Dr. Hirsch is Professor of Clinical Internal Medicine and Public Health Sciences, Division of General Medicine, UC Davis Medical Center, Sacramento, CA.

"Exercise: the Universal Antidote for Aging" appeared as the title of an 2009 article in the Johns Hopkins Medical Letter: Health After 50. If we didn’t know better, we might dismiss the title as reminiscent of tabloid hype for phony, over-simplified "cure-alls." It sounds too good to be true.

There’s just one problem with dismissing it as quackery: there are volumes of solid evidence that shows that exercise reduces the risk for a litany of serious diseases and conditions. It lowers our risk of breast, colon, and possibly prostate cancer. It improves our physical function and slows decline in general and in specific diseases like knee osteoarthritis. It prevents and treats type 2 diabetes mellitus,reduces fall risk, and lowers the risk of Alzheimer disease. And it reduces our risk of death from heart disease — and from any cause.

Seventy percent of U.S. adults over the age of 65 are either sedentary or not active enough to reap the health benefits from their exercise.

The 2008 Physical Activity Guidelines for Americans recommend that older adults get at least 75 minutes of vigorous, aerobic physical activity or 150 minutes of moderate-intensity activity per week, together with muscle-strengthening exercises two or more days per week. However, 70% of U.S. adults over the age of 65 are either sedentary or not active enough to reap the health benefits from their exercise.

National surveys in the last 20 years have shown major declines in how much exercise seniors are getting. What’s more, the same studies show that people over 60 are having more problems executing simple, everyday activities.

Physical inactivity among older people is both a public health concern and an important medical condition that can affect an individual’s basic functioning, quality of life and risk for chronic disease, both physical and mental. While it is, of course, a good idea to add exercise to your life, there are a number of issues involved in the safety of starting such a routine.

This article looks at the many and well-studied effects of exercise on seniors’ health as well as discusses some of the challenges of beginning an exercise routine. Done safely, and under the guidance of a doctor or trainer, it’s virtually never too late to begin adding exercise to your life — and life to your years.
Reducing Mortality with Exercise

As many people by now know, activity is linked to a significantly reduced risk of death from any cause, and from heart disease in particular. But because of the nature of studying exercise habits, it is difficult to tell whether active people are active because they are healthier in the first place, or whether activity makes you healthier. One study found that seniors 65 and older who added exercise to their lives had lower mortality and fewer hospitalizations than people who remained inactive.

The older you get, the more you can lower your risk of death or disability by being physically active, compared to sedentary individuals in your age group.

Other studies have found that people who stop their exercise habits do not have any less risk of death than those who never exercised, which suggests that continuing exercise is a crucial factor. Not only does exercise improve health and reduce the risk of death, but it also improves one’s ability to keep up with everyday activities like housework, grocery shopping, and basic activities like getting up from a low seat or getting out of your car. The older you get, the more you can lower your risk of death or disability by being physically active, compared to sedentary individuals in your age group. Even moderate physical activity has been shown to help seniors retain their ability to do recreational and household activity.

Strength Training Can Prevent Age-Related Functional Impairment

As many know, aging is linked to a decline is muscle mass, which can contribute to problems in motor movements. Approximately 12-25% of men and women 60-65 have reduced grip strength and slower gait, and the number rises to over 40% by age 80. This has a real impact on everyday life: for example, in crossing the street fast enough at crosswalks.

Even little changes in muscle mass can have significant changes in muscle performance.

Muscle loss is a particular concern for women, who are more likely to be impaired and ultimately disabled than men. Studies have found that the more muscle loss in the legs (determined with tests of knee extension strength), the greater the odds of having mobility disability in the years to come. These lower extremity measures reflect a variety of abilities (such as balance and stride length and are influenced by a wide variety of physical and neurological conditions. Older persons with poor strength in their upper legs are more likely to experience substantial slowing in their gait speed and to lose the ability to climb stairs or walk a kilometer during the next three years.

Seniors who add intensive resistance training have been shown to increase gait speed and overall physical performance. One study found that the effect of exercise can be exponential: sedentary, frail seniors who began exercise routines built their muscle mass by less than 2%. But their knee extension strength increased by 8%, suggesting that even little changes in muscle mass can have significant changes in muscle performance.

The relationship between exercise and seniors’ physical performance is a bit of a chicken-and-egg issue, but there is some good evidence to suggest that exercise improves everyday functioning (like rising from a chair and climbing stairs), and more studies are currently underway to explore this relationship.

Some promising interventions have involved short-term home physical therapy (PT) for community-dwelling frail seniors focusing on improving indoor mobility and gait, reducing the presence of environmental hazards, and providing a progressive exercise program designed to be continued without supervision. These interventions have been shown to result in a significantly slower decline in everyday activities, and half the loss of rapid gait speed, twice the ability to rise from a chair, and three times the ability to quickly perform essential tasks like taking a jacket on and off and picking up an object from the floor.

It should be said that severely frail seniors may not have such a marked benefit from exercise intervention, though they may experience some improvement. This may be seen as all the more reason to begin being active sooner than later.
Preventing and Treating Specific Conditions

Falls
Over one-third of persons over age 65 fall each year, which can have serious consequences, including hip fracture, permanent loss of independence, institutionalization and even death. Just the fear of falling itself can result in people placing significant restriction on themselves and their physical activity. This can lead to a vicious cycle of worsening leg strength, gait instability and further restrictions of activity that increase one’s risk for falls.

Muscle weakness has been shown to be the biggest risk factor for falls (whether measured by leg strength or by grip strength), even more than history of falls, poor balance, or impaired gait.

There are many factors that influence the risk of falling,, and these can be categorized as "intrinsic" (e.g., muscle weakness, visual impairment, cognitive impairment) and "extrinsic" (e.g., taking multiple medications and environmental hazards like throw rugs and lamp cords). Experiencing just three risk factors together – hip weakness, balance instability and taking more than 4 medications – has been associated with a 100% occurrence of falls after one year in a sample of older patients.

Muscle weakness has been shown to be the biggest risk factor for falls (whether measured by leg strength or by grip strength), even more than history of falls, poor balance, or impaired gait. Though the results are somewhat mixed, the American Geriatrics Society (AGS), the British Geriatrics Society (BGS) and the American Academy of Orthopaedic Surgery (AAOS) Panel on Falls Prevention still recommended exercise programs with balance training as an important component of an intervention to reduce falls in high-risk community-dwelling seniors.

The jury is still out on what types of strength training are best, how intense they should be, and how long the program should last, and the best methods to improve balance. A version of Tai Chi C’uan, modified for seniors, has been shown to be a promising method of reducing fall risk in seniors.

The AGS, BGS and AAOS recommend a long-term exercise and balance-training program for people who have fallen more than once, although this recommendation is based on expert opinion rather than hard data. It is also unclear how much of the exercises (including gait and balance training) should be conducted in a supervised environment by trained instructors and when or if older patients can safely perform these exercises on their own. The effectiveness of these interventions for actual patients will, of course, vary because of the differences in the types of interventions and in trainers who supervise them. It is important to talk to your doctor about the various programs and trainers available; he or she can advise you on what will work best given your specific needs.

Diabetes Mellitus
We all know that diabetes is strongly linked to being overweight and obese. As people age, the ratio of muscle to fat declines, which increases one’s insulin resistance, a major risk factor for diabetes. In the United States, these age-related changes in body composition, combined with the rise in overweight and obesity in adults, have resulted in a rise in diabetes in people over 65 from 20% to 27% in the past decade. Taking up exercise in middle age – even if you have not been active in your younger years – can actually prevent the development of diabetes. One study found that among non-diabetic people (average age=50) who had a borderline-elevated blood sugar (i.e., were at risk for diabetes), those who were randomly assigned to intensive lifestyle counseling increased their physical activity and had a significantly lower incidence of diabetes, compared to controls.

Both aerobic exercise (or "cardio") and strength training can improve blood sugar control in patients who already have diabetes, although studies have mainly focused on middle-aged adults. It is not so clear how long these changes last, but it is likely that if you maintain your change in lifestyle (and added exercise), your reduced risk for diabetes will persist.

Lifestyle changes, including exercise routines, are most effective when you have a personalized program, preferably with a trainer who works directly with you for at least six months, and takes into account your goals, abilities, and even your ethnicity and family history. Studies have shown that the majority of diabetic patients in exercise programs can often actually reduce their dose of medication after a period of time. Sticking to programs can be difficult, but studies have shown that those who do have much better blood sugar control than people who stop or don’t attend sessions regularly. Talk to your doctor about the options available in your community.

Osteoarthritis Of The Knee
The risk of developing knee osteoarthritis (OA) rises hugely after age 50, so that by age 80, about one-third of men and half of all women will have OA of the knee. However, just over 5% of men will have knee pain, compared to 16% of women. As knee OA progresses, it can cause pain, reduce a person’s mobility and increase difficulty in performing daily activities, all of which can lead to disability and reduced quality of life. But adding exercise to your routine can significantly reduce your risk for developing symptomatic OA. And adding an exercise program if you already have OA can vastly improve your mobility and can also reduce knee pain. One study found that seniors who took aerobic exercise or strength training courses for 18 months had significantly less disability that people who only received education about it.

Compared to the education group, the two exercise groups also reported less knee pain and had better scores on performance tasks like getting out of a car and the distance walked in six minutes. Not surprisingly, how well patients stuck to their exercise programs influenced how much their symptoms changed by the end of the study. Many studies have shown similar results that confirm the effectiveness of exercise interventions in reducing pain and disability scores in patients with knee OA.

More physical activity has been linked to better cognitive skills and a lower prevalence of mild cognitive impairment, a precursor to dementia.

The Osteoarthritis Service and Integration System (OASIS) endorses doing aerobic and/or strength training for OA of the knee. These studies also dispel the myth that walking as exercise is bad for patients because it can exacerbate knee OA. The OASIS group also tells patients that the choice of exercise can be based on availability, preference and tolerance. That said, certain sports may increase the risk of knee OA, and so should be avoided (for example, skiing and soccer are hard on the knees).

Cognitive Decline
Many large-scale studies have shown that higher levels of physical activity reduce the risk of Alzheimer disease, vascular dementia and all-cause dementia, There is also a link between physical functioning and physical activity, so that those with worse physical function who still engage in higher levels of physical activity experience the largest reduction in the risk of dementia. Even in studies of people without dementia, more physical activity has been linked to better cognitive skills and a lower prevalence of mild cognitive impairment, a precursor to dementia. However, the protective effect of physical activity appears to be limited to those who do not carry the gene that is linked to Alzheimer’s, APOE ε4.51

There are not many studies that look into whether taking up exercise in old age helps with Alzheimer’s risk. But one study did find that a year-long, moderate-intensity aerobic training program in 87 sedentary older persons helped people maintain their memory performance better, while the control group’s scores decreased. Other studies have found similar results with cognitive ability, suggesting that adding exercise relatively late in life can ward off cognitive problems and memory loss More research will be needed to determine whether exercise can prevent the development of dementia, and some studies looking into this are currently underway.
How Much Exercise Is Enough?

It’s easy to understand that exercise helps relieve and prevent a wide range of health problems, mental and physical, but it’s harder to know how much we should really be doing to reap the benefits. Studies have found that there’s a "dose-response" effect for the benefit of exercise on preventing death from any cause and from heart disease in particular: this means that the more exercise you do, the lower your risk of disease.

Walking is the most common form of leisure-time physical activity for most seniors. As little as 28 blocks per week (roughly equivalent to 1.4 miles) have been shown to reduce the risk for mortality, dementia, depression and needing help with everyday activities.

That said, people who engage in more strenuous programs tend to have higher drop-out rates, so it is important to choose a program that is the right level for you and enjoyable to you. (Luckily, the amount of exercise you need to produce a significant reduction in risk declines with age.)

Walking is the most common form of leisure-time physical activity for most seniors. As little as 28 blocks per week (roughly equivalent to 1.4 miles) have been shown to reduce the risk for mortality, dementia, depression and needing help with everyday activities compared to people who remain sedentary. However, it appears that intensity, or briskness, of walking plays a more important role in its beneficial effects than the overall time spent walking (in other words, it’s better to walk more briskly for shorter periods of time than slowly for loner periods of time). By the same token, the less time people spend sitting has also been linked to reduced heart risk

How to Begin A New Exercise Routine

When adding a new activity routine, everybody, regardless of age, should do so carefully, and choose activities that are in line with their abilities. This is particularly true for seniors — especially if you have not been active for a long period of time. People who are the most sedentary or who are at risk for falling should always talk to a health care provider about how to embark upon an exercise routine.

Picking activities that you actually find engaging is key to sticking with a program. Exercising with others can also be a good way to boost your interest in what you do.

Your doctor can help you determine your activity level now, and how active you can be in the future. Doctors will also often speak with you about your motivation, usually by asking about your top reasons for wanting to become active. He or she can instruct you about the activities that will best fit your lifestyle, needs, abilities, and interests. Picking activities that you actually find engaging is key to sticking with a program. Exercising with others can also be a good way to boost your interest in what you do.

Beginning a new routine is not only a matter of physical readiness, but it’s one of mental preparedness as well. There is a process that we go through before beginning a new project: pre-contemplation (not even thinking about it) moves to contemplation, then to preparation for change, next to actively changing behavior, and finally to maintenance of that new behavior. Many factors can influence how likely we are to stay with a new activity: some doctors don’t even like to use the word "exercise," since it often holds such negative connotations for people!

Determining Your Abilities and Risks
People who are experiencing difficulties with daily activities will generally need to have special exercise counseling To determine your current physical activity capacity, doctors will often ask the following questions:

How much difficulty do you have…
  • Walking ½ mile (1 km)?
  • Climbing 10 steps?
  • Lifting 4.5 kg (10 lbs)
  • Reaching for objects?
(None, a little, moderate, a lot, can’t do at all)

To determine your fall risk, doctors should ask a variety of questions such as your recent fall history and their circumstances. He or she should also determine your visual acuity, inquire into what medications you’re taking and any medical conditions that could contribute to falls, and do a careful neuromuscular examination. Your doctor should also test your leg strength, gait, and balance. For example, he or she may ask you to stand up from a chair without using your hands to push off, towalk a short distance, turn, and walk back, and sit down. Using a range of tools, questions, and simple physical tests, your doctor can determine how mobile you are as well as your risk of falling, and, therefore, be able to help design an appropriate program.

A Word About Risk
There are certain risks associated with beginning exercise programs, depending on your heath status, age, weight, and other factors. You need to find a program that fits your current fitness level and your health. Your doctor can help you determine what a good level of activity will be; or he or she can refer you to a specialist or physical therapist to help design an appropriate plan. The risk for injuries appears to be fairly low if exercise routines are matched to the individual.

The brief Exercise and Screening for You (EASY) questionnaire has been developed for older people who are considering exercise. EASY helps seniors recognize health problems that could increase the risk of harm from increased physical activity and encourages those at risk to consult a physician prior to beginning an exercise regimen. For patients with symptomatic or significant coronary heart disease, heart failure or pulmonary disease, highly structured cardiac rehabilitation programs, where training is custom-tailored to your needs, can be very helpful. Enrollment in these programs generally requires a formal referral from a doctor.

What Are You Waiting For?

Staying active and avoiding a sedentary lifestyle have great potential for improving physical performance, preventing and delaying disability, preventing falls, improving blood sugar, slowing (and possibly preventing) cognitive decline, reducing disability and pain from knee osteoarthritis, and even prolonging life. Choosing activities that will work best for you given your particular needs, and talking to your doctor if you are unsure of what these might be, is important Make sure to choose activities that you actually enjoy doing, since you’ll be much more likely to stick with them if they are fun, rather than seen as an unappealing chore that must be done. And exercising with others, either as part of a formal program or with your neighbors and friends, can add to the enjoyment of becoming physically active. Remember, it’s never too late: beginning an exercise routine even in your golden years has been shown to offer significant health benefits, mental and physical. So get started (safely), and enjoy!