When runners collapse or get sick at the end of a long race, it
seems logical to give them fluids. Sometimes, however, water is
the last thing these athletes need. All had taken in too much
water during their races, causing sodium levels in the blood to
drop. From there excess water is absorbed into blood and fluid
builds up in the brain. Eventually, fluid accumulates in the
lungs, and athletes become breathless and nauseated. When
runners collapse or become ill, the natural assumption may be
that they are having a heart attack. Yet, rather than being a
sign of heart attack, fluid build-up in the lungs -- called
pulmonary edema -- may signal brain swelling. The investigators
describe the cases of seven marathoners who collapsed and had
nausea and vomiting after their races. When brain scans revealed
swelling, six of the patients were treated with an intravenous
solution containing high amounts of sodium -- a water-depleting
treatment that is directly the opposite of the low-sodium
solutions that runners may r