Tuesday, July 25, 2017

Green Light in the Fitness Trackers is Harmful

 According to Apple, the Watch uses a technology called photoplethysmography, or PPG, to measure heart rate. It’s essentially testing how much red or green light it can see when looking at the skin on your wrist. Blood is red because it reflects red light and absorbs green light, so when your heart beats, there’s more blood flow in your wrist, and more green light absorption. Between heart beats, there’s less absorption of green light.\

By flashing its LED lights hundreds of times per second, Apple Watch can calculate the number of times the heart beats each minute — your heart rate.

Fitness trackers — such as the Fitbit, Jawbone UP24, and Nike+ FuelBand — collect data about your activity levels and sleep patterns, then send the information to your computer or smartphone via low-level radio-frequency waves.

“The lack of proof of harm is not evidence of safety. You have to decide for yourself if that’s a risk you want to take.” 

The non-ionizing waves emitted by wireless trackers are similar to those of cell phones, which have been classified as “possibly carcinogenic to humans” by the World Health Organization’s International Agency for Research on Cancer. The National Cancer Institute recommends limiting cell-phone calls that involve phone-to-head contact.

The non-ionizing waves emitted by wireless trackers are similar to those of cell phones, which have been classified as “possibly carcinogenic to humans” by the World Health Organization’s International Agency for Research on Cancer. The National Cancer Institute recommends limiting cell-phone calls that involve phone-to-head contact.

3 Ways to Limit Your Radiation Risk

Choose a device that must be plugged in to your computer or smartphone to sync data, rather than one that constantly transmits information. If your device comes with a wireless receiver, plug it in to your computer or phone only once a day.
Avoid wearing clip-on devices around your midsection especially near your breasts or reproductive organs. Wearable devices are required by law to follow specific absorption rate (SAR) limits, a measure of the rate at which energy is absorbed by the body when exposed to a radiofrequency electromagnetic field. 

But these limits do not take into account the possibility that reproductive organs and breasts may be damaged at levels well below official SAR limits, Davis says.

Use your fitness tracker for about a week to get a sense of your patterns. Then take it off and make adjustments to your lifestyle. Don it again to get revised benchmarks, then use the device to monitor your progress as desired.

The technology required to measure a person's pulse with light has been around for quite a while: Devices in hospitals called pulse oximeters (which place a clip on the finger) measure the amount of oxygen in the blood in a similar way.

Using light to measure a pulse is relatively straightforward when a person is at rest, but becomes challenging when the subject moves around. Ambient light, as well as the movement of the person's muscles, tendons and capillaries, can all interfere with the measurements, said Damon Miller, head of marketing at Basis.