Feeling the heat? Here’s how to beat it

by Carol Aloysius

Erratic changes in climate today, which have deviated from what we expect has led to our bodies being exposed to extremes of climate. Several theories have been put forward as to how these climatic changes impact on our bodies and health. A few of them are scientific based and many are rooted in superstitions and myths that can be traced back to several centuries.

Consultant Plastic Surgeon, Colombo North Teaching Hospital. Dr Kolitha Karunadasa drawing from his long experience explains in medical terms how the body reacts and why to such changes. He debunks some of the myths surrounding such changes in this intereview with the Sunday Observer.

Excerpts…

Q. The heat wave in Colombo and outside has led to some concerns regarding its impact on the human body. What happens when we get exposed to the sun?

A. Day time sun exposure is naturally unintentional and mostly unavoidable in a tropical country such as Sri Lanka, where we are used to engaging in many outdoor activities such as farming, construction, sports and recreation, mostly without sun protection.

That means we are exposed is to ultraviolet radiation from the sun and the heat generated from it. Ultraviolet Radiation (UVR) particularly in extreme exposures can potentially cause both short term and long term damages to health.

This has become a health problem as global climatic changes and ozone depletion are probable underlying causes for this. What we get from the sun is visible light, UVR and heat.

Solar UVR consist of three bands; UVA, UVB, and UVC. As the sunlight passes, all the UVC and about 90 % of UVB is absorbed by ozone, water vapor, oxygen and carbon dioxide. But UVA which reaches the Earth’s surface is largely unaffected, and the amount of UVB reaching the surface is less than three percent.

Q. What are the health effects of UVR?

A. Exposure to excessive/ prolonged exposure to solar UVR can cause acute and chronic effects on the skin, eye, immune system and raise problems concerning regulating them. It also affects the psychological well-being of the person.

Q. All these are negative impacts. Are there any positive impacts on our bodies from sun exposure?

A. Sunlight particularly UVB stimulates the production of vitamin D in the skin, and this provides approximately 90 % of the Vitamin D requirements of human being.

The tropical countries receive more than enough sun exposure for this and 10- 15 minutes of exposure to face and upper limbs would be sufficient. A. Vitamin D is also vital in maintaining calcium and phosphorus balance in the body,

Q. Who are most at risk of excessive sun exposure and why?

A. Children are at a higher risk of suffering adverse effects of sun exposure than adults.

A majority of children love playing outdoor in the sun, but are unaware of the harmful effects of UVR. The skin of a child is thinner and more sensitive, hence relatively shorter sun exposure especially mid-day can result in sun burn.

Q. What kind of health risks can develop as a result?

A. Epidemiological evidence demonstrates that frequent sun exposure in childhood is associated with a high rate of melanoma in later life. Melanoma is a serious form of skin cancer which is aetiologically related to UVR exposure.

Q. What are the long-term effects of excessive sun exposure ?

A. Long- term exposure accelerates skin aging resulting in skin wrinkles, dry and coarse skin due to progressive loss of skin elasticity.

However, the most important fact to note based on epidemiological evidence of chronic sun exposure, is that it can cause skin cancers. Basal cell carcinoma is the commonest skin cancer.

Basal cell cancer is rarely fatal but causes ulceration, disfigurement and removal needs an operation.

The second commonest type is the squamous cell carcinoma, which can spread locally and also in to distant sites. Squamous cell cancers can be fatal if untreated and neglected.

Malignant melanoma is a less common skin cancer but the fatality is high. The incidence of malignant melanoma is increasing. Intermittent and high exposure to UVR, fair skin and sun burn especially at early age are significant risk factors in causation of malignant melanoma.

Other acute effects of UVR exposure are on the eyes - e.g. photo keratitis and photo conjunctivitis. Particularly UVB exposure is associated with cataract development in the long run.

It is also claimed that there is an immunosuppressive effect of the UVR exposure as evident by the preliminary scientific evidence. Consequently, sun exposure may enhance the risk of developing cancer and contagious viral, bacterial, parasitic and fungal infections.

Q. How can we protect ourselves against these adverse effects of sun exposure?

A. Damaging effects of UVR are mostly preventable by reducing the instances of sunburn and cumulative UVR exposure, with simple protective measures that are available.

It is the responsibility of parents to reduce harmful effects of the excessive sun exposure especially in the case of children, because they are at a higher risk to the damaging effects of sun exposure than adults because of their sensitive skin.

Infants of less than 12 months of age should always be kept in the shade. Shade, clothing and hats provide best protection for them.

A hat with a wide brim offers good sun protection for the face and neck. Sunglasses with UVR protection (99-100%) will significantly reduce the eye damage.

Tightly woven and loose-fitting cloths will provide protection to the sun. Sunscreen should be applied to those parts of the body that are remain exposed.

Children should be encouraged to take these simple precautions while still allowing them to enjoy the time spend outdoors.

Shade should be used wisely especially when the UV rays are intense. The sun’s UVR are the strongest between 10 am and 4 pm and this mid-day sun exposure should be minimized if possible. Keep yourself well hydrated.

Q. Any other precautions that children and adults can take?

A. Public education on UV exposure is the need of the hour. This can bring about a change in attitude and beahviour when exposed to the sun. Sensible behaviour is relatively simple to incorporate and can eliminate sunburn and heat stroke, which are often due to prolonged sun exposure.

It has been claimed that four out of five cases of skin cancers can be prevented by sensible behavior. Regular use of sunscreens could reduce the incidence of skin cancers significantly in high risk areas.

Q. Since the heat wave is still continuing despite the rains, tell us some ways of coping with this hot weather?

A. Two ways to cope with heat are by perspiring and breathing.

Q. Please elaborate

A. Sweating is the most effective natural means of combating heat stress, with little or no change of body temperature. As long as the sweating is continuous, humans can withstand increase in the environmental temperature. But when the ambient humidity is high, the sweat does not evaporate easily and tend to stay on the skin. Heat is dissipated with the sweat as it takes heat from the skin surface during the process of evaporation.

A person can feel comfortable as far as the sweat does not retain on the body. They will feel uncomfortable and warmer in a humid environment than in a relatively dry conditions.

Q. Is humidity a key factor?

A. Humidity is a huge factor. If you have tremendously high temperatures and high humidity, a person will sweat but the sweat won’t dry on the skin. Disorders due to heat most frequently occur with rapid changes in environmental temperature, in low altitudes and in densely populated urban areas. Elderly urban dwellers have died due to heat because they are isolated and don’t have access to air conditioning. Obese people are at increased risk as are people on certain medications. Those who are exercising or working in the heat and don’t meet those criteria, can also be at risk. People with chronic diseases and frequent alcohol consumers also have problems with heat tolerance.

Q. Heat exhaustion and heat stroke are they the same? What are the symptoms?

A. Heat exhaustion is a relatively common reaction to significant heat. This is characterised by symptoms such as dizziness, headache, and fainting with a considerable exposure to heat. This is usually managed with rest, a cooler environment, and rehydration - replacing water and electrolytes.

Heat stroke is a severe form often accompanied with dehydration, dry skin, increased body temperature, confusion, and sometimes unconsciousness and requires urgent medical attention to save life. As the body temperature increases rapidly, the central nervous system and circulatory system are impacted. Heat rash and muscle cramps are early signs of people being overwhelmed by heat. If those aren’t dealt with, it can lead to more severe symptoms.

Q. Will fans help?

A. Not only does a fan Not work, it actually makes it worse. Blowing hot air on a person will heat rather than cool them down.