Cansancio vs. fatiga vs. agotamiento

Word practice demo
In the Spanish language, 'cansancio', 'fatiga', and 'agotamiento' are terms often used to describe different levels and aspects of physical or mental tiredness. Understanding the nuances between these words can help to accurately convey the level of fatigue you are experiencing.

Cansancio

'Cansancio' refers to a general feeling of fatigue or tiredness, which can be either physical or mental. It's usually the result of normal daily activities.
Después de correr, siento un ligero cansancio.
(After running, I feel a slight tiredness.)
El cansancio acumulado de la semana me ha dejado exhausto.
(The accumulated tiredness of the week has left me exhausted.)

Fatiga

'Fatiga' denotes a deeper level of exhaustion than 'cansancio', often with the connotation of being chronic, caused by overwork, stress or health problems. It is more specific and usually implies a longer duration or a more intense level of fatigue.
La fatiga crónica es una condición médica seria.
(Chronic fatigue is a serious medical condition.)
Siento una fatiga que no desaparece ni después de descansar.
(I feel a fatigue that doesn't go away even after resting.)

Agotamiento

'Agotamiento' describes an extreme state of exhaustion in which the person's physical or mental resources are almost exhausted. It indicates a higher level of severity than both cansancio and fatiga.
Después de la maratón, estaba en un estado de agotamiento total.
(After the marathon, I was in a state of total exhaustion.)
El agotamiento mental puede llevar a graves problemas de salud.
(Mental exhaustion can lead to serious health problems.)

Summary

While 'cansancio', 'fatiga', and 'agotamiento' all refer to forms of tiredness or weariness, they differ in intensity and implications. 'Cansancio' is the most common form, often resulting from normal activities. 'Fatiga' suggests a deeper, possibly chronic level of fatigue, often related to overwork or health problems. 'Agotamiento' indicates an extreme level of exhaustion that significantly affects one's ability to function.