Microgravity Increases Core Body Temperature: IIST Model

A new study from the Indian Institute of Space Science and Technology (IIST), Thiruvananthapuram, offers critical insights into how microgravity affects human thermoregulation—a key determinant of astronaut well-being during long-duration space missions such as future voyages matching Voyager 1’s trajectory.

What is Microgravity?

Microgravity is the condition in which people or objects appear to be weightless. The effects of microgravity can be seen when astronauts and objects float in space. Microgravity can be experienced in other ways, as well. “Micro-” means “very small,” so microgravity refers to the condition where gravity seems to be very small. In microgravity, astronauts can float in their spacecraft – or outside, on a spacewalk. Heavy objects move around easily. For example, astronauts can move equipment weighing hundreds of pounds with their fingertips. Microgravity is sometimes called “zero gravity,” but this is misleading.

Key Findings:

• Core Body Temperature in Space:
  • Microgravity consistently raises astronauts’ core body temperature. Over 2.5 months in space, body temperature may increase from 36.3°C to 37.8°C, and up to 40°C with exercise due to reduced sweating and increased metabolism.
• Body Heat Redistribution:
  • In near-zero gravity, blood shifts from the lower limbs to the upper body, making the head, abdomen, and core warmer, while hands and feet become cooler.
• Advanced 3D Computational Model:
  • IIST researchers developed a 3D thermoregulation model simulating:
    • Blood redistribution
    • Reduced blood volume
    • Bone and muscle atrophy
    • Metabolic changes
    • Environmental heat transfer (e.g., via clothing, vital organs)
• Verification and Application:
  • The model’s predictions match official reports from Mir Space Station and the International Space Station (ISS).
    Beyond space, such models are used in medicine (surgical planning), architecture (thermal comfort), and apparel design (climate-adaptive clothing).

Lead Researchers:

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• Prof. Shine S.R., Department of Aerospace Engineering
• Chithramol M.K., PhD researcher and first author

Publication:

The findings were published in Life Sciences in Space Research on March 29, 2025.

Significance:

This research strengthens the knowledge base for designing safer human spaceflights, aiding agencies like ISRO and NASA to prepare for extended missions beyond Earth orbit.

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