A lot of it comes down to lack of saliva production while you’re sleeping. Saliva normally clears out odor-causing bacteria. So overnight, when we’re not producing enough of it, the smelly bugs can multiply.
So, the drier your mouth, the higher your chances of getting nasty morning breath. Breathing through your mouth, snoring, and using certain medications can also contribute to dryness, which can make morning breath even worse.
In most cases, morning breath is nothing to worry about. But in some situations, unusually bad breath could indicate an underlying health problem. It’s often the first sign of gum disease, which is linked to heart disease and strokes. Other times, it indicates an infection like an abscess or a gastrointestinal problem like GERD.
If you want to make your breath more tolerable in the morning, make sure to brush and floss carefully right before bed, since leftover food particles provide more food for bacteria to multiply in your mouth overnight.
Dr. Natour recommends two to three minutes of brushing, a tongue scraper (over half of bad-breath-causing bacteria grows on the tongue, he says), and an alcohol-free mouthwash
p And to make sure you’re free of gum problems, abscess, cavities, and other contributors to bad breath, there’s no substitute for biannual dental visits.