Many individuals regularly experience weakness and it can be caused by a variety of conditions, such as a lack of sleep or malnutrition. Many times, weakness comes as the result of dehydration. In some cases, the fatigue can also be caused by sickness or a reaction to certain medications. Some individuals also suffer from a thyroid condition that can cause weakness in the body. Other times, the weakness can be caused by overexertion.

Weakness is experienced on many levels by different people. Some people generally feel weak in their muscles while others feel like they are too tired to do anything. Every condition can generate a different level of fatigue in every person.

One of the most common sources of this condition is not getting enough sleep. Many individuals do not sleep the recommended seven to eight hours and end up being negatively affected by it. They feel like they are tired all the time and do not have enough energy to get through the day.

Another common cause of weakness is poor nutrition. Individuals in today's society do not eat a healthy diet. They eat a great deal of junk food and fast food but do not get the nutrients they need. In order to increase energy production, people need to eat a healthy diet full of fruits, vegetables, and protein. Without this type of diet, an individual can feel weak and drained frequently.

Individuals also need to get plenty of water every day. Most people do not drink enough water, even though they believe they do. Drinking about eight 8-ounce glasses (1.9 liters) of water is a good rule of thumb.

Many times, weakness is caused by a sickness or a reaction to medication. For example, if an individual is suffering from mononucleosis or influenza, he or she will most likely feel very weak. Other times, people end up taking medication for sicknesses and other conditions and end up feeling weak as a result.

The thyroid gland also plays a vital role in energy production. Having either a high or low amount of thyroid production can cause an individual to feel very weak. This condition can be determined by a medical professional.

The simplest explanation for weakness is overexertion. If an individual works too hard or exercises too much, he or she could feel very weak. This commonly happens after a grueling workout.