An Introduction to Using Biofeedback to Decrease Stress
You no longer need a lab and electrodes to do biofeedback: modern sensors and apps make effective stress-reduction techniques easily accessible
Biofeedback is a method of using technology to amplify bio-information so that it may be reintegrated back into your body, with the aim of improving mental health and wellness. In particular, you can use biofeedback as a stress reduction technique. Stress causes physiological changes in your body that have a real, adverse effect on your health. You can be healthier simply by learning to control your breathing through biofeedback to reduce unnecessary stress responses in your body.
In the past, the procedures of biofeedback were limited to psychological laboratories and expensive integrative medicine institutes, but now basic data like heart rate are available to you through reasonably inexpensive smartwatches and rings. And if you are up for the challenge, more advanced biofeedback techniques can be accomplished with a heart rate variability (HRV) sensor and smartphone application.
I trained with biofeedback technology in graduate school. Now that I am a college professor, I teach students about it in my “Health Psychology” course. Here, I’m going to tell you how it’s done.
What is biofeedback?
Bio-information comes in many forms, transmitted through your skin, muscles, organs, and nervous tissue. It is something that you and I rely on every moment of our lives, aiding us in movement, balance, and navigation of our environment, as well as mediating our interaction with others.
Over the last 100 years, technologies have evolved that allow us to do even more with these natural organic processes. This article focuses on such technology. Popular biofeedback methods include the use of tools that measure heart rate and heart rate variability, skin conductance, skin temperature, and respiration, as well as technologies that scan the brain and other bodily processes that are otherwise invisible to the naked eye (see Moss & Shaffer, 2016, for a comprehensive list). See this story for more information on the history of biofeedback.
Important feedback is transmitted internally (through the body) and externally (through interaction with the environment). The clinical procedure of biofeedback combines these two by first externalizing a bit of internal feedback and amplifying it through a piece of technology, then reintroducing it back to the person so that it can be re-integrated.
For example, your brain produces varying wavelength patterns while you sleep. These wave-patterns can be measured by an electroencephalography (EEG) machine. Brain waves emitted during sleep can indicate periods of restlessness during the night or periods of deep/shallow sleep, and they can be useful in diagnosing sleep problems. This biological information is only available to us once externalized and amplified by an EEG. With this new feedback loop, the available information can be reintegrated into a patient’s sleep habits and a new (perhaps more restful) sleep habit can be developed.
Fortunately, you and I don’t need to hook a dozen electrodes to our scalp in order to benefit from biofeedback technology. Heart rate levels, which fluctuate throughout the day, can convey valuable information about levels of stress, anxiety, and relaxation. Your current heart rate, which can be detected by more and more accessories, can indicate autonomic nervous system arousal. This is important for understanding mental and physical health and wellness.
The autonomic nervous system and stress
Your autonomic nervous system (ANS) controls all of the automatic, life-sustaining processes in your body. This includes, among others, digestion, breathing, blood flow, and immune function. The ANS has two settings: sympathetic and parasympathetic.
The parasympathetic setting is when your body is taking care of itself: the immune system is at maximum functioning, combatting and clearing away pathogens; digestion and excretory functions are occurring without interruption, guaranteeing that you extract the maximum nutrition from your diet; and your cells and tissue are receiving adequate nutrition and oxygen so that they can continue functioning. These periods are essential for bodily restoration and rejuvenation.
Unfortunately, people do not spend enough time in the parasympathetic mode. This is because rest is increasingly the exception, not the rule. Mentalities such as “always give 110%” or “I’ll sleep when I’m dead” prohibit a person from spending enough time in a parasympathetic state.
The second autonomic nervous system setting is sympathetic: this is the “go get ‘em” setting. During autonomic arousal, heart rate increases along with blood pressure. Blood is diverted from the digestive organs and to the extremities such as arms and legs. Instead of feeling tired and heavy, your body feels like a tightly coiled spring, ready for action at a moment’s notice. The evolutionary benefit of this setting is obvious in the wild — when being able to fight off or flee from a predator could be the difference between life and death. But the benefits in the industrialized world are less clear. To be sure, life-threatening events do sometimes occur, but such events are increasingly rare. Yet, somehow we still see that anxiety levels are on the rise, and stress-related diseases sit at the top as contemporary causes of death.
It seems we spend greater and greater periods of our daily lives at an unprecedented level of nervous system arousal — that is, in sympathetic states. We have grown accustomed to having our attention dart back and forth as if we’re scanning the environment for predators. We have gotten used to breakdowns in parasympathetic processes, like with irritable bowels and sleepless nights. The heightened state of arousal has become so habitual that we seldom even notice it anymore, and we begin to think of it as normal. Meanwhile, our bodies are routinely prohibited from self-restoration.
There is one additional detail about the ANS without which biofeedback would be impossible. It is that the two branches of the ANS work against one another. You cannot be in both states at one time. This means that if you can interfere with any of the features of your ANS, then you can shift from one state to the other. This is why some people stress-eat — if they can initiate digestion by eating, then the parasympathetic state will replace the sympathetic one and they will relax.
Basic biofeedback technique: A smartwatch with a heart rate monitor
Noticing your heart rate is an easy way to get started with biofeedback. After watching your heart rate fluctuate throughout the day, you will begin to learn a bit about yourself. You’ll notice the level it is at when you are resting — that is, the lowest you see it go, such as when you are waking up in the morning. And you will see its higher levels, such as when you are rushing to work and worried about being late.
When your heart rate is at its lower level, this indicates that your body is in parasympathetic or up-building mode. When it is at its higher level, this indicates that your body is in sympathetic or arousal mode. With these baselines, you can begin using the heart rate monitor as new biofeedback loop.
For the sake of discussion, imagine that your resting heart rate is 60 beats per minute (BPM) and an elevated heart rate is 120 BPM. For comparison, your heart rate during exercise is likely much higher than this, somewhere near 180–200 BPM depending on your age. If you are eating breakfast in the morning and notice that your heart rate is at 100–120 BPM, then you can use this information to better understand the situation. First, you might ask yourself: “Should I be worried that I am under threat right now?” If the answer is “no,” which I suspect it is, then you might consider that your breakfast will sit like a brick in your stomach until you are relaxed enough to digest it. If you recall from above, your body cannot be on high alert and digest at the same time. If you decide that there is no reason to be on high alert, then relaxing is in your best interest. So how do you do this?
You can use the heart rate monitor to help you relax. While you cannot change your heart rate (and by extension, the autonomic nervous system) directly, you can do so indirectly. By focusing on it, you can influence your breathing rate and depth.
If you notice that your heart rate is high, you can consciously take deep and long breaths that activate your diaphragm as you begin to relax. As you are doing this, you can use the heart rate monitor as feedback of your ANS state of arousal. As you relax, you will notice your heart rate decreasing. As you practice this, the feedback of the lowered heart rate helps you see the results immediately.
If you focused on breathing this way for twenty minutes, your heart rate would be back down to 60 BPM and you would probably be ready for a nap (but slowing it all the way down that much would not be necessary).
Heart rate variability: An advanced biofeedback technique
The heart rate biofeedback technique described above is a basic, global account of ANS arousal. But if you are interested in trying something supported by a growing pile of promising research, you might consider learning how to influence your heart rate variability (HRV).
Your heart does not beat like a metronome; the rate changes from moment to moment. Even if over the course of a minute the average number of beats is 60, this does not mean that the individual beats are spaced one second apart. You can observe this yourself by checking your pulse for 60 seconds: you will notice that there might be three beats that rattle off in quick succession, followed by a brief gap before a couple more. The gap between the first and second beat might be 1.2 seconds, and the gap between the second and third might be .9 seconds, etc. Throughout a minute, the greatest difference in time minus the smallest difference in time is your heart rate variability (HRV).
HRV can be measured a variety of ways, but that is the main point. It just so happens that this measure shares a significant relationship with a variety of mental and physical aspects of health. Moss and Shaffer explain that there are a variety of ongoing studies demonstrating the influence HRV biofeedback has for “anger, anxiety disorders, asthma, cardiovascular conditions, chronic obstructive pulmonary disorder, irritable bowel syndrome, chronic fatigue, and chronic pain.” This is because there are optimum HRV levels, and they tend to follow specific breathing rhythms and frequencies. This is why taking a few minutes to focus on deep, diaphragmatic breathing can be an effective way to calm down. When taking long, deep breaths, your HRV will begin to line up with your breath cycle. As you are breathing in, your heart-rate increases, and as you breathe out it decreases. The ideal breathing rate occurs at about 6 breaths per second (which makes each breath cycle ten seconds: five seconds breathing in and five seconds breathing out). There are dozens of simple smartphone apps that can assist you in this, giving you cues for breathing in or out.
Biofeedback programs can monitor your HRV through an enabled sensor. The sensor has to be sensitive enough to discriminate between the parts of your cardiac cycle. This way it will generate the data for the HRV program. The program will calculate the time difference between each of your heart beats, and this is your HRV.
While this practice used to be limited to the laboratory with its computers and sensors, it is now something you can do at home or in your office at work. All it takes is an HRV program and compatible heart rate sensor.
HeartMath was the program that I trained with in graduate school, and there are smartphone applications that use this program as well. You can download the free app and get a compatible sensor directly from Heartmath on their web site.
You might be wondering about using Apple Watch data for biofeedback work on HRV. For biofeedback practice, it’s not a good option. This post by HRV4Training founder Marco Altini goes into some detail about that, and how you can get a daily baseline reading to use with the HRV4Training App. This post describes how you can get an HRV reading at any time using the Breathe App. But there doesn’t appear to be any way to monitor HRV in real time with the watch, and then consciously try to adjust it through your breathing. So the Apple Watch, unfortunately, isn’t useful for real-time HRV biofeedback.
The goal when practicing HRV biofeedback is to maximize your HRV, so that “respiration and heart rate co-vary in a near-phase or complete phase relationship.” Assume, for example, that you have a resting heart rate of 60 seconds, and you have been practicing the six-breath/minute cycle. As you breathe in, your heart rate will quicken, maybe beating every .75 seconds. As you breathe out, it will slow down, beating ever 1.25 seconds. At maximum HRV, your heart rate will be at its highest at the peak of the in-breath, and the lowest at the peak of the out-breath. This is known as heart rhythm coherence, and it is the goal of HRV biofeedback.
Depending on the program you use, your heart rhythm coherence can be exhibited in a number of ways. For example, in the many-year-old version of HeartMath that I used, there would be a picture of a forest setting that was washed out of all color. As my breathing and heart rhythm approached maximum coherence, the image would begin to fill with color. If I began to fall out of coherence, the color would leave the screen. All that matters is that the program supplies some sort of positive feedback that you are on the right track.
At first, it will seem like you have no control over your heart rhythm coherence (and HRV more generally). You might get upset and give up after only a few short attempts. But if you stick with it, this biofeedback technique will help you become more sensitive to moments of stress or tension, and to moments of relaxation. Soon enough, you will no longer even need the feedback at all. Noticing moments of stress and adjusting your breathing to reduce them will become second nature.