Microgravity increases core body temperature: IIST model Premium

IIST researchers use a model to study how microgravity impacts core body temperature and thermoregulation in astronauts.

The Voyager 1 spacecraft was 25 billion km away in February, somewhere in the outer edge of the solar system. It’s the farthest a human-made spacecraft has gone from the earth. The hope is that in the distant future, a human astronaut will be able to go where Voyager 1 has been — a journey that could take several years of spaceflight.

An important factor that determines an astronaut’s well-being on such journeys is thermoregulation: their body’s capacity to maintain a stable internal temperature. In the unique microgravity environment of space, this process faces significant challenges.

Now, researchers at the Indian Institute of Space Science and Technology (IIST), Thiruvananthapuram, have published a study reporting that “microgravity consistently increases core body temperature, with fluid shifts playing a crucial role in thermal balance,” in the words of Shine S.R., a professor of aerospace engineering at IIST and an author of the study.

Human bodies respond differently to temperature changes based on age, fitness level, and body fat, among other parameters. In environments with near-zero gravity like space, the human body changes significantly, affecting bones, muscles, the heart, the immune system, metabolism, even individual cells. Some of the resulting complications can be severe, so space agencies and astronauts continuously monitor the spacefarer’s body temperature.

Scientists using a computer model to evaluate the body’s ability to regulate temperature in specific conditions must also account for “physiological changes observed in space, including blood shifts, metabolic variations, muscle atrophy, and environmental influences”.

Shine said his team has developed a 3D computational model of human thermoregulation that “incorporates these changes to simulate the effects of microgravity on thermoregulation, including blood redistribution, reduced blood volume, changes in metabolism, and alterations in bone and muscle mass”.

According to Chithramol M.K., PhD student at IIST and first author of the study, the team’s studies were limited by sufficient as well as accessible data on metabolic changes. In situations where data was unavailable, she said they tested how different factors changed their results and used their “best judgment and standard engineering practices” to assess their impact.