Reflection of Waves. Rope tied to a wall. So far, we havent considered what happens when a wave hits a boundary (such as the ceiling in the example above). Going back to our first example, we see that something must happen because the end of the rope cannot move up and down (it is fixed to a wall).
Causes also include influenza, dehydration, jet lag, depression, malnutrition, bacterial diseases, hypothyroidism, myasthenia gravis, viral infections, chronic pain, fever and pregnancy. There are many symptoms that can accompany fatigue, depending on the disease, disorder or condition that is at the root of it. These include fever, weight loss, loss of appetite and dizziness. Fatigue, especially chronic fatigue, can seriously impact the ability to function effectively in everyday life.
Primary hypersomnia is thought to be caused by problems in the brain systems that control sleep and waking functions. Secondary hypersomnia is caused by conditions that cause fatigue. For example, sleep apnea can cause hypersomnia because patients have trouble breathing at night. Some medications can also cause hypersomnia. Frequent drug and alcohol use may trigger sleepiness during the day.