Most of the time, people mistake fatigue for tiredness even though there is a difference in degree between the two. Fatigue is a state of extreme tiredness or lack of energy, often called complete exhaustion. Unlike tiredness, it lasts even after getting enough sleep. There are many different kinds of conditions that can lead to fatigue in a person:
Medical causes of fatigue
1. Anaemia: Anaemia is a condition where the quality or the number of red blood cells in the body reduces. A person with anaemia does not have enough oxygen-rich blood which makes them suffer from dizziness, fatigue, shortness of breath and arrhythmias.
While in most of the cases anaemia is due to lack of iron in the body (iron-deficiency anaemia), it can also be a sign of underlying serious conditions such as ulceration in the stomach, kidney disease or autoimmune hemolytic anaemia.
2. Sleep apnea: Sleep apnea is a serious sleep disorder where the person is unable to breathe while sleeping. It can be caused either because of any blockage in the airway (falling back of the tongue in the back of the throat during sleep) or because of the inability of the brain to send signals to the body to be able to breathe. This makes them not only gasp for air at night but also wakes them up in the middle of the night which makes them feel exhausted throughout the day.
3. Hypothyroidism: Hypothyroidism is a condition where the thyroid gland makes too little thyroid hormone which is otherwise necessary for various functions in the body. In the absence of thyroid hormone, the person tends to gain weight, has pain in the muscles and complains of continuous tiredness.
4. Diabetes: Fatigue is one of the common symptoms of type-1 and type-2 diabetes. Due to excess glucose and insulin resistance in the blood, the cells of the body cannot produce energy thus the person feels extremely tired all the time.
5. Restless legs syndrome: People with iron deficiency anaemia may also suffer from a condition called restless leg syndrome, where the person experiences an irresistible urge to move their legs. Restless leg syndrome is mostly seen during the evening, making it difficult for the person to sleep at night. This makes the person irritated, extremely tired and sleepy during the day.
Lifestyle-related causes of fatigue
1. Alcohol: Alcohol depresses the nervous system and disturbs the normal sleep pattern of the body. This makes the person irritable, tired and exhausted. Persistent alcohol use could result in fatigue.
2. Physical inactivity: Regular exercising helps in improving health and wellbeing, reduces stress, and also maintains the sleep cycle. In the absence of physical activity, the body feels lethargic, tired and even fatigued.
Psychological causes of fatigue
1. Anxiety: Anxiety is a state of worry or fear which can be completely normal at some points of life. But some people have constant uncontrollable anxiety which affects their daily life. A person suffering from generalised anxiety disorder would present with shortness of breath, fatigue, headache, nausea and difficulty falling asleep.
2. Depression: Depression is a state of mind where the person suffers from depressed mood, loss of interest and increased fatigability. Depression makes it difficult for you to fall asleep which makes you feel more tired during the day.