Symptoms: coughing, shortness of breath. Some patients’ lips may turn purple if they remain for too long in an oxygen-poor environment

How to handle: move patients to better-ventilated places

Stroke patients

Agitated moods, smoking, drinking and crowded environments can trigger strokes. In summer, people sweat a lot and their blood may thicken, leading to infarction of the brain.

How to prevent: Stroke patients should pay attention to secondary prevention to avoid relapses. They should try to keep their blood pressure stable and stay calm. They should make sure they have a good night’s sleep before visiting the Expo and avoid getting impatient while queuing.

Asthmatics

Xiong Xudong, director of the University Hospital’s emergency department, said many asthmatic patients suffer relapses during vacations because they spend too much time in crowded and stifling stores and supermarkets. Tension, agitated moods and perfume may also trigger attacks. Patients should move to airy, less crowded spaces immediately if they start to feel unwell.

How to prevent: Asthma sufferers should bring their inhalers with them and avoid getting over-tired.

Kidney patients

Kidney patients tire easily and should avoid too much exertion. Their immunity tends to be low so they catch colds easily. But they need to take care with medication, especially antibiotics, as many medicines are not suitable for them. Shanghai Changzheng Hospital is providing special dialysis wards for Expo visitors.

How to prevent: Patients should not stay too long inside pavilions. They should try to stick to watching outdoor performances.

Common Cold

Most people think having a cold is no big deal. But a surprising number of young people die of acute myocarditis (inflammation of the heart) caused by colds. Myocarditis can also affect people with low immunity. People should take vitamins and have a good sleep before going to Expo. People with serious colds should wear facemasks.

Pregnant women

Pregnant women have reduced immunity and can be easily infected by harmful bacteria – especially in crowded environments. The bacteria are dangerous to both expectant mothers and their babies, so pregnant women should avoid crowded and poorly-ventilated places. Doctors suggest they watch the Expo on TV or visit when there are smaller crowds.