Exercise is one of the most underutilized treatment options in modern American healthcare which places an emphasis on medications and procedures. The benefits of exercise have been researched and documented by many groups and agencies over the past three decades. The American College of Sports Medicine (ACSM), 1 U.S. Centers for Disease Control and Prevention 2 , the U.S. Surgeon General, and the National Institutes of Health 3 have issued landmark publications on physical activity and health. 1,3,4 An exercise program that includes aerobic, resistance, flexibility, and neuromotor training is indispensable to improve and maintain physical fitness and health. 4 Despite this, physical inactivity has been cited as one of the greatest public health threats of the 21 st century. 5
Exercise has been shown to:
Exercise and physical activity are often overlooked as therapeutic treatment options. Additionally, prescribing exercise may be challenging as many patients are looking for an “easy fix.” When appropriately utilized, exercise can be an effective long-term treatment for many conditions. 10 The U.S. Department of Health and Human Services published Physical Activity Guidelines in 1996 and more recently in 2018. Recommendations for adults include at least 150 minutes a week of moderate-intensity aerobic activity, or 75 minutes a week of vigorous-intensity aerobic activity, or an equivalent combination of the two. ACSM defines moderate intensity as 3 to 5.9 metabolic equivalents (METs), 45-63% VO2 max, or 64-91% of maximum heart rate. They define vigorous intensity as greater than 6.0 METs, 64-91% VO2 max, or 77-93% of maximum heart rate (please also refer to Table 1). 4 Children and adolescents are encouraged to perform 60 minutes or more of physical activity daily, including aerobic, muscle-strengthening and bone-strengthening activities. 4 While these recommendations provide a general target for much of the population, many people need additional directions. Exercise prescriptions should be designed to meet the specific needs of an individual patient, geared towards their co-morbidities and age. Exercise prescription involves careful screening including history and physical examination to determine a patient’s capacity for physical activity, as well as a survey of their goals and interests. The evidence in favor of regular physical activity outweighs any inherent risk for adverse events. 11 Evaluating for issues such as cardiovascular, pulmonary, and metabolic health is an important part of an initial assessment. 12
An effective home exercise program should be individualized and directed to help the person develop fitness, maintain health, and/or treat specific conditions. 10 Special considerations need to be placed on pain, which can serve as a barrier and may lead to non-compliance. 13 Patients should be counseled on appropriate advancement or potential reduction of their exercise program. The person performing the exercise should be focused on maintaining proper form and what that feels like physically. Insistence on perfecting technique will allow the person to challenge him or herself while increasing strength and endurance gains, with less risk of pain or injury. Lastly, a home exercise program should prepare the patient for his or her normal activities, fitness needs/goals, occupation, sport, or recreational activities. Many well-intended practitioners prescribe exercises that are appropriate and fit the suggestions above, but do not assist the patient in returning to their desired job or activity. Other exercises can potentially put the area to be treated under too much strain, such as using resistance bands or weights to “strengthen” a still painful rotator cuff injury.
There are several methodologies to exercise prescription. One of the easier methods is the Frequency, Intensity, Time, and Type (FITT). The ACSM also recommends FITT-VP (Frequency, Intensity, Time, Type, Volume, and Progression). Utilizing these methodologies parallels writing a traditional medication prescription. Each component of the prescription provides a patient with specific information to incorporate aerobic, resistance, flexibility, and neuromotor exercise training into a fitness program. 14,6
Greenman’s idea of exercise discusses restoring length, strength and control of muscle function as the process of treating muscular imbalances. A successful exercise program restores nervous system control of muscle function as much as possible. To achieve this, he prescribes the following sequence:
Yet another method of exercise prescription, outlined by McGill, takes on a five-stage progression of training:
Additional consideration towards stages or progressions of the exercise can be made from the foundation laid by the initial prescribed regimen. While the recommendation of “some is good, more is better” is certainly well-supported, we should keep in mind that small and well-spaced increments will reduce the incidence of adverse events and improve adherence. 11 Progression of exercise allows the body to adapt to the stresses of it, from a musculoskeletal level. When exercise is progressed too quickly, patients are at an increased risk of injury. A patient must also understand how to recognize the difference between signs of exercise stress, such as increased heart rate and muscle soreness, and symptoms of overexertion or injury. 10 If a patient cannot perform the exercise due to pain, muscle tension or fatigue, various tools should be made available to the patient, such as medications – or other modalities such as massage therapy, TENS, manual therapy, etc. to facilitate the exercises. 17 Informing the patient that these symptoms generally improve after the first few days of starting or increasing a program can be helpful.
Current recommendations advise accumulation of moderate-intensity aerobic physical activity to attain a daily goal of around 30 minutes. Additional data is available to show that bouts of approximately 10 minutes each can be effective in attaining this goal and suggest that the volume of energy expended is more important than the duration of the exercise. 14 Large prospective studies of diverse populations show that an energy expenditure of approximately 1000 kcal/week of moderate intensity physical activity is associated with lower rates of cardiovascular disease and premature mortality. 14 Significant risk reductions for these have been shown to begin at volumes below the recommended targets, and as low as half the recommended volume. While measured kcal’s is useful, perhaps a more practical measure for aerobic activity is the MET. MET’s measure the absolute intensity of aerobic activity with 1 MET equivalent to the resting metabolic oxygen consumption rate of approximately 3.5 mL/kg/minute. 18 It is known that significant health benefits emerge with a volume of 500 to 1000 MET minutes/week and this volume can be met by walking at 3.0 mph, three days a week for 50 minutes. 18
Despite recommendations and guidelines, most people present with a variety of reasons why they do not exercise. Patients will note lack of time, lack of motivation, and poor ability to maintain adherence. Therefore, it is crucial to take these aspects into account when formulating an exercise prescription in order to increase compliance. 19 There are tools available to measure a person’s readiness to exercise more. The Physical Activity Readiness Questionnaire (PAR-Q) is a self-guided, seven question tool that can be used as a screening instrument. Engagement and finding activities that the person will enjoy doing also helps improve compliance with exercise. 20 For example, a person who enjoys socializing with others may be more successful when enrolled in group classes or participating in team sports rather than running on a treadmill alone. If a person is motivated and engaged, he or she may be more willing to find time to exercise. Other barriers include pain (pre-morbid and new onset due to premature exercise progression) or another medical condition that limits activity or the amount of activity that can be completed. Addressing these medical conditions or accommodating them by finding an alternative exercise can significantly improve their level of exercise adherence. For instance, a person with knee osteoarthritis, who experiences limitations with running, may do well with swimming or water aerobics in which the buoyancy of the water decreases the knee pain. 10,19 Another potential barrier is seen in those who are exercise novices or who have various physical impairments where more energy is required to perform what is typically thought of as low-intensity exercise. The ACSM uses walking at 3-4 mph as an example of moderate-intensity exercise. 4 However, people who are physically deconditioned, morbidly obese, or with various other physical impairments, walking at 3-4 mph may actually be vigorous exercise. These individuals can be taught to use tools such as heart rate or perceived exertion indices (e.g., Borg Perceived Exertion Scale) to monitor their activity. They can also be taught how to slowly increase the activity, starting with duration, frequency, or intensity. They should be taught not to increase all three at once. The ability of a personal trainer or physical therapist to provide additional instruction through close and frequent communication can help ensure compliance and safety. For individuals who cite time as a barrier, a physician can recommend utilizing high-intensity interval training (HIIT). As defined by the ACSM, HIIT is episodic, short bouts of high intensity exercise. For each high intensity bout, the lowest VO2 max should be 65% and the highest should be maximal possible effort. 4 HIIT differs from the more typical moderate-intensity continuous training as there is no fluctuation in aerobic energy expenditure in the latter. A recent meta-analysis on HIIT training for cardiometabolic health cited that compared to moderate intensity continuous aerobic training, HIIT may be more effective at increasing aerobic capacity and reducing risk factors associated with metabolic syndrome. Authors of one study encourage clinicians to incorporate HIIT, performed three times a week for at least 12 weeks, into exercise programs for obese patients. 19 Another recent review looking at HIIT in patients with coronary heart disease found that the optimal protocol involved short interval duration (15 seconds) and maintaining close work/recovery ratios. 20
A meta-analysis in 2016 quantified the dose-response association between physical activity and five chronic diseases (Diabetes, Ischemic Heart Disease, Ischemic stroke, Breast and Colon Cancer). They found that higher levels of total physical activity, compared to current minimums recommended by the WHO and ACSM, were associated with lower risk for all outcomes. 3 However, it should be noted that the dose-response relationship between volume and health benefits is curvilinear with the greatest return on investment at lower levels of activity and decreasing return of health benefits at higher levels of activity. 11
While the majority of the recommendations for exercise are targeted at the generally healthy adult or youth population, evidence suggests that specified exercise therapy prescriptions are beneficial for patient populations with certain co-morbidities. Guidelines and recommendations are available for chronic diseases such as diabetes, obesity, arthritis, peripheral arterial disease, COPD, coronary artery disease, multiple sclerosis, and cancer. Some of these diseases along with other specific conditions will be discussed below.
The benefits of physical activity on cardiorespiratory health are extensively well-documented. 4 Heart disease and stroke risks can be dramatically decreased with exercise. Regular aerobic exercise decreases arterial stiffness, reduces blood pressure, increases HDL, decreases LDL, and decreases resting heart rate. Exercise is known to decrease all-cause mortality in those with coronary artery disease. 4,21 But what is often overlooked are the benefits of the addition of resistance training to aerobic exercise. Resistance training and increasing skeletal muscle mass has similar effects as aerobic exercise and can complement the effects to further reverse disease and improve cardiovascular health. 22 Historically, several studies identified concerns that resistance training and strengthening exercises alone may increase arterial stiffness. However, recent studies have been inconclusive or contradictory by demonstrating actual improvement in arterial stiffness. 23
Results from the HF-ACTION trial (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) suggest that exercise therapy reduces cardiac mortality and hospitalizations in patients with coronary heart disease and that exercise therapy may be safely conducted in certain heart failure populations. 24 A recent meta-analysis found a reduction in the risk of re-hospitalization due to heart failure and improvements in health-related quality of life following exercise interventions. 25,26
The American Heart Association and the American Stroke Association have provided a detailed report on guidelines for prescribing exercise for stroke survivors across all stages of recovery. Points of emphasis include low- to moderate-intensity aerobic activity, muscle-strengthening activity, and reduction of sedentary behavior. 26 In terms of specific types of exercise for this patient population, community cycling exercise programs have been shown to significantly improve sit-to-stand capacity, activities of daily living, psychosocial functioning, energy, and depression. 27 A recent study also found that core stability exercises were beneficial in improving trunk control, core muscle strength, standing weight-bearing symmetry, and balance confidence of ambulatory patients with chronic stroke. 28 Additionally, forced, rather than voluntary, aerobic exercise can lead to enhanced motor skill acquisition when done prior to upper-extremity repetitive task practices. 29 Other specific exercise prescriptions being evaluated for stroke survivors include HIIT and physical exercise in real and virtual environments. 30,31
A review on exercise therapy for patients with multiple sclerosis (MS) found that combining aerobic training, strength training, and yoga yielded improvements in balance, dynamic gait, and symptoms of fatigue. 32 Resistance training programs have also been shown to improve lower limb isometric strength and functional capacity in people with MS. 33 Another review of exercise in neuromuscular disease (NMD) summarizes studies and information about a variety of neuromuscular conditions. Some basic recommendations for patients in this population include exercising carefully under physician supervision and targeting of certain muscles and breathing exercises rather than whole body aerobic conditioning. These recommendations include non-ambulatory individuals with NMD. 34,15 All in all, the current literature continues to confirm the benefits of exercise in MS patients, 35,36 but the absence of a conceptual framework and toolkit for translating this into practice remains a limiting factor in its implementation. 37
The ACSM published guidelines for physical activity in cancer survivors in 2010 with general recommendations. They instruct to avoid inactivity, and to continue exercise as soon and as often as possible. 38 Physical inactivity and obesity have been shown to increase a person’s risk of development and recurrence of certain cancers such as colon, breast, and endometrial. 39,40 For both aerobic and resistance exercises, the ACSM provided tumor-specific recommendations taking into account the pathophysiology and unique effects of specific cancer types (e.g. risk of pathologic fractures from bone metastasis or the risk of lymphedema status post mastectomy). The ACSM recommends a “low and slow” approach, and no upper limit on the amount of resistance an individual is capable of progressing towards. 38 A Cochrane Systematic review found that there is evidence supporting exercise for helping in fatigue related to chemotherapy either during or after adjuvant treatment. Aerobic exercise has been demonstrated to help in cancer-related fatigue in breast and prostate cancer patients specifically. Unfortunately, resistance training was not found to be as beneficial for improving fatigue. 41 One randomized controlled trial noted that the combination of both moderate intensity aerobic exercise and resistance training reduces the symptoms of chemo-induced peripheral neuropathy when used during treatment. 42 Caution must be taken with overtraining in individuals with hematologic malignancies who received hematopoietic stem cell transplantation, due to concern for adverse immune effects. 38 In general, exercise can reduce the incidence of a variety of cancers, inhibit the progression of cancer after diagnosis, alleviate the symptoms of cancer and the side effects of anti-cancer treatment, improve the tolerance of patients to treatment, and prolong patient survival. 43
The traditional advice to rest during pregnancy has changed, with current advice recommending a more active pregnancy. 44 Regular exercise during pregnancy promotes overall wellness and may reduce hypertensive disorders of pregnancy and gestational diabetes. 45 The American College of Obstetricians and Gynecologists recommends an exercise program of moderate-intensity exercise for at least 20-30 minutes per day on most or all days of the week for women with medical obstetric complications being monitored closely by their obstetrician. 45,46 The PARmed-X for Pregnancy is a tool that may be utilized by the healthcare provider to medically screen pregnant women for exercise therapy, track their progress with exercise, and monitor for indications to stop exercise. 47
In recent years, there has been excitement about exercise’s effect on cognition and potentially decreasing a person’s risk of dementia. Some research shows that immediate results of exercise include improved anxiety and sleep. With long-term exercise, there can be improvement in executive functioning including the ability to plan and organize, attention, processing, and emotional control. 4 Unfortunately, many studies have shown mixed results. Two recent randomized control trials found that a 3 to 4 month high-intensity functional exercise program can slow decline in ADL independence and improve balance in those with dementia. 48,49 However, a separate paper derived from one of those same studies showed no superior effects on global cognition or executive function. 50 A 2015 Cochrane review reported that there is promising evidence that exercise programs may improve the ability to perform ADLs but that there is a lack of evidence on their benefit on cognition. 51 Meanwhile, a meta-analysis performed in 2017 looked at the combined effects of cognitive and physical exercise training in people with mild cognitive impairment and found a small-to-medium positive effect on global cognitive function and a moderate-to-large positive effect for ADLs. 52 Interestingly, in the few studies that do show benefit, it appears that Tai Chi improves attention and processing when compared to no exercise. 53 Recently, an exercise trial conducted within individuals diagnosed with Lewy Body Dementia (PRIDE study) found that following high-intensity progressive resistance training, participants had improved functional independence, cognition, physical function, and strength. 54 Overall, more large volume, randomized-controlled trials regarding this topic are necessary in order to verify the utility of exercise in people with cognitive impairment/dementia.
Long COVID syndrome (LCS) has become readily apparent in patients previously infected with COVID. LCS is defined as symptoms lasting more than 12 weeks post COVID infection with the most common symptoms being breathlessness and fatigue. 55 It has been proposed that moderate activity promotes a healthy immunological response to infection, and possibly suppresses autoimmune activity in the absence of infection, whereas reduced activity impairs immune response to infection. 56 Various studies have demonstrated that different combinations of physical, aerobic, cardiopulmonary parameters, fatigue, cognition, perceived physical and mental health, depression and anxiety in LCS patients. 57,58,59 However, further research with large-volume and long-term studies must be completed as there is currently no clear guideline for exercise rehabilitation in patients with LCS. Regular exercise in these patients is important and can help return them to their prior level of function while promoting daily activities, independent living, and an increased quality of life. 59
The widespread availability of smartphones and tablets has increased the potential applicability of app-based exercise programs. The use of applications designed to administer preliminary instruction, real-time corrections during training, reward tones, positive feedback, and a summative report has been shown to promote motor learning, improve exercise performance, and reinforce/motivate patients to continue to exercise. 60 Studies have also been completed in patients with non-specific back pain, chemotherapy treated patients with advanced lung cancer and patients in the post-operative period after total knee arthropathy with results showing significantly improved exercise capacity, functional status, distress indexes, pain at rest and in motion and range of motion. 61,62,63 In terms of efficacy of app-based exercise, it was found that commercially available apps increased levels of cardiorespiratory fitness and improved body composition over 12 weeks to the same extent as supervised exercise sessions, showing that both are equally effective. 64 Of note, both the app-based intervention and supervised exercise intervention did not affect an individual’s level of moderate-to-vigorous physical activity. 64 One of the challenges regarding the use of apps remains sustaining long-term adherence and engagement of patients. More large-scale randomized-controlled trials are needed in order to fully determine the most feasible and effective method of utilizing app-based programs as early studies have already demonstrated its potential for promoting behavioral changes, changing behavior towards physical activity, and improving overall health and well-being. 63,65
Use of performance enhancing substances has become quite controversial. This is sometimes referred to as “doping.” Doping refers to the use of prohibited performance-enhancing drugs, hormones and growth factors, or methods (e.g., gene doping, blood doping, etc.) specifically used to enhance athletic performance beyond normal physiologic levels and not for the purposes of treating a legitimate medical condition. 66 Our role as physicians should be to direct our patients away from these substances and provide education on the harmful effects that can arise from their use.
Low-intensity resistance training combined with blood flow restriction (BFR) is gaining favor as an alternative means to increase muscular strength and hypertrophy. External pressure is applied to the area of interest and maintains arterial inflow while occluding venous outflow to the area. 67 Compared with low-load training, low-load BFR is more effective and tolerable, making it a good musculoskeletal rehabilitation tool in patients who would otherwise be unable to perform heavy-load training to increase muscular strength. 68 Potential safety issues of BFR include muscle necrosis and thrombus formation. Participants must be monitored closely by a qualified provider. BFR resistance exercise may be performed 2 to 3 times weekly for the same muscles, but higher frequencies may be implemented depending on individual training status and goals. Along with closely monitoring “time under occlusion,” it is also important to release pressure between sets to allow for adequate reperfusion. 67
Most exercise research is focused on outcomes for healthy adults. While current guidelines are available for the volume, intensity, and frequency of exercise for healthy individuals, additional research is needed to determine what guidelines would be beneficial for other specific populations. Further investigation into these disease processes will better emphasize the preventative and curative effects of exercise. Additionally, longitudinal studies to investigate how exercise impacts a person over a lifetime will also be helpful in further defining its role in maintaining overall health. Other directions include research and guidelines for those with physical disabilities, both congenital and acquired. The focus on acquired disability and aging will become more important in our nation as the American population becomes older and faces new health challenges. Additionally, accessibility to exercise at home with a personal trainer will continue to expand with growing comfort in telehealth and virtual communication platforms. As research and literature becomes more robust over time, it will become more evident that therapeutic exercise, when used in conjunction with medications and procedures, will lead to improved outcomes in our patients.
Table 1 Exercise Intensity
Adapted from ACSM 2018 guidelines 4
METs | %HRmax | %VO2max | |
Low | 1.6-2.9 | 50-63 | |
Moderate | 3.0-5.9 | 64-76 | 45-63 |
Vigorous | ≥6.0 | 77-93 | 64-91 |
Adam P. Cugalj, DO. Exercise prescription and basic principles of therapeutic exercise. 10/22/2013.
Kim Barker, MD. Austin Johnson, DO. Exercise prescription and basic principles of therapeutic exercise. 3/23/2017
Kim Barker, MD. Donald Kasitinon, MD. Exercise prescription and basic principles of therapeutic exercise. 10/5/2019
Alison Ho, DO
Nothing to Disclose
Kim Dan Do Barker, MD
Nothing to Disclose
Donald Kasitinon, MD
Nothing to Disclose