If you are a regular jogger, there's no telling what got you started. It might have been a desire to lose weight, a hankering for improved cardiovascular fitness, a yearning for stronger legs or simply the need to blow off some stress. Whatever your primary motivation for pounding the pavement, jogging addresses each of these areas in style.
Cardiovascular System
Jogging pushes your heart rate up to anywhere from 60 to 95 percent of its maximum, depending on the duration of the run and, of course, your goals for the session. The heart adapts by increasing its stroke volume, the amount of blood it can pump with each beat. You also generate more capillaries in the muscles you exercise and increase blood flow to the heart itself. In addition to being able to jog faster and for a longer period, you achieve general health gains in the form of reduced blood pressure and lower serum cholesterol.
Leg Muscles
Jogging works your calves and quadriceps especially hard, and your hamstrings to a lesser extent. You can build increased leg power and speed by either mixing in some sprinting, running uphill repeats, or both. The mitochondria in your leg muscles increase in number in response to jogging training, which increases the amount of oxygen these muscles can utilize and thus makes them capable of propelling you along faster and for a longer period of time. Downhill running tends to break muscle down, so be careful of overstriding on descents.
Your Mind
Running, as with other types of sustained exercise, provides notable calming effects. This is most likely the result of endorphin release, a phenomenon that accompanies physical stress of various sorts. These substances have a sedating effect and underlie the oft-mentioned "runner's high." In addition, scientists have learned that jogging stimulates to the production of new brain cells and can improve cognitive functions such as memory, adding a new dimension to the idea of "running for your head."
Your Waistline
If you started running mainly to lose weight, you have the right idea. Running burns more calories per unit time than any other type of conventional exercise, according to MayoClinic.com. Just how many calories you burn depends on both your speed and your weight; for reference, if you weigh 160 pounds and run for one hour at 8 mph, you'll burn close to 1,000 calories -- almost one-third of a pound.
