Outdoor exercise will bring more oxygen into the lungs and help clean out the system, reducing bad breath. In the lives of many, gum disease is a major cause of bad breath. Place goldenseal over the infected gums or mouth sores. Do this for 3 days, to help heal the gums. Far less likely, mouth breathing may cause bad breath.
Sinus infection produces a discharge with a bad odor.
If you have sinus trouble, this may be the cause of your bad breath. Do not eat spicy foods. Meat eating can produce bad breath, both because of the particles left in the mouth and because of later indigestion. Cheese and fish both cause bad breath. Yes, there is garlic, but it is such a powerful germ killer that you may need to take it anyway.