Breath 
If you are able to see your breath in a dream and it does not appear to be cold, consider what you are about to reveal in waking life. This doesn't mean disclose it verbally, it refers to something you will declare with your own actions or choices. Your subconscious mind is calling attention to what might come out of you before you've had the chance to divulge something.
If your breath is heavy or shallow, consider what kind of air you've been taking in and what type of people you have been surrounding yourself with.
Having trouble with your breath is a symbol of stale air, ideas, people, or situations.
Breathe
To dream that you are breathing rapidly implies that some issue in your life is causing you great worry or concern.
To dream that you are breathing underwater refers to your time spent as a fetus in utero. You wish to unburden yourself from the pressures of your adult life. You want to be released from obligations and stress. It's possible that you feel vulnerable and need someone to care of you.
You may be too caught up in your personal feelings and feel like you are drowning under the pressure.
To dream that you are holding your breath implies that you possess a strong will and are persistent and rigid in your beliefs and opinions. Perhaps the dream is suggesting that you should consider other points of view.
To dream that you cannot breathe reflects fatigue that you are experiencing.
To dream that you have bad breath implies that you are not being completely honest with yourself or other people
Breathalyzer Test
Dreaming that you are taking a Breathalyzer test represents guilt that stems from a bad decision. You were likely not caught or confronted about your poor judgement, but subconsciously you know that you could have been caught and it could have turned out much worse.
Oxygen Mask
Wearing an oxygen mask in a dream indicates that you need protection from outside influence. You may be concerned that your environment is causing you pain.
Alternatively, an oxygen mask may symbolize a need for freedom. You need to get out of a stifling atmosphere and express yourself.
Lie Detector
A lie detector in a dream represents a test which you are trying to pass. You may have a secret which is bothering you and you are afraid of being caught. You may also have a big interview ahead, or a final exam, which is causing you stress.
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