The Senior Athlete

General Considerations


  • It is widely accepted that the average life expectancy continues to increase; as it does, the proportion of older adults in the population also increases.

    • In Western industrialized countries, the average life expectancy increased from 47 years in 1900 to 78 years in 2007.

    • The number of individuals older than 85 years has increased by 232% from 1960 to 1990, along with a total population growth of 39% during the same period.

    • By 2030, 20% of the US population will be older than 65 years.

  • It is important to maintain a working knowledge of the anatomic and physiologic changes associated with normal aging and to be able to differentiate them from pathologic entities.

Physical Activity and Health Promotion

  • Numerous athletes are able to maintain a high level of participation and performance into their middle age and well beyond.

  • Cumulative recommendations from the American College of Sports Medicine (ACSM), the American Academy of Orthopaedic Surgeons (AAOS), and the American Heart Association (AHA) encourage older adults to maintain a physically active lifestyle with an emphasis on moderate-intensity aerobic and muscle-strengthening activities, as well as activities that promote increased flexibility and balance for older adults who are at a risk of falls.

  • Evidence over the years has demonstrated that senior athletes are not only able to participate in more endurance activities and competitive sports but also able to compete longer than ever and outperform historical comparisons.

  • This growth is demonstrated by the increasing number of athletes participating in the National Senior Games, marathons, and triathlon competitions.

    • Participation in the National Senior Games, which is a biennial competition for men and women aged ≥50 years, has increased from 2500 competitors in 1987 to >12,000 athletes in 2007.

    • Almost half of all US participants in marathons are aged over 40 years. One-fourth of marathon runners in their 60s are able to outperform half of the runners aged 20–54 years.

    • The overall participation in triathlons has increased by almost 60% since 2008, and now, an estimated 850,000 adults aged over 40 years compete in triathlons in the United States.

  • Despite increased rates of participation, older adults remain the least active group in the United States. Healthcare providers need to continue to counsel older adults regarding health benefits that coincide with an active lifestyle.

  • Several changes associated with aging can be limited, prevented, or even reversed with sustained exercise.

Physiologic Changes Associated With Aging

General Considerations

  • Aging is an individual process that is influenced by a multitude of factors, including genetics, ethnicity, culture, diet, illness, environmental exposure, occupation, and physical activity.

  • Age-related structural and functional changes occur at the molecular level and result in a gradual decline in the physiologic performance of virtually every organ system.

  • At the cellular level, multiple changes are observed:

    • Decreased capacity for division and cellular repair

    • Impaired exchange of nutrition, cellular waste, and oxygen

    • Intracellular accumulation of lipids and pigments

    • Lipofuscin—“aging pigment” breakdown product of erythrocytes that collects in multiple tissues, particularly smooth muscles and myocardium

Effects of Aging on Specific Physiologic Systems


  • An age-associated decline in cardiac output may be attributed to reductions in maximal heart rate, myocardial contractility, and stroke volume; these changes can result in an age-related drop in myocardial oxygen consumption/utilization (mVO 2 ).

  • Regular cardiovascular exercise and endurance training have been shown to increase mVO 2 in individuals aged up to 70 years.

  • Fatty and fibrous tissue deposits may occur in the myocardium that can interrupt normal conduction pathways, contributing to the occurrence of arrhythmias.

  • Cardiac valves may thicken and lose compliance, contributing to the formation of valvular regurgitation, clinically manifesting as a murmur.

  • Vascular physiology is affected by age-related changes in vascular compliance, microcirculation, and baroreceptor function; these changes, combined with atherosclerosis, can produce an increased peripheral vascular resistance, resulting in increased cardiac effort to maintain cardiac output.

    • Increased blood pressure and orthostatic hypotension are commonly observed as consequences of vascular changes.

    • Decreased capillary density and impaired vascular proliferation have also been implicated in reducing the exercise capacity of aging individuals.


  • Reduction in pulmonary microvasculature and alveoli number results in limitations in oxygen exchange and an increased sense of respiratory effort exerted during exercise.

  • Decreased lung compliance results from weakness of respiratory and accessory muscles, decreased alveolar tissue elasticity, and stiffening of costovertebral and sternocostal cartilages.

  • Overall, these changes contribute to a decrease in total lung capacity; vital lung capacity; inspiratory and expiratory air flows; and an increase in residual volume, respiratory frequency, and work of breathing.


  • A progressive loss in the number of glomeruli, along with increased vascular rigidity and atherosclerosis, results in a decreased glomerular filtration rate with aging. Coexisting renal disease and nephrotoxic medications can exacerbate this age-related decline.

  • In addition, the ability of the kidneys to concentrate urine decreases with age, resulting in a greater relative water output; this can negatively affect a senior athlete’s ability to remain adequately hydrated.


  • Progressive central nervous system deterioration has been shown to result in impaired hearing, short-term memory, balance, fine motor skills, and cognition. In addition, extrapyramidal dysfunction can result in impaired coordination and rapidity of motions and with a resultant increase in motor response time.

  • Even in the absence of any known neurologic disease, peripheral nerve conduction velocities are known to decrease with age, affecting vibration and proprioception nerve fibers first.


  • Progressive vision impairment is common with age. Typical changes include decreased visual acuity, accommodation, contrast sensitivity, peripheral vision, and ability to adapt to low-light situations.


  • As part of a normal consequence of aging, hormone levels gradually decline. Effects of this decline are noted in multiple organ systems:

    • With age, basal metabolic rate decreases, along with increased rates of metabolic syndrome, diabetes mellitus type 2, and obesity.

    • Adrenal function is reduced, resulting in decreased aldosterone and reduced ability to regulate fluid/electrolyte balance, as well as decreased stress response by cortisol.

    • Moreover, decreased rates of trophic hormones such as testosterone and insulin-like growth factor are associated with a decrease in skeletal muscle mass with age.


  • Senile sarcopenia is the age-related decrease in skeletal muscle mass. Between the ages of 50 and 80 years, an average person will lose one-third of their muscle mass. At the cellular level, decreased cell numbers and proliferative capacity of satellite cells leads to decreased muscle regeneration and response to injury. Extracellularly, dysfunction of actin-myosin cross-linking causes muscle units to become stiffer and more susceptible to injury, particularly muscular strains.

  • The structure of both ligaments and tendons changes with aging. Aging ligaments exhibit fewer fibroblasts and mechanoreceptors, which may contribute to decreased ultimate failure load and mechanical stiffness. On the other hand, aging tendons exhibit fewer fibroblasts and increased degenerative changes; this, along with a less robust blood supply (watershed areas), helps explain the epidemic of tendon injuries in senior athletes.

  • Articular cartilage is particularly susceptible to injury and degeneration with aging ( Fig. 13.1 ). Few, if any, chondrocytes are produced after skeletal maturity. Production of extracellular matrix proteoglycans is more variable with time, rendering them less effective. Response to mechanical loading is impaired by decreasing cartilage water content and more rigid collagen fibrils, secondary to increased cross-linking, which increases the risk of fissuring or shear injury.

    Figure 13.1, Osteoarthritis

  • With age, a progressive loss of bone mineral density results in compensatory widening of the diaphysis. Consequently, the susceptibility to fragility fractures and stress injuries increases.

  • Men exhibit a 0.5%–0.75% annual loss of bone mass after the age of 40 years. In women, bone mass decreases much more rapidly, at a pace of 1.5%–2.0% before menopause and accelerating further after menopause to up to 3% per year.

Decline In Athletic Performance With Aging

General Considerations

  • Successful care of aging athletes depends on understanding the differences between normal and pathologic aging.

  • It is well recognized that sedentary older adults exhibit more significant changes in functional capacity and body composition than adults who remain physically active as they age.

You're Reading a Preview

Become a Clinical Tree membership for Full access and enjoy Unlimited articles

Become membership

If you are a member. Log in here