2Learning ObjectivesLearn how height, weight, and body composition change with agingUnderstand how muscle size and composition, strength, and neuromuscular function are altered with agingDiscover what changes occur in cardiorespiratory function and aerobic and anaerobic function with agingFind out how aging affects the ability of older people to respond to various forms of training(continued)
3Learning Objectives (continued) Determine how these alterations in physiological function affect athletic performanceLearn how aging affects the ability of older people to respond to environmental stress: heat, cold, and altitudeUnderstand the relationship between a physically active lifestyle and longevity and the risk of injury and death
4Voluntary Running Activity in Rats Throughout Life Adapted, by permission, from J.O. Holloszy, 1997, "Mortality rate and longevity of food-restricted exercising male rates: A reevaluation," Journal of Applied Physiology 82:
5Aging Effects vs. Reduced Physical Activity Since physical activity tends to decline substantially as we age, distinguishing between the effects of aging and those of reduced physical activity on physiological function is difficult, especially in cross-sectional study designs.
6Height, Weight, and Body Composition Reduced height starting at ~35-40 years oldDue to compression of the intervertebral disks and poor postureOsteoporosis: severe loss of bone mass with deterioration of the microarchitecture of boneWomen age 40-50Men age 50-60Contributing factors include: poor diet and exercise habits throughout life, and decreased estrogen after menopause
7Changes in (a) Body Height and (b) Weight in Men and Women up to 70 Years of Age Reprinted, by permission, from W.W. Spirduso, 1985, Physical dimensions of aging (Champaign, IL: Human Kinetics), 59.
8Height, Weight, and Body Composition Increased weight typically occurs between ages (mainly fat) due to:Decreased physical activity levelsIncreased caloric intakeReduced ability to mobilize fat storesBeyond age 45 weight stabilizesAfter age weight decreases due to decreased appetite
9Height, Weight, and Body Composition Fat-free mass decreases progressively in both men and women beginning at ~ age 40-45Loss of muscle associated with the aging process is called sarcopeniaMuscle protein synthesis in 60- to 80-year-olds is about 30% lower than in 20-year-olds, and is associated with declines in growth hormone and insulin-like growth factorBone mineral density decreases with age (resorption exceeds synthesis) starting at years of age in women and in men
10Changes in Muscle Mass With Aging Adapted, by permission, from I. Janssen et al., 2000, "Skeletal muscle mass and distribution in 468 men and women aged yr.," Journal of Applied Physiology 89:
11Height, Weight, and Body Composition With training, older men and women can reduce weight, percent body weight, and fat mass and increase fat-free massMen appear to experience greater changes in body composition than women
12Differences in Body Weight and Composition in Young and Older Men and Women, Sedentary and Endurance TrainedAdapted, by permission, from W.M. Kohrt et al., 1992, "Body composition of healthy sedentary and trained, young and older men and women," Medicine and Science in Sports and Exercise 24:
13Body Composition and Aging Key PointsBody weight tends to increase with aging, whereas height decreasesBody fat increases with age due to increased caloric intake, decreased physical activity, and reduced ability to mobilize fatBeyond age 45, fat-free mass decreases due to a decrease in muscle and bone mass—both resulting at least partly from decreased activityTraining can help attenuate these changes in body composition, even in individuals as old as years of age
14Strength and Neuromuscular Function Maximal strength decreases with agingDeclines start ~ age 40 in men and womenCorrelated with reductions in muscle cross-sectional areaIncrease in type I muscle fibers and possibly a decrease in type II muscle fibersChange in fiber type may be due to decreased type II a-motor neurons and/or axonal sprouting from type I a-motor neuronsTraining may attenuate the change in muscle fiber type
15(a) Maximal Leg Strength and Speed of Standing and (b) Peak Knee Extensor Strength in Strength-Trained and Untrained Men Across the Lifespan
16Computed Tomography Scans of the Upper Arms of Three 57-Year-Old Men of Similar Body Weights UntrainedSwim-trainedStrength-trained
17Strength and Neuromuscular Function Motor unit activation is slower with agingOxidative enzyme activities in muscle decline slightly (10-15%) in endurance-trained older athletesThe number of capillaries per unit muscle area is similar in old and young athletes
18Changes in Muscle Fiber Type Composition in Elite Distance Runners Who Remained Highly Trained, Stayed Fitness Trained, or Became Untrained
19Strength and Neuromuscular Function Key PointsMaximal strength decreases steadily with aging, resulting primarily from a loss of muscle massIn general, normally active people experience a shift toward a higher percentage of type I muscle fibers as they age, possibly attributable to a reduction in type II fibersThe total number of muscle fibers and the fiber cross-sectional area decrease with age, but resistance training appears to lessen the change in fiber area(continued)
20Strength and Neuromuscular Function (continued) Key PointsAging appears to slow the nervous system’s ability to respond to a stimulus, process the information, and produce a muscular contractionTraining cannot arrest the process of biological aging, but it can lessen the impact of aging on performance
21Cardiovascular Function: Central Mechanisms .VO2max declines with aging (~1% per year)Decrease in maximal heart rate (HRmax)HRmax = [208 – (0.7 x age)]Downregulation of 1 receptors in the heartMaximal stroke volume is fairly well maintained in highly trained older adults but is reduced in untrained men and womenResponses to myocardial contractility and catecholamine stimulation are reducedDecreased maximal cardiac output due primarily to a decrease in HRmax
22Cardiovascular Function: Peripheral Mechanisms Peripheral blood flow decreasesIncrease in (a-v)O2 difference in older endurance athletesO2 uptake is similar in young and older endurance athletes
23Leg Blood Flow During Cycling Exercise in Young and Middle-Aged Orienteers Adapted, by permission, from B. Saltin, 1986, The aging endurance athlete. In Sports medicine for the mature athlete, edited by J.R. Sutton and R.M. Brock (Indianapolis: Benchmark Press). Copyright 1986 Cooper Publishing Group, Carmel, IN.
24Cardiovascular Function Key PointsMuch of the decline in endurance performance with aging can be attributed to decreased cardiovascular functionHRmax decreases ~1 beat/year as we ageCardiac output decreases with age because of the reduction in HRmaxStroke volume is maintained in older endurance athletes but declines in untrained peoplePeripheral blood flow decreases with age, but in trained older athletes this is offset by an increase in submaximal oxygen extraction by the working muscle(continued)
25Cardiovascular Function (continued) Key PointsIt is unclear how much of the decrease in cardiovascular function with aging is attributable to aging alone and how much is attributable to deconditioningThese cardiovascular changes are attenuated in older athletes who continue to train
26Respiratory FunctionVital capacity and forced expiratory volume in 1 sec decrease linearly with agingResidual volume increasesTotal lung capacity remains constantMaximal expiratory ventilation decreases with ageChange in pulmonary function is due to loss of elasticity of the lung tissue and chest wallDecreased pulmonary ventilation capacity does not decrease aerobic capacity in older athletes
27Aerobic and Anaerobic Function .Age-Related Reduction in VO2maxDecrease is largely explained by decreased Qmax due to decreased HRmaxDue to decreased sympathetic responsiveness and cardiac conductionSVmax and (a-v)O2 diffmax do not typically change with ageReduced blood flow to active muscles is associated with the reduction in Qmax..
28VO2max in Normally Active Older Adults, and Older Athletes .VO2max in Normally Active Older Adults, and Older AthletesNormally Active Older AdultsVO2max steadily declinesVariation dependent on activity levelOlder AthletesResults from studies differ (longitudinal vs. cross-sectional studies), but in general there is a similar decline in VO2maxSmaller reduction in VO2max compared to normally active or sedentary adults, particularly with training at high intensities...
29Cross-Sectional and Longitudinal Declines in VO2max With Age in a Group of Master Endurance Athletes .Adapted from S.A. Hawkins et al., 2001, "A longitudinal assessment of change in VO2max and maximal heart rate in master athletes," Medicine and Science in Sports and Exercise 33:
30Changes in VO2max With Age for Trained and Untrained Men .Changes in VO2max With Age for Trained and Untrained Men
31Factors Influencing the Decline in VO2max With Aging .GeneticsGeneral activity levelIntensity of trainingVolume of trainingIncreased body weight and body fat mass and decreased fat-free massAge range, with older individuals experiencing greater declines
32Aerobic and Anaerobic Function Key PointsAerobic capacity generally decreases by ~1% per year in sedentary men and womenSimilar declines are observed in endurance trained older adults, but VO2max will remain higher than in their sedentary counterpartsOlder athletes who continue to train have significantly smaller decreases in VO2maxLactate threshold, expressed as a percentage of VO2max, increases with aging, but decreases when expressed in relation to the absolute VO2 at which it occurs....
33Physiological Adaptations to Exercise Training Older adults get the same benefits from exercise training as younger and middle-aged adultsAging does not impair the ability to improve muscle strength or muscle hypertrophyEndurance exercise training produces similar absolute gains in healthy people, regardless of their age, sex, or initial level of fitnessWith endurance training, an increase in VO2max in older exercisers results mostly from improvements in muscles’ oxidative enzyme activities.
34Sport PerformanceRecords in running, swimming, cycling, and weightlifting indicate that we are in our physical and physiological prime in our 20s and early 30sPerformance generally declines with aging beyond age 30-35Most athletic performances decline steadily because of decrements in endurance and strength
35Change With Age in Men’s and Women’s World Records for (a) 100 m and (b) 10 km Runs
36Change With Age in 100 m Freestyle Swimming World Records Among Masters-Level Competitors
37Changes in U.S. National Masters Powerlifting Records With Age Among Male Weightlifters
38Environmental Stress Exposure to the Heat Increase in heat-related deaths over the age of 70Attenuated skin blood flowDecreased redistribution of blood flow to the skinEndurance training (sufficient to increase VO2max) can improve heat stress responsesThe impaired ability of older individuals to tolerate exercise in the heat is due to reduced aerobic capacity and impaired cardiovascular adaptations.
39Changes in Body Core Temperature in Response to Young and Older Subjects Exercising in a Warm EnvironmentAdapted, by permission, from W.L. Kenney, 1977, “Thermoregulation at rest and during exercise in healthy older adults,” Exercise and Sport Sciences Reviews 25:
40Environmental Stress Exposure to Cold and Altitude Reduced ability to generate metabolic heat due to decreased muscle mass and loss of fitnessAttenuated cutaneous vasoconstrictionAdapt through behavioral thermoregulation
41Longevity and Risk of Injury and Death An active lifestyle appears to be associated with a small increase in longevity, but more importantly it leads to a higher quality of lifeThere is an increased risk of injury from exercise as people age, and injuries tend to be slower to healThe risk of death during exercise is not increased in those who are regularly active but is increased in those who seldom exercise