No matter how much retinol cream and hair dye we slather on our faces and roots, we’ll all succumb to age eventually. There’s no cure for it, and it’s much more than skin-deep—aging takes a severe toll on our neurological well-being. Although biologists recently discovered how to reprogram the molecular processes of aging in yeast cells, we haven’t yet cracked the mysteries behind aging in the human brain. Nearly 16 million people in the US struggle with cognitive impairment, a debilitating condition that eventually robs individuals of their independence by chipping away at their memory, motor functions, and ability to concentrate or learn.
But neuroscientists in Israel are trying to turn back the biological clock with one simple ingredient: oxygen. Shai Efrati, a physician and director of the Sagol Center for Hyperbaric Medicine and Research at the Yitzhak Shamir Medical Center in Israel, has developed a new type of hyperbaric oxygen therapy that increases blood flow in the brain to prevent declining cognitive function in the brains of healthy, older adults. His team’s results were published in the journal Aging this month.
Hyperbaric oxygen therapy involves breathing in pure, highly concentrated, oxygen in a pressurized chamber for a long duration, allowing a person’s lungs to collect three times the normal amount of oxygen from air. With elevated blood-oxygen levels, body tissues supposedly heal at increased rates by stimulating the formation of new vessels at sites of injury. Historically, doctors have used the therapy to treat carbon monoxide poisoning, skin burns, traumatic brain injuries caused by strokes, and gas embolism, a condition that impacts deep-sea divers when nitrogen bubbles form in the circulatory system. More recently, hyperbaric oxygen therapy has been advertised as an all-encompassing treatment for many diseases—though the FDA emphasizes that the therapy hasn’t been clinically proven to treat cancer, diabetes, and autism.
In this recent study, Efrati tested the therapy on normally aging adults without preexisting conditions to improve their cognitive function. For three months, 63 adults aged 65 and older spent five days a week, two hours a day in a pressurized chamber, breathing in concentrated oxygen at twice the amount of pressure as that of the Earth’s atmosphere. By the end of the study, Efrati discovered that blood flow in the brain increased. Frequent cognitive assessments also revealed that patients scored much higher on attention and information-processing speed tests than prior to the experiment.
Here’s how the researchers say it works. By dramatically raising blood-oxygen levels in aging patients, Efrati harnessed oxidative stress to prompt some brain cells to go into survivalist mode. Oxygen atoms are free radicals—at concentrated amounts, they scour the body, damaging DNA, cells, and proteins in a phenomenon called oxidative stress. “These short periods of high oxygen actually impose a mild beneficial stress on cells in the brain,” says Mark Mattson, a professor of neuroscience at Johns Hopkins University. This pressure might promote neurogenesis, a process in which stem cells form new neurons and brain cells, essentially making the central processing unit look and run “younger.” Exercise and intermittent fasting invoke similar reactions in the brain, Mattson says, without extreme adverse impacts.
It’s not just about raising oxygen levels, however: Fluctuation is also key. During the study, Efrati instructed patients to keep oxygen masks on for 20 minutes, then remove them for five-minute breaks. “You put the mask on and breathe 100 percent oxygen,” says Alexander Alvarez, a physician at Aviv Clinics, who administers hyperbaric oxygen therapy. “Then, when you take off the mask, the body thinks it’s in trouble.”
Efrati thinks that stress caused by fluctuating oxygen levels in the blood might stimulate stem cell growth. But this chain of events hasn’t been scientifically proven yet, says Uri Ashery, a professor of neuroscience at the Sagol School of Neuroscience in Israel. “The mechanisms behind hyperbaric oxygen therapy are unknown,” he notes. When asked if increased blood flow means more brain activity, as indicated in the study, Ashery also hesitated. “Not necessarily,” he says. “It can allow the brain to be more active since it brings in new oxygen. But it doesn’t always mean the brain is more active.”
But what about the patients’ high scores on cognitive assessments after the treatment? While there’s no direct evidence of stem cell proliferation, the study participants exhibited better short term memory, longer attention spans, and the ability to process information at faster speeds than before. Cognitive performance peaked after 20 treatments, Alvarez says, and remained elevated six months after therapy. It did drop off eventually—and scientists still aren’t sure how long the effects last. The treatment doesn’t last forever, Ashery explains, and its longevity depends on each individual’s genetics and lifestyle.
Despite those caveats, the waiting list for the hyperbaric oxygen therapy at the Florida-based company Aviv Clinics is already starting to grow, says CEO Dave Globig. Despite the onset of the COVID-19 pandemic, adults 55 years of age and older have been scrambling to get appointments since the treatment was first rolled out in mid-June. While most clients come from the Villages, a sprawling retirement community that hems the clinic, Globig anticipates taking on patients coming from all over the world. Each treatment package costs $60,000 and spans sixty days, requiring individuals to commute to the clinic five times a week for two-hour sessions.
After their 60 days are up, patients will continue to be monitored with a wearable medical device. If their cardiovascular or cognitive health declines, they’ll be invited back for a physical test and perhaps another round of hyperbaric oxygen therapy, Alvarez says.
Ashery hopes that one day the treatment might be popularized enough that it becomes accessible for more populations. “This is something that the government could invest in,” he says. “The scientific and medical communities show that it is quite helpful and prevents a lot of care later on, so this could easily become part of our regular treatment for older adults.”
Efrati, meanwhile, dreams of an aging community that’s completely independent and well-functioning. Longevity isn’t enough—a high quality of life is what these neuroscientists strive for. “We will all die someday,” Efrati says. “But we want to die when we are functioning. We want to go down with our heads up, not when we are debilitated.”
Correction: The story previously said that the treatment allowed patients to breathe in 1,500 times the amount of oxygen found in the atmosphere. Plainly put, that was a dire error.