Astronauts go through a lot of training in preparation for spaceflights, including intensive exercise routines to stay fit and stave off the harmful effects of space travel.
Researchers writing in a commentary published Thursday in Cell say fitness programs could also have an application in cancer patients, who go through physiological changes that are similar to astronauts.
Prior to her current work in oncology, study lead author Jessica Scott of Memorial Sloan Kettering Cancer Center worked at the Johnson Space Center in Houston, where she studied how astronauts are affected by space flight and what could keep them healthy.
A colleague then pointed out the side effects of space flight — changes in muscle density, changes in the immune system, and the “fog” that astronauts describe feeling — mimicked what cancer patients can experience. That got Scott thinking about differences in how NASA manages astronauts’ side effects with exercise in a way that cancer physicians don’t with their patients. Places like Denmark and Norway have already begun incorporating exercise into routine part of cancer care, she said.
STAT spoke with Scott, an exercise physiologist at Memorial Sloan Kettering, to learn more. This interview has been lightly edited and condensed.
Can you describe what astronauts suffer as a result of space flight, and how it’s similar to cancer?
We think of astronauts as being exposed to three main “hits.” One is a baseline hit, which could be from age or if they have cardiovascular risks such as high blood pressure. The second is a direct hit: When they go into space, 2 liters of fluid goes from the lower body to upper body and causes changes. The third hit is when they’re in space. They’re not walking around and become deconditioned. Almost every system in the body is impacted this way, basically from their head down to their toes. Their taste changes. They have “space fog,” which is similar to what cancer patients call “chemo brain.”
But astronauts are prepped for these changes in a way that cancer patients aren’t?
NASA has two key elements: One is where clinicians and physicians know what astronauts have at their baseline level. And then astronauts go through exercise training months before their mission. They also have to exercise during their space flight. They also have to start this rehabilitation program that spans the length of the assignment, basically from when they know about it.
And how is that different from cancer?
When I started working in oncology, I learned that cancer is the only chronic disease where exercise is not a part of the standard of care. If you were diagnosed with coronary artery disease or heart failure, you are referred to a structured exercise program, or you can go to an exercise center and that’s reimbursable, but in cancer, that’s not the case.
Astronauts know they have to go on a mission, and that it’s likely to cause harm, but cancer patients don’t necessarily know they’re going to get cancer — is it a fair comparison?
We think there’s a difference here between preventative care and treating patients. A lot of studies over the past 15 years or so have started looking at exercise interventions in cancer patients. Even in the short time period between diagnosis and undergoing surgery — in those four to six weeks — cancer patients can start exercising and they have improved post-surgery outcomes, they stay in the hospital for shorter periods. So there’s starting to be evidence showing that exercise in the short interval before treatment and [in the] years after treatment can improve the health of cancer patients.
How are you testing this?
We’ve actually started measuring some elements of [the NASA program] in our lab. One of the key tests is a cardiorespiratory fitness test, which is a 10-minute test of patients’ functional capacity. Another part is delivering treadmills to patients in their own homes. They get an iPad and we can supervise their exercise remotely. It’s very much like what astronauts do hundreds of miles above the Earth, but we’re just doing it 30 miles away from our mission control at Memorial Sloan in Manhattan.
Is there a specific exercise regimen that all patients follow? Is it the same for all cancer?
One thing we’re starting to see is patients asking what the best exercise program for them specifically is. What we know right now is that one size of exercise likely does not fit all. Patients usually exercise three times to five times per week, but not everyone should do 150 minutes per week. Just like patients receive different doses and schedules of cancer therapies, the goal of our program is to take a more targeted approach to exercise.
Patients in our studies go through similar characterizations as astronauts — checking lung function, muscle function, or heart function. For example, lung cancer patients have muscle atrophy and changes in heart function, so for them it’s important to incorporate resistance and aerobic training in their exercises. We think there is a difference between cancers, and that’s what we’re researching and there definitely is a lot more work to be done.
What are you seeing so far?
It’s very promising. A lot of patients love being able to do this at home. We know we can quantify that they are improving their physiologic capacity, and sleeping better.
One group in our lab is looking at [impact on tumors] overall, and preliminary research shows that an exercise program does help with that. Another group studies the [different complications patients experience], and in breast cancer patients, exercise does improve cardiorespiratory fitness and how patients generally feel.
How can we be sure that exercise is helping astronauts, since there are long-term consequences from space flight we may not yet know about?
What we know from NASA’s 50-year history so far is that exercise is a very good tool to prevent a lot of the changes astronauts experience. But as astronauts go on these longer duration missions — Scott Kelly went for a year, but a majority go on six-month missions — we are continuously learning about their physiology. A study [published Wednesday] showed changes in astronauts’ blood flow that we didn’t previously know about. And it’s the first time that data has been noticed in almost 20 years of doing long-duration spaceflight. I think it will be very telling in the next 10 to 15 years what these astronauts who flew in the past 15 years experience.
It’s interesting because it’s a lot like what cancer patients are experiencing now. They’re surviving cancer much longer, but are facing secondary effects like cardiovascular disease. So, in that respect, cancer may actually inform some space flight research.