It appears that people who go swimming on a full stomach really do have a higher risk of drowning, researchers reported in Medicine, Science and the Law. Advice on how long one should fast before swimming varies widely, from 20 minutes to up to three hours. The authors say that previous studies had revealed scant evidence of a link between eating before going swimming and the risk of drowning.
Editor of Medicine, Science and the Law, Professor Peter Vanezis, said:
"The study highlights what we have always suspected and
seen on a case by case basis."
Prof. Vanezis is also Professor of Forensic Medical Sciences at Barts and the London, Queen Mary, University of London.
Scientists from Tokyo Women's Medical University gathered data on 536 autopsies between April 2000 and December 2007. They evaluated autopsy case files, reports and police reports to determine how each person had died - some deaths were classified as undetermined. They documented blood alcohol levels and whether there were solid food residues in the stomach which were visible to the naked eye (had they been eating recently).
In 79% of the cases where stomach contents were identified, the person had died from accidental drowning - 27 out of 34 autopsies. 59 of the deaths were undetermined, and included eight cases of people drowning in their bath (seven of them aged over 69).
There were 111 suicide cases. 51 of them had committed suicide by drowning - they were compared with the 34 who drowned accidentally.
79.4% of those who had drowned accidentally had visible stomach contents (had been eating recently), compared to 43.1% of those who had committed suicide by drowning.
The researchers say that they identified a link between food intake and drowning risk. However, further studies are required to determine how much food raises the risk, and how long one should fast for before swimming.
The authors believe that two factors raise the risk of death:
- Aspirating vomited stomach contents and subsequently asphyxiating
- Blood is diverted to the intestine during digestion, causing circulation problems while the individual is swimming. This may reduce blood flow to the brain, resulting in loss of consciousness.
"Frequent detection of stomach contents in accidental drowning"
Kazuhiko Kibayashi MD, Ryo Shimada PhD and Ken-ichiro Nakao PhD
Med Sci Law 2011: 1-3. DOI: 10.1258/msl.2011.010150
Written by Christian Nordqvist