Fatigue
The influenza virus, which causes the flu, is a highly contagious respiratory infection. Although the most severe flu symptoms persist for two to three days, the average duration is roughly a week. Once people get better, they can still feel weak, exhausted, and cough for another week.
One of the first signs of the flu is sudden, extreme weariness. It could show up before other symptoms. The flu usually causes fatigue to be more severe than it is with a cold.
The fatigue caused by influenza is a feeling of utter weariness, not the ordinary exhaustion following a restless night’s sleep or the muscle weakness brought on by a highly intense exercise session. It typically shows when sick with the flu and for a few weeks after other symptoms have subsided.
The immune system must expend significant energy to combat the flu virus. As a result, white blood cells are diverted from their usual task of maintaining the muscle fibers and joints repaired and healthy to fight the virus. As a result, patients quickly lose muscle strength, making it harder to stand and move around.
