Headaches, constipation and muscle cramps are the top three illnesses people suffer from during summer, according to the Department of Health.
Dr Achara Nithiaphinyasakul, director-general of the department, said 21.9% of the 682 respondents in the department survey on health and wellness during the summer frequently suffered from headaches, followed by constipation (13.6%) and cramps in their legs and belly (12.7%).
The survey, collected from March 1 to April 4, also showed that 52.8% of respondents had moderate concerns about the effect caused by heat, and 19.8% showed a high level of concern.
For their plan on health protection, Dr Achara said 93.9% of the sample tried to eat newly cooked food to prevent diarrhoea.
The sample also kept their guard up by constantly handwashing (93.8%) and drinking water (87.8%), said the survey.
According to the Meteorological Department, 15 provinces, including Bangkok, will be affected by a red-level, or a highly dangerous heat index until April 27. As the high heat index directly affects health conditions, Dr Achara warned people about the risk of heatstroke flare-ups.
Heatstroke, said Dr Achara, leads to the body's core temperature jumping drastically to 40C or more. Symptoms include skin redness, a faster pulse, headache, dizziness, vomiting, unconsciousness, or even fatality in some cases, she added.
Heatstroke can be treated by applying ice or cooling cloth over the body, especially the back of the neck, armpits, and the crotch, to lessen the body temperature before sending the patient to the hospital, said Dr Achara.