Today there is no dearth of cardio routines to choose from and it has become much easier to choose one that suits you best.

There are two basic types of exercise – aerobic and anaerobic.

Aerobic literal means "in the presence of oxygen," and has evolved to refer to endurance exercises in which your body first burns stored sugars (glycogen) before it burns fat stores for energy.

Aerobic exercises typically increase your heartbeat to 65% of its maximum rate for long stretches – averaging about 20 minutes or so. Examples of these are brisk walking, running, or bike riding from a medium to a quick pace.

Anaerobic activities, on the other hand, are done in short and quick bursts such as calisthenics, weightlifting, or sprinting. In these types of exercises, your body uses glycogens for as long as it can and improves muscle strength, tone, and agility.

If you are a novice, trainers would normally suggest that you emphasize the former type to promote overall fitness and maintain your heart's health.

However, to refine your aerobic skills, anaerobic activity is recommended. For instance, a runner who can constantly do 5-6 miles at the same pace each day has clearly demonstrated above-average endurance. Thus, she could take her workout to the next level and do strength training or sprints to shock her muscles and complete her cardio targets.

And then there's flexibility training , which many of us often forget . You need to work in exercises that would constantly stretch the same muscles you're working on during aerobic and anaerobic workouts.

Now that you know the types of exercises, you need to first get professional advice on the state of your health. Although cardio is for people of all ages, women over 40 generally need to consult their doctors' advice first before joining a group of women in their prime, especially if they have been sedentary for quite a long time.

In the same vein, if your family has a history of coronary artery disease, your cardio would be limited in intensity, frequency, and duration. Moreover, if you have no idea about what your blood pressure, blood sugar, and cholesterol levels are, the more reason for you to first check with your doctor if your planned exercise regimen is manageable.

Lastly, do not immediately jump into a routine if you have experienced any of the following in the past: chest pains; dizziness; pain while walking; joint or bone problems; very slow or fast; irregular heartbeats; wounds or cuts on the feet that do not heal; and unexplained rapid weight loss.

Once you're given the go signal, you can then choose which cardio can both increase your heart rate (within safe limits, of course) and is enjoyable for you at the same time . As you engage in regular cardio, your lungs, heart, and muscles all increase their efficiency in their use of oxygen.

The capacity of your lungs increases, your heart pumps more blood for every stroke, and your muscle fibers extract oxygen from the blood more efficiently.

This is quite obvious when you compare a well-trained athlete with a sedentary individual. The former will have a lower resting heart rate – sometimes even 50 beats per minute (bpm) – while the person who has rarely moved away from her desk may have a resting rate of 80 bpm.

As you begin your cardio sessions, you will find that your heart rate increases rapidly during the duration of the session. However, the longer you are into the program, your heart rate will not rise nearly as much.

Once you've chosen the program (or "programs" – it's a good idea to cross-train to keep from feeling bored ) that you feel you're going to enjoy for quite some time, always keep in mind that you can ' t immediately see results!

Practice gradual progress to avoid the risk of injuries.

The instant effect you'll experience, though, comes by way of a reduction of "stress hormones" such as cortisol and an increase in the production of endorphins, or the so-called "feel-good hormones". Now, who does not want that?