If you saw footage of astronauts Suni Williams and Butch Wilmore returning to earth after nine months stuck in space, you might have noticed that they were both carried out on stretchers. This wasn’t because they were injured during landing, or got sick on the space station — it’s normal for astronauts to need assistance walking after returning to Earth’s gravity. That’s because their bodies have adapted to the weightlessness of space, which causes them to lose muscle mass, impacts coordination, and decreases bone density. When they return, the muscles and bones need time to adjust from this lack of use, which can take weeks. But it’s not just physical changes that accompany this space hangover. According to Jessica Scott, Ph.D., a former NASA scientist at the Exercise Oncology Program at Memorial Sloan Kettering Cancer Center (MSK), some returning astronauts report difficulty concentrating or thinking clearly, a condition they describe as “space fog.”
If you or someone you know has ever gone through cancer treatment, you might have noticed some similarities with these symptoms. According to Dr. Scott, “Astronauts have a lot of the same symptoms as cancer patients — being inactive and weightless can hurt fitness in a way similar to receiving a cancer treatment like chemotherapy. And what we call ‘space fog’ is similar to what people with cancer call ‘chemo brain.’”
Given the havoc that life in zero gravity can wreak on the body, astronauts are encouraged to exercise for about two hours per day while in space, to combat adverse physical and mental side effects. Having seen the benefits that exercise could have on astronauts, Scott wondered if there was a way to apply these findings to cancer patients. So in 2017, she joined the Exercise Oncology Program at MSK to put her theory to the test.
We’ve all heard that when you’re sick, the best thing to do is to stay in bed and let your body rest and recuperate, but the research from the Exercise Oncology Program at MSK is turning that idea on its head. In a study of men with prostate cancer scheduled for surgery, the team monitored each patient while they exercised on a treadmill, with different patients assigned between 90 and 450 minutes of exercise per week. Before and after exercise, researchers tested the patients’ blood for biomarkers that indicate prostate cancer risk and progression.
The results were encouraging: Although none of the patients had received treatment or undergone surgery yet, prostate cancer biomarkers either decreased or remained stable among every exercise group. The ideal amount of exercise turned out to be around 225 minutes (or 3 hours and 45 minutes) of exercise per week. While the results don’t definitively prove that exercise leads to better outcomes for cancer patients, this is a step in the right direction. The MSK team will be conducting further tests on how cancer responds to exercise.
So if you or a loved one has cancer, what does this mean for you? Regardless of the blood-based evidence, study participant Robert Blumber says the experience helped him in ways researchers may not have expected: “It took my mind off the upcoming surgery,” he says. “I really benefited from focusing on my physical well-being and doing things like checking my blood pressure every day. I think the sense of control the exercise gave me was very important at a time when I was feeling somewhat helpless.”
While there’s still a long way to go in determining the exact impact that exercise has on cancer outcomes, the initial findings suggest that, at the very least, exercise is good for a patient’s mental health…and they don’t have to push themselves too hard. The effectiveness of exercise plateaued at 45 minutes per day, which Scott says “challenges the notion that ‘more is always better’ when it comes to exercise.”
Whether you’re returning from nine months in space or recovering from nine rounds of chemo, moderate exercise will likely help you feel a bit more like yourself again. And it’s worth noting that even the group assigned a minimal amount of exercise saw benefits. So if you can’t commit to 45 minutes a day, start with 5. Your body — and your mind — will thank you.
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