Exercising is, hands-down, one of the best physical things you can do for your health. Besides being beneficial for weight management, exercise can reduce your risk of heart disease, cancer, diabetes, and depression, and it can increase your energy levels, help you think clearer, and slow down the aging process.
Both young children and animals clearly demonstrate the proper way to exercise: in short but aggressive or intense spurts with rest in between.
you don't need to exercise for long periods of time—as long as you're exercising correctly! As it turns out, the most effective and efficient way to work out is to 'remember' your ancestral roots, meaning, how humans used to move; session only requires about 20 minutes or less, two or three times a week, opposed to an hour or more on the treadmill, several times a week.
One of the main reasons for this is that in order to achieve muscle definition, regardless of what area of your body you're targeting, you need to lose fat, and spot-specific exercises like crunches are not an efficient way to boost fat loss.
High intensity exercises can make a dramatic difference here, because these exercises not only boost fat burning, they also automatically help create muscle definition all over your body, while simultaneously improving your aerobic fitness; but so is what you eat and drink.