Benefits of Regular Aerobic Exercise
You will accrue many health and fitness benefits if you perform regular aerobic exercise. Here's a partial list:

Burns calories (see below for calorie expenditure of different activities)
Improves endurance
Reduces the risk of chronic diseases like heart disease and diabetes
Lowers moderately high blood pressure
Improves bone density (particularly weight-bearing activities like walking)
Reduces the risk of certain cancers (breast, colon)
Improves the likelihood of surviving a heart attack
Alleviates symptoms of depression (in some cases as effectively as medication or psychotherapy)
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Reduces body fat
​Can reduce the pain and swelling of arthritis
​Increase HDL cholesterol (the good cholesterol)
Decreased blood triglycerides
​Improve weight control
Improve glucose tolerance and reduce insulin resistance

WEIGHT LOSS MEDICATIONS AS WELL AS DIET AND EXERCISE PLANS...
How Much Do I Need to Do to Gain All These Benefits?
The Surgeon General recommends 30 minutes or more of accumulated moderate intensity physical activity on five or more days per week to improve health and fitness. "Accumulated" means you can do it in shorter bouts throughout the day (for example, 10- or 15-minute intervals throughout the day), and "moderate intensity" means you feel warm and slightly out of breath when you do it.

The American College of Sports Medicine recommends 20-60 minutes of continuous activity, three to five times a week, at 60-90% of maximum heart rate, and two to three days of resistance training.

Both recommendations include aerobic exercise, and your health and fitness will improve if you follow either.

The American Heart Association recommends the following dietary guidelines, which are suitable for most adults.
Eat five or more fresh fruits and vegetables each day.
Eat six or more servings of grains (preferably whole grains) each day.
Eat fat-free and low-fat dairy, legumes, seafood, and lean meats.
Avoid foods with more than 2 grams of saturated fat per serving.
Balance your caloric intake with your energy expenditure.
Limit junk food, which is high in simple carbohydrates and low in nutrition.
Limit foods high in saturated fat and cholesterol. Eat less than 6 grams of salt each day.