This Vascular Biologist Wants You To Address Blood Vessel Health ASAP

If there's anything we've gained in the past year (other than a vast collection of face masks), it's an understanding that COVID-19 is far more than your typical respiratory virus. 

Sure, some people have minor cold-like symptoms and go on their merry way. But others experience symptoms like "COVID toe" (red, swollen toes), headaches, body aches, brain fog, fatigue, vision problems, blood clots, kidney and liver issues, and more—sometimes for months after they've recovered from their initial acute infection. What's even more concerning is that some of these "long-COVID" or "long-haul COVID"1 symptoms can actually crop up after a pretty mild bout of the virus, catching people totally off-guard. 

It's perplexing and scary. And while there's still so much we don't know, experts believe many of these diverse and widespread symptoms can at least partially be explained by COVID's effect on our body's vast 60,000-mile network of blood vessels—our vascular system. 

Last spring (i.e., the early days), vascular biologist and physician William W. Li, M.D., was intrigued by the ever-growing collection of strange and widespread COVID symptoms. It got him thinking: "Because blood vessels are a common denominator across all of the body and organs, could these symptoms all be due to a vascular problem?" Turns out, he was on to something.

Shortly after, Li and a group of international researchers performed autopsies on the lungs of COVID-19 victims and made a key discovery2: Not only was the virus causing damage to the lung tissue—which is typical of respiratory viruses—but it was also directly invading and damaging the endothelial cells that line the smallest blood vessels (i.e., microvessels or capillaries) of the lungs, and causing many tiny blood clots as a result.

Li compares this blood vessel damage to an ice rink before and after a hockey game: The lining of healthy vessels is like a perfectly smooth ice rink where the puck glides effortlessly. But when COVID damages vessels, it essentially shreds their lining, making them resemble the scuffed-up ice after a hockey game. "Blood flow slows, and things tend to stick to the walls and clot," he says. 

The implications of this aren't great. "When we saw the first pictures of that little spiked ball penetrating blood vessel cells, it sent a chill down my spine," says Li. Because the virus can infect blood vessels, and because blood vessels supply oxygen and nutrients to every cell in the body, this means you can potentially experience COVID-induced microvascular damage anywhere—from your brain to your toes. And research suggests this damage doesn't always resolve quickly, which is why Li believes it's a major contributor to long-haul COVID symptoms, including brain fog, impaired vision, and organ damage. 

Probably not. We already know that people with certain underlying medical conditions4 are at greater risk for severe illness and death from COVID-19. And while more research is needed, some experts believe preexisting conditions that already tax and inflame the blood vessels can essentially prime you for greater vascular damage if you get COVID-19. "We are really worried that people who already have weakened, vulnerable blood vessels are at even greater risk for long-term COVID," says Li.

Other experts agree. "It's very likely that people who already have trouble with their blood vessels will have more trouble with COVID-19," says John P. Cooke, M.D., Ph.D., chair of the Department of Cardiovascular Sciences at the Houston Methodist Research Institute and Science Advisory Board Member for Humann. That's why it's so important to try to prevent or treat conditions like high blood sugar, high cholesterol, and high blood pressure before you get COVID-19, he explains—since reversing these conditions will help improve blood vessel function. 

Maybe! (Don't hate us for being noncommittal; we need more research.) 

"There is no evidence to support this directly; however, there is indirect evidence to support the concept," says Cooke. "Vascular damage [in general] can be repaired, and we know that treatment of risk factors such as high blood pressure, diabetes, high cholesterol, and smoking allows the vascular system to improve." Cooke also believes some of the vascular damage inflicted by COVID-19 will improve with diet and lifestyle changes that support the blood vessels.

Similarly, Li thinks we should be doing everything we reasonably can to support vascular health, especially now. "The stronger your circulation and vascular health is, the more likely you are to get through any illness without a vascular problem," he says.