In addition to healthy diet, regular and adequate physical activity are major factors in the promotion and maintenance of good health throughout the entire life course of a person. Unhealthy diets and physical inactivity are two of the main risk factors for many chronic conditions such as raised 
blood pressure, raised blood glucose, abnormal blood lipids, overweight or obesity, and for the major non-communicable diseases such as coronary heart diseases, hypertension, stroke, cancer, and diabetes mellitus. Physical inactivity is an independent risk factor for many chronic diseases, and cause of millions of deaths globally.
Physical activity is defined as any bodily movement produced by skeletal muscles that require energy expenditure. It is a key determinant of energy expenditure, and thus is fundamental to energy balance and weight control.
| Thousands of us suffer from diseases or illnesses that can be prevented or improved through regular physical activities like walking, jogging, bicycling, swimming, etc. |
It reduces the risk of coronary heart disease and stroke. Physical activity also reduces the risk of Type II diabetes mellitus. It reduces the risk for colon cancer and breast cancer among women too. Exercise is a subset of physical activity that involves purposive and repetitive bodily movements. Exercise is carried out in a more structured manner.
The proportion of adults in this planet who are sedentary or nearly so ranges from 60 to 85 %. That is, at least 60% of the world's population fails to complete the recommended amount of physical activity that is required to induce health benefits. Levels of inactivity are high in virtually all developed and developing countries. This is partly due to insufficient participation in physical activity during leisure time and partly due to an increase in sedentary behaviour during occupational and domestic activities. Urbanization has resulted in several environmental factors, which may discourage participation in physical activity. Population over-crowding, increased poverty, increased levels of crime, high density traffic, low air quality and a lack of parks and sidewalks, increased tendency to TV watching and lack of sports or recreation facilities make physical activity a difficult choice.
Consequently, non-communicable diseases associated with physical inactivity such as coronary heart diseases, hypertension, stroke, cancer, and diabetes are the greatest public health problem in most countries around the world.
It is recommended that individuals engage in adequate levels of physical activity throughout their lives to benefit their health. Physical activity is a key determinant of energy expenditure, and thus is fundamental to energy balance.
Different types and amounts of physical activity are required for different health outcomes. At least 30 minutes of moderate-intensity physical activity 5 days per week, such as walking at a speed of 100 steps per minute for 30 minutes 5 days per week reduces the risk of several common non-communicable diseases in adults, which are also called ‘life-style diseases’:
cardiovascular disease
stroke
type II diabetes
colon cancer
breast cancer.
Regular exercise or physical activity lowers blood pressure, lowers bad cholesterol ‘LDL’, increases good cholesterol ‘HDL’ and thus lowers the chance of build up of plaques in arteries. In this way it reduces the chance of hypertension, stroke and cardiovascular diseases. There is also evidence to suggest that increasing levels of various types of physical activity may benefit health through positive effects on:
hypertension
osteoporosis and falls risk
body weight and composition
musculoskeletal conditions such as osteoarthritis and low back pain
helps build and maintain healthy bones and joints
mental and psychological health by reducing depression, anxiety and stress
promotes better sleep
improves mood
control over risky behaviours particularly among children and young people (e.g. tobacco use, alcohol / substance use, unhealthy diet and violence).
Thousands of us suffer from diseases or illnesses that can be prevented or improved through regular physical activities like walking, jogging, bicycling, swimming, etc. We should keep ourselves active at our workplaces too. Promoting physical activity can be a highly cost-effective and sustainable public health intervention for maintaining good health.
Effective public health measures are urgently needed to improve physical activity behaviours in all populations to prevent and control the lifestyle diseases.