A worker takes a rest after feeling tired in an office. / Korea TImes File

By Park Min-sun .
Contributing Writer

Tiredness or fatigue is normal, particularly after a days hard work or physical exercise, or under prolonged stress or mental strain. Chronic fatigue, however, is not a normal state. Although it is not a normal state, its definable or curable cause is found among only about 15 percent of patients visiting a primary care clinic.

There are common etiologies to consider suggested by family medicine.

Fatigue from organic disease is constant and only relieved by sleep and decreased
activity, while fatigue from anxiety or depression may be reduced with exercise and is often not relieved by simple rest. Then, what makes 85 percent of patients tired if there is no definable cause? Is it the same chronic fatigue syndrome?

The answer is ``No!'' Chronic fatigue syndrome is a specific clinical diagnosis that includes symptoms of a sore throat, joint pain, muscle pain, lymph node swelling, and is at least characterized by 6 weeks of fatigue limiting activities by 50 percent or more.

Modern life style per se can be an important cause of chronic fatigue. Physical and mental strain from work, heavy traffic, air pollution in big cities, smoking, heavy drinking, over calorie intake, etc. may increase stress-related hormones that result in chronic fatigue.

Chronic fatigue is quite common among shift workers. In addition, shift workers are known to have accelerated aging problems due to hormonal-disturbances-related circadian rhythms such as catecholamines and cortisols. These hormones are known as stress hormones that increase the risk of diabetes, hypertension, atherosclerosis, obesity and other life style related diseases.
Frequent international travelers also have the same problems as shift workers. Physical and psychological stress of these travelers is even worse as they suffer from not only jetlag but also struggle of adapting oneself to new environment and new people every time.

Free radicals are a chemical species that possess an unpaired electron in the outer (valence) shell of the molecule. They are highly reactive. It means that they have low chemical specificity; i.e. they can react with most molecules in its vicinity. This includes proteins, lipids, carbohydrates and DNA. Currently, it is highlighted as a cause of many previously unexplained disease phenomena such as rheumatoid arthritis, Alzheimer's disease, hypertension, myocardial ischemia, liver cell injury and carcinogenesis. It is also known as a common cause of subclinical syndromes, i.e., chronic fatigue. They are produced continuously in cells either as by-products of metabolism or deliberately as in killing invaded bacteria.

Some drugs, radiation therapy, and tobacco smoking are known to increase free radical synthesis. Air pollutions, chemical additives, and heavy-metal-contaminated water and soil also play a role in increasing free radical synthesis. Biological stress from increased free radical is called as "oxidative stress".

If you are tired every day for quite sometime, not relieved by sleep, decreased activity or refreshing exercise, it may mean that you are suffering from "oxidative stress". Reducing physical and mental strain is the best way to fix it. However, it is not really possible in modern life. In general, a healthy life style such as good balance between work and personal life, less calorie intake, eating fresh vegetables and fruit, regular exercise, etc. can be helpful in reducing oxidative stress. Oxidative stress can be easily measured from a drop of blood from the finger tips. If oxidative stress is found to be high, oral or parenteral forms of high potent antioxidant should be considered.

For more information on fatigue, visit www.drparkrenal.com or email to Park's Kidney Clinic, renal00@naver.com.