You are here: Introduction to Human Aging > Subtopic 2 > Exercise

Image: Elderly woman lifting weights

Effects of Exercise
If you ask most people if they want to grow old, the answer would be no. If you consider the alternative—not reaching old age—the answer should be an emphatic, YES! Now the question becomes: What do you want to look like when you get there? Do you want to be healthy and feel vital? Or do you want to reach old age with some physical or mental impairment? If you answered “healthy and vital,” now is the time to start with positive lifestyle changes. This section and the following will deal with the effects of lifestyle changes in exercise and diet. Keep in mind that these changes impact positively on health regardless of age, from children to the oldest-old.

Exercise will influence the total amount of fat and its distribution in people of all ages. Those who are physically fit will have less fat and more lean tissue and more favorable waist-to-hip measurements. Percent body fat increases consistently from age 25 to 65+ in men and women. Women experience a loss of bone and muscle starting at age 40 with an accelerated loss of each after menopause, around age 50. Bone loss may result from both loss of minerals and loss of muscle acting as a mechanical stress on the bone which would promote remodeling. Men, on the other hand, start losing lean tissue later, at age 50. Although the fat to lean ratio changes with age, the degree of individual variability among the elderly can be great. 

There are age-related shifts in hormone secretions. The anabolic hormones—growth, estrogen and testosterone—promote the laying down of tissues including protein and bone. Testosterone levels decrease by half that of young men by age 50. Estrogen levels drop precipitously during the first three years after menopause. Estrogen replacement therapy has been shown to preserve muscle mass and prevent the usual increase in intra-abdominal fat accumulation.

Physical activity can lead to a positive change in fat pattern.  Absolute weight may remain constant but there is usually a decrease in abdominal fat and iimproved waist-to-hip measurements. An exercise level of about 30 minutes a day can bring about these positive results.

A decrease in skeletal muscle mass is called sarcopenia. Muscle mass decreases by 50% over the course of adulthood. Loss of muscle strength results from a loss of muscle mass alone and not from a loss of the functional ability of the remaining muscle cells. This means that strength training can lead to an increase in muscle fibers and muscle mass, even in the elderly who are frail or in the oldest-old group. 

Endurance training leads to cardiovascular fitness and a loss of body fat without a significant increase in muscle mass. Resistance training, usually over the course of 10 weeks leads to an increase in muscle size and strength. Once training stops, however, muscles begin to atrophy after 4 weeks.

Apart from an increase in muscle mass and strength, exercise has many other benefits for the elderly. Improved walking ability and overall strength leads to greater independence as they can accomplish the tasks of daily living better and have fewer falls accompanied by hospitalizations.

Changing body composition from more fat to more lean increases basal metabolic rate since lean tissue is more metabolically active than adipose tissue. This means that the active, leaner person can take in more calories per kilogram body weight than an inactive person with more adipose tissue given the same weight. Higher calorie intake allows for more opportunities to take in nutrients in adequate amounts especially protein, and vitamins and minerals. The burden of consuming nutrient dense foods is lessened. Also, those who are concerned  about their physical condition are more likely to be concerned about their nutritional intake. 

In addition to a change in body composition, the location of the fat tissue is changed in the active aged with less accumulating in the visceral trunk region. Central body fatness is associated with increased risk of stroke, diabetes, hypertension and coronary artery disease. Weight loss and exercise are two of the few ways to increase high-density lipoproteins (HDL) that are protective against heart disease.

Mechanical stress on long bones provided by resistance training can prevent or improve osteoporosis and improve balance leading to fewer falls and breaks. Exercise can also lead to an increase in insulin sensitivity and improved blood glucose levels.

 

The immediate psychological benefit of exercise is relaxation and stress reduction. In the long-term, exercise can counter depression and anxiety. Depression is a major issue among the elderly. Loss of a spouse and/or functional ability can lead to depression. Depression may also be secondary to side effects of medication used to treat chronic disease. Exercising in a group setting offers an opportunity for socialization and is an important factor in maintaining an exercise program.

It would not be appropriate to recommend a generic exercise program for all elderly due to individual differences in health and fitness.  A good place to start is seeking advice from an exercise science professional. Those who have been sedentary should start with a thorough medical exam. Programs exist that are  tailored to clinical population groups: cardiac rehab, arthritis and diabetes.

The best programs for most elderly will include components of cardiovascular fitness, strength training and flexibility. Cardiovascular fitness involves moving large muscle groups in low-intensity, rhythmic activities like walking, swimming, jogging, biking. Benefit can be gained from as few as 2 to 3 exercise sessions a week. The ideal would be 5 to 6. The important point, though, is that once an exercise program is established, the gains in muscle strength, and fitness can be reversed within weeks of its cessation. Sadly, fewer than one out of three seniors exercises on a regular basis. The percentage decreases with age.

Chart source: Federal Interagency Forum on Aging-Related Statistics. Older Americans 2004: Key Indicators of Well-Being. Federal Interagency Forum on Aging-Related Statistics. Washington, DC: U.S. Government Printing Office. November 2004.

Although previously thought inappropriate for the elderly, low to moderate strength training is now accepted as part of an overall exercise program for older adults.

The declines in flexibility and range of motion that accompany aging can be due to a decrease in elasticity of the connective tissue and also a lack of physical activity. Stretching exercises can increase ankle, knee joint and lower back flexibility in the aged.

Exercise sessions can last from 45 minutes to an hour. Frail and previously sedentary individuals can start with sessions of shorter duration and work their way up. Many of the elderly were younger when the motto, “No pain, no gain” was in vogue. This is a myth. Low-intensity exercise can result in significant health benefits. According to Dr. Miriam Nelson, author of Strong Women Stay Young, strength training is the fountain of youth, capable of turning back the clock even for women in their 70s, 80s, and 90s.

More information on this topic can be accessed through the Texas Gerontology Curriculum Consortium at http://www.eastfieldcollege.edu/ger/future.html. (See course on Fitness and Wellness.)

Take the quiz on this section's content.