What variations can suffer the BIA?
- On the same day: Like blood pressure, the hydration level varies all through the day. The normal hydration cycle is the following: During sleep, the extracellular fluid and the blood flows to the internal organs, far from the extremities. This would cause an increase of the impedance. When you are awake, the blood and the extracellular fluids flow all over the body and the extremities have a higher hydration. For this reason, the best time for the body fat measurement is 3 or 4 hours alter having woken up, when the fluids flow with higher activity all over the body. Do not forget that hydration may be affected by the diet.
- On several days: From one day to another, it is possible that the measurement of the body composition suffers slight variations. This is why it is strongly advised to compare the results of the measurements made during 3-4 weeks to determine whether the changes respond to a tendency or are spontaneous.
- Conclusion: Making the measurement at the same hour every day and observing the recommendations above for a period of several weeks will offer consistent and repetitive results, which will allow the determination of the method to follow if a weight control program appears to be necessary.