Our Quest to Solve Stress: Types, Symptoms, and Effects of Stress

As we’ve just updated our app Healthzilla with a bunch of new features, we wanted to step back and share what we’re doing here, and why it matters. As part of our work on a stress test, we have looked into types of stress, symptoms of stress, and effects of stress.

Our Vision: Automated Wellness and Longevity

We’re on a path to automating health. We want to take the worry out, and make becoming and staying healthy easy and cheap. The simple objective would be longevity, in the form of increased health-span and lifespan. Lifespan being simply dying later, and health-span being the absence of morbid or debilitating disease. Ideally, you’d like to live in perfect health until the day you die peacefully in your sleep. People will have different sub-goals like losing weight or building muscle, but most would prefer to do those without sacrificing longevity. In fact, most sub-goals are directly contributing to longevity.

Sidebar: If you want to dig into the definitions and strategies around longevity, I’d recommend this video by Dr. Peter Attia. It’s the best single resource to give you an overview.

In the world of the future, you might easily imagine a device, like a Tricorder from Star Trek, that has a complete understanding of human genetics and biology, a real-time measure of all your relevant metrics from hormone levels to blood markers, and can therefore tell you what to do at any given time to optimize your health. It would take the worry out of health and allow anyone to maximize their human potential while minimizing unavoidable suffering.

“We want to make living a healthy life something that’s easy and free for everyone, to remove all excuses.” — Laura Ranin, CEO of Healthzilla

Are we there yet? Not even close. There is no definitive answer to almost any health-related question, because the cause, effect, and mechanism simply haven’t been conclusively identified. If anything, we’re still scratching the surface. We don’t have a complete understanding, at all, despite having sequenced the human genome nearly two decades ago. There are many reasons, among which is that most research has to be conducted on non-human animals for ethical reasons, and all research is slow and expensive. Due to the ethical limitations, we may not even have a path to that complete understanding. We also can’t measure almost anything meaningful in real-time. That is changing finally, through sensor technology and machine learning.

So what can be done, then? Well, we can focus on a) what is known about human health b) what can be measured c) what can be optimized. So we go piecemeal, with a view to widening the scope of the ABC as new research and new technology comes out.

Our Progress on Longevity and Wellness

For us, that started with exercise, because it is a key ingredient in longevity, and has such a large number of variables to control for. Plus, it is relatively easy to quantify those variables without any needles. If we can reduce those variables, then we can at least partially automate that process to take the worry out, and optimize the efficacy of the exercise for the purposes of longevity. The variables are: what kind of exercise, in what dosage, in what frequency. Of course, all of those must be baselined to your starting point and adapted over time as your body adapts to the training.

For the purposes of longevity, the four main metrics you’d want to solve for are muscle mass, VO2Max, resting heart rate (“RHR”), and functional mobility. Why specifically those four? You can check out the research links at the end. It’s well established, if not causally proven.

Muscle Strength: There are biochemical and physiological reasons to maintain muscle. Muscle eats up glycogen from your blood like it’s a bowl of spaghetti. More efficient muscles mean less glycogen floating around upsetting your metabolism. More strength also means not overloading your joints because of the lack of posture from supporting muscles. Even if we can’t measure this perfectly, your lean body mass and weights lifted to body mass are useful indicators.

VO2Max: While not a perfect measure, at least it’s a good first order approximation that’s measurable for your body’s energy efficiency. The ability to process oxygen through aerobic metabolism using glycogen and fat as fuel to produce movement. Research shows having more results in dying less. Look it up.

Resting Heart Rate: A related measure of efficiency is resting heart rate or the frequency at which your heart pumps when resting. This is actually a function of three things: vagal tone, stroke volume, and hormones. Exercise can directly hit at least two of those. Exercise can literally increase the size of your heart. A useful measure of vagal tone is heart-rate-variability, but more on that later.

Mobility: Let’s say you can bench press your own weight, but can’t actually lift your hands above your head anymore. Is that healthy? No. You’ve over-optimized for a sub-goal and compromised on longevity. You want to maintain a natural range of motion through your main joints: hips, knees, shoulders. This allows you to keep doing things normal humans do, without overloading joints and developing debilitating chronic injuries, that end with you in a bed you’ll never rise from again.

All four are mainly a function of the exercise you do, despite your genetics or environmental factors. Remember, we aren’t here to win the Olympics. Just live long and prosper. So we did all that. We looked at the exercise methods used in research, some anecdotal expert opinions, and automated those programs into an app. Methods like High-Intensity Interval Training, Tabata Intervals, High-Intensity Training (Super Slow), Daily Undulating Periodization, Cardiac Output (Long Slow Distance), and of course Mobility. We did the math and put in the app, so you don’t have to do the math every time you go to the gym. You’re most welcome.

The next problem that introduced was to adapt the exercise to your body’s response. Since we can’t measure everything, we can’t know what else is going on in your life. When is the best day for a hard gym workout? When is low impact cardio or mobility better? Should you train the same way if you’re sick? If you just don’t feel like it, is that a legitimate excuse? If you slept poorly? If you got totally wasted last night?

Traditionally, this would fall under what is called recovery in sports. Since the athlete wants to maintain a high level of athletic performance, or even improve, it is critical to optimize just the right amount of exercise. Why? Because exercise is actually hurting your body. It’s a form of stress, that your body must overcome. At the correct dose, your body has just enough time to repair itself between exercise doses, that it starts adapting. You may have heard the word super compensation used in this context.

When we looked at solutions to measuring and managing recovery, we realized the wider context of this particular problem. Life itself is a pattern of acute and chronic stress, mostly through our ongoing relationship with our environment including work, family, and money. So we thought it might be useful to solve for that, too, while we’re at it. If we solve stress, we get recovery along for the ride.

So here’s what we know about stress, and what we’ve been working on lately.

Stress 101: Symptoms, Effects, and Types

First things first, stress isn’t some abstract unmeasurable quantity. There are three main systems in the body that manage the stress response. All three are defined by a balance, i.e. you want a Goldilocks amount of each. When in balance, that state is called homeostasis. Most importantly, all three are linked together quite tightly.

This is actually an oversimplification of the interactions but goes to show these systems are intimately interconnected.

Central nervous system: Your nervous system is the wiring from your brain to your organs. It controls things like your autonomous heart-beat and semi-autonomous breathing. It knows you better than you do (or at least thinks it does) and controls a balance between fight or flight and rest and digest modes to your body. External stressors sensed by your nervous system and brain trigger changes in that balance. That change signals your endocrine system and your immune system accordingly to take action using chemicals called neurotransmitters.

Endocrine system: Stress hormones are emitted by the adrenal, pituitary, and hypothalamus. Among other things like waking you up in the morning, keeping you alert and focused, shivering when cold, they trigger your body’s immune response. This same system also controls all your other hormones, like testosterone and insulin which manage the growth of your muscle and fat cells for instance. So if you mess around here, you mess up your body head to toe.

Immune system: There are many types of immune cells, that react to stress hormones to either chill or kill. This is how your body knows to build scar tissue, burn out germs with a fever, or induce nausea, or make you sleepy. It’s trying to keep you alive in the face of an active threat.

How do you get stressed?

There are some pretty nuanced scientific frameworks to categorize stressors, but honestly, this is perhaps the only intuitive part of stress. You know the causes, cause everybody has them!

Mental: This is your perception of your experience that translates your thoughts, emotions, and moods into physical manifestations through your nervous system and neurotransmitters. Bad vibes lead to bad things in your body.

Behavioral: Things that upset your body’s natural balance, called homeostasis, are the usual suspects in sleep, food, and exercise. There are good and bad doses of each.

Environmental: This would cover all sorts of toxins you expose yourself to, which includes the big ones like smoking and drinking, but also more subtle toxins like chemicals, radiation, allergens, molds, and other nasty stuff out there in the world.

Effects of Stress: What Stress does to the Body

To be clear, we need to consider the good stress responses along with the bad. We absolutely don’t want to eliminate all forms of stress. We couldn’t live without it. We just need to titrate the amounts and avoid chronic accumulation.

Acute stress

Which is a fancy way to say instant or short-term, i.e. hours to days. Good doses cause short-term hormesis, which is a dose of stress the body can recover from, and actually creates an adaption that makes you more resistant to that stress over time. Like bicep curls to blow up your guns. If you overdo it, say like a bottle of Tequila, well let’s just say it isn’t a good form of stress.

Oxidative stress: When you use tons of oxygen during a workout, aerobic or anaerobic, it creates waste products from your mitochondria like reactive oxygen species. If you do too much, like say run a marathon, your body will struggle to clear everything out and will cause oxidation damage in surrounding tissues.
Cell repair: Exercise actually causes damage in your cells like muscle fibers through oxidative stress, and this triggers a good type of inflammation to repair those and be stronger for the next bout.
Nervous system fatigue: The exact mechanisms of how we feel fatigued aren’t well established, but it is clear that the nervous system controls the rise and fall of your heartbeat during and after exercise. By repeating this cycle more often, you increase the nervous system’s control over the heart.

Chronic stress

Meaning long-term, i.e. months to years. Most chronic stress is bad, with the exception of exercise. At the right levels, of course.

Exercise: Chronic exercise can shift the balance of the nervous system from being sympathetic dominant to parasympathetic. As we learned, that can prevent a whole cascade of bad things from developing in your endocrine and immune systems. Exercise really is the best medicine!
Oxidative stress: The same reaction that helped you recover from your killer ab crunch challenge, can accumulate in your body letting tissue damage and inflammation get out of hand. This could happen due to overtraining, i.e. not allowing for recovery, or even things like toxin buildup in your body.
Anxiety, depression, burnout: The traditionally more well-known link between stress and health is that of mental health. Once your neurotransmitters get out of whack, they stay out of whack until you change something and wreak havoc on your endocrine and immune systems like it was drunk texting. Sadly, the usual cycle involves mediation and then counter-medication, which removes the symptoms but doesn’t solve the root cause.
Inflammation: In the presence of physiological or psychological stressors, your body upregulates proinflammatory cytokines, and they stick around since the stress isn’t going away. Like you refuse to heal. The bad news is the cytokines start to cause problems themselves. Chronic inflammation is linked to premature aging, cardiovascular disease, and metabolic disorders like diabetes, so this stuff will actually kill you.
Weakened immune response: Once you compound these factors over time, you actually significantly weaken your body’s natural armor, the immune response. You are suddenly more likely to a) get sick but also b) stay sick due to your body’s inability to fight back as it should, or fight back when it really didn’t need to.

How does one “solve” stress, exactly?

Well, let’s break down the problems and how they can or can’t be addressed. To clarify, the goal isn’t to eliminate stress. More so to manage acute stress for optimal daily performance, but more importantly, prevent the accumulation of chronic stress.

This is how analysis and recommendations are shown in the app.

1. You have to measure stress.

As we established, we have to establish measures, preferably non-invasive, to see what kind of acute stressors and symptoms of chronic stress are present in your system. That includes not just physiological measures, but behavioral and psychological.

Heart Rate Variability: In terms of clinical validation and mechanistic explanation, the number one measure for stress across the board is heart rate variability (“HRV”). It’s a measure of your nervous system balance, which is the trigger for stress management through your body. HRV measures the time between heart beats, which is small but meaningful, and is a proxy for your nervous system balance. Low HRV means high sympathetic bias, i.e. fight or flight, a state of stress. Useful to evade predators, less useful to relax after a day at the office. High HRV means high parasympathetic bias, i.e. rest and digest. Dangerous in the presence of saber tooth tigers, but useful pretty much most of the time. So if this one number encapsulates physiological and even psychological stress, how do we measure it?

Wearables: The miniaturization of sensors and electronics have led to wrist computers like the Apple Watch. They come in many forms now, including rings like Oura. Simple cheap devices usually just measure activity, but top end devices provide tons of valuable data like resting heart rate, heart rate variability, and sleep cycles. Non-invasive glucose monitoring is coming.

No wearable? To make these tools available to everyone, we had to find another solution to simply waiting for everyone to get expensive wearables for Christmas. Santa, come on?! What everyone does have though, is a smartphone. Smartphones have cameras and flashes. In a neat bit of technological coincidence, if you put your fingertip on the lens of a smartphone camera with the flash on, the camera can pick up the subtle pulsation of your blood vessels. Which means we can calculate your heart rate, and more importantly, your heart rate variability, with a free app. Great success!

Blood: There are some established biomarkers for chronic stress you can test for, but the downsides are cost and needles. If you did do a test recently, you might look out for elevated cortisol, alpha-amylase, and pro-inflammatory cytokines.

Questionnaires: If you’ve ever done an “HR survey”, you know what I’m talking about. From 1–5 how emotionally satisfying do you find your boss? Truthfully, and sadly, these kinds of questionnaires are how most of the burnout prevention is handled (or mishandled). It doesn’t take much to assume most employees might be hesitant to a) disclose they’re going bananas b) disclose they hate their bosses guts. The simple subjectivity and low frequency make this the worst kind of data. Not worthless, in the absence of literally any other option.

2. You have to track stress.

So if we just have that HRV number, aren’t we done here? Low bad, high good. Right? Well, that’s kind of true, if you know what’s low and high for you, and are putting those into a spreadsheet to see trends from days to weeks to months. And factor in all the workouts you do. And sleep. And meditation. And food. So yeah, we’re done if you do the math. But we’d prefer to do the math for you if you don’t mind.

Baseline: To find out what’s low and high, we’ve turned to research studies conducted on healthy individuals, controlling for age and gender and using standard deviations above and below the mean. So over a chronic period of 3 months, we can just tell you where you stand compared to the average healthy human like you. Just for brownie points, we also did this for resting heart rate, VO2Max, body fat percentage, sleep, and mindfulness.

Trend analysis: To identify when things are good, and when things are bad, we took all those physiological and behavioral data points we get from wearable devices and combined them with findings from research studies on good and bad scenarios. Then we trained a machine learning algorithm to find those patterns in your own data. That way, instead of crunching numbers on a spreadsheet each morning to figure out if you’re getting sick or should hit the gym, you just get a simple plain English score from Good, Easy, or Rest.

3. You have to manage stress.

Knowing your stress status is one thing, but what do you do about it? If HRV is the joystick for stress, then we have to point it in the right direction.

Behaviors: When your data is good, you can do what you want pretty much since it’s working for you. The question is more so what to do when the data sucks. Then it starts to matter more what you’re doing in terms of sleep, food, breathing, and meditation. You can certainly turn around a bad day with increased emphasis on those, and most of all avoid going from a bad day to a bad week. That’s exactly the pattern you need to get out of.

Exercise: Well, since we already did exercise, we’ve trained yet another machine learning algorithm to recommend specific types of workouts based on your stress scores each morning. Some days, the most you’ll want to aim for is stretching or walking. It’s not even limited to our own workouts, we also read everything you do in other apps like Strava and Nike, to help you train and rest just right according to your body’s data.

4. You have to do it at scale.

While certainly there’s an increasing population of health geeks out there, who want all the latest tech and have a genuine desire to improve, there’s the rest of us. Who mostly don’t have the time or capacity to care, or just seek out the information needed to care. So we can bring the mountain to Moses, and go to the workplace.

There’s a lot of corporate wellness initiatives going on in the Western world, driven by policies and insurance schemes. The reason is clear: burnout is a cost partially borne by the employer. We’re talking hundreds of thousands of dollars per case. Millions are therefore being spent on wellness programs, to prevent exactly that, while boosting productivity. What’s the problem? There’s no measurement. As everyone knows, you can’t control what you can’t measure.

In many countries, this is not the case yet. If you get stressed, you get fired. So there, it would be great to introduce low-cost solutions that don’t break the bank. Even if the hard costs are avoided by the employer, they still lose a valuable employee, and as fellow humans would prefer if everyone was healthy and happy.

Either way, we think there’s a lot of room for a scalable, low-cost solution to measuring and tracking stress. If you agree, holler at us.

Try it out?

If most or even any of this made sense to you, maybe you’d like to give it a spin? Oh, and it’s all now completely free. You’re welcome. Working on an Android stress scan app, stay tuned.

References

Longevity: muscle strength, VO2Max, resting heart rate
Stress impact: cost of stress, burnout classification.
Stress physiology: immunity, psychological stress, hormones.
Exercise stress: oxidative stress, nervous system.
Chronic stress: biomarkers.
Stress reduction: mindfulness, corporate wellness.