Coughing is a physical process that requires muscular contraction, meaning it does burn calories. A calorie is a unit of energy, and any action requiring muscle movement demands energy expenditure. However, the energy consumed by a single cough is so minimal that it holds no significance for fitness or weight management goals.
The Mechanical Action of Coughing
A cough is a defensive reflex that involves a rapid, forceful sequence of muscular actions to clear the airways of irritants or mucus. The process begins with a quick, deep inspiration, utilizing the diaphragm and external intercostal muscles. This inspiration increases the volume of air within the lungs, setting the stage for the powerful expulsion.
The reflex then proceeds to the compression phase, where the vocal cords snap shut, trapping the air inside the lungs. Simultaneously, the abdominal muscles (including the rectus abdominis) and other expiratory muscles contract violently. This contraction against a closed glottis causes a sudden buildup of pressure within the chest cavity. The final expiratory phase occurs when the vocal cords suddenly open, allowing the high-pressure air to be forcefully expelled at high velocity. Since muscle contraction requires the breakdown of adenosine triphosphate (ATP) for fuel, each step of this coordinated reflex consumes a small amount of energy.
Quantifying Energy Expenditure
The caloric cost of a single cough is small, estimated to be in the range of 0.5 to 3 calories. This figure is variable depending on the cough’s intensity and the individual’s body mass. To put this into perspective, vigorous activity like running can burn approximately 8 to 12 calories per minute.
Even a sustained fit of coughing, such as a hundred repetitive coughs, would only expend a fraction of the energy burned during a few minutes of light walking. Scientific studies measuring oxygen consumption, a proxy for energy use, show that directed, vigorous coughing increases metabolic rate only moderately above a resting state. The energy required to simply breathe quietly or laugh for one minute can quickly surpass the total calories burned by a series of isolated coughs. This action is too fleeting and infrequent to contribute meaningfully to daily energy expenditure.
Caloric Impact During Illness
While the act of coughing itself is a negligible calorie burner, a sustained illness causing the coughing can lead to a noticeable increase in overall energy expenditure. When the body fights an infection, the immune system becomes highly active, requiring a significant amount of extra energy. This elevated demand results in an increase in the body’s Basal Metabolic Rate (BMR).
Illness-related factors, such as a fever, further accelerate the metabolism. For every one-degree Celsius increase in body temperature, energy expenditure can rise by 10 to 13 percent as the body works to regulate temperature and fight the pathogen. This increased BMR, driven by the immune response, is the reason people may experience weight changes during sickness, not the mechanical effort of the associated coughing.