Fatigue can often be a hard symptom to evaluate, as it is highly subjective. Also known as tiredness, fatigue can be described as a lack of energy. Under normal circumstances the feeling of fatigue should be alleviated by sleep and a period of rest. Daily life in modern society with many different commitments can be tiring, however, consistent fatigue, which is not alleviated by sleep or rest is not normal.
Fatigue is thought to be a defence or survival mechanism of sorts, conserved throughout our evolution. The thinking behind this is in days when we would have been hunted by predators, fatigue during an infection or injury would ensure that rest or sleep was taken, therefore making it less likely that a predator would find you and give the immune system opportunity to do its job and find off infection.
In the case of unexplained, persistent fatigue further investigation into the root cause should be sought. There are many possibilities such as allergy, food intolerance, viruses, anaemia and depression. There are also a great number of health conditions of which fatigue is a symptom. In understanding the underlying reason for fatigue, it is always important to consider any further symptoms an individual may be experiencing. We would highly recommend speaking to your GP about your symptoms.