The dog days of summer

PUBLISHED : Tuesday, 31 May, 2011, 12:00am
UPDATED : Tuesday, 31 May, 2011, 12:00am


As you revel in the heat of a Hong Kong summer, it pays to remember that the hotter weather and higher humidity can give rise to a host of seasonal health issues. So, maximise your fun and stay healthy with this guide to avoiding the season's most common health problems.


Perspiration is the body's way of cooling us down, but hot and humid conditions can sometimes overwhelm this natural ability to dissipate heat, leading to heat exhaustion or heatstroke. Infants and the elderly are less able to control body temperature and are at greater risk, says Dr Regina Lo Chung-man.

How to stay healthy: your body needs water to perspire. Hence, dehydration can make you more prone to heatstroke, so drink lots of fluids. Avoid exercising in hot, humid conditions, advises Lo. Be vigilant against heatstroke symptoms - if detected early and immediate corrective action is taken, a sufferer can recover in 10 to 15 minutes.

What to watch for: early signs of heatstroke include dizziness, nausea, fatigue, chest discomfort and excessive sweating. If you feel unwell, immediately cool off in the shade, drink fluids, and loosen clothing to ventilate sweat and help the body dissipate heat. Help a victim by fanning them and spraying water on them, or applying a wet cloth to the neck, armpit and groin. If they continue to feel unwell, have difficulty breathing, appear confused or hallucinate, get medical help immediately, or it could lead to seizures, coma or death.

Expert tip: 'Know your body,' says Lo. 'Never overdo exercise and stop if you feel uncomfortable. If you intend to exercise outdoors, train indoors first.'

Hand, foot and mouth disease

A usually mild viral infection, hand, foot and mouth disease commonly affects children and, occasionally, adults. Outbreaks of the disease - which bears symptoms such as fever; a rash on the palms of the hands, soles of the feet and the diaper area; and painful sores in the mouth - are more common during summer for reasons unknown, according to a spokesman for the Health Department. In the first 18 days of this month alone, the Centre for Health Protection recorded nine cases; there were just two cases altogether for March and April.

How to stay healthy: the virus is found in an infected person's stool, saliva and blister fluid, and can survive for long periods on surfaces such as on toys, table tops and floors, so good personal hygiene is key to avoiding the disease. Teach children to wash their hands frequently and thoroughly with soap and water.

What to watch for: Dr Paul Leung Chik-wa, a paediatrician, advises parents to seek immediate medical attention if a child appears very irritable, drowsy, vomits repeatedly, has convulsions, shortness of breath or is running a high fever (above 39 degrees Celsius). Complications are rare but can be severe and include viral meningitis (infection of the lining of the brain and spinal cord), viral encephalitis (potentially fatal swelling of the brain) and polio-like paralysis.

Expert tip: Leung encourages cleaning of surfaces with a solution of one part bleach to 99 parts water. Double the strength of the bleach solution for surfaces contaminated with blister fluid or vomit. Victims should stick to a soft, liquid diet and avoid acidic foods such as oranges, which can aggravate oral discomfort.


More than just your common cold; influenza is a highly contagious respiratory tract illness that can lead to deadly complications. A Health Department spokesman says Hong Kong experiences seasonal influenza peaks in winter and summer, but the reasons are unclear.

How to stay healthy: the influenza virus is carried in airborne droplets exhaled by infected people, and transmission occurs when those droplets land on the mucous membrane (eyes, nose and mouth linings) of another person. Annual vaccinations and good personal hygiene will help.

What to watch for: Dr Kenneth Tsang Wah-tak, a specialist in respiratory medicine, advises seeing a doctor immediately if you experience persistent fever, shortness of breath, chest pains, or coughing, lots of mucus or phlegm, or if you cough up blood. In severe cases, a victim can deteriorate in a matter of hours, he says. Pneumonia is the most common cause of influenza-related deaths, although a host of other complications such as heart inflammation and meningitis can also occur.

Expert tip: 'If someone coughs or sneezes near you, hold your breath and walk away,' Tsang says. If you get sick, taking prescription antiviral medication in the first 24 hours can reduce the severity of symptoms and their duration by a day.


We all know not to roast in the sun intentionally, but even 15 minutes outdoors can lead to sunburn. The ultraviolet (UV) rays in sunlight also cause pigmentation, accelerate ageing and increase the risk of skin cancer.

How to stay healthy: Dr Tinny Ho Tin-yee, a specialist in dermatology and venereology, advises staying indoors at midday when UVB rays that cause sunburn are most intense. When outdoors, stay in the shade and wear protective accessories such as wide-brimmed hats, sunglasses and long-sleeved clothing. Apply the right amount of sunscreen - about 1.5ml (1/2 teaspoon) for the face, and 35ml for the body (or a teaspoon each for the arm, leg, front and back of body).

What to watch for: reddened skin, of course. To soothe inflamed skin, apply cool water or aloe vera gel - but avoid using heavy moisturisers that 'trap' the heat in. In severe cases, doctors may prescribe corticosteroid creams and oral anti-inflammatory painkillers.

Expert tip: Ho says that while a dry T-shirt offers sun protection of SPF7 to 10, a wet T-shirt does not reflect UV rays well and offers only SPF3 protection, so use special UV protective clothing instead. Skincare with antioxidants such as vitamin C, and oral antioxidants such as fern plant extract can provide additional protection.

Food poisoning

Bacteria flourish in heat, which is why food poisoning cases peak in the summer months. The good news is that the number of cases has steadily decreased over the past four years, says a Health Department spokesman. Dr Michael Cheng says public education efforts have helped improve hygiene at food outlets, thereby reducing food poisoning outbreaks.

How to stay healthy: foods can be contaminated at any point in the preparation and serving process. The best defence is to eat foods that have been cooked well and recently, says Cheng. Refrigerate leftover food only once, and cook it thoroughly before serving. Personal, food and environmental hygiene are also important.

What to watch for: dehydration - the body can quickly lose fluids through vomiting and diarrhoea, possibly leading to death. Young children in particular can dehydrate quickly because water makes up a bigger proportion of their body weight, says Cheng. See a doctor quickly if you are producing very little or no urine, if there is blood or mucus in the stools, if there is excessive vomiting that does not respond to medication such as Gravol, or if the diarrhoea is very severe.

Expert tip: 'Whether you're in Hong Kong or travelling, just remember: boil it, cook it and peel it or forget it,' Cheng says.