Physical inactivity has been cited as a major contributor to many chronic diseases that plaque the modern world. Labelled as ‘the new smoking’, being physically inactive may have dire consequences for your physical, metabolic, cardiovascular and psychological well-being as well as reducing independence and functionality in later years. Most topically, physical inactivity has recently been identified as one of the strongest risk factors for suffering severe outcomes from COVID-19.1
In this retrospective observational study of nearly 50 000 American adults,1 meeting physical activity guidelines (>150 minutes of moderate-to-vigorous exercise per week) prior to the pandemic was associated with significantly reduced odds for hospitalisation, ICU admission and death among COVID-19 patients. Being consistently inactive conferred an even greater risk for severe COVID-19 outcomes compared to smoking and underlying comorbidities, such as obesity, diabetes and cardiovascular disease.1 It seems that physical activity should thus be promoted as a primary behaviour and preventative treatment against severe COVID-19 outcomes, especially for individuals with underlying comorbidities. Indeed, the benefits of physical activity on immune function have been well documented.
The human body’s immune system is highly responsive to exercise.2 Perceived as a further ‘stress’ to the body, the immune system is acutely roused to action with an increased circulation of immune cells (e.g. leukocytes) to help cope with the stress of the exercise bout. The immune response is somewhat proportional to the degree and duration of each exercise session.2 The resultant exchange of immune cells between tissues and systemic circulation has been found to confer a net anti-inflammatory and anti-oxidant effect, provided the exercise sessions are not excessively intense or prolonged (e.g. ultra-marathon).2