Apple Watch gets serious heart monitoring with the new Kardia wrist strap

Wearable manufacturers talk a big game about "health" and "fitness", but a new accessory for the Apple Watch is looking to up the stakes significantly with a medical grade electrocardiogram (ECG).

AliveCor already makes an FDA-approved ECG accessory for your phone, and the company is now bringing its technology to the Apple Watch.

Kardia Band is pretty much what it sounds like: a strap for the Apple Watch. The magic, though, is the medical-grade ECG built into it. The Kardia Band can also record your heart rate using an integrated sensor, while most current wearables with a heart rate monitor use an LED to track what your heart is up to.

The LED light of these wearables illuminates your capillaries and then measures the frequency of your blood flow. As CNET's Sharon Profis discovered some time ago, it can be a decent indication of resting heart rate, but it's often not particularly good when your heart rate is elevated.

And that's where the Kardia Band comes in. It not only monitors your heart rate, but it directly communicates with the Kardia app, which runs the data through an analysis algorithm to detect the presence of atrial fibrillation. That's basically a fancy term for a wildly irregular heartbeat and it's a common cause of stroke.

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The Kardia app will alert you when you've got the all clear for a normal heart rate, and you can take voice notes to accompany each reading. The idea behind the voice memo is to let doctors and caregivers know if an elevated heart rate is coming on the end of a simple coffee binge or due to something potentially more alarming.

AliveKor already operates a healthcare provider dashboard for its current ECG product, allowing your doctor to access your readings, and the Kardia will work in the same system.

Even if you're not too worried about the intensive medical care side of things, the Kardia Band will work with the Apple Health app to provide a much more accurate heart rate reading to go with your step count and calorific intake.

Vic Gundotra, the CEO of AliveCor and ex senior vice president of social at Google, said in a statement that the Kardia Band was the "introduction of the Wearable MedTech category" as well as the "future of proactive heart health".

At the moment, it's unknown how how much the Band will cost. But it's clear that AliveCor are hitching its wagon to the Kardia Band: the company is changing the name of its existing AliveCor Mobile ECG to the Kardia Mobile.

Skygazers ready for rare Mercury sighting

Earthlings will witness Mercury make a rare passage between our planet and the Sun Monday, appearing as a black dot tracking the surface of the star we share with the solar system’s smallest planet.

Mercury completes an orbit every 88 days, and passes between the Earth and the Sun every 116 days, according to the Royal Astronomical Society (RAS).

But its orbit is tilted in relation to Earth’s, which means it usually appears—from our perspective—to pass above or below the Sun.

Thirteen times each century, however, the two orbits align such that even amateur astronomers can see the tiny planet tens of millions of kilometres away.

“It is always exciting to see rare astronomical phenomena such as this transit of Mercury,” RAS president Martin Barstow said in a statement.

“They show that astronomy is a science that is accessible to everyone.”

But be warned: looking directly at the phenomenon can result in permanent eye damage, as only a very small part of the Sun will be blocked out.

One option is to use a telescope or binoculars to project the image onto a white surface.

An image of the Sun is captured by the main, front lens and projected backward, out through the eyepiece. The Sun will appear as a white disk on the card, and Mercury as a black dot crawling over it.

Stargazers can also observe the event through a telescope with a strong filter.

According to the RAS, large parts of the world—most of Western Europe, the western parts of North and West Africa, eastern North America, and most of South America—will be able to view the entire transit, which will last from 1112 GMT to 1842 GMT.

The rest of north and south America, the eastern Pacific, the remainder of Africa and most of Asia, will see parts of the event.

Observers in east and southeast Asia and Australasia, however, will miss out entirely.

French astronomer Pierre Gassendi was the first person to observe a Mercury transit through a telescope in 1631, two decades after the instrument was invented.

German astronomer Johannes Kepler had correctly predicted that transit, but died in 1630 before he could witness the event.

The last Mercury orbit was 10 years ago, and the next will be in 2019.

Mercury is the planet nearest to the Sun. Its elliptical orbit brings it as close to the earth as 46 million kilometres (28.5 million miles), and no further away than 70 million kilometres.

It rotates so slowly—three times for every two orbits—that, bizarrely, Mercury’s day is twice as long as its year.