIFFER IN WOMEN AND MEN. SOME INTERESTING SEX-RELATED HEART DISEASE DIFFERENCES INCLUDE:

FOLLOWING A HEART ATTACK, WOMEN USUALLY DIE SOONER

WOMEN WHO SURVIVE A HEART ATTACK FREQUENTLY EXPERIENCE A SECOND EPISODE

WOMEN BECOME MORE INCAPACITATED BY HEART DISEASE-RELATED PAIN AND DISABILITY

WOMEN ARE LESS LIKELY TO SURVIVE CORONARY ARTERY BY-PASS SURGERY

SEVERAL FACTORS SEEM CLEAR: A SIMILAR PROCESS PROBABLY EXISTS FOR CHD DEVELOPMENT IN MEN AND WOMEN, I.E., FATTY DEPOSITS NARROW CORONARY ARTERIES AND REDUCE BLOOD FLOW TO THE MYOCARDIUM. HORMONAL DIFFERENCES MAY ALSO AFFECT BLOOD CLOT FORMATION, CORONARY ARTERY SMOOTH MUSCLE CELL PROLIFERATION, AND THE TENDENCY OF CORONARY VASCULAR WALLS TO SPASM IN THE FINAL STAGES PRECEDING A HEART ATTACK. MOREOVER, CHD DIAGNOSIS MAY DIFFER IN WOMEN AND MEN. DIAGNOSTIC TESTS, LIKE THE TREADMILL STRESS TEST AND ECG RESPONSE, HAVE LIMITED USE WITH WOMEN BECAUSE MEN HAVE PROVIDED THE SUBJECT POOL FOR TEST VALIDATION. A DIAGNOSTIC GAP ALSO OCCURS BECAUSE SOME PHYSICIANS DO NOT TREAT HEART DISEASE SIGNS IN WOMEN AS AGGRESSIVELY AS IN MEN. CONSEQUENTLY, THEY DO NOT PRESCRIBE CORONARY ANGIOGRAPHY (THE MOST VALID WAY TO DIAGNOSE CHD) AS OFTEN FOLLOWING A POSITIVE STRESS TEST.

DESPITE A LOWER CHD RISK, PREMENOPAUSAL WOMEN ARE NOT IMMUNE FROM HEART DISEASE, PARTICULARLY IF THEY SMOKE. CIGARETTE SMOKING ACCOUNTS FOR ALMOST ONE-HALF OF ALL HEART ATTACKS IN WOMEN BEFORE AGE 55. SMOKING AS FEW AS FOUR CIGARETTES DAILY DOUBLES A WOMEN’S CHD RISK. HYPERTENSION ALSO EXISTS IN MORE THAN 50% OF WOMEN OVER AGE 55 WHO SUFFER A HEART ATTACK; AFTER AGE 65 IT AFFECTS TWO-THIRDS OF FEMALE VICTIMS. ELEVATED BLOOD SUGAR AFFLICTS WOMEN MORE OFTEN THAN MEN. THE PRESENCE OF EITHER TYPE 1 OR TYPE 2 DIABETES RAISES A WOMAN’S CHD RISK TO EQUAL THAT FOR A NONDIABETIC MAN OF THE SAME AGE, AND PUTS HER RISK OF DYING FROM A HEART ATTACK EVEN GREATER THAN THE MAN’S. USE OF BIRTH-CONTROL PILLS ALSO RAISES A WOMAN’S CHD RISK.

RISK FACTORS FOR CORONARY HEART DISEASE

VARIOUS PERSONAL CHARACTERISTICS AND ENVIRONMENTAL FACTORS IDENTIFIED OVER THE PAST 45 YEARS INDICATE A PERSON’S SUSCEPTIBILITY TO CHD. IN GENERAL, THE GREATER THE NUMBER OF THE RISK FACTORS, THE MORE LIKELY CORONARY ARTERY DISEASE EXISTS OR WILL EMERGE IN THE NEAR FUTURE. THIS DOES NOT MEAN THAT A SPECIFIC RISK FACTOR CAUSES DISEASE, AS DIVERSE FACTORS MAY ACT AND INTERACT IN A CAUSE-AND-EFFECT MANNER. HOWEVER, RISK FACTOR IDENTIFICATION AND PRUDENT MODIFICATION IMPROVES AN INDIVIDUAL’S CHANCES TO AVOID CHD.

THE FOLLOWING RISK FACTORS CAN BE MODIFIED:

CIGARETTE SMOKING

PHYSICAL INACTIVITY

HYPERTENSION

ELEVATED BLOOD LIPIDS

ABDOMINAL-VISCERAL ADIPOSITY

DIABETES MELLITUS

OBESITY

HIGH FAT DIET

ECG ABNORMALITIES

ELEVATED HOMOCYSTEINE LEVELS

HIGH-STRUNG, NERVOUS PERSONALITY

PSYCHOSOCIAL CHARACTERISTICS OF WORK (E.G., LOW JOB CONTROL AND LOW PAY)

HIGH URIC ACID LEVELS

PULMONARY FUNCTION ABNORMALITIES

TENSION AND STRESS

THE FOLLOWING RISK FACTORS ARE CONSIDERED FIXED, I.E., THEY CANNOT BE MODIFIED.

AGE

GENDER

HEREDITY

RACE

MALE PATTERN BALDNESS

QUANTIFYING THE IMPORTANCE OF EACH CHD RISK FACTOR IN RELATION TO THE OTHERS BECOMES DIFFICULT BECAUSE MANY OF THE FACTORS INTERRELATE. FOR EXAMPLE, BLOOD LIPID ABNORMALITIES, DIABETES, HEREDITY, AND OBESITY OFTEN GO HAND-IN-HAND. IN ADDITION, INCREASING DAILY PHYSICAL ACTIVITY GENERALLY LOWERS BODY WEIGHT, BODY FAT, BLOOD LIPIDS, TENSION, STRESS, AND RISK FOR DEVELOPING TYPE 2 DIABETES.

FOUR “TREATABLE” FACTORS (ELEVATED SERUM LIPIDS, HIGH BLOOD PRESSURE, PHYSICAL INACTIVITY, AND CIGARETTE SMOKING) REPRESENT PRIMARY RISK FACTORS FOR CHD. BODY FAT AND PERSONALITY TYPE PROVIDE LESS PREDICTIVE VALUE THAN THESE FOUR. ALTHOUGH SOME RISK FACTORS LINK CLOSELY WITH CHD, THE ASSOCIATIONS DO NOT NECESSARILY INFER CAUSALITY. IN SOME INSTANCES, RISK FACTOR REDUCTION MAY NOT OFFER EFFECTIVE PROTECTION FROM THE DISEASE. NONETHELESS, A PRUDENT APPROACH TO PREVENTING CHD ASSUMES THAT ELIMINATING OR REDUCING ONE OR MORE RISK FACTORS DECREASES THE LIKELIHOOD OF CONTRACTING CHD.

AGE, SEX, AND HEREDITY

AFTER AGE 35 IN MALES AND AGE 45 IN FEMALES, THE CHANCES OF DYING FROM CHD INCREASE PROGRESSIVELY AND DRAMATICALLY. CONSEQUENTLY, AGE PER SE REPRESENTS A SIGNIFICANT CHD RISK FACTOR. FROM THE PERSPECTIVE OF CAUSALITY, HOWEVER, CHRONOLOGICAL AGE SYMBOLIZES MORE OF AN ASSOCIATIVE RISK BECAUSE OF ITS CLOSE LINK TO OTHER MORE LIKELY “CAUSAL” RISK FACTORS LIKE HYPERTENSION, ELEVATED BLOOD LIPIDS, AND GLUCOSE INTOLERANCE.

BETWEEN AGES 55 AND 65, ABOUT 13 OF EVERY 100 MEN AND 6 OF 100 WOMEN DIE FROM CHD. AT MOST AGES, WOMEN FARE MUCH BETTER THAN MEN. FOR EXAMPLE, IN MIDDLE AGE, A MAN HAS ABOUT A SIXFOLD GREATER CHANCE OF DYING FROM A HEART ATTACK. AMERICAN WOMEN STILL LEAD ALL OTHER COUNTRIES IN HEART DISEASE; THE SPECIFIC “GENDER ADVANTAGE” DECREASES SIGNIFICANTLY AFTER MENOPAUSE. THIS HAS FUELED SPECULATION THAT HORMONAL DIFFERENCES BETWEEN THE SEXES PROVIDE CHD PROTECTION FOR WOMEN. FOR SOME UNKNOWN REASON, HEART ATTACKS THAT STRIKE AT AN EARLY AGE TEND TO RUN IN FAMILIES.

BLOOD LIPID ABNORMALITIES

OVERWHELMING EVIDENCE LINKS HIGH BLOOD LIPID LEVELS WITH INCREASED HEART DISEASE RISK.

CHOLESTEROL AND TRIGLYCERIDES

TABLE 1 AND 2 PRESENTS SERUM CHOLESTEROL, TRIGLYCERIDE AND LIPOPROTEIN LEVELS, ABOVE WHICH YOUNG AND OLDER ADULTS SHOULD SEEK ADVICE ON TREATMENT. IN GENERAL, A CHOLESTEROL VALUE OF 200 MG•DL-1 OR LOWER REPRESENTS A DESIRABLE LEVEL. A CHOLESTEROL OF 230 MG•DL-1 INCREASES HEART ATTACK RISK TO ABOUT TWICE THAT OF A PERSON WITH 180 MG•DL-1, AND A VALUE OF 300 MG•DL-1 INCREASES THE RISK FOURFOLD. THE TERM HYPERLIPIDEMIA REFERS TO AN INCREASED LIPID LEVEL IN BLOOD PLASMA.

|TABLE 1. SERUM CHOLESTEROL AND LIPOPROTEIN CLASSIFICATIONS |

|TOTAL CHOLESTEROL |CLASSIFICATION |

|>200 MG•DL-1 (5.2 MMOL•L-1) |DESIRABLE |

|200-239 MG•DL-1 (5.3-6.2 MMOL•L-1) |BORDERLINE HIGH |

|< 240 MG•DL-1 (6.2 MMOL•L-1) |HIGH CHOLESTEROL |

|LDL CHOLESTEROL |CLASSIFICATION |

|>130 MG•DL-1 (3.4 MMOL•L-1) |DESIRABLE |

|130-159 MG•DL-1 (3.4-4.1 MMOL•L-1) |BORDERLINE HIGH |

|< 160 MG•DL-1 (4.1 MMOL•L-1) |HIGH |

|HDL CHOLESTEROL |CLASSIFICATION |

|>35 MG•DL-1 (0.9 MMOL•L-1) |LOW |

|TABLE 2. SERUM TRIGLYCERIDE CLASSIFICATIONS |

|SERUM TRIGLYCERIDES |CLASSIFICATION |COMMENTS |

|>200 MG•DL-1 |NORMAL | |

|200-400 MG•DL-1 |BORDERLINE HIGH |CHECK FOR ACCOMPANYING DYSLIPIDEMIAS |

|400-1000 MG•DL-1 |HIGH |CHECK FOR ACCOMPANYING DYSLIPIDEMIAS |

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