Health, for a long time, was considered as a state of body and mind where there was a balance of certain ‘humour’.
This is what early Greeks like Hippocrates as well as Indian Ayurveda system of medicine asserted.
It was thought that persons with ‘black bile’ belonged to a hot personality and would have fevers.
The discovery of blood circulation by William Harvey using the experimental method and the demonstration of normal body temperature in persons with black bile using thermometer disproved the ‘good humour’ hypothesis of health.
Biology stated that mind influences, through the neural system and endocrine system, our immune system and that our immune system maintains our health.
Hence, the mind and mental state can affect our health. Of course, health is affected by–
genetic disorders – deficiencies with which a child is born and deficiencies/defects which the child inherits from parents from birth;
infections and
lifestyle including food and water we take, rest and exercise we give to our bodies, habits that we have or lack etc.
Health could be defined as a state of complete physical, mental and social well-being.
When the functioning of one or more organs or systems of the body is adversely affected, characterized by various signs and symptoms, we say that we are not healthy, i.e., we have a disease.
Diseases can be broadly grouped into infectious and non-infectious.
Diseases which are easily transmitted from one person to another, are called infectious diseases.
Infectious diseases are very common and every one of us suffers from these at some time or other.
Some infectious diseases like AIDS are fatal.
Among non-infectious diseases, cancer is the major cause of death.
Drug and alcohol abuse also affects our health adversely.