Mechanical mechanisms through which obesity contributes to disease

There are also biomechanical mechanisms involved in the development and progression of chronic disease, which relate to the increased body mass present in individuals who have excess adipose tissue. This excess tissue causes changes in gait, balance, muscle strength and muscle endurance. Increased body weight causes compensatory changes in gait and increased plantar pressure along the longitudinal arch and at the metatarsal heads, which is associated with pain and discomfort in the feet. In addition to this, extra weight generally presents extra stress and spine on the joints, and this can be associated with a range of musculoskeletal concerns presenting pain, discomfort and limiting physical activity. In particular, high body mass index is associated with chronic knee pain, and also with back pain since excess abdominal adipose can causes postural changes.

The physical load presented by excess adipose tissue also has consequences on heart function since a higher cardiac output is required to supply blood and oxygen to the extra body mass, often accommodated by an unhealthy increase in blood pressure. In respiratory disorders, the increased body mass around the thorax presents an additional load which the respiratory muscles need to oppose to ventilate the lungs, which can lead to restrictive impairments to breathing in a number of clinical manifestations. Excess fat around the neck can cause obstruction of airflow particularly during sleep (obstructive sleep apnea).