At some point we have all come to feel lacking in energy . Without wanting anything except to lie down and rest, exhausted. We feel weak and almost unable to move, needing a break.

This feeling of fatigue will probably pass after a while, after a period of rest. However, due to multiple causes, sometimes this feeling is reluctant to subside and is prolonged over time. We would be dealing with a case of asthenia .

Defining the concept of asthenia

We call asthenia to a picture in which there is a reduction in the level of energy and strength in the organism , also reducing motivation and producing a feeling of exhaustion both physically and mentally.

Despite the fact that pathologies such as spring asthenia are well known, asthenia is generally classified as a symptom, as it is an indicator of a deeper process than the cause, regardless of its etiology.

This alteration may be accompanied by difficulties in attention and concentration, alteration of sleep and memory, loss of appetite and sexual desire, bradykinesia or slowness of movement, dizziness, emotional lability, depressive symptoms and even, depending on the cause, it is possible to experience alterations such as fever and hallucinations. In some cases it can cause loss of consciousness, changes in vision or difficulty in speech in which case one should go to medical services quickly, and this can be a symptom of a serious organic disorder.

This exhaustion produces a series of complications in the life of the person who suffers it , affecting their life in different areas of life by reducing the amount of behaviour carried out and their state of mind.

Etiology or causes of asthenia

As we have mentioned, asthenia is usually catalogued as a symptom of a medical process or a mental state , there being multiple possible causes for its appearance. On a general level, it is observed that together with asthenia there tends to be a decrease or alteration in the immune system, so this is considered a possible explanation for the symptoms.

On a medical level, it can be caused by the presence of allergies and autoimmune problems (such as in the case of spring asthenia or in some cases of HIV patients). It is also frequent in infectious processes, in the absence of sufficient nutrients in the body as in the case of anaemia, as well as in neurological disorders, tumour processes and even as a reaction or side effect of some drugs such as benzodiazepines and tranquillisers or antihistamines). Metabolic disorders such as diabetes mellitus can also cause episodes of asthenia.

In more than half of the cases, asthenia is due to purely psychological causes.

Known then as psychogenic or functional asthenia , it often appears in the presence of continuous stress , such as that suffered by subjects with burnout or in times of exam preparation in the case of students. In these cases the asthenic episode worsens in the mornings, generally appearing together with problems of conciliation or maintenance of sleep. It also appears when faced with a dysregulation of circadian rhythms such as that produced by jet-lag. Finally, this symptom appears in a large number of disorders that produce emotional wear, being frequently visible in cases of depression, anxiety disorders, obsessive-compulsive disorder and post-traumatic stress disorders.

At a more normative level, asthenia is also common due to ageing, pregnancy or too sedentary lifestyle.

Brain mechanisms involved

Although the concrete causes of asthenia may be, as we have seen, multiple and varied, at the cerebral level the presence of alterations in the system that governs wakefulness is discussed : the activating reticular system or RAS, located in the brainstem.

These alterations are based on the non-activation of this centre, which causes a sensation of tiredness both on a physical and mental level. In this aspect, there is a problem at the level of noradrenaline production in the locus coeruleus or its transmission.


Asthenia is treated on a general level from the resolution of the specific cause that has caused it , there not being a specific treatment for this problem in general.

However, it is very useful to do physical exercise which, we must remember, helps to reduce stress and relax, as well as generating endorphins endogenously.

Likewise, cognitive behavioural therapy has been successful in the treatment of asthenia, especially if it occurs chronically, helping to de-dramatize the problems present, improve the cognitions and behaviours that can influence the appearance of asthenia and presenting techniques and planning activities so that the patient is able to better manage stress and present optimal functioning in daily life.

On a pharmacological level, antidepressants or anxiolytics have sometimes been used, as well as multivitamin preparations in order to increase the energy level. One medication that is also sometimes prescribed as an antiasthenic is sulbutatin, especially for sexual symptoms.

Basic difference of asthenia from normal fatigue

Asthenia is often confused with a normal fatigue process. The main difference between asthenia and fatigue is that while fatigue with a period of rest tends to revert, in the case of asthenia it remains and even gets worse, and can become chronic if the problem persists for more than six months, producing a deterioration in the patient’s life at the work, social or personal level of more than 50% with respect to their base level.

Bibliographic references:

  • Casanovas, J.M. (2009). From symptom to disease: asthenia. Rev Pediatr Aten Primaria. vol.11, 17, 425-431.
  • Feuerstein, C. (1992): Neurophysiological data concerning fatigue. Role of the activating reticular system. Entreteins de Bichat.11-19.
  • Price, J.R. & Couper, J. (2000). Cognitive behaviour therapy for adults with chronic fatigue syndrome. Cochrane Database Syst Rev.

  • Walkman, K.E.; Morton, A.R.; Goodman, C.; Grove, R. & Guilfoyle, A.M. (2004). Randomised controlled trial of graded exercise in chronic fatigue syndrome. Med J Aust. 180(9):444-8.
  • Waynberg, J. (1991). Asthenia and male dysfunction. JAMA (French ed.); 222 (suppl):4-12