Obesity i.e overweight is a common condition the world over, including in India. It is not altogether wrong to say that there is almost an epidemic of obesity particularly noticeable in the developed countries. Even the developing countries are not spared of the menace of over-weight.

Obesity is common among adults as well as children. It is largely attributed to a sedentary life-style and excessive use of ‘junk foods’ rich in fats, carbohydrates and calories. Even though a good weight is surely a sign of a healthy body, overweight is considered as a ‘medical problem’ or even a ‘disease’ in itself. Excessive weight is an unnecessary burden on the body which poses risks for almost all body systems. In particular, it is responsible for muscle and joint problems and diseases of the heart and the lungs.

Effects on the respiratory system

Obesity affects the respiratory system in multiple ways. Some of the important effects are described as under:

  1. Lung function: Lung function is poorer in the overweight persons. To a large extent, the lung capacity is adversely affected by excess body weight. Thoracic and lung expansion is restricted due to the mechanical effects of fat on the chest wall and diaphragm in the obese people. Clinically significant restriction is generally present whenever there is massive obesity defined by the patient’s weight-to-height ratio of 0.9-1.0 kg/cm or greater. Obese people may complain of breathlessness due to poor lung function even in the absence of a definite lung disease.
  2. Asthma: There is some association of asthma with obesity. Obese asthmatics have more significant symptoms of breathlessness, wheezing and cough. Moreover, asthma is difficult to control in obese patients. This is particularly worrisome in obese children who present with a severe form of asthma.
  3. Chronic obstructive pulmonary disease (COPD): COPD is a progressive form of airway obstructive disease which is more commonly seen in smokers. Obesity is usually not a problem with most patients of COPD who often complain of significant weight loss and muscle wasting. Obesity may however be present in patients with chronic bronchitis in whom it will add to the symptoms of breathlessness.
  4. Obstructive sleep apnea (OSA): OSA is an important problem characterized by intermittent obstruction of the upper respiratory tract especially during sleep. The obstruction occurs due to loss of tone and inability of the pharyngeal muscles during sleep to keep the airways open and thus resulting in its partial closure. It causes momentary cessation of breathing and fall in oxygen saturation, snoring and other physiological effects. In due course of time, OSA is responsible for hypertension, diabetes, cardiovascular and cerebrovascular diseases.
    Obesity is an important risk-factor for OSA, a potential fatal disease. Patients with OSA tend to fall to sleep within minutes and even while driving resulting in frequent and sometimes fatal accidents. Undoubtedly, OSA is the most serious complication of obesity. Weight reduction is an important component of treatment of OSA. Mild OSA may even be reversed with treatment of obesity.
  1. Obesity hypoventilation syndrome (OHS): OHS is characterized by hypoventilation i.e. decreased (than normal) amount of air entering the lungs with each breath resulting in lower oxygen saturation and increased carbon dioxide pressure in the blood. In the long run, the condition leads to failures of the respiratory and cardiovascular systems. Weight reduction is the most important component of treatment.


Weight reduction is the most significant component of all forms of problems associated with obesity. Dietary control and physical exercise are important but often difficult to achieve.  Frequently, one has to resort to other measures of weight reduction which may include bariatric surgery. The doctor can advise about the type of management required in a case. Standard treatment of the respiratory disease associated with obesity should be done as appropriate for the individual patient.