If the problem is not a lot of hot and healthy sex, you might have sleep apnea.
It means that some part of your body closes off your breathing passage during sleep and your body pumps adrenaline in to wake you up enough to get you safely inhaling again.
It can happen every minute. You can't get any decent sleep that way. So, if you are sleeping and sleeping and not getting rested, waking up several times a night (that you recognize), or snoring really loudly (another symptom), you might want to get it checked out.
It can cause heart problems. It can send your blood pressure, even normal blood pressure, through the roof every night. Which can lead to a lot of damage, including the potential loss of eyesight from a retina tearing. (This one happened to my dad before he was diagnosed.)
The American Sleep Apnea Association has good information without any of my theatrics.