C HAPTER 17. C HAPTER 17. AGING AND THE OLDER ATHLETE. AGING AND THE OLDER ATHLETE. w Discover what changes occur to muscles with aging and how these changes affect athletic performance. (continued). Learning Objectives.
AGING AND THE OLDER ATHLETE
AGING AND THE OLDER ATHLETE
w Discover what changes occur to muscles with aging and how these changes affect athletic performance.
w Compare the changes in strength and endurance records with aging.
w Learn what cardiorespiratory changes occur with aging and the effects of training on these changes.
w Find out how training affects biological aging and learn the differences in aging and physical activity.
w Learn the effects of aging and training on body composition.
w Discover the trainability of older athletes for strength and endurance.
Since physical activity tends to decline substantially as we age, distinguishing between the effects of aging and those of reduced physical activity is difficult when studying lifelong changes in physiological function.
Sports Performance and Aging
w Running, swimming, cycling, and weight-lifting records indicate that we are in our prime during our 20s and early 30s.
w Some swimmers have seen their best swimming performances in their 40s and 50s; this is often attributed to improvements in swimming technique, skill, and endurance.
w Performance generally declines with aging beyond our prime, primarily due to decrements in muscular and cardiovascular endurance and strength.
w Central and peripheral circulation decrease
w Aerobic capacity decreases about 1% per year
w Maximum heart rate decreases
w Stroke volume decreases
w Cardiac output decreases
Changes in VO2max Among Normally Active Men
Age VO2max % change from (years) (ml kg min ) 25 years
35 43.1 -9.6
45 39.5 -17.2
52 38.4 -19.5
63 34.4 -27.7
75 25.5 -46.5
Comparing per unit of body weight might not accurately measure decline in VO2max because we tend to gain weight as we age, which falsely lowers the VO2max per unit of body weight and because these values do not account for a person's initial VO2max. Comparisons should be based on the percentage change in VO2max in L/min.
Did You Know…?
w Aging alone may not necessarily decrease VO2max.
w When you keep intensity and volume of training high, your rate of decrease in SV and VO2max with aging slows, especially between ages 30 and 50 and less so after age 50.
Studies of Older Athletes
w There are individual differences in the rate of decline with aging.
w Prior training offers little advantage to endurance capacity later in life unless you stay active.
PERCENT CHANGE IN VO2MAX
CHANGES IN VO2MAX WITH AGE
w VEmax decreases after maturity
Respiratory Changes With Aging
w Vital capacity (VC) and forced expiratory volume in 1 s (FEV1.0) decrease linearly
w Residual volume (RV) increases
w Total lung capacity (TLC) remains unchanged
w RV:TLC increases (less air can be exchanged)
w Elasticity in lung tissue and chest walls decreases
w Limitations in oxygen transport to the muscles and a decreased a-vO2 diff are the main causes for reduced VO2max.
Respiratory Aging and Performance
w Endurance training in middle and older age reduces the loss of elasticity from the lungs.
w The pulmonary ventilation capabilities of endurance-trained athletes are only slightly decreased with aging.
w Arterial oxygen saturation does not decrease during strenuous exercise for normally active older adults.
Maximal heart rate can be estimated with the following equation:
HRmax = 220 – age
However this estimates an average value for a given age; individual HRmax can vary by ±20 beats per minute or more.
w Qmax decreases due to decreased HRmax and SVmax.
w VO2max decreases due to reduced blood flow to active tissues and reduced Qmax.
Cardiovascular Changes With Aging
w HRmax decreases due to decrease sympathetic nervous system activity and changes in cardiac conduction.
w SVmax decreases due to increased total peripheral resistance and decreased left ventricular contractility.
Aging alone might decrease cardiorespiratory less than the deconditioning that occurs with inactivity, decreased activity, or decreased intensity of training. If body composition and physical activity are kept constant, VO2max decreases only 2% to 5% per decade, rather than the 10% per decade normally attributed to aging.
w Maximal strength decreases
w Muscle mass decreases
w Percentage of ST muscle fibers increases
w Total number and size of muscle fibers decreases
w Nervous system response slows
w Little change in oxidative enzyme capacity or number of capillaries
While endurance training does not prevent the aging loss in muscle mass, strength or resistance training can maintain or increase the muscle fiber cross-sectional area in older men and women.
Environmental Stress and Aging
w The capacity to perform normal activity at high altitude is not reduced with aging.
w Aging might provide some protection against the symptoms of acute altitude sickness, HAPE, and HACE.
w The ability to adapt to exercise in the heat is reduced due to reduced sweat production with aging.
w Increased dietary intake
w Decreased physical activity
w Reduced ability to mobilize fat
After age 30, fat-free mass decreases due to
w Decreased muscle mass
w Increased bone mineral loss
w Decreased physical activity
Body Composition and Aging
Physical training can help offset age-related changes in body composition.
w Produces similar gains in healthy people regardless of their age, sex, or initial fitness level
w Produces greater improvement in muscle oxidative enzyme activities than in younger endurance-trained athletes
w Produces increases in muscle strength and muscle hypertrophy
Trainability of the Older Athlete