Yes! A stress to improve your health

CHRONIC and prolonged stress related to relationship problems, finances, unsustainable workloads or lack of sleep is toxic for the body.

But another type of stress, hormesis, is good for you. Hormesis refers to “controlled, acute stressors that result in healthy adaptive responses" and includes high-intensity interval training (HIIT; short bursts of intense exercise alternating with short periods of recovery), exposure to heat or cold, calorie restriction and even hypoxia (breathing techniques that deprive your body of oxygen for short periods).

The old saying “what doesn't kill you makes you stronger" holds more truth than we thought.

How does it work?

The science behind hormesis is as follows: when specific stressors are administered in the correct dosage (short bursts), they activate a series of defence mechanisms and adaptive responses to cope with that stress. And this stress response is beneficial for the body. It leads to increased production of antioxidants and better regulation of cellular recovery mechanisms and immune function.

Examples

Intermittent fasting, which I recently wrote about, is an excellent example of hormetic stress. It involves depriving your body of calories for a specific period. The most common method is not eating 16 hours a day, although there are several variations.

Research shows the benefits of intermittent fasting include improved heart health, reduced inflammation, enhanced cellular recovery processes and better weight regulation.

Other examples of hormetic stress include:

Exposure to cold water through therapy, swimming, or simply a few minutes in a cold shower.

Heat exposure, such as in a sauna or steam room.

High-intensity interval training, where short bursts of intense exercise are alternated with periods of recovery/rest. (Interestingly, this research in Ageing Research Reviews suggests that moderate but regular exercise provides the same benefits for older adults.)

Cognitive exercises that push you out of your comfort zone, such as video games, crossword puzzles and games like chess that exercise the mind's strategic capabilities. According to a research article in Frontiers in Medicine, older adults can reap several health benefits, including improved memory, balance and muscle strength, by playing online video games.

Research

The research on cold therapy explains how hormetic stress activates a wide range of physiological responses.

Autoimmune disorders such as rheumatoid arthritis and fibromyalgia are inflammatory responses. Cold therapy has been proven to relieve symptoms. Read more.

Cold water immersion therapy stimulates the vagus nerve, which in turn lowers the heart rate and improves heart rate variability. These changes reduce stress and induce relaxation. Read more.

Similar to the short-term benefits to athletes from vasoconstriction, such as reduction of inflammation and oedema, studies indicate that the brain receives similar benefits. Cold water immersion may be a cost-effective preventative measure for dementia before symptoms develop. Read more.

There is strong evidence of improvements in psychological conditions such as depression and mood disorders with whole-body cold therapy, with effects lasting at least two weeks after the final session. Read more.

Additional studies also show that inflammatory markers such as TNF-alpha and IL-1 significantly reduce with cold therapy, indicating a long-term effect. Read more.

The key lies in the dose

Prolonged exposure to any form of stress, including hormetic stress, is unhealthy. For example, prolonged exposure to cold will lead to hypothermia. However, when applied in short bursts, hormetic pressure acts as a mild irritant, pushing the body out of its comfortable homeostasis and activating various cellular mechanisms and signalling pathways that promote stress resilience.

The bursts of oxidative stress generated by hormesis also influence a variety of cellular signalling pathways, repair damaged cells and DNA, combat oxidative stress, producing new mitochondria, reduce inflammation, support toxin removal, improve blood sugar regulation and lower the risk of cancer.

Hormetic stress activates mechanisms that help repair cells through autophagy, where cells break down and recycle damaged material. Mild oxidative stress activates antioxidant defence systems that help combat oxidative damage caused by free radicals. 

Reducing inflammation is another beneficial effect of hormetic stress. Activating specific signalling pathways helps regulate inflammatory responses, promoting a healthier immune system and reducing chronic inflammation.

Hormesis also supports the elimination of toxins from the body, assisting in detoxification processes and promoting overall cellular health.

Furthermore, hormetic stress can improve blood sugar regulation by enhancing insulin sensitivity. And some research suggests it can help reduce cancer risk by stimulating protective mechanisms within cells that enhance immune surveillance against malignant cells.

Dr Elissa Epel is the director of the Center for Aging, Metabolism, and Emotion at the University of California, and she is a leading researcher on hormetic stress. She says acute intermittent hormetic stressors of moderate intensity can promote stress resilience and enable cells and tissues to recover and potentially rejuvenate.

But she goes a step further. She doesn't just talk about the therapeutic value of hormetic stress; she says optimal health is impossible if you don't expose yourself to enough hormetic pressure: “Biologically, the lack of acute stressors prevents the intermittent episodes of cellular ‘house-cleaning' activities that slow ageing."

How does it work?

We know that oxidative stress (free radicals) is terrible for our health, but surprisingly, oxidative stress appears to be the primary underlying reason why hormetic pressure benefits us. Most of the hormetic stress factors mentioned above — from cold therapy to HIIT — induce low levels of free radicals in the body. And here's the reason why it's not bad for us:

Mitochondria produce the energy our body cells need to function. A hallmark of ageing is the loss of mitochondria. Having fewer mitochondria results in less energy to nourish our cells properly. Stimulating mitochondrial biogenesis can, therefore, improve both short-term and long-term health — and that's precisely what happens with hormetic stress: the mitochondria are stimulated to replicate.

The bursts of oxidative stress generated by hormesis also influence various cellular signalling pathways in your body, including one that involves the transcription factor Nrf2 (transcription factors are proteins that bind to DNA to activate genes).

In summary, the low levels of free radicals induced by hormetic stress stimulate beneficial processes, such as mitochondrial replication and activation of cellular signalling pathways, including Nrf2. This ultimately improves mitochondrial function, energy production and overall cellular health.

The presence of free radicals prevents Nrf2 proteins from being broken down as quickly. This means more Nrf2 can penetrate the nuclei of cells, where it binds with DNA and produces powerful antioxidant enzymes such as glutathione (the body's “master antioxidant") and activates detoxification enzymes.

These enzymes help the body better process toxins and high levels of oxidative stress. In other words, by causing a little oxidative stress now, hormetic stress factors can help you neutralise more oxidative stress later.

Nrf2 is just one example of how hormesis promotes health. Other hormetic cellular signalling pathways include AMPK, FOXO3, SIRT1 and mTOR. Many are simultaneously activated and have overlapping benefits.

And then the proverbial icing on the hormesis cake: there is increasing evidence that the stress resilience we gain from one hormetic stressor can help the body adapt to other stressors.

In her book Immunity: The Science of Staying Well, immunologist Jenna Macciochi, a proponent of cold water therapy, explains what she calls “cross adaptation".

“There is increasing evidence linking depression and anxiety with the inflammation that accompanies a chronic stress response to the physical and psychological problems of modern life," she says.

“Through cross-adaptation, cold water swimming may be able to reduce this chronic stress response together with the inflammation and mental health problems that affect so many of us."

What are you waiting for? Turn on those cold taps in your shower! 

♦ VWB ♦

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