More people are falling ill because of the scorching summer days. Hospitals across the country are reporting a 10 to 20 percent increase in patients, and doctors say a considerable number of them suffer from gastrointestinal problems.
According to a latest study published in The American Journal of Gastroenterology, scientists found that sustained periods of hot weather may cause symptoms related to gastrointestinal conditions, such as inflammatory bowel disease, to flare up.
It is known that high temperatures can directly affect human health given the mortality rates during heat waves.
However, indirect effects, such as how disease symptoms may change in such conditions, are not well understood.
Inflammatory bowel disease (IBD) and infectious gastroenteritis (IG) are diseases characterized by inflammation of the gastrointestinal tract. Symptoms include abdominal pain, vomiting and diarrhea.
The study shows that the presence of a heat wave increased hospital admissions for both conditions by more than 4.5 percent, for each day of a heat-wave period.
The data also suggests that the effect of heat waves on IBD is immediate, while IG flares are more prominent after seven days.
Although the mechanism behind these responses is unknown, the authors speculate that an increase in temperature could favor the expansion of the pathogenic bacteria and/or viruses that play a role in IG, allowing the disease time to develop.
"In terms of traditional Chinese medicine, humans' gastrointestinal systems are in a weak condition during the summer time, and are easily hit by outside factors if not protected well," says Yu Fei, a doctor from Shanghai No 10 People's Hospital.
"There is also a very high possibility in summer of eating rotten or stale food and drinking filthy water. So people are more likely to suffer gastrointestinal problems now than at other times," he says.
"It's quite common to see about a 20-percent increase of patients in hospital's gastrointestinal problems department during the summer season," he adds.
The authors of the study also suggest that IBD's more immediate effects may be caused by the physical and mental stress associated with heat waves.
Improving daily hygiene is an important way to keep gastrointestinal problems away, according to doctors.
Washing hands with soap before eating, drinking boiled water, eating homemade or fresh food, and keeping prepared food inside the refrigerators are also suggested by doctors.