Why You Should Measure at the Same Time of Day Each Time

Oserio’s Body Fat / Body Composition smart scales make it easy for you to conveniently receive a calculation of your body fat, water, muscle, and more! (depending on your purchased model)

These devices use “Bioelectrical Impedance Analysis” (BIA), which combine data such as bioelectrical impedance, weight, height, age, gender, and more to calculate your results.

If you’ve gone to a health clinic to get a regular check-up, you may have been instructed to go in the morning on an empty stomach. Why is that the case? Oftentimes, factors such as whether or not you’ve eaten, or the time of day can influence measurement results. For example, blood pressure tends to rise a few hours before waking up, continuing to rise until midday and then dropping in the afternoon and evening. So if you were to go to a clinic in the morning this month, but go in the evening the next month, the measurements might be different even if your body has not in fact changed very much! It’s simply a temporary difference caused by biological circumstances being a bit different from each other.

It’s important to keep in mind that the same applies for BIA as well if you want to make sure your measurements are as accurate as possible! Yes, you can safely measure at any time of day. However, a measurement conducted in the morning may be different compared to a measurement conducted at night, even though your body’s fat level has not actually changed. This is because the impedance in your body can be different depending on the time of day (and which segment is being measured).


Source: “Within-day variability of whole-body and segmental bioelectrical impedance in a standing position, European Journal of Clinical Nutrition (2006) 60, 938-941”

Research by Oshima and Shiga indicates that segmental impedance in particular can change noticeably throughout the course of a day. For feet-to-feet impedance such as that used by Oserio’s smart scales, impedance tends to be higher in the morning, and lower in the evening. Because the devices utilize impedance as one variable to calculate results, this means your results will be slightly different as well!

Therefore, to ensure that you’re getting the most consistent snapshot of your body, we strongly recommend measuring at the same time, and under the same conditions! If the most convenient time for you is shortly after waking up and drinking a glass of water, then try and do that at the same time of day each time.

BIA is an easy-to-use tool that is much more convenient (and less expensive) than other options such as X-rays or MRIs. However, you still have to try and ensure consistency to make sure you’re getting accurate results, and not seeing “false” change when in fact, the change is not that significant yet.