How the Basis B1 Band Works

Black or white Basis B1 bands for the discriminating self-tracker
Photo courtesy Basis Science Inc.

The term biofeedback, which describes how people improve their health by using signals from their own bodies, usually conjures up images of patients hunkered down in geeked-out hospital rooms with sensors and gadgets strapped to their bodies. Think Dr. Emmett Brown from "Back to the Future," decked out in his elaborate brain-wave analyzer, and you'll get an idea of what many regard as state-of-the-art biofeedback.

Not so anymore. Two trends are driving a revolution in this poorly understood and often controversial field. The first is a movement from clinical care to self-care, which shifts the burden of monitoring health from the doctor to the patient. And the second is the same technology transformation that has led to gadgets such as the iPod Nano, which can pack 4,000 songs into a machine no bigger than a book of matches.


The Basis B1 band sits at the nexus of these developments -- one part watch, one part "Star Trek" mobile body-scanning device. OK, that's an exaggeration. The device can't peer through your skin and instantly assess every tissue, organ and system, but it uses five different sensors to measure a variety of biosignals and then translates all of that raw data into useful insights about your overall health. It's the one and only product of Basis Science Inc., a privately held company located in San Francisco that's backed by a couple of venture capital firms.

Basis founder Nadeem Kassam conceived of the initial concept, then gathered a team of software engineers, gamers and product development specialists to bring the vision to life. The result has generated a lot of buzz: In November 2011, the Consumer Electronics Association awarded the Basis B1 band a 2012 International Consumer Electronics Show (CES) Best of Innovations Design and Engineering Award and then, in January 2012, named the gadget a finalist at the 2012 International CES Last Gadget Standing challenge, which looks for products "likely to change the face of technology."

What makes the Basis band so special? That's what we're going to answer on the following pages. We'll start with the basics -- of course.


The Basics of Basis

It seems like such a simple concept: help people measure key biosignals so they can make lifestyle changes that improve their health. But which signals, exactly, do you target when the human body contains trillions of cells, and each cell contains trillions of molecules?

Like many elegant solutions, the band embraces the KISS principle -- keep it simple, stupid. Because it can't possibly measure every system in the body, it measures just one and uses the data the same way a financial expert would leverage key economic indicators to make decisions about the health of the global economy. That system is the cardiovascular system, which reveals itself most plainly in the number of times the heart beats per minute. "The heart is fundamental to understanding your health and continuously measuring heart rate can offer unprecedented insights," said Basis CEO Jef Holove in a press release.


To make those insights more meaningful, the Basis B1 band evaluates heart rate as a person moves through three natural states:

  • Sleeping -- During sleep, your heart rate drops to minimum level, but it doesn't remain constant. Research now indicates that the heart typically cycles from 63 to 67 beats per minute [source: Giorno]. Different factors can cause heart rate to increase, but one common culprit is apnea, or the suspension of breathing. The Basis band monitors your heart rate while you're catching Z's to determine the quality of your sleep and uncover any cardiovascular stresses that escape your attention while you're snoozing.
  • Waking -- In Basis lingo, "waking" describes any time you're awake but not exercising. At these times, your heart rate is higher than your sleeping level (the Mayo Clinic puts the typical resting heart rate for men at between 60 and 100 beats per minute), and your body is engaged in frequent, low-intensity motion. By monitoring your waking heart rate, Basis can establish a benchmark to compare activity levels in other states.
  • Being active -- Ever see people interrupt a workout routine to check their pulse? They're trying to see if they've reached an exercise target heart rate. According to the American Heart Association, this number should range between 50 and 75 percent of a person's maximum heart rate, which can be calculated by subtracting someone's age from the number 220 [source: WebMD]. A 40-year-old jogger, for example, would have a maximum heart rate of 180 beats per minute and an exercise target heart rate of, say, 108 beats per minute. If you have the Basis B1 band on your wrist, you'll get this information delivered automatically and, more importantly, evaluated against your sleeping and waking states. Not only that, you'll begin to understand how you transition between the various states, which can be just as revealing.

All of this self-tracking may seem novel, but it's part of a movement that has gained a lot of momentum -- and attention -- in recent years. Before we take a closer look at how the sensors on the Basis B1 band work, let's go inside a trend that would make Narcissus proud.


The Self-tracking Movement

The self-tracking movement has seen some early successes in helping people with hypertension lower their blood pressure.

Products like the Basis B1 band appeal to people known as self-trackers. While the term is relatively new, the concept is quite old. In fact, if you've adjusted what you eat during the day based on a bathroom scale's morning reading, then you already know about self-tracking. So, the concept has been around for years.

What's different now is that more people are joining the movement -- and not just because they have a chronic health condition. The other difference: Folks aren't measuring one health variable at a time. They're measuring several variables simultaneously, taking advantage of sophisticated technology that simply wasn't available to consumers 10 years ago.


Many trace the beginning of the modern self-tracking movement to Kevin Kelly, a co-founder of Wired magazine, and Wired contributing editor Gary Wolf. Kelly and Wolf believed that today's smarter -- and smaller -- electronic gadgets could do much more than read e-mail and play music. They hoped to use their smartphones, MP3 players and watches to measure key attributes of their physiology and then display the information so they could modify their behavior to improve their health. It was like old-school biofeedback but with new-school technology. They described the approach as self-quantifying, and their movement became known as The Quantified Self, or QS.

Regardless of the name (you'll also hear it called medical self-care or personal informatics), the process is the same: People collect data about their own biology and then use that data to gain insight about health and affect behavior change.

If you've been burned by a few fad diets, then you might be skeptical about the effectiveness of self-tracking. But there's mounting evidence that people can use self-tracking to develop healthier lifestyles. Some of that evidence is coming from the Center for Connected Health, an offshoot of Harvard Medical School founded in 1995. The center's mission is to put health care, by way of information technology, back into the hands of patients.

For example, one of its programs -- Blood Pressure Connect, which supplies hypertension patients with a blood pressure cuff and a transmitter to send data to a Web-based management tool -- has shown very promising results in clinical trials. A May 2012 study demonstrated that hypertensive patients lowered their systolic blood pressure (the first number), on average, 6 millimeters of mercury after participating in the program. A decrease in systolic blood pressure of just 5 millimeters of mercury can reduce mortality due to stroke and heart disease by 14 percent and 9 percent respectively, so the results are significant [source: Kvedar].

The Basis B1 band operates on the same principles as Blood Pressure Connect: It uses a patient-worn monitoring device and transmits data to an online portal for analysis and feedback. Although no researchers have studied the Basis technology in a clinical trial, it stands to reason that the device could deliver similar positive results. Of course, the band doesn't focus on just one variable -- it measures five using a suite of sophisticated sensors.


The Basis B1 Band Sensors: Monitoring Heart Rate

Among other things, the Basis B1 band evaluates blood flow in your wrist. It's actually a rather telling exercise.

Because heart rate forms the foundation of the Basis platform, the device's optical heart-rate sensor pulls the heavy load. The technology takes advantage of a well-studied technique for monitoring cardiac activity known as photoplethysmography (PPG), which uses light to measure variation in the volume of a part of the body. The light comes from a light-emitting diode, or LED, situated on the underside of the Basis watch face. The LED shines light onto the wearer's wrist, and a sensor detects how much comes back.

Here's how it works. As the light passes through the skin and into the underlying tissue, some is reflected, some is scattered and some is absorbed, depending on what it encounters. Blood absorbs light more readily than surrounding tissue, so if there's more blood in the area, less light will come back to the sensor. With each heartbeat, blood surges through arteries and veins and then ebbs, meaning blood volume first increases, then decreases. The Basis B1 sensor "sees" these heartbeats as changes, or pulses, in the reflected light.


Interestingly, PPG works differently with different wavelengths of light. Longer wavelengths penetrate more deeply than shorter wavelengths, so infrared radiation can be used to assess blood volume in deep tissue, while light in the visible range is ideal to measure blood just beneath the skin. The Basis B1 optical monitor relies on green light to count heartbeats. Not only that, it comes to know a user's unique skin topography. If a person has a hairy wrist, for example, special Basis algorithms make adjustments, accounting for how the hair fibers affect light transmission. It makes similar allowances for body type and skin tone.

The Basis B1 Band Sensors: Monitoring Everything Else

The emitter and detector of the Basis optical heart-rate monitor are surrounded by four more sensors. Here's a quick tour:

  • Accelerometer -- Your heart rate changes frequently during a typical day. Often, these changes are related to activity, but your heart can also race when you're sitting still (remember those surprise questions your high-school physics teacher would ask when you least expected it?). To help differentiate pulse-pounding exercise from pulse-pounding stress, the Basis B1 band comes equipped with an accelerometer -- a device that measures acceleration forces caused by movement. Some accelerometers detect motion along a single axis, but the 3-D version on the Basis band measures motion along three axes. That means it can detect whole-body movement, like the kind you exhibit during exercise or during that recurring nightmare, as well as small-body movement, such as writing or texting.
  • Thermometers -- The Basis B1 band includes two sensors for measuring temperature. One detects changes in the wearer's body temperature, the other changes in outside temperature. Taken together, both sensors can provide insights into a person's metabolism. That's because body temperature increases when muscles work, which requires the consumption of more food energy, measured in calories. External temperatures can also influence metabolic processes. For example, when it's cold outside, our bodies expend more energy to maintain body temperatures.
  • Galvanic skin response (GSR) sensor -- Human skin is a good conductor of electricity. It's even better when it's wet. The GSR sensor on the Basis B1 band measures the conductivity of a person's skin, which is directly related to how much sweat is present. The skin's moisture output, in turn, reveals a great deal about the wearer's level of exertion during exercise, which, when combined with temperature and heart-rate data, provides a clear picture of how a person responds to different levels of activity.

All of this data flows into the Basis "brain," where complex algorithms look for patterns unique to the wearer's physical activity and cardiac response to that activity. After doing some analysis, the device returns useful metrics, such as calories burned, hours slept, steps taken and heart rate that can help users take action to improve their health and wellness. Additional algorithms on the Basis Web site provide even more analytics and reporting, including how a user stacks up against other Basis participants.


Sound good? Ready to buy? Keep reading.


Buying the Basis B1 Band

The MOTOACTV, one of a group of self-tracking gadgets to hit the market, also made an appearance at CES 2012.

As of this writing, the Basis B1 band hasn't been made available in retail outlets. You can, however, preorder the device on the Basis Web site. When it does hit the shelves, it will set you back $199. That gets you the monitor and a band, as well as the basic version of the online dashboard. If you've got a little extra to spend, you can buy additional bands (yes, the Basis monitor detaches easily) and a subscription to a premium Web-based service, which provides a more robust set of analytics and reports.

Basis will face some stiff competition from other user-worn self-tracking gadgets already established in the market. Jawbone UP ($99.99) looks like a bracelet, but it contains a motion sensor to track movement and sleep. It communicates data to an iPhone app, which makes it easy to monitor health statistics and stay connected to other UP users. Motorola's MOTOACTV ($249) actually resembles the Basis B1 band in that it looks like a watch. That's where the similarities end, however. MOTOACTV combines an MP3 player with GPS to track how far and how fast you run or cycle. If you want to measure heart rate with the product, you have to buy an additional chest strap. Finally, there's the BodyMedia LINK Armband ($199), which is backed by some big-time names, including Jenny Craig, Jillian Michaels and IBM. Yes, you read that correctly -- BodyMedia tapped IBM's Watson artificial intelligence team to develop new algorithms that can more effectively mine data coming from the LINK Armband's sensors, which measure heat flux, motion and galvanic skin response.


As you might expect, the patents associated with these products are protected fiercely. In February 2012, BodyMedia filed a patent infringement suit against Basis Science, claiming that Basis used BodyMedia inventions as the foundation for its product. In May, Basis filed a counterclaim, asserting that BodyMedia's patents are invalid. In a press release issued by the company, Basis CEO Jef Holove said, "We believe these allegations are baseless. We haven't launched the Basis band yet so BodyMedia has no firsthand knowledge on which to base their claims. This appears to be a reaction to our market potential and an attempt to hinder our launch."

It's not clear exactly when the launch will occur or if the lawsuit with BodyMedia has delayed the Basis band's entry into the market. If it does become available and if it lives up to its hype, the Basis B1 band will most certainly send a few ripples through the health technology community. And it just may represent the future of self-care, where we all practice a modern form of biofeedback.


Author's Note

There's been a lot of talk lately about personal health records, or PHRs. A PHR is my health information, recorded electronically and controlled by me. Wouldn't a product like the Basis B1 band be a great way to supply data to a PHR? If so, self-tracking gadgets might move from novelties to health care necessities.

Related Articles


  • "Basis Awarded 2012 CES Best of Innovations Design and Engineering Honors; Tops Health and Wellness Category." PR Newswire. Nov. 10, 2011. (May 28, 2012)
  • Basis B1 Band Product Tour. Basis Web site. (May 28, 2012)
  • • Basis Technology Review. Basis Science, Inc. Oct. 14, 2011. (May 28, 2012)
  • "BodyMedia sues BASIS Science over wearable body monitoring technology patent infringement." Feb. 3, 2012. (May 28, 2012)
  • Bradley, John. "Your Body Is an API: 9 Gadgets for Tracking Health and Fitness." Wired. Feb. 9, 2012. (May 28, 2012)
  • Chan, Alice. "Basis Counters BodyMedia’s Allegations and Asserts BodyMedia’s Patents Are Invalid." May 24, 2012. (May 28, 2012)
  • Chan, Alice. "Basis Reveals Details of Heart Rate and Health Tracker; Plans To Showcase Basis Band at Health 2.0." Sept. 23, 2011. (May 28, 2012)
  • "Counting every moment." The Economist. March 3, 2012. (May 28, 2012)
  • DesMarais, Christina. "Behind the Basis Band's Pre-Launch Hype." Inc. Jan. 12, 2012. (May 28, 2012)
  • Giorno, Fabio. "Typical Heart Rate During Sleep." Livestrong. May 26, 2011. (May 28, 2012)
  • Jonsson, Annika. "New Sensor Design to Discriminate Between Tissue Blood Flow." Ph.D. thesis. April 18, 2006. (May 28, 2012)
  • Kvedar, Joseph C., M.D. "Home Monitoring Improves Hypertension Management." The Doctor Weighs In. May 31, 2012. (June 6, 2012)
  • Locke, Susannah F. "Personal Monitoring Tech: Invasion of the Body Trackers." Popular Science. Mar. 21, 2012. (May 28, 2012)
  • Nelson, Fritz. "Basis Wristwatch Measures Your Body Signals." InformationWeek. Jan. 11, 2012. (May 28, 2012)
  • Singer, Emily. "Is 'Self-tracking' the Secret to Living Better?" Technology Review. June 9, 2011. (May 28, 2012)
  • WebMD. “Heart Rate Calculator.” Reviewed Oct. 20, 2008. (May 28, 2012)