Vascular's findings reinforce how a sedentary lifestyle can contribute to cardiovascular disease and Type 2 diabetes
A growing body of research shows that a sedentary lifestyle, defined by extended periods of inactivity, can be harmful to your health. Scientists have determined that a sedentary lifestyle not only accelerates aging, but it also increases the risk of developing serious illnesses including heart disease, cancer, high blood pressure and diabetes. These findings are consistent, in part, with those of Vascular, a Canadian experiment led by Dr. Richard Hughson of the Schlegel-University of Waterloo Research Institute for Aging, with funding from the Canadian Space Agency (CSA). The study was conducted between and on astronauts on the International Space Station (ISS).
- The study also identified changes in the blood markers (substances found in a blood sample that provide evidence of a possible disease or condition) of female and male astronauts that might play a role in cardiovascular health during space exploration.
At this time, it is unclear why men and women are affected differently. This will likely be the topic of further research.
Arterial stiffness, a condition that occurs when arteries become less elastic, influences how hard the heart has to work to pump blood through the body. Hardening or stiffening of the arteries can eventually lead to cardiovascular disease, which increases the risk of heart attacks and strokes.
What happens to our bodies in space?
Since the lack of gravity makes walking in space impossible, the only way to move around on the ISS is to float. As shown in the CCISS experiment,Reference 1 another study funded by the CSA and led by Dr. Hughson, this reduces the physical demands on the astronauts' bodiesReference 2 and negatively impacts their blood vessels, muscles and bones. To help prevent this, astronauts eat healthy foods and exercise for up to two hours daily.
Physical exercise is important, in space and on Earth, to keep your heart healthy and prevent serious illnesses. In this photo, former CSA astronaut Bob Thirsk is exercising on the advanced Resistive Exercise Device (ARED) on board the Unity node of the ISS. (Credit: NASA)
Vascular's findings suggest that the daily exercise performed by astronauts was not sufficient to counter the effects of space on the body that resemble accelerated aging. On average, over their six months in space, astronauts in the Vascular study exercised six times per week, performing aerobic activities for about 30 minutes per day and exercising on the ARED, following a prescribed series of exercises, including squats, heel raises, and deadlifts.Reference 3 Time for aerobic exercise was limited due to scheduling constraints and the need to prepare for and clean up after the activity. After six months in space, the astronauts' arteries stiffened by 17% to 30%, which could be compared to 10 to 20 years of normal aging on Earth. Stiffer arteries increase the risk for cardiovascular disease. Astronauts' ability to respond to insulin is also affected. Since insulin helps keep blood sugar at a stable level, this change could lead to developing Type 2 diabetes with further risk for cardiovascular disease.
Vascular was conducted on nine astronauts between and . Blood samples were collected from each of them two to three months prior to launch as well as during and after their six-month spaceflights. When analyzing these samples, the research team focused on specific proteins and hormones, examining them closely for any changes in their levels while the astronauts were in space. In addition to regular monitoring of their blood pressure, the astronauts had ultrasounds to measure the elasticity of their arteries before and after their flight.
- Professor Richard Hughson, Ph.D., of the Schlegel-University of Waterloo Research Institute for Aging
- Professor Philippe Arbeille, M.D., Ph.D., Université François-Rabelais, Tours, France
- Marc-Antoine Custaud, M.D., Ph.D., University of Angers, Angers, France
- J. Kevin Shoemaker, Ph.D., Western University, London, Ontario, Canada
- James W. Rush, Ph.D., University of Waterloo, Waterloo, Ontario, Canada
- Danielle Kathleen Greaves, M.Sc., University of Waterloo, Waterloo, Ontario, Canada
- Reference 1
Fraser KS, Greaves DK, Shoemaker JK, Blaber AP, Hughson RL. Heart rate and daily physical activity with long-duration habitation of the International Space Station. Aviat Space Environ Med 83: 577-584, PMID: 22764612
- Reference 2
Hughson RL, Shoemaker JK, Arbeille P. CCISS, Vascular and BP Reg: Canadian space life science research on ISS. Acta Astro 104: 444-448, . doi: 10.1016/j.actaastro.2014.02.008
- Reference 3
Hughson RL, Robertson AD, Arbeille P, Shoemaker JK, Rush JWE, Fraser KS, Greaves DK. Increased post-flight carotid artery stiffness and inflight insulin resistance resulting from six-months spaceflight in male and female astronauts. Am J Physiol Heart Circ Physiol. 310: H628-H638, . PMID: 26747504
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