Your respiratory system is the organ network in your body that supplies oxygen to your bloodstream. Once in your blood, oxygen feeds a wide variety of tissues and processes. When you perform aerobic exercises, you increase the load on your respiratory system and speed the flow of blood-borne oxygen.
Respiratory Basics
Your respiratory system includes your mouth, nose, airway or trachea, lungs and a muscular sheet below your lungs called your diaphragm. When you breathe in, your diaphragm pulls oxygen from your nose or mouth down your trachea to your lungs. Inside your lungs, this oxygen enters roughly 600 million miniscule air sacs called alveoli, which are surrounded by tiny blood vessels called capillaries. Once in your alveoli, oxygen passes to your capillaries in a process called diffusion, and enters your bloodstream. When you breathe out, this process reverses. Waste products such as carbon dioxide and lactic acid pass from your bloodstream to your alveoli and exit your lungs through your trachea.
Respiration Changes
When you perform repetitive aerobic activities, such as walking, swimming, running, jogging or bicycling, you engage the large muscles located in your legs, hips and arms. This engagement increases your muscles' oxygen requirements. To meet these requirements, your breathing rate increases, and your diaphragm pulls in greater amounts of air with each breath. Inside your lungs, the capillaries associated with your alveoli expand and pull increased amounts of oxygen into your bloodstream. At the same time, your heart rate increases, and greater amounts of oxygen-rich blood flow to your muscles.
Exercise Intensity
Different types of aerobic activities increase your oxygen requirements by different amounts. For this reason, exercises are commonly categorized by the aerobic intensity. Most exercises done in everyday aerobic programs -- including brisk walking and cycling on level ground -- are moderate in intensity, the CDC notes. More experienced athletes prefer high-intensity activities, such as running or cycling on uneven ground, in their routines.
Considerations
To protect your health during exercise, match the intensity of your activities with your current fitness capabilities, says the Mayo Clinic. Typically, moderate-intensity exercises accelerate your breathing, stress your muscles and make you sweat while still allowing you to carry on a coherent conversation. High-intensity exercises cause physical changes that make conversations difficult to conduct. Consult your doctor for more information on the respiratory changes caused by exercise and for an assessment of your overall health and aerobic fitness.
References
- The Franklin Institute: Respiratory System; Oxygen Delivery System
- The Mayo Clinic: Aerobic Exercise; Top 10 Reasons to Get Physical
- American Academy of Orthopaedic Surgeons: Aerobic Exercise
- The Mayo Clinic: Exercise Intensity; Why It Matters, How It's Measured
- Centers for Disease Control and Prevention: Physical Activity for Everyone; How Much Physical Activity Do Adults Need
