We’ve all heard the phrase “what doesn’t kill you, makes you stronger”. It may seem like just something your trainer tells you to make you work harder, but there is truth in this statement. Adding some stress on the body activates mechanisms that make you stronger and more resilient. This is called hormesis and it is one of the best and most effective tools we have for improving our health and promoting longevity. Hormetic stressors are small and controlled stressors that cause positive adaptations to our body. We will discuss a few easily accessible examples including exercise, fasting, heat and cold.

Exercise – We know that when we exercise, we are putting small doses of stress on our bodies to bring about positive results. The SAID Principle (Specific Adaptation to Imposed Demand) explains this brilliantly. For example, when we do weight bearing exercises, the mechanical stress causes an adaptation in the bones which makes them thicker and less porous. Putting our ligaments and tendons through ranges of motion that are slightly outside of our comfort zone, makes them stronger.

Increasing our heart rate through cardiovascular exercise will improve our oxygen intake and overall aerobic capacity. This study from 2018 concluded that cardiorespiratory fitness is inversely associated with long term mortality and those with high aerobic fitness live longer. In his book, Outlive, Dr. Peter Attia compares smoking at a 40% greater risk of all-cause mortality, to poor cardiorespiratory health which doubles the risk.

Strength training will build muscle in response to overloading, and it has been shown that having more lean muscle mass and strength are the most important tools we have for living a long and independent life. Older adults with less strength and low muscle mass are at the greatest risk of dying from all causes. Please read our blog on muscle for more information on this key element of longevity.

Fasting/Caloric Restriction – When we wrote our first blog about fasting in 2018, it was not as popular as it has become in recent years. Now it is commonplace in the health and longevity space. There are different types of fasting including time-restricted feeding in which eating is limited to a window from 8-12 hours, intermittent fasting which can be a water-only fast for 24 hours, 3 days or even 7 days, or fasting-mimicking diets that “trick” your body into thinking it’s fasting due to the extreme decrease in caloric intake. Some of the benefits of fasting include:

  • Promote autophagy, or the clean up of damaged cells. This allows our mitochondria to function better, producing more energy for our entire body.
  • Stimulates stem cell production.
  • Decrease inflammation. Most chronic disease stems from chronic inflammation.
  • Improve insulin sensitivity and metabolic flexibility. Approximately 96 million American adults are pre-diabetic, 80% don’t even know it. Improving insulin sensitivity is the key to reversing or preventing Type 2 Diabetes.
  • Can also help to decrease body fat, improve cognitive function and stimulate the immune system.

Cold Exposure – Cold exposure can be achieved through cold showers, cold plunges, cryotherapy or even getting outside in cold weather. The benefits include decreasing inflammation, increasing brown fat, regulating our dopamine response, increasing insulin sensitivity, lowering blood pressure, and improving mood and cognitive function.

When you first get into the extreme cold, there is a sympathetic response in which your breathing quickens, blood pressure rises and dopamine increases. Your brown fat is also activated immediately which, in theory, increases your metabolism. Soon after, the parasympathetic nervous system is activated in response to the stress. It works to slow everything down – breathing, heart rate and blood pressure – to put the body in a protective mode against hypothermia. This activation also stimulates the neurotransmitter, serotonin which is important for regulating mood, sleep and appetite, to name a few.

If you want to immerse yourself in more cold exposure knowledge, check out the book, Water Swimming: The Nordic Way Towards a Healthier and Happier Life.

Heat Exposure – While exercise, fasting and cold exposure all require some amount of dedication and may not always be easy, heat exposure might be one hormetic stressor that most of us enjoy! 20 minutes of relaxation and breathing in a hot bath or sauna to help us live longer…who doesn’t want to sign up for that?!

Sauna bathing has been shown to decrease all cause mortality by 40%, with at least 4 sessions per week. This potent tool of exposure to high heat triggers defense mechanisms in the body to repair cells, improve immunity, increase stem cell production and repair DNA, among many other benefits. For more information, delve in here.

Too Much of a Good Thing – While we love these “good” stressors, it’s important to keep in mind that too much of a good thing can be harmful. Too much stress can deleteriously affect our hormones which affect our metabolism and all of the processes in our body. Cells become less resilient when exposed to too much stress.

Just as more medication is not necessarily better, too much cold exposure can lead to hypothermia, overtraining can lead to musculoskeletal injuries and diminishing returns, and too much fasting can lead to nutrient deficiency and lower muscle mass due to decreased protein intake. Too much time in the sauna becomes a negative stress on the body. According to Dr. Susanna Soberg, a maximum of 20 minutes is sufficient. Over 30 minutes starts to become more of a negative stress than a beneficial one. More is not better! Also, if you are combining all of these hormetic stressors, the need for more of one decreases. Exercise regularly, do some type of fasting that works for you, sauna a few times per week (if you don’t have access to a sauna, get in a hot bath and you can still reap the benefits). Lastly, try ending your showers with 30 seconds of cold. A little hormesis goes a long way for longevity.