Asthenia or fatigue can have its origin in innumerable causes. The phrase "you will have low defenses" is very popular, although it really is a statement that does not have much scientific basis. It is common the existence of different times of the year in which the person is a little more tired than normal, either due to overwork, stress or mood, among other reasons.
Spring itself can cause a feeling of tiredness or fatigue, known as spring asthenia. We should consult with the professional when this feeling of tiredness and lack of energy lasts over time, that is, when we have been more than one or two months and do not recognize it as normal in our body. Your doctor will probably perform an analysis with the necessary parameters to identify the causes.
One of the most frequent reasons of tiredness in people (especially in young girls and older people) is anemia. In girls, menstrual bleeding causes blood and iron losses that are not compensated for by the daily diet. Thus, progressively, month by month, red blood cell deficit is entering until anemia develops. In this case, the supplementary contribution of iron for a few months will solve the problem. Low defenses – or a drop in white blood cells -, on the contrary, is uncommon as a cause of anemia or fatigue. Normally, the defenses suffer few variations, except in people with very specific diseases (such as HIV), so they are certainly not the first cause of fatigue.
Dr. Joseph Perez. Clinical Hospital of Z Rehab Center