One common health universal question is how can someone become so tired sometimes that it feels as if they ran the marathon?  Most people do not understand this but experts have come up with three culprits that cause most cases of tiredness and fatigue.
The first common cause of tiredness is lack of sleep or poor sleeping habits.  Sleep is supposed to be a time when the body recovers what it used in the day and give time to muscles and body organs to recuperate but most people do not observe this.  A normal adult should sleep for a minimum of 6 hours a day.  People recovering from sicknesses also experience weakness in the body and feel that they have no energy always tired and just want to rest.  The last common cause of tiredness and fatigue is stress.  This can be work related, domestic or any other stress, anxiety or depression.