Lungs – Our sensation of breathing in our dreams often follows our outward physical experiences. Dreaming of swimming, for instance, only rarely includes the necessity of holding your breath underwater, and many dreamers find that their lungs function perfectly in their dreams, no matter what events are happening that ought to be preventing them from breathing. For this reason, if you have dreams where your lungs do not work or you cannot breathe, this is a possible indication that you have a physical breathing problem when you sleep, such as sleep apnea. Sleep apnea is a serious condition that can cause a wide range of health problems, and you should be evaluated immediately if you suspect you have it.