As the world battles the devastating challenges of COVID-19, one thing has become clear: the pandemic may have changed the way we live, but our health is not going to wait for the pandemic to end.
A normal, healthy adult has two to three upper respiratory tract infections (URTIs) a year. When it comes to fighting these infections, including COVID-19, exercise remains a vital preventative tool.
Exercise jump-starts the immune system temporarily for about three hours after every moderate session.
In one study of more than 1,000 adults published in the British Journal of Sports Medicine, people who exercised for at least 20 minutes a day, five or more days a week, reported 43 percent fewer days with URTIs than those who were sedentary. And when they did get sick, their symptoms tended to be less severe.
Other research shows that people who walk briskly for 40 minutes a day have half as many sick days due to sore throats or colds compared to those who do not exercise.
The pandemic may have changed the way we live, but our health is not going to wait for the pandemic to end.
However, research regarding vigorous sustained exercise has been less consistent. It shows that more than 90 minutes of high-intensity endurance exercise can make athletes more susceptible to illness for up to 72 hours after the session.
This type of immune suppression is most common in marathon runners or those with highly active roles, such as the military.
The message? Everything in moderation.
COVID-19 and weight gain
As well as supporting our immune systems, exercise fights COVID-19 by helping us keep weight on track.
Two out of five Australians say they have gained weight post lockdown, according to a CSIRO study of 4,000 people. Obesity is arguably the single biggest co-morbidity challenge we face during the pandemic.
Many studies show obesity linked to alarmingly high numbers of COVID-19 deaths and intensive care admissions. This is especially true in morbidly obese people under 50.15.
In fact, even mild obesity doubles the risk of respiratory failure in young populations, according to an Italian study of more than 400 COVID-19 patients. Obesity was also a factor in 67 percent of severe COVID-19 infections that required mechanical ventilation in children.
Exercise and COVID-19 complications
Leading exercise researcher Zhen Yan, from the University of Virginia School of Medicine in the US, says exercise may reduce the risk of Acute Respiratory Distress Syndrome (ARDS), a deadly complication of COVID-19, with a 45 percent mortality rate.
Yan compiled an in-depth review of existing research looking at the antioxidant known as “extracellular superoxide dismutase” (or Ec-SOD), and its impact.
The potent antioxidant hunts down harmful free radicals and helps to protect tissues and prevent disease.
Yan, who has his bike faithfully by his workspace, says that even a single session of exercise increases production of the antioxidant.
“What you hear now is either about social distancing or ventilators, as if all we can do is either avoid exposure or rely on a ventilator to survive if we get infected,” Yan said.
“We cannot live in isolation forever. Regular exercise has far more health benefits than we know. The protection against this severe respiratory disease condition is just one of the many examples.”
Exercise: Why It’s The New Prescription For Cancer, Too
While surgery, chemotherapy and radiotherapy are the accepted mainstays of breast cancer treatment, there is mounting evidence that exercise reduces the risk of cancer recurrence.
One recent study of 3,813 patients in Breast Cancer Research Journal found that at least 150 minutes of moderate intensity physical activity a week was associated with lower all-cause mortality among postmenopausal breast cancer patients, regardless of their level of activity before diagnosis.
Just walking three to five hours a week reduces the risk of breast cancer recurrence by 40-50% percent, according to US Brigham and Women’s Hospital Physical Activity and Survival After Breast Cancer study.
Exercise spurs recovery and improves physical and emotional well-being and quality of life,” says breast cancer surgeon Dr Mary Ling. Exercise has also been shown to reduce the risk of cancer recurrence due to its impact on the immune system, and by helping to maintain a healthy weight.
“Some cancer treatments such as hormone therapy or chemotherapy can result in weight gain, plus patients tend to be more sedentary during this time,” she says. “So that’s why, under professional guidance, it’s essential to remain active.”
For twice world age duathlon champion Margaret Beardslee, it was exercise that got her through the exhaustion of cancer treatment.
“Before my breast cancer diagnosis I had just trained to my max for a bike race and was racing alongside people years my junior,” she says.
“During my cancer treatment daily exercise (swimming, cycling and running) allowed me to feel somewhat normal and hopeful that I could regain fitness after treatment finished.
“I tried to exercise almost every day throughout chemo, even if it was just a few minutes’ walk. If I felt my body was telling me to take the odd day off, I did.”