Tag Archives: brain

Visualizing HR, HRV, and GSR While Watching ‘Interstellar’ by Bob Troia

This blog repost is from one of our more “connected” users, Bob Troia, also known as Quantified Bob.  Bob enjoys tracking and analyzing his metrics based on the effects of many factors such as, his Bulletproof Diet, his glucose reading, even his personality type. To see exactly what Bob is tracking and read into his prior experiments go to his blog.


In this case, Quantified Bob took something as simple as watching the movie, Interstellar, and turned it into a Quantified Self experiment. He used a Polar H7 to capture 3-hours of biometrics, specifically RR-Intervals. The SweetBeatLife app then uses clinical grade algorithms to analyze the data. Anyone with one of our applications and a heart rate monitor chest strap (BTLE) can do the same. Bob exported his heart rate and heart rate variability data from SweetBeatLife, and his Galvanic Skin Response from a Basis B1. Read below to see his heart rate and heart rate variability response.

Heart Rate

“Interestingly, my heart rate trend (on the left, below) looks very similar to the original Reddit user (on the right)! Both of us are using data from our wrist-worn Basis devices – in my case, the older B1 model, and for the Reddit user the newer Basis Peak. Although the Peak is capable of capturing more samples, the data returned from Basis is always an average value for each minute.

Interstellar HR comparison

However, SweetBeatLife is recording data at a resolution of 1 sample per second via the Polar H7. The per-second pulse data is a little bit jumpy and hard to follow (in gray), so I’ll also include a 60-second moving average as well (in blue):

Interstellar Heart Rate Polar H7

It looks very similar to the data recorded by my Basis. Good!

Heart Rate Variability (HRV)

Heart Rate Variability uses a technique in which the spaces between heart beats are measured, and is a good way to measure stress via an individual’s “flight or fight” response (the higher one’s HRV, the better). There are a number of ways HRV can be calculated, and in this case we are using what’s known as rMSSD (root mean square of successive differences). You can check out Wikipedia for a pretty good overview of HRV.

Interstellar Heart Rate Variability

Not only can Bob see when the movie had him in sympathetic versus parasympathetic but he can point out when he was having deep thoughts of gravity and space. Bob was also able to determine that there is, “an inverse relationship between heart rate and HRV, which makes sense – if your heart starts beating faster, you are most likely encountering more stress, which increases your sympathetic response and thus lowers HRV.”

Read more about his Galvanic Skin Response and how Bob interpreted this data, read the original article here. If you want to better understand HRV and the many benefits of tracking it, I recommend browsing around the SweetWater Health Library.

Important Information for SweetBeat Users

SweetWater Health is a very young company. SweetBeat™, our iPhone app, has been on the market for just a little over a year. We started with no users at all (except for us SweetWaterites), and during the months that followed SweetBeat’s debut, we have watched with interest as our audience of users has grown.

And you, our users, have surprised us. We thought that most people would purchase SweetBeat to help reduce stress. There are certainly some users that fit that profile, but the dedicated users, the ones who really use SweetBeat all the time, are athletes—often elite athletes—who use SweetBeat for HRV training to help understand their bodies better and to optimize training schedules.

And you—our dedicated users—told us that the product needed tweaking so you could use it even more effectively. So tweak it we did, and we need to tell you about the changes we made. This is important to know even if you are not an athlete, as your HRV levels will appear lower than in previous versions. This does not mean your HRV has changed—only the scale.

SweetBeat version 1.2.2 (and beyond) includes a refinement of the HRV calculation algorithm to fine-tune it for athletes. Some of you ultra-fit individuals were “maxing out” the HRV reading at 100. The new algorithm fixes this with the result that the calculated HRV will appear lower than in previous versions of SweetBeat. We have included some charts to illustrate what you can expect with version 1.2.2.

For SweetBeat users who have been measuring HRV for athletic training, your HRV will appear to decrease with version 1.2.2. For this reason we recommend starting with a new baseline taken on a day that you know you are fully recovered. We believe this will provide more accurate results in the long run as your fitness levels improve.

Below are a couple of charts that illustrate how your new HRV scores may differ from your previous scores.

How is HRV calculated? SweetBeat measures the RR intervals (the time between heartbeats) then calculates the HRV parasympathetic parameter rMSSD. We then run a scaling algorithm on rMSSD to create an HRV value. Typical values will be in the range of 0-100. rMSSD is the square root of the mean squared difference of successive RRs. Elite athletes will experience very high rMSSD scores compared to others.

If you want to see the raw numbers, look at the “Geek Screen” on the flip side of the ECG heart beat screen. To see the Geek Screen, press the button in lower right corner of the window where the animated ECG appears. You will see the summary numbers from your last session. Below are the same charts from above that include rMSSD.

As a reminder on how to use HRV for training:

  1. Take your HRV every morning prior to any activity.
    1. This session can be measured sitting, standing or lying down, but be consistent in the position you select.
    2. Do a five-minute session.
      1. HRV is time dependent so be consistent in the length of the session
      2. If HRV drops significantly (more than 10 points) a low exertion or rest day is in order.
      3. If HRV drops significantly two or more days in a row, a rest day is in order.

Questions? Please send them to support@sweetwaterhrv.com. We’d love to hear from you.



Can We Fight Diabetic Neuropathy with Your Help?

Diabetic neuropathy is one of the most hideous symptoms of a devastating disease, and can result in loss of limbs and eyesight, debilitating pain—and even death. I’m about to ask a favor of anyone reading this who is diabetic, but first, a brief description of diabetic neuropathy for those who haven’t already learned about it.

There are various kinds of neuropathies, or damage to the nervous system, that can result from diabetes. In diabetes, neuropathies are believed to be caused by long-term exposure of the nerve cells to high blood glucose and possibly by low levels of insulin.[1] Symptoms of neuropathies depend on the type of nerve damage:

Peripheral neuropathies, the most common, cause pain or numbness in toes, feet, legs, hands, arms, or fingers.

Diabetic autonomic neuropathy  (DAN) affects the autonomic nervous system and may cause changes in digestion, bowel or bladder function, sexual response and perspiration.

Cardiovascular autonomic neuropathy (CAN), one of the most serious versions, damages the nerve fibers that control the heart and blood vessels, resulting in cardiovascular disease.[2]

Proximal neuropathy causes pain in the thighs, hips or buttocks and leads to weakness in the legs.

Focal neuropathy results in the sudden weakness of one nerve or group of nerves, causing pain or weakness in that area. While painful, focal neuropathy usually does not lead to more severe, long-term problems.[3]

The most insidious aspect of diabetic neuropathy is that by the time you experience symptoms, the nerve damage is already done. Various therapies are available for treating the symptoms and slowing nerve damage, but the best of all approaches is PREVENTION. The best prevention is keeping blood sugar under control, but as the nerve damage often takes place long before you notice symptoms, wouldn’t it be great if there were some way to detect the onset of neuropathy before damage has been done?

While neuropathy testing has been added to the treatment recommendations of the American Diabetes Association, testing for diabetic neuropathy is usually not a part of your annual or biannual visit to the doctor. (If it is, we applaud your physician!) Neuropathy is usually diagnosed after you have developed symptoms—by which time, it is too late to reverse the damage; it can only be managed.

There is, however, a way to test for diabetic neuropathy that is non-invasive, not painful, and easy. Heart rate variability (HRV) can be used to identify nerve damage in very early stages, which would allow diabetic patients to seek help from their physicians before greater damage has occurred. (For an explanation of HRV, download our whitepaper on HRV or see the article on HRV in Wikipedia.)

SweetWater Health is working on an iPhone app that would allow diabetics to test themselves at home as often as desired (though twice a year is usually sufficient). The app would require the purchase of a compatible heart rate monitor such as athletes use, usually priced under $100. You would perform three simple physical exercises while wearing the monitor and the app will tell you if you are experiencing damage to your nervous system.

Now for the favor. If you are diabetic and are interested in the development of such an app, please go to http://www.sweetwaterhrv.com/dan.php and let us know. Your input will help us by letting us know there is a genuine need and desire for such a product. You can also sign up for more information about the product and volunteer to be a beta tester if you want.

Sincere thanks for taking the time to help us help you!

[1] National Diabetes Clearinghouse, http://diabetes.niddk.nih.gov/dm/pubs/neuropathies/

[2] “Diabetic Cardiovascular Autonomic Neuropathy,” A. Vinik, MD, PhD, FCP, MACP; D. Ziegler, MD, PhD., FRCPE; Contemporary Reviews in Cardiovascular Medicine, Jan. 22, 2013.

The Anatomy of Desire

In “The Willpower Instinct,” by Stanford University psychology instructor Kelly McGonigal, she defines willpower as composed of three parts: “I Will, I Won’t and I Want.” These three functions reside in the prefrontal cortex of the brain—something we humans have more of than most other animals.

“I Will” is the function that allows you to get things done, even if they are hard. “I Won’t” is the function that prevents you from eating something unhealthy or spending more money than you should. “I Want” is the function that tells you what you desire—what you really desire. So when your sweet tooth is screaming at you to drink a chocolate frappucino, “I Want” can remind you that what you really desire is losing 15 pounds. These three elements combine to create what we call willpower—the ability to control impulses that tempt us to do things that may not be in our best interests.

Our willpower is often at odds with our impulsive self, rooted in a deeper, more primitive part of the brain. We still need that older, less sophisticated system because it also provides us with valuable instincts such as fear and disgust that work to keep us safe and healthy. But our baser selves are always urging us to act on impulse, so it’s a pretty constant struggle.

Fortunately, there’s an easy way to increase willpower, according to McGonigal: meditation. Dr. McGonigal is a scientist, not a Buddhist nun or new-age guru, and she backs up her assertions with scientific evidence.

The enemy of impulse is mindfulness: being present and aware of what you are doing and which decisions you are making at all times. A lot of poor decisions can be made while you are thinking about something else. For example, how many times have you suddenly come to the realization during a meal that you have eaten more than you intended, or eaten something that you shouldn’t have? Maybe you were reading a book or talking to a friend, and “didn’t notice”. That was your impulsive self, slipping one over on the prefrontal cortex while you were distracted. When you are fully aware of your decisions, you are more likely to make the right ones.

Meditation improves mindfulness. Neuroscientist have discovered that meditation trains the brain to become better at self-control, including “attention, focus, stress management, impulse control, and self-awareness,” according to McGonigal’s book. Just three hours of meditation practice led to an increase in these benefits, and after 11 hours, novice meditators increased the neural connections needed for focus and impulse control. Eight weeks of daily meditation increased the gray matter of the prefrontal cortex and led to increased self-awareness, or mindfulness in the individuals studied.

Meditation is easy, and does not necessarily involve spiritual seeking or levitation, or any of those other weird things you sometimes hear about. It is a matter of setting aside a period of time to sit and be quiet (including the inner voice we always hear). Be quiet, don’t fidget, and focus on something neutral, like breathing. It isn’t necessary to turn off that inner voice entirely; just notice that you have become distracted, and return to your focus on breathing. Start with five minutes and work up to a longer period. Even distracted meditation is better than none and will have positive benefits, so don’t get discouraged.

For excellent and simple instruction on how to meditate, see page 26 of McGonigal’s book, “The Willpower Instinct”. There are also several meditation resources online—try Googling “how to meditate” and you’ll find something that works for you.

Losing Weight Is #$@**!!?> Hard! Here’s Something To Help.

“Up to 60% of the population can be affected by hidden food sensitivities …that can cause symptoms like weight gain.”Dr. Mark Hyman, speaking to Dr. Mehmet Oz in “Are Food Allergies Making You Fat? Part 1”

Maybe you’ve tried dieting and exercise, but nothing works. Perhaps you’ve tried weight-loss groups and paid for the privilege. Maybe you tried Atkins, South Beach, The Zone, Pritikin, Jenny Craig–and nothing works.

Maybe it’s not your fault. Maybe you have undiscovered food sensitivities. We’re not talking about allergies, where you might get hives,  migraine, nausea, or worse. Food sensitivities can go undetected forever because the symptoms may not be obvious.

When you eat a food to which you are sensitive, the body reacts as it does to any stressor; it releases stress hormones. Stress hormones cause inflammation in the body that short-circuits the body’s insulin response, causing two problems:

  • Fat gets released into the bloodstream, an underlying cause of hypertension, type 2 diabetes and heart disease.
  • Glucose in the blood gets stored as fat, and your stressed body is determined to hold on to every precious gram of fat as long as it can.

Now there is a way to test yourself for food sensitivities easily and non-obtrusively with the new version of SweetBeat™, the iPhone app from SweetWater Health, LLC.  The test is a pulse test originally developed by immunologist Dr. Arthur F. Coca, who found that when a person eats a food to which he or she is sensitive, the pulse accelerates at least 16 beats per minute over the average resting rate.

With the new camera sensor included in the new version of SweetBeat, you take your pulse first thing in the morning, then right before eating and another three times after eating. (And a final one at night when you go to bed.) If you wear a chest strap monitor instead of using the camera sensor, the testing occurs automatically after you have recorded a meal.

If you have eaten something to which you are sensitive, your meal is given a red “X.” If you ate no offending foods, your meal receives a green check mark. In the event that you discover a red “X,” you will need to test different components of the meal to see what caused the problem—and then you can get rid of the stuff that’s making you fat.

It turns out that stress also causes inflammation, with the same distressing effect on your waistline. The original function of SweetBeat was to monitor and manage stress—and all those features are still included in the new SweetBeat (along with some nifty new features such as heart rate recovery and some cool graphs). The two features—stress management and testing for food sensitivities—are designed to help you lower major causes of inflammation—and assist you in losing those extra pounds.

The new SweetBeat is available in the Apple App Store now for $4.99. Users who have already purchased SweetBeat can upgrade for free.

Here’s our press release that went out today:

October 4, 2012—Los Gatos, CA—A new weight-loss feature has been included in the new, upgraded version of SweetBeat, originally released last February as a stress detection and management app. The dual-purpose app can help people manage food sensitivities, willpower, stamina, resilience, stress and heart rate variability with in-app graphs. The new and improved SweetBeat, from SweetWater Health LLC, is available now from the Apple iTunes Store for $4.99. People who have already purchased SweetBeat can upgrade to the new version for free. The new version of SweetBeat is compatible with the iPhone 4, 4S, and 5. Future versions will be compatible with Android phones.

“Stress management is an important component of a weight-loss program,” said Ronda Collier, the CEO of SweetWater Health and SweetBeat’s developer. “Stress releases hormones such as cortisol that can signal the body to retain fat or even cause fat cells to grow. Combining stress management and weight loss in a single app makes perfect sense.”

SweetBeat offers clinical-grade heart rate variability biofeedback for stress monitoring and management, and now offers a food sensitivity test using a methodology developed by immunologist Dr. Arthur F. Coca. According to Dr. Coca, foods to which the body is sensitive will elevate the heart rate by sixteen beats per minute or more.[1] SweetBeat allows users to measure their hearts’ reactions to different foods and eliminate inflammation by dropping incompatible foods from their diets.

How the Food Sensitivity Test Works

Food sensitivities are a reaction from the immune system or a result of the body’s lack of proper enzymes to digest foods. When the body reacts to a food, it sends out inflammatory messenger proteins, cortisol and adrenaline, to tag the food particles for removal. This sets up a cascade of events, creating low-level inflammation that can affect the body in a number of ways. For example, low-level inflammation may affect the gastrointestinal tract, resulting in impaired digestion, it may cause sore joints or headaches, and it can prevent weight loss. A person with low-level inflammation may never notice the symptoms, or may not connect them with the foods he or she has eaten. By eliminating inflammation caused by food sensitivities, users should find losing weight less difficult. To use the food sensitivity test, a user must first take a morning reading of the pulse to establish a baseline for the day. Before eating a meal, the user records the foods comprising the next meal and performs a pulse test. After the user is finished eating, the app will prompt users to record their heart rates every 30 minutes until 90 minutes have passed. Once testing is complete, the meal will either pass or fail for food sensitivity, indicated by a red “X” or a green checkmark.

The new feature comes with a camera sensor for taking quick and easy heart rate measurements. While customers can also use one of the affordable heart rate monitors compatible with SweetBeat, the camera sensor is a convenient way for consumers to adopt the food sensitivity test into their everyday life. Using the camera sensor merely requires holding the tip of one’s index finger over the iPhone camera lens and flash.

New SweetBeat Features

SweetBeat has been updated with several new measurements based on heart rate variability. Using a compatible heart rate monitor, the user can now measure willpower and resilience. At the end of an exercise session, the user can also measure stamina through heart rate recovery. This is helpful to those who want to see how quickly the heart recovers its normal resting rate. The faster the heart recovers, the greater the stamina.

Users can now view their sessions over time to see specific trends in heart rate variability, stress or heart rate. The monitor screen with heart rate variability and stress management, the breath pacer, and the sensitivity and personality settings are still available in the upgraded version.

The calendar is available to registered users through the secure and private MySweetBeat page on SweetWater Health’s website. For more detail on using SweetBeat’s weight-loss feature, please download our whitepaper: “Five Easy Steps to Weight Loss.”




[1] Dr. Coca’s Pulse Test document is available free at http://www.soilandhealth.org/02/0201hyglibcat/020108.coca.pdf


More News about the Food/Health Connection

There have been a number of interesting articles in the news lately about food and health. Here’s a compilation of some of the ones we have seen.

Scientists have discovered a way to “turn on” brown fat to burn energy more quickly, potentially resulting in another approach to combatting obesity. Wait a minute—isn’t fat supposed to be whitish? Most of the fat in an adult human is whitish, but there are also small deposits in the upper chest and neck. Brown fat, which is associated with skeletal muscle, is brown because it is rich in iron-containing mitochondria, which provide its brown color. It is particularly important to newborns (who have about 5% brown fat) and hibernating mammals. The mitochondira, which are the cells’ powerhouses, burn energy at a higher rate than white fat, and are essential to protect animals from hypothermia. A research team found that brown fat could be activated by a hormone called irisin that is normally produced by muscles during exercise. Other hormones have also been identified as brown-fat stimulators. Eventually, these studies may lead to a practical way to stoke our internal fires to burn away unwanted pounds. For more information, see Science News.

Dr. Mark Hyman, best-selling author and advocate of functional medicine, has written extensively about how food sensitivities can make you gain weight. His three-week anti-allergy plan involves removing all dairy the first week, take probiotics the second week to repair the digestive tract, then add dairy products back in one at a time the third week. If bloating, fatigue, or fluid retention occur you may have found the culprit. For more detail, see dr.hyman.com

Forbes.com reports that scientists have discovered a way to turn on the enzyme that burns fat, lipase. It turns out that enzymes only work a set number of hours during the day. Researchers were able to make lipase work three times harder, upping fat digestion activity from 15% to 45% of the time. This has the potential to be lifesaving for people whose metabolism makes it difficult to lose weight with diet and exercise. Also, it turns out that all enzymes can be manipulated in this manner, with enormous implications for enzyme-based diseases. To read the Forbes story, see forbes.com

Cocoa powder may sharpen the aging brain, according to a study published in Hypertension. (Full disclosure: the study was sponsored by Mars, Inc., one of the largest chocolate manufacturers in the world.) The study included 90 elderly people who had mild cognitive impairment. They drank a cocoa drink for eight weeks that had high, medium, or low levels of flavenols, a type of antioxidant. Those who drank high or medium levels of flavenols performed better on tests of cognition than did those who received low levels. However, the improvements were measurable but mild, and many scientists think that exercise yields much greater benefits than flavenols. For the whole story, see webmd.com

HuffPost asked its experts in medicine and nutrition to come up with a list of the 50 healthiest foods. The top 10 are:

  • Strawberries
  • Water
  • Blackberries and raspberries
  • Almonds
  • Olive oil
  • Blueberries
  • Cherries
  • Oranges
  • Apples
  • Pistachios

To find out the rest of the foods deemed healthiest and why these foods are so good for you, see huffingtonpost.com

Wheat Can Make You Crazy? That’s Crazy. Isn’t It?

Our last post, “Wheat: The New Strychnine?” enjoyed enormous popularity, pointing up how concerned people have become with the potential health risks of wheat.

In addition to obesity (in particular the disproportionate distribution of fat to the belly, which is a marker for potential cardiac disease), joint pain, digestive issues, headaches, etc. mentioned by Dr. William Davis in his book, “Wheat Belly,” he claims that wheat can exacerbate serious mental illness such as schizophrenia in some people.

We didn’t mention this in our last blog because we wanted to look further into this alarming claim. It seemed just a tad too far-fetched that mental illness could be worsened just by eating toast and pasta and cured by giving up wheat. It sounded too much like the proverbial snake-oil salesman: “Cures gout, eczema, female troubles of all kind! Does away with thinning hair, cures arthritis and will make your children grow strong and tall!” So we did a bit of looking around the Internet to see if anyone’s come up with substantive proof that wheat can affect mental health.

Dr. Davis claims that, unique among foods (although there is evidence that milk has the same property), wheat can cross the blood-brain barrier. The blood-brain barrier refers to a mechanism of the central nervous system that prevents microscopic particles from passing into the cerebrospinal fluid that bathes the brain. This is a very good thing; otherwise, our brain would come under attack by bacteria, which would multiply like wildfire in the ideal growth medium supplied by this fluid. When the blood-brain barrier is breached, as in the case of spirochetes which physically bore through the blood vessel walls to reach the central nervous system, the result can be life-threatening, like syphilis or Lyme Disease.

Wheat is able to cross this tough barrier because when wheat gluten is exposed to pepsin, a stomach acid that helps break down food, the gluten is degraded into a variety of polypeptides, which are basically short-chain proteins. In a study at the National Institutes of Health (NIH), these polypeptides were found to cross the blood-brain barrier in rats. Because the polypeptides look to the brain’s receptors like endorphins (the naturally-produced proteins that produce “runner’s high” and act like opioids), the wheat polypeptides bond readily to the brain.

And what do they do when they reach the brain? Researchers in the mid-1960s at the Veterans Administration Hospital in Philadelphia decided to remove all wheat products from the diets of schizophrenic patients. Four weeks later, there was a marked reduction in schizophrenic symptoms such as hallucinations. When wheat was returned to the diet, the symptoms likewise re-emerged. Other instances of improvement or even cures of schizophrenia exist in the scientific literature, such as a study published in 2003 that explored the possible connection between celiac disease and schizophrenia. (Huebner et al)

Obviously, not everyone who eats wheat succumbs to schizophrenia. However, it does mean that wheat can tweak your brain as well as your body. A Danish study of 55 autistic children showed marked improvement in autistic behaviors with the elimination of wheat gluten and casein from milk products. Wheat is not suspected as the cause, but it apparently worsens conditions in people with schizophrenia, autism and celiac disease.

So what does wheat do to the psyche of a normal, healthy individual? There don’t appear to be any studies of this (at least none that we could find, which is not the same thing). Dr. Davis says that the endorphin-like polypeptides set up a reward response; eat wheat, and your brain feels good. Your subconscious likes that, so it tells you to eat more wheat. In a study done at the Psychiatric Institute of North Carolina, wheat-eating subjects were given an opiate blocker, naloxone. These subjects consumed approximately 400 fewer calories over the course of lunch and dinner than the control group. Can you envision what 400 fewer calories a day might do for your waistline? Further, when wheat is withdrawn, many people feel strong cravings for bread, crackers, and other wheat-containing foods, so there is such a thing as “wheat withdrawal” for some.

So in effect, wheat acts like a little devil on one shoulder, urging you to eat more, while the little angel of your better self gets knocked off his perch.

This entire topic again illustrates how our physical and mental selves are inextricably interconnected; you can’t tinker with one without affecting the other just as strongly. As we have mentioned before in this blog (see “Five Things You Didn’t Know About Losing Weight”), purely mental stress can cause you to gain and retain weight through the action of cortisol and other stress hormones. Reducing stress should be an essential component of a weight-loss effort—and apparently, so is losing the wheat.

* * * *

Addendum: The Wall Street Journaljust published an article on the dangers of gluten in schools. Act fast, because this URL expires in a few days: http://online.wsj.com/article_email/SB10000872396390444840104577549350524941964-lMyQjAxMTAyMDAwNjAwODY3Wj.html?mod=wsj_valetleft_email

Feeling stressed? Download SweetBeat™, the iPhone stress management app: http://itunes.apple.com/us/app/sweetbeat/id492588712?mt=8