Aerobic exercise, often called cardio, is any activity that increases breathing and heart rate for a sustained period. Its effects on the cardiovascular system are well-documented and multifaceted. Here is a list of key effects.
- Enhances Heart Muscle Strength: The heart is a muscle. Regular aerobic exercise makes it stronger. A stronger heart can pump more blood with each beat, a measurement known as stroke volume. This increased efficiency means the heart does not have to work as hard during rest or low-level activity.
- Lowers Resting Heart Rate: As the heart becomes more efficient at pumping blood, the resting heart rate decreases. A lower resting heart rate is generally a sign of good cardiovascular fitness and reduced strain on the heart.
- Improves Cardiac Output: Cardiac output is the amount of blood the heart pumps through the circulatory system in one minute. Aerobic training increases maximum cardiac output, enhancing the body’s ability to deliver oxygenated blood to working muscles during exertion.
- Increases Blood Volume and Red Blood Cell Count: Regular aerobic activity stimulates the production of more blood plasma and, to a lesser extent, red blood cells. This expansion of blood volume improves the blood’s oxygen-carrying capacity and makes thermoregulation more efficient.
- Lowers Blood Pressure: Exercise helps maintain the elasticity of arteries. It can stimulate the production of nitric oxide, a molecule that signals blood vessels to relax and widen (vasodilation). This reduction in peripheral resistance helps to lower both systolic and diastolic blood pressure over time.
- Improves Blood Lipid Profile: Aerobic exercise has a favorable impact on cholesterol levels. It can increase the concentration of high-density lipoprotein (HDL), often termed ‘good’ cholesterol, which helps remove other forms of cholesterol from the bloodstream. It can also decrease levels of triglycerides and low-density lipoprotein (LDL), or ‘bad’ cholesterol.
- Enhances Capillary Density: Within muscles, aerobic training encourages the growth of new capillaries, the smallest blood vessels. This denser capillary network reduces the distance oxygen and nutrients must diffuse from the blood to the muscle cells, improving efficiency.
- Improves Insulin Sensitivity: By using glucose for energy during activity, aerobic exercise helps muscles better respond to insulin. This improved sensitivity helps regulate blood sugar levels, which is beneficial for overall metabolic and cardiovascular health.
- Reduces Systemic Inflammation: Chronic low-grade inflammation is a risk factor for cardiovascular disease. Regular aerobic exercise can reduce the circulating levels of certain inflammatory markers, contributing to a healthier cardiovascular environment.
- Aids in Weight Management: As a significant consumer of energy, aerobic exercise helps maintain a balance between calories consumed and calories expended. Managing a healthy body weight reduces the mechanical and metabolic strain on the heart and blood vessels.
The collective impact of these adaptations is a cardiovascular system that operates more efficiently under stress and is more resilient to disease. The American Heart Association recommends at least 150 minutes of moderate-intensity aerobic exercise per week for adults.