The COVID-19 is a highly contagious viral disease that has affected over 17 crore people worldwide and caused over 38 lakh deaths. The outbreak of COVID-19 was initially reported at the end of 2019 in Wuhan, Hubei, China. After the initial outbreak in China, the disease spread like wildfire, incurring deaths all over the globe. It is an acute disease that primarily targets the lung and is spread through droplet transmission.
Profiling COVID-19
The COVID-19 primarily affects middle-aged and elderly patients. The mean incubation period is about five days from exposure but ranges between 2 to 14 days. A higher risk of infection has been noticed in older, male patients, with medical comorbidities, patients with chronic pulmonary, cardiac, or kidney disease, and patients with diabetes. This scenario has changed considerably with the appearance of newer strains like the delta strain-B.1.617.2, responsible for the second wave of the pandemic in India. The delta strain is many times more infective, virulent, and more invasive than its parent strain.
The symptoms of COVID-19 are akin to other viral, upper respiratory illnesses. Gastrointestinal symptoms, including nausea, vomiting, or diarrhea, are present in a minority of patients. Alteration of taste and smell is suspected to be an early symptom of COVID-19.
To date, no proven effective treatment is available for COVID-19. Vaccination is the only known preventive medical strategy. However, questions do arise about the efficacy of the prevalent vaccines to prevent newer strains in circulation or those likely to be produced in the foreseeable future. Hence, prevention remains the only option available to manage the COVID-19 outbreak. Self-hygiene, social distancing, and using personal protective equipment like appropriate masks are, unfortunately, the sole preventive measures for COVID-19. To ensure strict social distancing, many countries across the world have undergone a complete lockdown, which unfortunately, is the only effective mechanism to cool off the rampaging epidemic, as presently ostensible in India. This has led to multiple psychological and physical complications, including anxiety, depression, and panic attacks, all known to downregulate the immune system, opening the floodgates to infection. Associated economic downturns featuring job losses and financial hardships have accentuated these psychiatric afflictions.
Innate immunity is the rapid-acting first line of defense that effectively inhibits infective agents from entering the body. If it fails, it facilitates the more powerful adaptive immunity to be generated.
Understanding Immunity, Our Armamentarium Against COVID-19
The human immune system comprises a vast effective network involving multiple organs, including the spleen, thymus, lymph nodes, tonsils, and bones. They mediate the death and destruction of intruding infective organisms using a vast array of specialised immune cells. Several chemicals are produced that directly neutralise these entities or activate cells that devour them. The immune system encompasses what is technically called ‘innate’ immunity and ‘adaptive’ immunity.
Innate immunity is the rapid-acting first line of defense that effectively inhibits infective agents from entering the body. However, if it fails, it also facilitates the more powerful adaptive immunity to be generated. This natural arrangement ensures that the present infection is driven out, but the memory of the infecting organisms is preserved to prevent further re-entry of such invaders.
This is one reason why COVID-19 reinfection does occur but is quite rare.
Innate immunity is garnered to restrict infections by pathogens that have never invaded before, COVID-19 being one such novel candidate. This immunological cascade appropriately arrests the disease. It helps to initiate the repair mechanism, thus ensuring the satisfactory resolution of infection and generating targeted resistance to defend the body against any reinfection by the same organism. In essence, the innate immune system activates the adaptive immune system. The adaptive immune system involves a bunch of blood cells that either devour the invading pathogen or generate chemicals that neutralise and help eliminate the pathogen.
Infection with COVID-19 may present with three different clinical scenarios:
1) asymptomatic carriers who have adequately functioning innate immunity,
2) symptomatic carriers with mild symptoms who achieve spontaneous recovery as innate immunity detects infection and restricts it while also generating adaptive immunity that optimally gets rid of the virus, and
3) patients who develop moderate to severe illness and may ultimately either recover or die from the infection.
In the third category of patients, the body’s immune reaction leads to either recovery from the infection or to die from it. In the last group of unfortunate individuals, the immune system is overwhelmed, leading to what is known as the ‘cytokine storm.’ This is a massive cascading release of chemicals by the immune system that initiates massive destruction of the body’s own organs and the invading organisms. This overexpression of the immune system actually results in multiorgan failure, ultimately leading to death. In essence, the virus does not directly kill. Instead, it triggers a violent immunologic reaction that is morbid and occasionally fatal.
Role of Yoga in Preventing Disease
To understand the role of Yoga in preventing disease, it is essential to grasp the above concept. Moderate to severe illness and death is triggered due to overwhelming unrestrained action of the immune system. It unleashes a barrage of deadly chemicals that enhance tissue destruction and organ failure, precipitating death. The primary amongst the candidate chemical suspected of perpetrating such mayhem is called Interleukin-6 (IL-6).
Mental Health Factors
Pandemic situations often contribute to increased anxiety, and in some cases, trigger or aggravate existing anxiety and panic disorders.
During the lockdown, many people experienced dullness, loneliness, boredom, and a lack of interest in any activity. Disturbed routines, a lack of positive interaction, and decreased physical activity are known to precipitate dysthymia and depression.
Studies have shown that even minor depression has a negative impact on the immunological system, which is associated with an increased risk of bacterial infection. Individuals with depression are found to have a 60% increased risk of infection as compared to non-depressed cohorts.
Yoga
Yoga is a mind-body practice that recommends a healthy lifestyle by fostering a healthy diet, adequate sleep, self-hygiene, and a positive attitude. Yoga entails multiple components but typically includes the practice of postures (asana), yogic breathing techniques to reduce stress (pranayama), mindfulness (dharana), and meditation (dhyana). Accumulated evidence over the last few decades underscores Yoga’s effectiveness on various systems, including the respiratory system, cardiovascular system, and immune system.
Yoga and Immunity
Studies have demonstrated that Yoga helps improve immune function in both the healthy and the diseased. Research supports the use of Yoga in reducing inflammation due to abnormal immune reactions. Multiple studies have documented its role in increasing the number and activity of immune cells following Yoga intervention, thus enhancing cell-mediated annihilation of cancer, and invading infective agents.
Agnihotri et al. found that six weeks of Yoga intervention (30 minutes/day, 5 days/week) caused a reduction of inflammatory cells. One of the dominant players in innate immunity is Immunoglobin A (IgA), which lines the exposed tracts of body linings like those of the lungs and the gastrointestinal tract and protects from invasion by microorganisms like the COVID-19 virus.
A study by Chen et al. reported a significant improvement in CD3 and CD4 counts of healthy women who received a 60-minute Yoga session twice in a week for 20 weeks. CD3 and CD4 are specialised immune cells that increase immune mediated attack on invading organisms like the COVID-19 virus. The Yoga group was also found to have a significantly higher-level of IgA at the end of the study.
Cytokine profiles in patients diagnosed with COVID-19 showed marked elevation of certain immune cells and inflammatory chemicals such as IL-6 for at least two weeks after disease onset. IL-6 is a predictor of mortality in COVID-19 patients. In other words, higher and prolonged the level of IL-6, greater is the chance of death. Multiple studies have documented the therapeutic role played by Yoga practice to reduce rogue immunological dysfunction.
Kiecolt-Glasser (2014) used a randomised controlled trial (RCT) to examine the effect of 12 weeks of Hatha Yoga intervention on breast cancer survivors, aged between 27 and 76. The Yoga group participated in two 90-minute, instructor-led sessions per week. The control group was asked to continue normal activities but refrain from any Yoga practice. The study showed that at the 3-month post-treatment visits, the yoga group had significantly lower cytokine levels.
Multiple randomised controlled trials documented a significant reduction of IL-6 levels in the Yoga group when compared to controls, and the researchers observed a significant reduction of IL-6 in breast cancer patients who were taught Yoga compared to the control group at 3 months follow-up.
Multiple studies have substantiated the positive effect of Yoga on inflammation and how it leads to reduction, if not inhibition of dangerous chemicals causing the cytokine syndrome. Rajbhoj et al. observed the impact of Yoga on the production of these chemicals in industrial workers. Researchers divided participants into a control group and a Yoga group and blood samples were taken before the beginning of the study and after three months. The Yoga group was asked to participate in an instructor led 45-minute Yoga sessions six days a week for 12 weeks. According to the results, there was a significant decrease in inflammatory markers like IL-6 and a significant increase in anti-inflammatory chemicals like Interleukin-10 for the Yoga group, while the control group saw no differences.
In a meta-analysis by Holger et al., it was reported that Yoga is an effective intervention in improving depression, which is significant because of the negative impact of depression on immunity.
Long-term Yoga practitioners may be immune to the dystrophic immune response seen in moderate to severe COVID-19.
Thus, innate immunity is greatly enhanced with Yoga in many studies, but more research is needed to substantiate the role of Yoga specifically in COVID-19 immune response.
Multiple studies have substantiated the positive effect of Yoga on inflammation and how it leads to reduction, if not inhibition, of dangerous chemicals causing the cytokine syndrome.
Yoga and Stress
In one study, 16 distressed women examined during their internship period received three months of the Yoga intervention, and a group of eight women served as a control. After three months, women in the Yoga group showed a significant decrease in perceived stress, depression, salivary cortisol, and anxiety. Their wellbeing improved significantly compared to the waitlist control group. Yoga practice helps to develop a positive attitude during stress and enhance self-awareness and coping ability.
Another study by Kiloor et al. reported a significant decrease in anxiety, depression, and stress among patients with serious infections following eight weeks of Yoga intervention.
Yoga has a positive impact on the stress pathway. It reduces HPA axis (Hypothalamic-pituitary-adrenal axis) dysfunction and sympathetic overactivity. Yoga practice helps to improve stress hormones like glucocorticoids, adrenaline, and nor-adrenaline. Yoga intervention has been found to be useful as a complementary intervention in managing various chronic infectious diseases, such as tuberculosis, AIDS, and influenza. In a study among 131 participants with mild to moderate levels of stress, ten weeks of Yoga intervention was provided. After a ten-week practice, a significant decrease in stress and anxiety, along with enhanced relaxation, was reported.
Yoga improves parasympathetic tone during a stressful situation, which counteracts the sympathetic overdrive.
Yoga also helps to improve various cognitive facets, such as attention, concentration, memory, and executive functioning. It increases self-awareness and helps individuals remain physically active, calm and be mindful during stressful situations like the lockdowns.
Arsenal Against Disease
Combating a pandemic like COVID-19 requires us to strengthen our health arsenal at many levels — physical, mental, social, and spiritual. Yoga is a unique modality that helps improve immune response, reduce stress, adopt an attitude of acceptance, look at life in a non-judgmental fashion, and help make good choices with food and physical activity. The conglomeration of pathophysiological aberrations, both psychological and somatic, seen in locked-down states secondary to COVID-19 infection may increase susceptibility to infection. Based on accumulated evidence, it can be hypothesised that Yoga practice, for many, may effectively attenuate it. Similarly, long term Yoga practitioners may be immune to the dystrophic immune response seen in moderate to severe COVID-19, secondary to Yoga induced modulation of immune response to stress. While Yoga may also play a dominant role in preventing COVID-19 infection in the first place by accentuating innate immunity as described eloquently through multiple studies. Since COVID-19 is a new disease, the experience with Yoga in this disease in particular is limited and thus, appropriate clinical trials are mandated to prove this.
