What is Hormesis? Should I care?

Have you wonder why people do crazy things like having ice baths, saunas and fasting? What do they all have in common? They're all unusual, somewhat extreme environmental conditions to what our body is used to.

In fact, we've been exposed to different environmental hazards for decades and decades. The reason we’re still here is because we’ve developed complex systems to cope. Is it neccesary? You bet. Hormesis is a basic concept in evolutionary theory.

The term hormesis is first used in scientific paper in 1943. While hormesis is generally viewed as an external agent (e.g a plant food) or an environmental condition (intense cold), these agents or environment forces our body to respond in a way that is absolutely necessary for the basic normal function of our cells. 

Our hormetic response pathways typically involve proteins which regulate the expression of genes that protects our cells. Several major categories of hormetic stress resistance proteins have been identified including protein chaperones such as the heat-shock proteins, antioxidant enzymes such as superoxide dismutases and glutathione peroxidase, and growth factors such as insulin-like growth factors and brain-derived neurotrophic factor 

A common observation in studies of hormesis is that exposure to low levels of one type of hormetic agent can protect cells/organisms against more than one type of stress. 

Recent findings suggest that health benefits of many phytochemicals may also be conferred by cross-modal hormesis mechanisms in which a phytochemical activates one or more adaptive cellular stress response pathways

Several articles in this special issue of ARR describe evidence supporting hormesis as a mechanism responsible for the health benefits of a variety of lifestyle and environmental factors. This is best documented for exercise which increases the resistance of musculoskeletal and cardiovascular systems to injury and disease

But moderate regular exercise also benefits other tissues including the nervous system 

Accumulating evidence suggests that the reason that regular engagement in intellectual activities is beneficial for the brain is that it activates hormetic pathways in neurons. Similar to the changes that occur in muscle cells during exercise, neurons engaged in challenging activities are subjected to repeated bouts of calcium influx, free radical production and moderate (aerobic) energetic stress. As a result, transcription factors such as cyclic AMP response element binding protein (CREB) and nuclear factor κB (NF-κB) are activated