Many of the benefits of exercise come from the body having to undergo a new experience. When you start walking, running, weight lifting, or doing any other sport, your body gets exposed to new movements and strains. The human body has learned to accommodate to new stresses by adjusting itself to respond to that stress. When you lift weights, your body responds to the stress on your muscles by building more muscle. When you perform cardiovascular exercise, your body responds by the heart building more muscle to accommodate to the need for increased blood flow. Other changes occur as well. In addition to your muscles and heart, other areas of your body also strengthen. Your bones, tendons, and ligaments all restructure to increase their strength. You build more oxygen-carrying red blood cells and oxygen-transporting blood vessels. The body's response to the work of exercise is to make it stronger, and this new strength benefits all aspects of your life.
Cross-training not only gives the sustained excitement of different exercises to your mind and body, but also allows you to reap the benefits of every form of exercise. You can strengthen your heart, open your lungs, and build the different muscle types used for quick movements and sustained activity.
To get the most benefit, you should allow your body exposure to different stresses. While any amount of moderate exercise is very beneficial, the most benefit comes from doing different forms of exercises. Serious weight lifters and runners follow this strategy. Weight lifters are always changing their movements and therefore how they stress their muscles. This produces the greatest muscle growth from the constant accommodation to new strains. Runners will vary paces and distances to maximize stress on different types of muscle fibers.
Of course, if you are starting from a position of no exercise, then you should start with one new activity. As you get comfortable in that activity and pursue it to a level where you feel you are reaping a significant benefit, then you may realize even greater benefit by seeking out new forms of exercise. Not only will this maximize the benefit to your body, but it will also help stave off boredom and encourage motivation.
The benefits of exercise cannot be overstated. Exercise improves your entire cholesterol profile, including raising your HDL, lowering your LDL, and lowering your triglycerides. Exercise also reduces your blood pressure, lowers your blood sugar, makes you slimmer, and decreases stress. All of these independently reduce your risk for cardiovascular disease. Therefore, by exercising, you make a tremendous reduction in the likelihood of suffering a heart attack or stroke. You should have a goal of at least thirty minutes total of moderate exercise at least three times per week. By getting active, you will boost your health, look better, have more energy, and improve your mood. The benefits are innumerable to you and those around you. So get out there, and get moving!