Nearly half of the sumo wrestlers examined in a study suffered from sleep disorders that apparently made them weaker in the ring, a researcher said Wednesday.
Eleven of the 23 professional sumo wrestlers participating in the study did not receive enough oxygen while they slept because their respiratory tract was too narrow and constricted, said Naohito Suzuki, a doctor at Douai Memorial Hospital in Tokyo.
"This disorder is commonly seen among heavier people as the pressure of their own body weight on the pharynx and respiratory area can make it difficult to breathe," he said.
Low oxygen levels during sleep prevent the body from getting sufficient rest and reduces people's ability to concentrate, Suzuki said.