Blood pressure, blood sugar and ECG: Background and review of the iHEAL 6 - A potential health hazard

The iHEAL 6 is advertized by Kospet as having an enormous range of functions. In this article, we will be taking a critical look at its advertizing promises—with the help of medical measuring devices and not without restrictions.

March 01, 2024 update: Kospet has reached out to us to state that it has stopped the production of the iHeal 6.

Blood glucose levels and blood pressure can—in principle—be determined photometrically. This allows the interaction between glucose and electromagnetic waves to be detected and the glucose content of a solution to be measured accordingly. In a laboratory environment, glucose is often measured using a photometer after an enzymatic conversion. The optical measurement of blood pressure is possible with several Galaxy smartwatches from Samsung, but requires a support calibration.

The Kospet iHEAL 6's advertized features are therefore not physically impossible. However, optically measuring blood glucose levels—especially without the need for calibration—is in some ways a holy grail. This would be the first practical, non-invasive method for measuring blood glucose levels and as no consumables in the form of blood glucose test strips or pods would be required, this would result in considerable cost savings. On the other hand, the fact that this function is to be provided by affordable smartwatches from the Far East in particular is a cause for concern.

Several wearables—including the Apple Watch—support ECG creation. This may only be a single-channel ECG, but it can already detect certain irregularities in the heart. Their measurement principle is in some ways more direct than optical measurement, as the heart currents are measured. In the medical field, a 12-lead ECG is often used due to its greater informative value.

The same applies to measuring blood glucose levels. The corresponding DIN EN ISO standard 15197:2015 requires a maximum deviation of 0.8 mmol/l from the true value for measured values below 5.6 mmol/l; for values above 5.6 mmol/l, the deviation may then be up to 15 per cent. 95 per cent of the measured blood glucose values must be within this range. We used approved FreeStyle blood glucose meters as reference devices and an Omnipod 5 for the longer measurement. The measurement was carried out on two different people, whereby both physiological ("normal") and pathological ("abnormal") measured values were available to us for the test to assess the watch's measuring accuracy. The inclusion of a diabetic person is practically mandatory: blood glucose levels are regulated within narrow limits in metabolically healthy people and don't normally reach values above 7.8 mmol/l. Accordingly, a watch that displays random values in the normal range without actually measuring is "correct" with a high degree of accuracy in metabolically healthy people.

The iHEAL 6 is advertized as featuring a blood glucose level measurement function. We have already mentioned this in our news article: The blood glucose curve seemed a little atypical to us, and the test revealed that the iHEAL 6 is not actually able to measure blood glucose levels at all. As already described, the measurement is only inadequate for checking the quality in the physiological range, whereas pathological readings show a huge deviation.

It is clear that the iHEAL 6 can detect neither hypoglycemia nor hyperglycemia. In the case of hypoglycemia, it even displays a higher value than in the case of hyperglycemia; all values generated by the iHEAL 6 during the test were within the normal range. For type 1 diabetics, using the iHEAL 6 is potentially life-threatening if they rely solely on the watch and, for example, hypoglycemia is detected too late. As a result, patients with type 2 diabetes may be lulled into a false sense of security—which can lead to long-term damage.

The ability to measure blood pressure is also advertized by the manufacturer. Optically measuring blood pressure could in principle be useful both for monitoring the progress of widespread hypertension in particular and for screening and—as a continuous measurement—could detect blood pressure peaks, for example. However, the iHEAL 6 is not able to generate accurate measured values.

The values shown in the last line are particularly striking. There, the difference in systolic pressure is 33 mmHg. The iHEAL 6 still shows optimal blood pressure here, while the certified measuring device already shows mild hypertension. As with blood glucose measurement, the iHEAL 6 only displays physiological readings when measuring blood pressure.

A manual, tenfold measurement using the iHEAL 6 resulted in a mean value of 117.9 mmHg for systolic blood pressure—with a relative standard deviation of only 2.5 per cent. This means that the measured values are very precise, but precisely incorrect and therefore not accurate, as the reference value generated by the measuring device was 150 mmHg.

The iHEAL 6 is advertized as having a virtually ground-breaking range of functions—and in practice is a potential health hazard. According to our analysis, neither its blood pressure measurement nor its blood glucose level measurement works as advertized, which can lull customers into a false and fatal sense of security as only physiological readings are displayed. The ECG function, on the other hand, is decent—at least the recording we were able to evaluate. 

Disclosure: The author was supported in their evaluation of the ECG function by a cand. med. and doctoral student of medicine.

The iHEAL 6 can be purchased directly from the manufacturer for around US$50. An alternative with a blood pressure measurement function featuring support calibration and a certified ECG would be the corresponding Galaxy Watch models from Samsung.

Photo by Mockup Graphics via Unsplash, photo by Elias Tsolis via Pixabay