What is Hormetic Stress?

Meet hormetic stress, a new method of tackling stress by adding … more stress.

It sounds like a paradox. Why would you want to add more stress into your life, especially these days?

Well, a growing body of research explores the benefits of exposing your body to short bursts of pressure — aka hormetic stress. Some studies suggest this can help prepare you emotionally, mentally and physically for life’s tough moments.

You may have already heard of one form of hormetic stress: high-intensity interval training, or HIIT. It’s the idea behind diving into a short explosive exercise that raises your heart rate, then recovering for a brief period. You then rinse and repeat to aid in stress resistance.

But, as a recent Wall Stress Journal article details, things such as hot saunas and intermittent fasting also fall into this category. These practices create brief surges in your biological stress response, followed by a type of recovery you can’t typically manage otherwise. Ultimately, it could help build up your resiliency.

So let’s look at why these types of activities could strengthen your stress response and the possible risks involved.

What is Hormetic Stress?

First, let’s define stress.

Stress is a normal physiological reaction to a perceived threat. In fact, it’s an essential part of your survival mode. When you’re stressed (physically or mentally), your internal alarm system flips into “on” mode. Suddenly, your adrenal glands produce hormones such as cortisol to help you face the threat. This quick hormonal burst can raise your blood pressure, heart rate, blood sugar and more, before bringing you back to your baseline — all to help you. This is acute stress.

However, your “flight, fight, freeze or fawn” response or “tend and befriend” response (most women) was not built for the unique problems of modern-day life. Stressors today are difficult to fight off without the right tools and nearly impossible to flee from. Just worrying about something can set off a hormonal response.

As a result, many people’s alarm systems are stuck in “on” mode, causing the stress-related issues we often talk about. This is chronic stress.

So where does hormetic stress come in?

In a nutshell, acute stress becomes hormetic when you quickly return to homeostasis — your baseline. Remember, the goal is to shock your very biology into quickly adapting to stressful events. This, ideally, conditions your stress response, allowing you to build up your resiliency.

Knowing that, timing is a key component of hormetic stress. The quick stressful event should be mild or moderate, followed by a swift recovery. As mentioned in a 2020 analysis: “The exact timing of stressor exposure is an important determinant of a hormetic or pre-conditioning effect, as some stressors lead to sensitization across stressors, rather than habituation.”

For example, researchers published a study in November 2021 about the benefits of exposing mice to hormetic stress. They found that a quick stressor — confinement for five minutes each day — could reverse depressive-like behavior over two weeks. However, when held captive for longer, say 15 minutes, those benefits didn’t occur.

Hormetic stress may even go beyond building resiliency or reversing issues such as depression. Some evidence suggests it could slow the aging process. For example, in one study, mice exposed to low dose gamma radiation saw improved longevity. This type of stressor was found to extend their average lifespan by up to 30%.

4 Examples of Hormetic Stress

Hormetic-stress activities can come with medical concerns, particularly for people who fall into risk-sensitive categories. With that in mind, here are four examples of hormetic stress and some associated risks.

Keep in mind: Whenever attempting a new activity, it’s important to consult a trusted health care provider.

Vigorous Breathing Exercises: Elissa Epel is a professor in the psychiatry department at the University of California, where she is leading a study into hormetic stress and whether short-term stress interventions make us more resilient. Her team is researching and comparing the effects of a meditation practice, intense exercise and hypoxic breathing — a practice developed by Wim Hof, an extreme athlete known for his ability to withstand extreme cold.

Hypoxia (insufficient oxygen in the body’s tissues) has been studied for decades. Since the 1960s, researchers have detailed how sublethal hypoxic events “can improve the tolerance of not only cells or tissues, but also entire organs and even the organism itself, to subsequent hypoxia.”

Now, Wim Hof has developed a method for tapping into that “pre-conditioning.” His hypoxic breathing practice includes 30 to 40 deep, intense breaths followed by an extended exhale and one more breath held at full capacity for 15 seconds. You can repeat this cycle three to four times.

This technique is considered controversial though. After all, you’re denying yourself oxygen. Wim Hof’s website advises this can lead to light-headedness and a tingling sensation in your fingers. It also warns that it could affect motor control and cause, in rare cases, loss of consciousness. So they don’t recommend the practice for people who have serious health conditions, such as high blood pressure, heart disease, epilepsy and more.

Exposure to Extreme Temperatures: Another form of hormetic stress includes exposure to extreme hot or cold temperatures. In 2015, one study examined 2,315 Finnish men. Those who enjoyed going to the sauna two or three times a week for 20 minutes were 23% less likely to die of cardiovascular disease than those who visited the sauna once a week. The more extreme sauna users, who went four to seven times a week, were 48% less likely to die.

Another case showed extreme cold exposure (along with hypoxic breathing exercises) significantly increased adrenaline production. It underscored how acute stressors boost autonomic activity, expedite immune cell proliferation and differentiation, and stimulate the immune system’s anti-inflammatory response.

Think of it this way: Cold exposure can give a jolt to your cardiovascular system by constricting blood vessels, causing a workout for your heart and possibly pre-conditioning you against future stressors.

One method of doing this is with showering in cold water for as long as you can take, according to Mr. Hof. This could start at 15 seconds then get bumped up as tolerance grows.

Intense Bursts of Activity: Next we have high-intensity interval training, also known as HIIT. Higher intensity exercise can increase your cortisol (stress hormone), but it can suppress your cortisol response to future stressors.

It makes sense: Cortisol initially rises to manage your body’s growth as you tackle the stressful exercise. But your system can adapt, muting your future hormonal response and building your resiliency. That comes with a host of potential health implications for dealing with chronic stress.

In one study published in 2021, researchers studied the effects of HIIT and moderate-intensity training (MIT) on anxiety, depression, stress and resiliency during lockdown. Both exercises significantly lowered stress, anxiety, and depression levels and even increased resilience. Yet HIIT was more effective at reducing depression than MIT.

Dietary Disruptions: Finally, we come to diet. Intermittent fasting or caloric restriction may also provide the type of stressful event that kicks off an adaptive response, increasing your resilience to stress down the line. After all, hormetic stress experts theorize that we adapted to common stressors such as food scarcity as we evolved — so those triggers “became integral parts of who we are.”

For example, in two observational studies, intermittent fasting was linked to reduced instances of coronary artery disease and diabetes. And one 2017 review underscored that it can extend lifespan and aid in the fight against cardiovascular and neurodegenerative diseases (think Alzheimer's and Parkinson's) in animals. It can even slow the progression of cancer in those models.

But remember: As with other forms of hormetic stress, doctors are concerned about possible risks, especially for those with medical conditions or who are elderly or pregnant.

Interestingly, phytochemicals or “plant chemicals” such as polyphenols, alkaloids and terpenoids found in plants and fungi also cause nutritional hormesis — meaning ingesting them can create low-level stress in your body. As a result, they can trigger the same adaptive response as caloric restriction, fasting and exercise.

As mentioned in a 2018 review, they can potentially protect “against cancer, neurodegenerative diseases, cardiovascular diseases, inflammatory and immune diseases by acting on multiple stress-response pathways.”

Ultimately, this body of research continues to expand. But hormetic stress is a good reminder that not all stress is bad for your health. And that humans are more resilient than you might think.

Before you go, we have one more question for you: How can we get better? Here at Pardigm.com, our goal is to gather the best information to help you understand the science of stress. If you think we missed anything in our research, please let us know.

Original post by Jessica Cohn-Kleinberg:

Another helpful link to Professor Huberman: