KOCHI: Asthma,is the second most prevalent chronic respiratory disease globally, affecting 3.6 people. The Global Burden of Disease (GBD) study has estimated that India is home to over 30 million asthmatics, accounting for 13.09 per cent of the global burden. When it comes to mortality, India accounts for over 42 per cent of all global asthma deaths. Several risk factors, such as smoking, inhaling cold air, air pollutants and allergens can trigger asthma symptoms and exacerbations. Also, the impact of ambient warm temperature on asthma hospitalisation has received considerable attention recently.
Recent studies from Hong Kong, Japan, Taiwan, Maryland, New York, and Beijing have reported an increase in asthma hospitalisation risk with higher temperatures, especially during summer months.
Humidity is frequently associated with worsening of respiratory symptoms such as breathlessness, nasal congestion, cough, excess mucus production and wheezing. Humid air is denser as it has a high water content. High density leads to increased airway resistance in the body. Humidity makes the air stagnant due to which pollutants and allergens like pollen, dust, mould, dust mites, and smoke get trapped in the airway.
Most intense bronchoconstriction occurs when inhaling hot humid air. Increased humidity may also encourage the growth of mould in the home or workplace.
The United States Environmental Protection Agency (USEPA) says keeping indoor humidity levels below 60 per cent can help prevent the growth of mould. Dust mites that live in furniture, carpets and bedding thrive at humidity levels of 70 to 80 per cent.
The most vulnerable asthmatic population during these intense summer months are male smokers aged between 16 and 64 years. This is due to severe airway inflammation and lower lung function.
However, the direct biological mechanism by which higher temperatures trigger asthma exacerbations is unclear. High temperatures may also activate the C-fibre nerve endings and enhance bronchoconstriction leading to higher morbidity.
Warmer temperatures can increase allergen. It can spread viruses and bacteria causing or aggravating respiratory diseases.
Tips to protect the lungs from hot and humid weather
Avoid exercise, especially during the hottest time of the day (between 11am and 3pm)
Wear loose, cool, and light-coloured clothing and a hat if you go outdoors.
Keep yourself hydrated and drink plenty of fluid.
Increase intake of citrus fruit juices such as oranges, pineapple, cranberry, blueberry etc.
Open all the windows of your car once you sit inside it; this will release hot air and harmful gases from the car.
Regular servicing of the AC and heater of the car is necessary as these devices leave hazardous gases such as carbon monoxide in the air.
Avoid being outside on humid days, especially when the air quality is poor.
Check the local weather forecast to determine suitable conditions to get outdoors.
Try to reduce indoor humidity by using an air conditioner or dehumidifier.
The writer is an associate consultant at the department of Respiratory Medicine, KIMSHEALTH