DALLAS, TX (August 9, 2022) – Are astronauts more likely to have higher rates of heart disease mortality due to zero gravity? The Cooper Institute collaborated with NASA on a new research study that found astronauts experience future rates of heart disease-related death similar to Cooper Center Longitudinal Study (CCLS) participants of the same age, sex and fitness level. The results were recently published in the Mayo Clinic Proceedings.
Known health concerns of space travel include changes in exercise routines, a change in diet, impaired sleep, psychological stress, and exposure to some radiation. During and after space flight, astronauts sometime experience changes in their blood lipid profiles, insulin resistance, and increased levels of inflammation. Physical changes include loss of bone density and muscle mass depending on their time in space. However, it is unclear whether some of these concerns are long-lasting.
“Understanding the lifelong impact of space travel on the human cardiovascular system is paramount given the planned increase in length of NASA missions, not to mention the rising interest in space tourism. We collaborated with NASA investigators to examine possible long-term effects of space travel on heart disease and mortality,” said Carolyn E. Barlow, PhD, a physical activity epidemiologist at The Cooper Institute and co-author of the new study.
A group of 303 astronauts with space mission experience since 1970 was compared to a group of 1,514 Cooper Center Longitudinal Study participants of similar age, sex, and health status. Importantly, because astronauts must be physically fit to carry out their missions, CCLS participants were chosen for this study based on their qualifying fitness level. The merits of using fitness in the study were expressed in an accompanying editorial. The authors stated “Cardiorespiratory fitness is an incredibly powerful control herein, as fitness likely serves as a mediator of cardiovascular health and mortality as well as a marker of innumerable unaccounted for comorbidity.”
Results showed that both groups experienced below-average rates of heart disease and death during an average 30 years of follow-up. No difference was found in future risk of heart disease-related death in astronauts compared to CCLS participants. However, evidence of increased risk of non-fatal heart attacks and strokes was seen in the astronauts studied. For those considering a trip to space, the study supports the need for heart-healthy living and preventive healthcare.
“In general, I found the results reassuring and frankly not surprising. Both astronauts and clients of the Cooper Clinic are relatively affluent, well-educated and have good access to health care. Astronauts spend the vast majority of their time on the ground as opposed to in space, and given the small numbers (there were only 4 myocardial infarctions in the astronauts) and short durations of spaceflight exposure in the older astronauts, I would not over-interpret the risk of non-fatal events in this population, and would be even more cautious about attributing the small increase in risk of non-fatal events to exposure to spaceflight. For future missions that spend more time outside the Van Allen belt (and thus exposed to higher amounts of radiation which may accelerate the atherosclerotic process), that risk may change. But for now, I think that these data provide reassurance that in general, astronauts are well cared for, and do not experience an elevated risk of dying from cardiovascular disease,” said Benjamin D. Levine, MD, a cardiologist and professor of medicine at the University of Texas Southwestern Medical Center.
Charvat Mayo Clin Proc. 2022;97(7): 1237-1246
Josephson Mayo Clin Proc. 2022;97(7): 1222-1223