Apart from the various disorders like diabetes, hypertension etc., that are its secondary consequences, obesity leads to a gamut of breathing difficulty ranging from Obesity Hypoventilation syndrome to Obstructive Sleep Apnoea Syndrome (OSAS). During the lying down position especially during sleep, the upper respiratory tract muscles’ tone is decreased, due to which there is partial or complete obstruction of
the breathing pathway. In obese people, who usually have thicker neck and snore, pharyngeal muscle tone is lesser than that of a thin person, compromising the narrow breathing pathway in the neck thus leading to intermittent obstruction in the pathway of breathing. This is called Apnoea, the transient cessation of breathing. Apnoeas and hypopneas (Partial obstruction) are more pronounced in the supine position during REM (dream) sleep and result in recurrent night time awakenings and increased respiratory effort. Furthermore, oxygen saturation often falls during, resulting in sympathetic system activation to restore the same. As and when the air+low and oxygenation return to normal, sleep usually continues. Recurrent arousals and sympathetic stimulation are associated with poor quality sleep as the cycles of obstruction, followed by restoration of airflow at the termination of events, continues throughout the night, sometimes repeating a number of times per hour. The measured episodes of apneas, plus hypopneas, per hour, is used to quantify the severity of disease as the apnoea- hypopnea index (AHI).
OSAS, even in those patients where the etiology is other than obesity, may cause hypertension, systemic inflammation, and insulin resistance thus creating a cycle of the co-morbidities leading to one another.
In this scenario, simply by losing weight and bringing their body weight to the ideal would improve the respiratory tract obstruction and distressed breathing and better the quality of life in these patients.