The word<unk>  is used in everyday living to describe a range of afflictions, varying from a general state of lethargy to a specific work-induced burning sensation within one's muscles. It can be both physical and mental. Physical<unk>  is the inability to continue functioning at the level of one's normal abilities. It is ubiquitous in everyday life, but usually becomes particularly noticeable during heavy exercise. Mental<unk> , on the other hand, rather manifests in somnolence.
Fatigue
Sedation
Somatization
Somnolence
Anorexia 
Xerostomia
Dyspnea
Hyperhidrosis