Depending on the type and intensity, your normal breathing pattern may change dramatically during physical activity. With cardiovascular exercise such as running or swimming, the number of breaths you take per minute will typically increase. Resistance training such as weightlifting usually prompts deeper and longer breaths. Increased breathing effort during exercise happens in response to your body's demands. Your blood, muscles, and heart undergo changes that require you to inhale more oxygen to maintain function and generate energy.
Changes in Blood
During exercise, blood flow to your heart, muscles, and skin increases. The blood must be rich with oxygen to sustain these systems adequately, so your breathing should become more intense. As you inhale, oxygen is absorbed through the lungs. The hemoglobin in your blood will then carry the oxygen to your heart and other muscles. This intake of oxygen also prompts the body to expel carbon dioxide, which is necessary for maintaining the pH balance of the blood, Washington University chemistry researchers explain.
Heart
When you exercise, your heart rate, blood pressure and amount of blood pumped per heartbeat will all increase. Rigorous activity will stimulate greater oxygen demands in the heart. Because the heart is responsible for pumping oxygenated blood to the rest of your muscles, it will have a relatively high oxygen consumption during exercise, requiring you to breath more.
Muscles
Metabolic activity in the muscles is increased during exercise, so more oxygen is needed. Because oxygen in the muscles is depleted at a faster rate, your consumption of oxygen becomes more rapid. When oxygen levels become too low, you could experience muscular fatigue and be unable to continue exercising at a high level or at all.
Considerations
During exercise, your body's natural course is to consume larger amounts of oxygen to fulfill increasing needs. In these circumstances, some degree of heavy breathing or shortness of breath can be normal. However, breathlessness may occur if your heart is unable to pump enough blood to supply oxygen to your body, an indicator of heart disease, the MedlinePlus online medical encyclopedia warns. If you experience any difficulty breathing that comes on suddenly or interferes with your daily activities, consult your doctor.
References
- Washington University; Blood, Sweat, and Buffers: pH Regulation During Exercise; Rachel Casiday and Regina Frey; Sept. 5, 2008
- James Madison University: Pulmonary Function and Respiratory Regulation
- "Physiological Reviews"; Regulation of coronary blood flow during exercise; D.J. Duncker, et al.; July 2008
- MedlinePlus; Breathing difficulty; June 12, 2009
