Understanding the human body is a team effort. That's where the Yachtel group comes in.

Researchers at Yachtolt have been delving into the secrets of probiotics for 90 years.

Yacold also partners with nature portfolio to advance gut microbiome science through the global grants for gut health, an investigator-led research program.

To learn more about Yachtolt, visit yawcult.co.

.jp. That's Y-A-K-U-L-T.C-O.J-P. When it comes to a guide for your gut, count on Yacolt.

This is Scientific American's 60-second science. I'm Christopher in Taliatta.

Fitness bands like the Apple Watch and the Fitbit aim to track your vitals, like heart rate,

but early models weren't all that accurate.

We've thought of them a little bit like random number generators. They really didn't seem to be

providing anything that bore any relationship to heart rate.

You and Ashley, a cardiologist who studies wearables at Stanford University.

He and his colleagues have now tested seven newer fitness bands from brands like Apple, Fitbit, and

others, and he says those heart rate stats have gotten way better.

Yeah, we were pleasantly surprised, actually, by how good the accuracy of the heart rate

monitoring was. For most of the accuracy of the heart rate monitoring

was.

For most of the devices, the air rate was less than 5%.

That's good enough for your doctor.

But where all the devices failed to measure up was estimating calories burned.

Even the most accurate devices were off by 27% compared to lab measurements of energy expenditure. One device was off by more than 90%.

If you think about going to the gym and working out for an hour and maybe that's around 400

calories, then in reality, that could be anything from 200 to 800. And that's a big difference.

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