In the late 400s BC, Plato recognized that a “lack of activity has the potential to destroy the good condition of every human being, while movement and methodical physical exercise save it and preserve it.” Evidence-based exercise programs, such as pulmonary rehabilitation (PR) have been shown to optimize physical conditioning and improve health outcomes in patients with chronic respiratory disease (CRD). We discuss the evidence base for their use and consider if and how they may be utilized to prehabilitate “self-isolating” patients and promote positive lifestyle behaviors aimed at reducing the burden of COVID-19-related illness. Should we prehabilitate high-risk groups? Since the World Health Organization declared a global health pandemic on March 11, 2020, many patients in “high-risk” categories have been “self-isolating” to reduce their risk of contracting COVID-19. These include patients with CRD, such as chronic obstructive pulmonary disease, pulmonary arterial hypertension, and pulmonary fibrosis (1). While these public health orders have been a necessary first step to reduce the transmission of the virus, they also risk exposing patients to the negative consequences of physical deconditioning and a loss of cardiopulmonary and musculoskeletal fitness. Recent data from the UK Biobank have shown that lifestyle habits, such as physical inactivity, smoking, and obesity, are associated with an increased risk of hospital admission due to COVID-19 (2). For many patients, the ability to take part in exercise or disease-specific PR is an important component of their treatment. PR programs have been shown to reduce the risk of hospitalization in patients with CRD and to optimize exercise limiting factors, such as skeletal muscle function, respiratory muscle function, exertional dyspnea, and improve patients' overall quality of life (3–6). Educational elements of PR also help patients to self-manage their condition by providing guidance on nutrition and healthy lifestyle habits. Based on these data, structured prehabilitation exercise programs should be considered to prevent physical deconditioning and reduce the risk of hospitalization in this cohort. Traditionally, PR programs have been delivered in group outpatient settings, but COVID-19 infection control measures and travel restrictions meant that these have been suspended. Exercise professionals will, therefore, need to consider using technology to deliver remote or web-based versions of PR during the current pandemic. Practical considerations when delivering web-based PR Web-based PR programs conducted at home have shown to be well tolerated, achieve clinically significant results in 6 wk, and achieve comparable outcomes to center-based programs (7). Current guidelines recommend that patients should receive supervised PR alongside educational materials that promote long-term behavior change and compliance (8). It is important that patients obtain medical clearance before taking part in exercise and are prescribed exercises that are appropriate to their clinical condition and current level of fitness. A criterion standard for assessing maximal performance, oxygen uptake, and dyspnea in patients is a symptom-limited incremental cardiopulmonary exercise test on a treadmill or cycle ergometer in a laboratory setting (9). Exercise professionals can use the data obtained to devise an optimal rehabilitation program for patients with CRD. This is by no means a prerequisite for an exercise prescription and, in the current climate, is not feasible. Alternate validated tests should, therefore, be considered, such as the 6-min walk test alongside a measure of dyspnea or fatigue (10,11). Additional self-reported measures, such as the Short-Form-36 or Quality of Well Being Scale can be used to assess preintervention function and to assess post intervention outcomes (12). The aim of medical supervision during PR is to make sure that patients can safely engage in exercise and are aware of the “red flag” symptoms that would necessitate them stopping exercise. This is a particular challenge for web-based PR as facilitators will need to consider additional safety protocols to ensure that they can monitor the physiological status and clinical observations of the patients remotely. These include disease-specific peripheral oxygen saturation targets, blood pressure, and heart rate responses to exercise. To safely participate, patients also may require additional equipment, such as pulse oximetry, blood pressure, home oxygen, and nebulizer devices, to be prescribed. We explore the current evidence-based recommendations for existing PR programs and how they can be adapted to prehabilitate patients during the current times. Aerobic exercise training The goal of aerobic exercise training is to improve cardiorespiratory fitness and optimize ambulatory muscles (3,8). Training intensity can be monitored and adjusted using the Borg dyspnea score or an RPE scale (8). Patients should be challenged appropriately with the encouragement to build toward an RPE of 12 to 14 of 20 (8). The American College of Sports Medicine (ACSM) recommends a frequency of three to five times a week for aerobic training (13). Walking is the easiest way to train cardiovascular endurance, and it does not require any additional exercise equipment (8). Starting at baseline tolerance and building cardiovascular endurance to 60 min of continuous exercise should be an individualized goal; however, interval training can be an alternative (8). Interval training is ideal for those individuals who cannot sustain continuous bouts of exercise due to symptoms (8). To ensure symptom scores are low, less than 1-min intervals are recommended, which can be repeated after suitable rest periods (8,14). Resistance exercise training There are no specific resistance training guidelines for individuals with CRD; however, optimizing peripheral skeletal muscle function is an important goal in PR (8,13). CRD patients are at higher risk of sarcopenia and exhibit disease-specific patterns of peripheral skeletal muscle weakness that compromise their functional capacity (15). As a result, resistance exercises should involve major muscle groups with a variety of single joint and multijoint exercises. They should start at a resistance equal to 40% to 50% of one repetition maximum for 1 to 4 sets with 10 to 15 repetitions per set more than 2 d·wk−1 (8). Some patients may be able to progress to moderate-intensity resistance training at 60% to 70% of 1 repetition maximum. In addition, ratings of perceived exertion or dyspnea should be used to guide intensity and progression (8,13). Flexibility training There are no studies to show the efficacy of flexibility training in CRD, but it is commonly incorporated in PR as per the ACSM recommendations for healthy adults (13). Flexibility training should be performed a minimum of 2 d·wk−1, involving major muscle groups. Each static exercise is held for 10 s to 30 s, with 2 to 4 repetitions of each exercise (13). Inspiratory muscle training Inspiratory muscle training (IMT) has been proposed as a way to selectively improve the strength and endurance of respiratory muscles in patients with CRD, either as a stand-alone intervention or as an adjunct treatment to traditional PR programs. To date, studies have shown that IMT increases physiological measurement of inspiratory muscle strength, but it is unclear how this translates to exercise tolerance outcomes in patient already performing PR (16). There are currently no standardized protocols for IMT, but web-based IMT training protocols have been shown to be well tolerated and could be utilized for disease- or symptom-specific cohorts during the current pandemic (17). These include patients with evidence of significant respiratory muscle weakness or patients who cannot take part in PR due to severe exercise-limiting dyspnea. Conclusions PR is an evidence-based intervention that has been shown to improve the quality of life, cardiopulmonary, and musculoskeletal fitness of the patients. Individualized versions of PR should be considered as a novel way to prehabilitate “high-risk” patients with CRD during the current pandemic. These programs have the potential to promote physical activity and promote positive lifestyle behaviors that have been shown to reduce the risk of COVID-19-related hospitalization. Exercise professionals also should consider embracing digital technology to deliver web-based personalized training programs to patients who are currently “self-isolating” or unable to attend exercise facilities. Key Points Pulmonary rehabilitation programs have been shown to improve function and prevent hospital admission in patients with chronic respiratory conditions; Physical inactivity and poor lifestyle habits have been shown to increase the risk of COVID-19-related hospitalization; Clinicians and physiotherapists have the opportunity to supervise and adapt existing PR programs to improve the function and fitness of patients; Exercise clinicians will need to factor in additional protocols to safely deliver and supervise remote web-based prehabilitation programs during the current COVID-19 pandemic.