Pennington Biomedical: Obesity and COVID-19 FAQs

In these five FAQs, the experts at Pennington Biomedical Research explain why obesity affects COVID-19—and how. Providers of these responses are Steven Heymsfield, MD, FTOS, former executive director of the Center; Eric Ravussin, PhD, Boyd Professor and associate executive director of clinical science; and Peter Katzmarzyk, PhD, FACSM, FTOS, associate executive director for Population and Public Health Sciences

Why are those with obesity more at risk for a severe case of COVID-19?

Inflammation that often accompanies obesity can cause the body to rev up the immune system response to any infection such as COVID-19.

Under normal circumstances, inflammation indicates that the immune system is fighting off infection by sending blood cells and other messengers to the injury.  Once those cells show up to the injured tissue, you’ll notice swelling and you may see a reddish or “inflamed” color. Once the wound heals, the immune system backs off, swelling goes down and color returns to normal.

In people with obesity, the immune system may see fat that surrounds organs in the abdomen, or visceral fat, as a threat like a potential injury. So the immune system is working overtime, sending out blood cells and other chemicals every day, all day long, to attack those visceral fat cells. This leads to chronic inflammation.

In the case of COVID-19, the immune system goes into even higher overdrive in a way that can cause a “cytokine storm” reaction. Cytokine molecules are part of healthy immune system response, except when the number of molecules soars. Then immune cells may build so quickly that they crowd and break through the walls of an inflamed lung, as just one result. That’s when fluids will build up in the lung, making it hard to breathe and triggering the need for ventilator support.

Roughly 40 percent of U.S. adults have obesity, which helps explain the severity of COVID-19’s impact on our healthcare system.

Is inflammation the only reason COVID-19 is more dangerous to people with obesity?

No. It gets worse. Impaired immune systems make an individual more susceptible to viral infections in general. One study shows that adults with obesity had twice the incidence of flu or flu-like illnesses despite being vaccinated.

Obesity is also often accompanied by other conditions that are risk factors for COVID-19 complications, such as type 2 diabetes, cardiovascular disease, and pulmonary disease like obstructive sleep apnea.

What BMI is most at risk?

Those with severe or class III obesity which is defined as a BMI of 40 or higher.  A person who is 5’9” and weighs 271 pounds has a BMI of 40. A person with severe obesity who requires hospitalization presents a greater challenge. He or she may need a special, bariatric hospital bed.  Even hospitals with bariatric surgery units have a limited number of these beds.  Other hospitals may not have any.

People with obesity and COVID-19 are more likely to need a ventilator. But intubations may be more difficult and require personnel with specialized training.  Hospitals have been able to reduce mortality rates for some patients who need ventilators by placing the patients on their stomachs.  This option may not be available for people with class III obesity because they, like pregnant women, may not do well in that position.

Obtaining an imaging diagnosis may also be more complicated because many imaging machines have weight limits.

How does obesity affect my respiratory system?

A person with obesity carries excess chest and abdominal fat, and that extra weight puts pressure on their diaphragm, lungs, and chest cavity. This can lead to breathing problems and even lung damage.  In simpler terms, a person with obesity can’t get enough oxygen.  He or she can’t catch a (full) breath.

It’s also possible that the extra weight may damage the diaphragm muscles. The respiratory system of a person with obesity is already laboring at a disadvantage before the added distress of a COVID-19 infection.  With the infection, their blood oxygen levels could drop to near-fatal levels or fatal levels without them knowing. 

How should I prepare for coronavirus if I have obesity?

Follow the Centers for Disease Control and Prevention guidelines. 

-Wash your hands often with soap and water for at least 20 seconds. If soap and water aren’t available, use a hand sanitizer that’s at least 60 percent alcohol.

-Avoid close contact with people who are sick, even at home. Stay at least 6 feet away from other people outside your home. Avoid crowds and large gatherings.

-Cover your mouth and nose with a cloth face cover when around others.

-Clean and disinfect frequently touched surfaces – tables, doorknobs, light switches, countertops, etc. – every day.

-Exercise. Change your diet. Lifestyle changes, like a daily workout routine or a better diet, can help you stay healthy. Check out Pennington Biomedical’s YouTube page or follow us on Facebook and Twitter for quick tips on exercise and eating healthy.