Can Fever Affect BIA?

In 2015, researchers investigated the influence of acute fever caused by an influenza infection on BIA. To this end, they carried out repeated bioelectric vector impedance analyses (BIVA) in 52 patients and showed that elevated body temperature had a significant influence on BIA parameters. The fever therefore increased the reactance, which is an indicator of the amount of metabolically active cells in the body (e.g. skeletal muscles). The resistance, on the other hand, which is due to the amount of electrolyte-containing body water, decreased.

The researchers suspected that the cause of their observations was not only dehydration and the associated loss of extracellular fluid, but also temperature-related increased tissue conductivity and the long-known influence of skin temperature on BIA. The main reason for this is a temperature-dependent decrease in skin resistance. However, the changes shown by the researchers were temporary and normalised after the defibrillation. Fever-related processes and changes in body and skin temperature can influence BIA and limit its significance. These results are also important for the routine use of BIA. In order to obtain consistently valid and comparable results, it is recommended to check the body temperature before each measurement and to refrain from measurements at elevated temperatures.