The term cardovascular refers to your heart and circulatory system. Any exercise which raises your heart rate significantly or simply encourages circulation should help your cardovascular fitness. Aerobic exercises generally would fit that category, but not exclusively. Walking for example, while not aerobic, is good for your circulation.

n physical exercise, aerobic exercise is complementary to anaerobic exercise. Aerobic literally means "with oxygen", and refers to the use of oxygen in muscles' energy-generating process. Aerobic exercise includes any type of exercise, typically those performed at moderate levels of intensity for extended periods of time, that maintains an increased heart rate. In such exercise, oxygen is used to "burn" fats and glucose in order to produce adenosine triphosphate, the basic energy carrier for all cells. Initially during aerobic exercise, glycogen is broken down to produce glucose, but in its absence, fat metabolism is initiated instead. The latter is a slow process, and is accompanied by a decline in performance level. The switch to fat as fuel is a major cause of what marathon runners call "hitting the wall." Anaerobic exercise, in contrast, refers to the initial phase of exercise, or any short burst of intense exertion, in which the glycogen or sugar is consumed without oxygen, and is a far less efficient process. Operating anaerobically, an untrained 400 meter sprinter may "hit the wall" after only 300 meters. There are various types of aerobic exercise. In general, aerobic exercise is one performed at a moderately high level of intensity over a long period of time. For example, running a long distance at a moderate pace is an aerobic exercise, but sprinting is not. Playing singles tennis, with near-continuous motion, is generally considered aerobic activity, while golf or doubles tennis, with their more frequent breaks, may not be. Among the recognized benefits of doing regular aerobic exercise are: Strengthening the muscles involved in respiration, to facilitate the flow of air in and out of the lungs; Strengthening and enlarging the heart muscle, to improve its pumping efficiency and reduce the resting heart rate; Toning muscles throughout the body, which can improve overall circulation and reduce blood pressure; Increasing the total number of red blood cells in the body, to facilitate transport of oxygen throughout the body. Increased storage of energy molecules such as fats and carbohydrates within the muscles, allowing for increased endurance Neovascularization of the muscle sarcomeres to increase blood flow through the muscles As a result, aerobic exercise can reduce the risk of death due to cardiovascular problems. In addition, high-impact aerobic activities (such as jogging or jumping rope) can stimulate bone growth, as well as reducing the risk of osteoporosis for both women and men.

I would describe a cardio exercise as any activity that raises and holds the heart rate up, however to get any long term benefit you need to 1) raise the heart rate 20% in other words to simplify the math if you have a standing rate of 100 beats a minute you need to raise your heart rate to 120 beats 2) and hold this for at least 20 mins in duration. You need to ALWAYS begin slow and gradually increase the activity once your DR says that you are healthy enough to even begin a cardio work out. The 3 important things to ALWAYS keep in mind is 1) you must warm up and stretch before all workouts 2) You must cool down for 5-10 mins after the intense workout (app 50-60% of Max heart rate 3) The frequency of workouts and for advanced workouts the proper rest between workouts to prevent injury You dont need to kill yourself to benefits simply investing an hr 3 times a week can greatly improve your overall health in a very short amount of time, Stretching and just simply walking at the proper heart rate then a cool down (slower walk) I hope this helps put a real face on this, good luck and a helpful tip is to make the workout fun maybe some music to take your mind off the sweating Good luck and be careful you only have 1 body and taking care of it is your best defense to injury and illness