The biology of stress

The biology of stress
- May 14, 2021

Do you ever have so much to do that you can’t focus on anything? Or how about lying awake at night unable to sleep because your mind is racing. Or when you’re run down and sore after a stressful day? There’s a biological reason for all of this. 

Chronic stress strains the whole body by over-activating our sympathetic nervous system, commonly known as the “fight-or-flight response”. When your sympathetic nervous system is working overtime, you’re not set up for a happy, healthy life, and unfortunately, this is the baseline for many of us these days.

When the fight-or-flight response is engaged, it is physiologically harder to focus, relax, and sleep, because our body and mind are both signaling that we are under threat and need to escape danger. This is when the negative feedback loop begins: it feels impossible to make healthy decisions when we’re exhausted and unfocused. So, how do you bring your nervous system back to a balanced state, where the parasympathetic “rest and digest” response is in play?

Sleep, meditation, relaxation practices and regular exercise help us to recover from stress by engaging the parasympathetic (rest and digest) nervous system, but they are all physically and mentally harder to do when we’re overwhelmed by chronic stress [1,2].

When left unchecked, chronic stress increases your risk of developing insomnia, anxiety-disorders, depression, and chronic pain [2-6]. Chronic stress exhausts us, makes us unhappy, disrupts our mood, causes tension and pain, and impairs our sleep.

How does chronic stress lower HRV and why does it matter?

Heart Rate Variability (HRV) measures the rate of change of the heart beat over time[2]. Having high HRV is a good thing. It means that your body can quickly adapt and recover from stress.

When we encounter stress in our environment, our heart rate, respiratory rate, and blood pressure should go up so we can quickly respond to a threat[1,2]. When we’re calm, our heart rate, respiratory rate, and blood pressure should be at a comfortable resting rate. This is our body’s way of maintaining balance between thriving and surviving over time.


Having consistently low HRV indicates that your body isn’t adapting to or recovering well from stress[2].

This could mean a number of things:

  • You aren’t sleeping well
  • You’ve exhausted your body
  • You’re getting sick

Those of us with consistently low HRV have a higher likelihood of developing:

  • Injuries
  • Insomnia
  • Chronic pain
  • Cardiovascular illness.
  • Anxiety-related disorders
  • Depression

High HRV

High HRV indicates that your body is resilient, recovering well, and able to bounce back from stress quickly[2].

The following contribute to high HRV:

  • Restorative sleep
  • Mindfulness practice
  • Balanced diet
  • Regular exercise
  • Healthy relationships

Those of us with consistently high HRV are more likely to have better:

  • Focus
  • Calm
  • Performance (athletic and cognitive)
  • Breathing
  • Pain tolerance
  • Blood pressure
  • Sleep
  • Resilience

HRV is the most reliable, non-invasive biometric of stress, measuring the balance between the parasympathetic and sympathetic systems[1.2]

The autonomic nervous system governs all the activity in our body from our heart beat, blood pressure, respiratory rate, and hormones to our digestion, blood flow, how much sugar is in our blood, our vision, our reproduction, and the list goes on[1].

Our health and survival (no kidding) are dependent on the dynamic relationships between the two branches of the autonomic nervous system: the parasympathetic (rest and digest) branch and the sympathetic (fight or flight) branch [1].

Parasympathetic branch

The parasympathetic branch is responsible for conserving energy for when we need it next[1, 2]. It is activated by safety. When we are safe enough to sleep, meditate, listen to soothing music or experience soothing touch, our parasympathetic system engages, lowering our heart rate and blood pressure, improving our HRV (heart rate variability), and supporting reproduction, creativity, and energy recovery. This rest and relaxation are key so that we have enough energy to survive a threat whenever it comes.

Sympathetic branch

The purpose of our sympathetic “fight-or-flight” system is to kick in so we can survive a threat[1, 2]. When we experience a threat, whether that be a lion or a stressful email, our heart rate and blood pressure go up, blood rushes to the heart and to our muscles, our liver releases sugar into the blood, and digestion slows down so we can escape from whatever is threatening us and reach safety.

The problem is that chronic stress from modern life is constantly sending signals to our bodies that we’re under threat. This excess of activity in our fight-or-flight response has real consequences for our wellbeing and our long-term health.

Left unchecked, stress increases the risk of developing chronic health conditions such as insomnia, anxiety disorders, depression, chronic pain, memory loss, metabolic disorders, cardiovascular disease, and even birth defects in our children[3-25]. Chronic stress also disrupts personal well-being, relationships, and sexual activity. As we all know, stress commonly interferes with our ability to be kind and good-natured with our family, co-workers, and our friends. While low HRV predicts poor sleep, focus, and an elevated risk of physical and mental illness, high HRV predicts resilience, consistent performance, better sleep, and lower chances of getting sick[2].

The Science Behind Apollo

Apollo uses waves of vibration that are demonstrated in both the lab and the real world to change the balance of our nervous systems through our sense of touch.

Here’s what we know from the Scientific Literature:

Touch changes how we feel, and science proves that. Touch is a powerful sense. Evolutionarily, it is the most important way that mammals communicate safety to one another[30-40]. Different forms of touch (vibration, electricity, heat, cold, soothing massage, etc) can change how we feel in ways that can be measured biologically. Extensive reports demonstrate that certain frequencies of vibration are found to be soothing and significantly increase parasympathetic tone, as measured by heart rate variability (HRV), while others can be more energizing, increasing our heart rate and other measures of sympathetic activity[2, 41-54].

What makes Apollo different from any vibration you’ve felt before?

It’s about balance. Apollo isn’t just about relaxing, and it isn’t just about performing. Apollo is about physical and mental balance and we’ve designed each set of modes to help your body gently transition through your natural response to touch.

How? We combined frequencies of vibration known to change our energy levels by increasing or decreasing parasympathetic and sympathetic nervous system activity[41-54]. Modes designed for rest and relaxation contain more slow-moving gentle frequencies known to increase parasympathetic activity, the branch of your nervous system that is activated when you meditate, deep breathe, and sleep [2, 9, 14, 27-31]. Modes for energy contain vibration frequencies known in the literature to increase heart rate and blood flow for increased energy and alertness[2, 41-54].

Every single Apollo mode, whether it is designed to increase wakefulness or to help you fall asleep, is designed to restore your body by improving heart rate variability (HRV).

How does Apollo change HRV?

Apollo vibrations feel like waves coming and going. This sensation feels natural because it is. Apollo’s modes match a natural oscillation pattern between our heart and our lungs when we deep breathe, which consistently improves HRV in lab trials and in real world use. When our bodies feel the rhythm of the Apollo vibrations, it is automatically recognized by the body as soothing gentle touch, just like a friend giving you a hug on a bad day.

We’ve gone beyond the literature to independently test Apollo in academic-led trials.

Before we built Apollo, Dr. David Rabin MD, PhD and Dr. Greg Siegle PhD studied Apollo vibrations at the University of Pittsburgh. They went beyond the literature to test how Apollo vibrations would change the body in a double-blind randomized placebo-controlled crossover trial of 38 subjects at the University of Pittsburgh.

Preliminary findings suggest that the specific vibration patterns used in the Apollo technology increase the ability to focus and remain calm during periods of stress and that these specific vibration patterns improve the body’s ability to recover and be resilient to stress, as measured by HRV. These improvements in HRV are accompanied by proportionate improvements in cognitive and physical performance under stress.

Subsequent university pilots and trials have shown that Apollo consistently improves HRV under stress, improves athletic recovery, and supports access to meditative states.

We studied the literature before we created Apollo’s frequencies. We tested Apollo’s frequencies in university trials before we built the product. Each and every program is based on our knowledge of the body’s response to vibration and we learned so much from listening to our real-world users. They told us how they felt, what they used Apollo for, and they shared their data. Check out our research

And we listened – Apollo Neuro’s modes are organized based on the science of how our body responds to Apollo vibrations, Apollo trials in the lab, and the experiences of our users.


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