both physical and mental health benefits and can lower the risk of acquiring many disease processes. Frailty is defined as “an age-associated biological syndrome characterized by decreases in the biological functional reserve and resistance to stressors due to changes in several physiological systems, which puts individuals at special risk for poor outcomes from minor stressors” (Cadore et al., 2014). Frailty can cause disability, loss of independence and hospitalization (Cadore et al., 2014). Biological aging is associated with declines in muscle power, neuromuscular systems and cardiovascular systems, which can cause a decline in a person’s ability to perform daily activities. Aging combined with the loss of muscle mass has been associated with higher levels of DNA damage and deteriorated anti-oxidant defense (Franzke et al., 2015). Those with chronic diseases, such as cardiovascular disease, Type-2 diabetes and cancer, show increased levels of DNA damage (Franzke et al., 2015). Franzke et al. published a study in 2015 showing that exercise with resistance training and cognitive training produced similar biomechanical changes and demonstrated enhanced anti- oxidant defense. Functional capacity also is said to decline with age. A deterioration of functional ability can decrease a person’s ability to perform basic daily activities. One study showed that 28 percent of men and 66 percent of women 75 and older could not lift objects that weighed more than 4.5 kg (Evans & Meridith, 1989). A reduction in dynamic muscular strength between the ages of 50 and 70 ranged from 24 to 36 percent according to a study by E.B Larson, 1991.
Not only can functional capacity decline with age, gait speed can also reduce as we get older. Gait speed can be associated with survival in older adults, according to a study performed by Studenski et al., 2011 based upon data collected between 1986 and 2000. Life expectancy based on age and sex alone provides limited information since survival can also be influenced by health and functional ability (Studenski et al., 2011). Gait speed has been shown to reflect health and functional status and is recommended as a potentially useful clinical indicator of well-being among the older adults (Studenski et al., 2011). Gait speed can predict survival because walking requires energy, movement control and support, in addition to placing demands on multiple organ systems including the heart and lungs, and the circulatory, nervous and musculoskeletal systems (Studenski et al., 2011). When a person walks with a slower gait speed, it may be indicative of damaged systems and the person may be experiencing a high-energy cost of walking (Studenski et al., 2011). Walking speed may be indicative of damaged systems, but can also alert health-care providers to a possible reduction of physical activity that can lead to deconditioning. If a health- care provider is aware that gait speed may be directly linked to the amount of physical activity the person performs, they may refer the patient to a physical or occupational therapist for a supervised exercise program to enhance overall health and function. If a person presents in the clinic with a slower gait speed, this may also cue physical and occupational therapists to obtain a more detailed medical history and to monitor the patient more closely if there are other co-morbidities present.
Adapted from the “Summary of Typical Changes in Physiological Function and Body Composition with Advanced Age in Healthy Humans.” Variables Typical Change Functional Significance Muscle Function Muscle strength and power. Deficits in strength and power predict disability in old age and mortality risk.
Isometric, concentric and eccentric strength declines from about age 40, accelerates after age 65 to 70. Lower body strength declines at a faster rate than upper body strength. Power declines at a faster rate than strength.
Muscle endurance and fatigability.
Endurance declines.
Unclear, but may impact recovery from repetitive daily tasks. Impaired balance increases fear of falling and can reduce daily activity.
Balance and mobility.
Sensory, motor and cognitive changes alter biomechanics. These changes, in addition to environmental risk factors, can adversely affect balance and mobility. Reaction time increases. Altered control of precision of movements. Declines are significant for hip, spine and ankle flexion by age 70, especially in women. Muscle and tendon elasticity decreases.
Motor performance and control. Flexibility and joint ROM.
Impacts daily activities, increases risk of injury and task learning time. Poor flexibility may increase risk of injury, falling and back pain.
Cardiovascular Function
Cardiac function.
Max HR, stroke volume and cardiac output decline. Slowed HR response at exercise onset. Altered diastolic filling pattern, reduced left ventricular ejection fraction percentage and decreased HR variability. Aorta and its major branches stiffen, vasodilator capacity and endothelium-dependent dilation of most peripheral arteries decrease. BP at rest increases. BP during submaximal and maximal exercise is higher in old versus young, especially in older women.
Major determinant of reduced exercise capacity with aging.
Vascular function.
Arterial stiffening and endothelial dysfunction increase CVD risk.
Blood pressure.
Increased systolic BP reflects increased work of the heart.
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