Cardiovascular exercise (or "cardio") refers to any type of activity that involves the continuous and rhythmic movement of large muscle groups. Cardio exercise strengthens the heart and lungs and improves the cardiovascular system’s ability to deliver oxygen to the body.

All types of exercise fall into one of two categories: anaerobic and aerobic. Anaerobic exercises are those that do not significantly raise the heart or breathing rate. Strength training and stretching are two examples of anaerobic exercises.

Aerobic exercises are activities that require a great deal of oxygen. The term aerobic is often used interchangeably with the term cardio. Cardio activities include a vast number of exercises, including running, kickboxing, rowing, brisk walking and swimming.

Many people associate "aerobics" with a type of group dance performed to high-energy, exercise-inspiring music. Whether swimming laps alone or exercising in a group, the purpose of cardio exercise is the same: To strengthen the heart and cardiovascular system, improve stamina and, for many people, to lose weight.

This article explains how cardio exercises benefit the body and offers a few pointers to help an individual get started. Always consult a physician before beginning any exercise program.

The body gets energy from food, and this energy is stored in a chemical form (usually in fat cells) until needed. Oxygen is necessary to release this energy. The more oxygen a person breathes, the more potential energy is released from his or her cells.

Cardio exercise increases the rate of breathing (part of the respiratory system), boosts the heart rate and opens up the blood vessels (both of which are part of the cardiovascular system) during exercise. This allows more oxygen to circulate throughout the body to tap into stored energy reserves. This is why cardio exercise is so important in weight management.

In addition, regular, sustained cardio exercise (performed safely and properly) strengthens the heart muscle, lowers the resting heart rate, and increases lung capacity. The lungs can breathe in more oxygen and the heart can circulate this oxygen (carried by red blood cells) with less effort. An aerobically fit individual can exercise longer, more vigorously and achieve a quicker recovery at the end of the cardio session. Cardio exercise can be performed at varying intensities, but the most recent recommendations advise people to exercise a minimum of 30 minutes at moderate intensity on most, if not all, days of the week.

Cardio exercise offers many important health benefits, including reducing the risk of coronary artery disease, high blood pressure and stroke. It is even more effective when teamed up with a regimen of strength training to help raise the metabolism.

Always consult a physician before beginning any exercise program. This is especially true for men over the age of 40 and women over the age of 50, as well as anyone who has cardiovascular disease, diabetes mellitus, exercise induced asthma or a seizure disorder.

People should start with an exercise activity that they think they will enjoy doing and will likely continue over time. 

Cardio can cause injuries if performed incorrectly. Injuries fall into two categories: overuse and traumatic:

• Overuse injuries occur gradually, especially as a person increases the number or intensity of his or her workouts. Shin splints and tendinitis are common forms of overuse injuries.
  
  
• Traumatic injures are caused by a fall or sudden twist of a joint. The ankle or knee is usually the site of such injuries.

Preparing questions in advance can help patients to have more meaningful discussions regarding their conditions. Patients may wish to ask their doctor and trainer the following questions related to cardio basics:

1. How frequently do you recommend that I participate in aerobic activities?
   
   
2. What type of aerobic activity do you recommend for me?
   
   
3. How should I stretch before and after my cardio workout?
   
   
4. Do any of my health conditions limit the types or amount of aerobic activities I can do?
   
   
5. What health benefits can I expect to see from my cardio activities?
   
   
6. Is my cardio workout intense enough?
   
   
7. Am I overdoing it with my cardio workout?
   
   
8. Could my symptoms be caused by an injury related to by cardio workout?
   
   
9. Should I also consider strength training activities in addition to aerobic activities?
   
   
10. Will you be reviewing my medications and are there supplements I should be taking or avoiding with my cardio activities?