1. Lung Disease: Early morning awakenings can be a symptom of lung diseases like asthma and COPD. The lower temperatures in the morning can cause bronchospasms and oxygen deprivation, leading to symptoms such as coughing and chest tightness. 

2. Heart Disease: If you wake up at 3 or 4 am with chest pain or tightness, it is important to seek medical examination to rule out heart disease. 

3. Type 2 Diabetes: Increased nighttime urination, known as nocturia, can be a sign of type 2 diabetes. When blood sugar levels are high, the kidneys cannot reabsorb all the glucose, leading to frequent urination. 

4. Head Disorders: Abnormalities in the head can cause early morning awakenings. Narrowing of cerebral blood vessels can reduce blood and oxygen supply to the brain, triggering cerebral ischemia and stimulating wakefulness.

5. Psychological Disorders: Some individuals who experience early morning awakenings may not have any physical issues but may suffer from anxiety, depression, or excessive worry about their health.