Blood flow in astronauts on Earth after long space stay

• Published in: Acta astronautica 2020-10, Vol.175, p.462-464
• Main Authors: Ishihara, Akihiko, Terada, Masahiro, Kouzaki, Motoki, Hagio, Shota, Higashibata, Akira, Yamada, Shin, Furukawa, Satoshi, Mukai, Chiaki, Ishioka, Noriaki
• Format: Article
• Language: English
• Subjects: Astronaut; Astronauts; Blood flow; Fluid shift; International Space Station; Long space stay; Muscles; Recovery; Space stations; Time dependence; Venous return
• ISSN: 0094-5765; 1879-2030
• DOI: 10.1016/j.actaastro.2020.05.017

Time-dependent responses of blood flow in astronauts after return to Earth were investigated. Five male astronauts who stayed in an international space station for long periods (115–199 days) were enrolled in this study. A probe for the measurement of blood flow was attached to the skin surface on the central region of the gastrocnemius muscle of the right lower limb while the subjects were standing. The blood flow before long space stay and during recovery after return to Earth, i.e., at preflight, postflight day 1, postflight day 7, postflight month 1, and postflight month 3, was measured with a laser blood flow meter. Each subject stepped five times on the same spot at their own speed in standing position. Blood flow at both the first and fifth steps was decreased at postflight days 1 and 7. However, at postflight month 1, blood flow at both the first and fifth steps had recovered to normal levels (i.e., level before long space stay). We conclude that the decrease in blood flow induced by long space stay from 3 to 6 months recovers 1 month after return to Earth. •Five astronauts stayed in a space station for long periods (115–199 days).•Time-dependent responses of blood flow after return to Earth were investigated.•Blood flow in the lower limbs was measured with a laser blood flow meter.•Decreased blood flow after long space stay recovered 1 month after return to Earth.