Physical Activity for the Older Adult

by Susan Ingraham, Group Fitness Instructor (May 2024)

According to Canadian government guidelines, “Children and youth should get at least 60 minutes per day of moderate to vigorous physical activity involving a variety of aerobic activities. Adults, including seniors, should accumulate at least 150 minutes of moderate to vigorous physical activity per week.”

“On the bright side of this issue, decades of research has made clear that the changes in physical and mental capacities that occur with aging, the rate at which those changes occur, and the extent to which they occur can all be positively modified by a healthy lifestyle that includes regular physical activity and a nutritious diet. Equally positive is that regular physical activity improves a variety of health outcomes that are particularly relevant to older adults.”¹

What Changes with Aging?

A variety of changes occur in the body during aging. Simple tasks such as opening jars, lifting groceries, walking up or down stairs, rising easily from a chair, and maintaining balance can become much more difficult as one ages. As well, body weight tends to increase in many people after age 25. After age 65, body weight tends to gradually decrease in many older adults as appetite and physical activity decline and muscle mass is lost at an accelerated rate.

Although some changes are unavoidable, most of us can see positive results by eating a nutritious diet and participating in regular physical activity.

Here is a list of some of the basic changes which occur as we age²:

• Height decreases starting around age 35 due to compression of the gelatinous discs between vertebrae.
• Strength and neuromuscular function deteriorate, which can eventually interfere with daily activities.
• Some types of muscle fibres are lost.
• Muscle mass can begin to decline as early as age 30.
• An increase in body fat can occur.
• Maximal heart rate decreases with age at a rate of 1 beat per minute per year.
• Maximal stroke volume declines slightly with age, which is due to increased stiffness of the left ventricle and large arteries.
• Bone mineral content falls as bone synthesis slows and bone resorption increases.
• Reflexes slow and motor unit activation falls.

Most of these changes can be slowed or even improved with regular physical activity.

Health Benefits of Regular Physical Activity for Older Adults³

• Improved ability to accomplish activities of daily living
• Improved sleep quality, functioning and feelings of well-being, as well as perceived quality of life
• Increased loss of fat weight and increased prevention or minimization of weight gain
• Reduced risk of falls and related injuries
• Increased prevention or remediation of frailty and sarcopenia (see definition below)
• Reduced risk of cardiovascular diseases and osteoarthritis
• Improved physical function in multiple sclerosis
• Improved memory, processing speed, attention, and executive function (task initiation, emotional control)
• Reduced symptoms of depression, anxiety, and dementia
• Reduced risk of breast, colon, bladder, endometrial, esophageal, kidney, lung, and stomach cancers
• Reduced risk of (and part of treatment for) diabetes and hypertension
• Improved physical function in Parkinson’s disease and spinal cord injury

A Healthy Diet Is as Important as Exercise

“Older adults should strive to consume diets that are sufficient in energy (calories), protein, vitamins D and B12, omega-3 fatty acids, and antioxidants provided by whole foods (fruits and vegetables). A nutritious diet and regular physical activity help preserve muscle mass and neuromuscular⁴ function with aging.”⁵

“In addition to helping support muscle strength and mass in older adults, diets higher in protein (e.g. 1 gram of protein per pound of body weight per day) is associated with greater weight loss, more fat loss, and better protection of lean body mass.”⁶

“After retirement, many older adults move to warmer climates where staying well hydrated can be challenging. Being even slightly dehydrated day after day can impair cognitive function and increase the risk of chronic kidney disease.”⁷

“The muscle cells of older adults become less sensitive to the amino acids supplied by the diet (anabolic resistance), so muscle protein synthesis tends to be lower compared to younger adults. For this reason, adults should try to consume 40 grams of high-quality protein⁸ after exercise to optimize muscle protein synthesis.”⁹

How Can Exercise Training Benefit Older Adults?

“After age 60, the failure rate for opening the lid on a jar rises substantially. Loss of strength and muscle mass are due to [many things, including] … reduced physical activity, and inadequate protein intake.”¹⁰

“After age 40, sedentary individuals lose an average of 1% of their muscle mass each year along with a loss in strength that averages 3% per year. The severe loss of muscle mass and functional strength associated with aging and a sedentary lifestyle is called sarcopenia, a word coined in 1988 that means ‘poverty of flesh’ in Greek. Sarcopenia occurs as a result of poor diet and a lack of exercise, leading to a gradual decline in muscle mass and strength.”¹¹

“Strength training can slow the loss of certain types of muscle fibres, and physical activity that incorporates weight-bearing exercises helps slow bone loss. Reducing the loss of muscular strength, muscle mass, and bone mass during aging is critical in maintaining the ability to live independently, decreasing the incidence of accidental falls, promoting more rapid recovery from injury and illness, and improving the overall quality of life.

“With age, the normal close relationship between muscle mass and muscle strength is altered. Many older adults lose substantial muscle mass as they age, but if properly trained, can maintain sufficient muscle strength to preserve functional capacity and independence. It is also important that older adults maintain muscle endurance because leg muscles that fatigue quickly increase the risk of falling.

“Proper strength training improves an older adult’s ability to voluntarily recruit and activate the appropriate muscles. As well, improvements in muscle strength, endurance and power in older adults prolongs the ability to live independently, to accomplish activities of daily living, to recover more quickly from illness and injury, and to reduce the risk of falling.

“Endurance training has little impact on the loss of muscle mass with age. Only strength training preserves muscle mass with age while endurance training can slow the decline in breathing and respiration rates. Being physically fit also lowers the risk of heart attack and improves the outcome when a heart attack does occur.”¹²

“Regular physical activity lowers the risks associated with heat and cold exposure. Heat stress in particular can be a problem for older adults, especially for those who are ill or at a very low level of fitness. When older adults are exposed to heat stress, blood flow to the skin and sweating are less than in younger adults, causing core temperature to rise more quickly. Fortunately, aerobic training can improve blood flow to the skin, increase sweating, and enhance the distribution of blood flow among skin, active muscles, and internal organs. These adaptations improve heat tolerance in older adults.

“With cold exposure, the blood vessels of the skin constrict less in older adults; because muscle mass is typically lower, older adults have a reduced ability to generate and retain metabolic heat. These changes make older adults (especially the elderly) more susceptible to the cold.”¹³

Low bone mineral density in swimmers and cyclists appears to be due to increased bone resorption (minerals move from bone into the blood) during training along with a lack of adequate stress and strain to stimulate bone formation. Weight-bearing activities are better for bone health because bones are exposed to more stress and strain, stimulating bone-building osteocyte activity.¹⁴

Considerations in Designing Training Programs for Older Adults

Here are a few suggestions¹⁵:

• Include all aspects of physical fitness, including basic aerobic conditioning as well as conditioning exercises to improve muscular strength and mass.
• Multicomponent activities help improve agility, balance, and coordination.
• Intensity is more important than duration at improving physical function and health outcomes.
• Body-weight exercises (squats, lunges, toe stands, knee curls, pelvic tilts, and back extensions) can improve functional capacity and muscular strength.
• Strength training can also improve the aerobic capacity of older adults, particularly those who do little aerobic exercise.

Summary¹⁶

1. In sedentary individuals after age 40, the decline in aerobic capacity and muscular function (muscle mass, strength, etc.) approximates 1% to 2% each year.
2. The gradual reduction in aerobic capacity is largely a result of lack of exercise.
3. Loss of muscular function with aging is due to many things, including inadequate dietary protein intake and reduced physical activity.
4. With proper training, older adults can improve all aspects of physical fitness, although not to the levels achievable when they were younger.
5. Sarcopenia among the elderly increases morbidity and mortality but can be reversed with proper diet and exercise.
6. For older adults who are not able to meet current physical activity guidelines for exercise, small and brief bouts of activity such as stair climbing or brisk walking done on a regular basis (e.g. 3 days per week) can also confer benefits to fitness and health.
7. Physical activities that engage many muscle groups and require whole-body movements improve overall fitness and significantly reduce the risk of falling.