This is an imperative concept to the rehabilitation program. Education of the patient to non-pharmacological therapies in PR helps in improving adherence [26]. Education has a strong association with modification in health behaviors, self-management, and health-related outcomes [26]. The approach has been evolving, but the most commonly used methods are didactic lectures through web-based applications or social media platforms [23]. Knowledge about the disease process can empower the patients to understand disease pathophysiology, thereby resulting in ineffective interventions to manage the symptoms. In some research, it has been stated that education can play vital support for exercise training programs, thereby lowering the drop-outs rate in the PR. Hence education is a multifactorial aspect of the PR program. It must not be delivered in short courses but rather as an integral aspect to motivate the patients to continue the PR [23].

Another growing concern during the pandemic era for COPD patients is anxiety and depression or psychological issues. The critically ill patients surviving a protracted period of mechanical ventilation, complications, and long-drawn-out disease process are profoundly debilitated and may require psychoeducation aspect of PR [27]. The psychoeducation aspect of the PR refers to dealing with the psychological issues that the patient encounters in the disease process of isolation and, in some instances, social stigma because of disease. Motivational interviews, mindfulness practice, education regarding the disease process, and breathing exercises can be highly beneficial in the road to recovery [27]. Psychological, educational support is currently recommended during the PR’s educational component as the patient learns how to manage the signs and symptoms of anxiety and depression, which are usually associated with COPD and Asthma [28]. This concept has, however shown promising results in cardiac rehabilitation [26, 29].

Exercise training is the foundation stone of the PR program and helps in improving exercise performance and quality of living in Asthmatic and COPD patients [23, 30, 31]. Before starting any type of exercise training, it’s vital to determine the participants’ exercise capacity in the program. Exercise capacity evaluation can be done through cardiopulmonary exercise testing and field tests like six min walk test, shuttle walk test, and so on [32]. The rationale behind the exercise program is to increase physical fitness and mental fitness and thereby increase the social participation of the person, thereby decreasing the psychological aspect of disability [30]. Exercise also induces an anti-inflammatory effect in the body and strengthens the body’s immune response [33, 34]. This concept will be of vital importance in the management of patients post COVID-19 with COPD and Asthma.

Aerobic exercise is regarded as the best means to improve muscle functions and exercise tolerance in patients suffering from respiratory diseases [35]. Aerobic exercise could produce short-term safe improvements in the process of immune and respiratory systems. Exercise has an anti-inflammatory role and could improve immunity by improving immune cells and immunoglobulins’ function, regulating CRP levels, decreasing anxiety and depression [34]. The exercise also improves respiratory system functions by acting as an antibiotic and antioxidant effect [16]. Supported and unsupported exercises for both upper and lower limbs will be of vital importance using a subjective scale of rating to modulate the intensity of the exercise regime [34].

Patients with COPD and Asthma also show greater exercise intolerance, frequent bouts of dyspnea, more significant participation restrictions, and lower quality of life [36]. Aerobic exercises combined with bronchodilators can remove the struggle with most of the patients initiating the exercise program. The current guidelines for PR are programmed to two to five times a week for 6–12 weeks [23, 36]. It’s advisable to incorporate a short-acting b2-agonist before 15 min of starting the exercise to prevent exercise-induced airway hyper-responsiveness [23].

The exercise training workload is categorized based on a cardiopulmonary exercise test or field walking test (60–70% VO2 max or 60–80–100% Heart Rate (HR) max) with continuous or interval type of exercise for at least 20–30 min [23]. Mechanism related to the adaptations induced by aerobic exercise remains somewhat hypothetical [23]. It is usually postulated that peripheral muscle adaptations and sensitization due to exercise help reduce feelings of dyspnea, reduce respiratory rate, work of breathing, and bring about positive psychological effects to increase participation at societal levels [23].

Recently it has also been hypothesized that a moderate-intensity exercise regime can also play a vital role in modulating the pre-existing inflammatory states, boost the immune response, thereby may prevent or lower down the fatality rates among moderate to severe staging of COPD and Asthma in the population [17, 33].

3.2.2.2 Strengthening exercises. This training is an essential aspect of the PR program, which involves both upper and lower limb muscles. The concept is to repetitively lift moderate to high loads to strengthen peripheral muscles, which in turn augments the functional capacity of a person [37]. Another idea is to strengthen respiratory muscles. The approaches of respiratory muscle training (RMT) generally conceptualize on inspiratory muscle training (IMT) and expiratory muscle training (EMT) as training components. Inspiratory muscle training is still an inclusive part of the program, but EMT is still dubious [38].

3.2.2.3 Skeletal muscle strengthening. It is vital to select an appropriate exercise training strategy, which is to provide cardiovascular, pulmonary, and peripheral muscle involvement for the individual patient and should be targeted to maximize the effect of exercise conditioning [39, 40]. Resistance training of peripheral muscles may be well tolerated and results in a reduction in symptoms of COPD and asthma patients, thereby improving health-related quality of Life [37]. The upper and lower extremities training is designed according to the previous 1 Repetition Maximum (RM) Strength test [23]. The participants usually start with eight repetitions and progress it up to 10 reps. If the exercises are well tolerated, then the load should be increased by 2–10% [23]. The frequency of training ranges from three to five sessions weekly for a total duration of 15–20 minutes ranging from 6–12 weeks [23]. The Probable advantage of resistance exercise, which involves single muscle groups, may result in lower oxygen consumption and minute ventilation, and therefore it provides additive benefit to the training [23].

In the COVID19 era, these training have to be modified to shorter sessions with a careful watch on the patients’ oxygen saturation levels (SpO${}_2$). The affected population may present with profound hypoxemia at rest, without any proportionate signs of respiratory distress (i.e., happy hypoxemia) with rapid worsening [41, 42]. There might be signs of well-preserved oxygen saturation despite low partial pressure of oxygen in arterial blood samples due to the leftward shift of the oxyhemoglobin dissociation curve brought by hypoxemia-driven hyperventilation may possibly result due to direct viral interactions with hemoglobin [43].

3.2.2.4 Respiratory muscle strengthening. There is compelling evidence to support that inspiratory muscle strengthening has ameliorative effects on dyspnea in COPD and is endorsed activities in the pulmonary rehabilitation plan of care [38]. It has been reinstated through metanalysis of randomized controlled trials that IMT improves muscle strength, endurance, functional exercise capacity, reduces symptoms for dyspnea, and enhances the quality of living [44] in COPD. It has also been observed that an eight-week home exercise program with partial supervision to perform inspiratory muscle training (IMT) in patients with COPD and low maximal inspiratory pressure (Pi ${}_{max}$) was found to improve respiratory muscle strength and endurance dyspnea, and exercise performance. Dyspnea relief is also reported in trials combined with a lower stimulation of the diaphragm in the absence of any substantial variations in ventilation and breathing pattern [45].

For expiratory muscle training, a randomized controlled trial in COPD conditions outlines that the intervention for five weeks had improvement in the exercise capacity, symptoms, and quality of life. Still, the lung functions remained unchanged post-training [46]. The effect observed may be partially attributed to a change in expiratory muscle strength [46].

Most of the moderate to severe cases in COVID-19 usually affect the lung compliance system causing increased work of breathing and feeling of dyspnea [47]. Requirement of mechanical ventilation with intubation may be regarded as surrogate markers for severe illness and low lung compliance [47]. In such a scenario, post COVID-19 recovery patient during respiratory muscle training (RMT) exercising with a duration of 4 to 8 weeks in hypoxia usually results in (1) decreased respiratory muscle fatigue, (2) late respiratory muscle metaboreflex activation, (3) and better maintenance of oxygen saturation (SaO${}_2$) and blood flow to the active muscles [48].

In PR program, there is usually a need for devices to clear the mucus and improve pulmonary lung functions. These devices are an essential supplement to the program and increase patient adherence as they can use the therapy as a home program. These devices include the positive expiratory pressure (PEP), the high-frequency chest wall oscillation (HFCWO), the oral high-frequency oscillation, the intrapulmonary percussive ventilation, the incentive spirometry the flutter, and the Acapella and the Cornet. These devices may be administered after therapist discretion [49]. The apparatus, as mentioned earlier, seems to operate in bronchial hygiene and improve airway permeability, SpO${}_2$, and dyspnea.

A study found that airway clearance techniques are the most integral part of managing any acute exacerbation in chronic respiratory disease [50]. The study also found that the most frequently used ACTs were PEP devices (90%), at second directed huffing (88%), and third cough (71%) among physical therapy practices for airway management [50].

Usually, PR program is not recommended in the acute stage but only in the latent stage. Still, a noticeable precaution is required to use these devices for lung clearance in the latent stage. As these techniques may generate aerosol, if the patient has a risk of infection or re-infection, using these devices may be limited or done in isolation with appropriate use of personal protective equipment (PPE) is recommended [12]. There is also a need for a separate individualized approach for COPD and asthma patients requiring supplemental devices for treatment.

Breathing retraining may be considered as a complementary exercise training that is specifically used to induce relaxation, modulate the high respiratory rate and anxiety which may be encountered in COVID-19 patients with pre-existing COPD and Asthma through its role in pulmonary rehabilitation is still unclear [23]. Studies report that up to 30% of patients practice breathing techniques to regulate their symptoms [51]. The basic technique for breathing exercise utilizes breathing through the nose with slow breathing and pursed-lip expiration which is usually passive; it can be intermixed with controlled breath holds, and relaxation exercises can be managed in person by a therapist or home exercise telerehabilitation [23].

Airway clearance technique (ACT) in PR aims to remove sputum from the lungs during acute exacerbations of COPD or stable COPD [52]. Airway clearance techniques are the most prescribed and trusted techniques used during any acute exacerbations [53]. Authors observed in the survey that most prescribed ACTs among physical therapists were physical exercises (89%), followed by forced expiratory techniques (81%) and active cycle of breathing technique (79%) [53].

Obesity is an important risk factor for COVID-19 and may cause significant morbidity and mortality in the population with obesity [54]. It has been estimated that overweight people are at a higher risk of developing Asthma than patients with normal weights. Obesity is commonly stated comorbidity in asthma patients. It is also reported that the obese population grows a challenging situation to control asthma symptoms, with a poor prognosis of respiratory symptoms and decreased response to corticosteroid therapy [23]. Hence nutritional therapy will play a vital role in controlling obesity and promoting diet with anti-inflammatory effects and enhanced immune response. The western diets that promote obesity tend to be high in saturated fatty acids, sugars, and low fiber and anti-oxidants. Hence a single meal loaded with the aforementioned diet will increase neutrophilic airway inflammation and decreases bronchodilator responsiveness [55].

Moreover, exercise and weight loss programs can also play a decisive role in the program’s success for the afflicted population during COVID-19 era.

Self-management strategies are essential to modify the health-related domain by acquiring the knowledge and skills for self-care in COPD and Asthma [56]. A structured self-management program can reduce the number of hospitalization, thereby reducing the person’s social, mental, and physical aspects [56]. A structured self-management program consists of additional education regarding the disease process and respiratory management during acute exacerbations [56]. These self-management strategies can be directly linked to improved quality of life (QoL) in COPD and asthma population [57]. Some studies have also identified investment in leisure time activity also to be directly associated with QoL [57]. Decreased self-management of breathing issues has been associated with a lower level of QoL [57].

Chronic fatigue syndrome(CFS) is usually reported in rheumatic and other diseases [18]. The prevalence of chronic fatigue in the general population is reported to be 30%. Fatigue-like symptoms may develop in the acute stage of COVID-19 and progresses further as severe chronic fatigue syndrome [18]. As the current situation for COVID-19 is still evolving, early detection and management of post-viral fatigue (PVF) is recommended. A study surveyed participants with symptoms lasting more than 90 days and found the presence of COVID-19 post-viral fatigue [58]. Psychological, social, cognitive, behavioral, and emotional factors may be vital for long-term fatigue [59]. Currently, the non-pharmacological management of PVF in COVID-19 recommends using rehabilitation according to the available evidence [58, 60]. It is assumed that post-viral fatigue, which may be considered as a subacute form of chronic fatigue syndrome, may have management strategies similar to CFS [59].

It is usually recommended that a graded exercise regime be followed with periodic assessment after recovery [61]. Some authors also suggest that exercise in this population with CFS symptoms should be commenced vigilantly and abstain if the patient develops fever, breathlessness, severe fatigue, or muscle aches [18]. Cognitive therapy, energy conservation techniques, pacing could be vital therapies of management [59].

COVID-19 primarily affects the respiratory system in moderate, moderately severe, and critical cases [62]. Fatigue, anxiety, and depression are also commonly associated with the post-recovery phase [63]. Hence in the pulmonary rehabilitation phase, energy conservation techniques (ECTs) will play an essential role in breaking the vicious cycle of fatigue, anxiety, and depression among the afflicted population. ECTs are precisely intent at performing the activity of daily living (ADL) with low energy cost. To make the patients more functionally independent, it’s essential to conserve energy as much as possible. Energy is spent efficiently utilizing conservation techniques for each ADL, thereby constructing day-to-day activities in a thoughtful way [64].

A great number of human activities involve movement of the arms and legs. Even tasks that appear to be simple can cause higher oxygen uptake and minute ventilation, which may also induce the sensation of dyspnea. In the light of current evidence, it is foremost essential to evaluate the impact such activities have on daily life in a population with chronic obstructive pulmonary disease [65]. It will also be necessary to assess the affected population post-recovery to categorize the need for ECTs. A simple way could be by asking the patient to perform a common ADL. At the same time, the therapist examines the reaction time, execution, and total duration of the act, simultaneously recording the heart rate, respiratory rate, oxygen saturation, and dyspnea (if any) following the NYHA scale [65].

Some simple techniques can be used for ECTs as diaphragmatic breathing, controlling the cycles before, during, and after activity to avoid brief periods of apnea. In addition, respiratory exercises can be associated with upper and lower limb training, using subjective scales to monitor training intensity. It is crucial to commence with light, slow activities that require a reduced amount of energy expenditure, such as personal hygiene activities, followed by activities performed in sitting without upper limb support. It is also essential to modify the home and office environment to enhance the ergonomics or use assistive technologies that suit the patient’s need [65].