22 Hard-To-Detect Illnesses, From The Commonplace To The Truly Bizarre

8. Sleep Apnea

Sleep apnea occurs when the muscles in your throat relax while you are asleep, causing your brain to wake up and restore normal breathing. What makes this disease hard to detect is that the symptoms only occur when you are asleep. However, if left untreated, sleep apnea can lead to severe fatigue, liver problems, or even heart disease.