RESULTS
To determine if long-term exposure to microgravity
aboard the ISS had any detrimental effects on lung
function, pre-and post-flight measurements of lung
function were performed on 10 crew members who lived
for 130-196 days on board the ISS. The same crew
members also performed lung function measurements
while in microgravity. Lung volumes, maximum inspiratory
and expiratory flows, respiratory muscle strength, resting
gas exchange, and numerous indices of the uniformity of
lung function were measured on several occasions before
flight, and again on several occasions following return to
Earth’s gravity. Results show that, unlike many other organ systems in the human body, lung
function returns to normal almost immediately after long-duration exposure to microgravity.
The most important, and somewhat surprising, aspect is the almost complete absence of a
change in lung function before and after spending 4-6 months in low-Earth orbit, despite the
fact that the lung is highly sensitive to gravity, as shown by previous in-flight studies. The
magnitude of the observed changes in the 10 subjects were so small that the conclusions, of no
lasting effect of microgravity on lung function, would hold even if the study had included a
greater sampling group. Investigators uphold that the subtle changes in lung function that
persist soon after landing are possibly due to a reduction in circulating blood volume and
alterations in lung fluid balance, and while statistically observable, have little physiological
consequence. This finding is significant and encouraging since it proposes that lung function is
not a concern under the normal oxygen and pressure environment such as that inside the ISS
(Prisk 2005, 2006, 2008).
PUBLICATION(S)
Prisk GK, Fine JM, Cooper TK, West JB. Lung function is unchanged in the 1 G environment
following 6-month exposure to microgravity. European Journal of Applied Physiology.
2008;103:617-623. doi: 10.1007/s00421-0080754-2.
Prisk GK, Fine JM, Cooper TK, West JB. Vital capacity, respiratory muscle strength, and
pulmonary gas exchange during long-duration exposure to microgravity. Journal of Applied
Physiology. 2006;101:439-447. doi: 10.1152/japplphysiol.01419.2005.
Prisk GK, Fine JM, Cooper TK, West JB. Pulmonary gas exchange is not impaired 24 hours after
extravehicular activity. Journal of Applied Physiology. 2005;99(6):2233-2238. doi:
10.1152/japplphysiol.00847.2005.
Cowell SA, Stocks JM, Evans DG, Simonson SR, Greenleaf JE. The exercise and environmental
physiology of extravehicular activity. Aviation, Space, and Environmental Medicine.
2002;73(1):54-67.
This investigation is complete and all results are published.
ISS006E22979 – View of the HRF
PuFF Volume Calibration Syringe,
PSC Kit, Cargo Transfer Bag in the
U.S. Laboratory.