“That which does not kill us, makes us stronger.” — Friedrich Nietzsche
It turns out Nietzsche was right.
This quote gets at the concept of hormesis (although with hormesis you see benefits well before approaching death!).
Hormesis is when something is damaging or toxic in excess, but highly beneficial in smaller doses.
We are learning that short-term acute “stress” has powerful health and longevity benefits (as long as the stress subsides at some point).
For example, we have always known that exercise was good for us, but we weren’t exactly sure why. Hormesis is the likely explanation.
If you intensely exercised all day, you would cause undo wear and tear on your body and eventually you would break down. But short bursts of exercise (i.e. high intensity interval training) stresses the body just enough to activate your survival genes. Once that stress response is engaged, your body will recover and build back even stronger than before.
An obvious example is weightlifting. Lifting weights stresses your muscles, then they get sore and grow back bigger than your baseline. But lifting too much weight, too often, or at too high of an intensity can lead to serious injury. It is all about finding the right dose.
When it comes to exercise, a dose of just 15 vigorous minutes per day can reduce the chance of death from a heart attack by 40% and all-cause mortality by 45%.
In addition to exercise, here are several other scientifically-proven ways to benefit from hormesis:
Heat and Cold Exposure
Mild heat stress has therapeutic effects. The best example of this is sauna use.
Sauna use has actually been shown to mimic the effects of exercise in the body — causing increased core body temperature, sweating, and increased heart rate.
And while extended exposure to extra-hot temperatures would be toxic, short periods yield tremendous benefit.
In fact, a large study in Finland identified strong links between sauna use and reduced death and disease.
Men who used the sauna 2–3 times per week were 27% less likely to die from cardiovascular-related causes than men who didn’t use the sauna. And men who used the sauna 4–7 times per week were 50% less likely to die from cardiovascular-related causes. Additionally, frequent sauna users were found to be 40% less likely to die prematurely from any cause.
Frequent sauna use has also been shown to reduce the risk of dementia and Alzheimer’s Disease by 65% (again, the more days per week the better), lower blood pressure, reduce inflammation in the body, and alleviate symptoms of anxiety and depression.
The duration of each session need not be very long. You want to stick it out for around 20 minutes for maximum benefit (in a dry Finnish-style sauna heated at a temp of at least 174 degrees F), but much longer than that is not necessary or recommended.
To amplify the benefits, you can do as the Finnish do and immediately plunge into ice cold water following the sauna session. This further stresses the cardiovascular system (but not to the point of posing a risk for healthy people).
Cold immersion on its own has significant benefits. Being uncomfortably cold for short periods of time activates protective brown fat in the body and can lead to weight loss, improved immune function, and reduced feelings of stress and anxiety.
You don’t want to get to the point of frostbite or hypothermia — a daily 5-minute cold shower can do the trick. Exercising in the cold is especially beneficial (try running outside in the winter or cold water swimming). Or if you are feeling especially committed, try the Wim Hof Method which combines cold therapy with breath work and mental conditioning.
Eat Stressed Plants
We know that eating vegetables is healthy, but hormesis helps explain why.
Longevity and anti-aging expert Dr. David Sinclair says eating stressed plants is one of the most powerful things we can do to extend lifespan.
What does that even mean?
Well, plants can get stressed too. Whether from drought, fungal attack, or simply the threat of being eaten, plants are faced with many external stressors. But unlike us, plants are rooted to the ground and can’t run away to escape harm.
Therefore plants produce a variety of chemicals to defend themselves. And when humans ingest these compounds, it protects us not only from the plant chemicals, but also the environmental stressors to which we are exposed on a daily basis, such as air pollution or overexposure to UV radiation.
Plant-based compounds activate cellular protective mechanisms in humans, a phenomenon known as xenohormesis.
Here is just a small sampling of specific foods and drinks to consume to see these benefits:
Cruciferous vegetables such as broccoli, broccoli sprouts, cauliflower, cabbage, kale, and Brussels sprouts (which contain the compound sulforaphane)
Dark Chocolate (which contains catechins)
Green Tea and White Tea (which contains the polyphenol Epigallocatechin gallate or EGCG)
Turmeric (which contains the chemical curcumin)
Coffee (which contains chlorogenic acid)
Red Wine (which contains resveratrol — although this one is controversial since the negative effects of alcohol could outweigh the small amount of resveratrol found in a glass of wine)
Hormesis is another reason why you want to eat organic fruits and vegetables (including wine), otherwise the beneficial stress compounds will be sterilized away.
Fasting
When you aren’t eating stressed plants, try consuming nothing at all to put your body into a temporary state of nutritional adversity.
Extended malnourishment is not good, but smaller doses of calorie restriction is incredibly powerful for longevity.
The ideal fasting regimen appears to be a combination of daily time-restricted eating with a periodic prolonged fast (5 days appears to be optimal for a prolonged fast, done 1–4 times per year).
For the daily time-restricted eating, you want to consume all of your calories within a maximum of 12 hours (for example, eating all of your meals between 8am and 8pm and fasting for the other 12 hours). Some people choose to extend the daily fast to 14 or 16 hours, most commonly by eating an early dinner and then skipping (or eating a late) breakfast the following day.
Time-restricted eating has been shown to produce a number of beneficial health effects, including weight loss, improved heart function, and enhanced aerobic capacity, all without altering diet quality or quantity.
The prolonged fast is only done on a periodic basis (usually not more than once per quarter), which resets and rebuilds your body at the cellular level. I am a fan of Dr. Valter Longo’s 5-day Fasting Mimicking Diet, which gives you all the health benefits of a water-only fast while still allowing small amounts of food each day (It is advised to check in with your doctor before doing a multi-day fast, especially if you choose to do the water-only variety).
Time-restricted eating along with a periodic prolonged fast make for a powerful combination. Think about time-restricted eating as daily maintenance for your body and a prolonged fast as your 6-month or annual checkup (similar to how you brush and floss your teeth daily and then visit the dentist 1–2 times per year).
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Other more controversial triggers of hormesis include sun exposure and alcohol consumption.
UV Rays in excess cause sunburn and skin cancer, but small doses provide beneficial Vitamin D and sunbathers have actually been shown to live longer. Overall you still want to play it safe — a little bit of sun might be good for you, but you should wear protective sunscreen for any longer exposure.
A similar principle applies to alcohol. Moderate drinking has been shown to have longevity benefits but excess alcohol consumption is undoubtedly toxic.
Your best bet is to activate hormesis via exercise, eating stressed plants, cold and heat exposure, and fasting.
Overall you want to put your body through short bursts of mild stress to live longer, better.
This is a great reminder to get out of your comfort zone.
Andrew Merle writes about healthy living. Read more and subscribe to his email list at andrewmerle.com.
