CrossFit And The Human Longevity Hypothesis


As a Mechanical Engineer, I design thermal management systems for large electrical generators. Fundamentally, these systems take mechanical power from a turbine and turn it into electrical power to be distributed on the power grid. One aspect of my job is to understand the design life of these very complicated machines. Part of this understanding comes from accelerated life tests. These tests are designed to quickly simulate multiple years of operation by exposing the machine to extreme loads that are beyond the designed load points. When you do this to a machine, it accelerates the deterioration of the machine and can potentially highlight design flaws that would normally take decades to discover. Some of the generators in this industry are designed for 30 years of operation.  We can’t exactly wait around for 30 years while the generator is tested under normal operating conditions to find out that our design doesn’t meet the life requirements.

How does this relate to human longevity? Well, as the proud owner of a new CrossFit facility, I am very interested in applying my technical domain expertise from the power generation industry to the science of human performance and the study of human longevity. CrossFit is a game-changer in how humans evaluate their fitness. Soon, those gym rats that brag about how much they can curl or bench press will be viewed as fitness dinosaurs. Constantly varied, functional movements performed at high intensity is the way of the future for human fitness, performance and yes, longevity.

When I first started doing CrossFit two years ago, I became addicted to the highly intense workouts that sometimes felt like getting hit by a bus. All of my strength and conditioning metrics were improving. Some metrics improved as much as 2X greater than previous plateaus. Most of my gains were due to learning the proper movement mechanics and where my metabolic thresholds really were. I also cleaned up my diet tremendously which contributed to those gains.

After about a year, I injured my shoulder and began to question the intense nature of this protocol. I started to realize that these intense workouts resembled the accelerated tests that I was familiar with in my engineering day job. Was I subjecting the biomechanical machine that is my body to an accelerated life test every time I worked out? Would I start to break down faster than if I trained at a more conservative load point? These questions are all very valid and the jury is still out. However, as I began to question this approach further, I realized that although the human body is fundamentally a “machine” it is one with ultra-sophisticated adaptive capability. In other words, when we overload a generator, it doesn’t subconsciously bolster its own capability so that next time you overload it, it has more capacity and can handle more extreme loads. This is exactly what the human body does when we push the limits of our performance. After a really intense workout, with proper recovery techniques such as ample sleep, hydration, nutrition and daily movement habits (i.e. not sitting all day), the body starts building reinforcements so that the next time you experience that extreme load, it is more capable. This style of threshold training allows us as human beings to increase our rating autonomously.

Additionally, when we train with this approach the mundane, nominal loads that we experience in every day life such as picking up our kids, loading laundry, moving furniture, etc. take far less of a toll on us than they would have without the training. These minor everyday load points are cycled millions of times throughout our lives. Without increased capacity and proper movement mechanics, our biomechanical lifespan entitlement is drastically reduced. Barring catastrophic injury and/or disease, being able to move is what keeps us alive and well.


Learning how to move with stability and efficiency will increase our bio-mechanical lifespan entitlement. Additionally, if we increase our capacity in tandem to bio-mechanical stability/efficiency, we will reduce the everyday wear and tear on our joints, keeping us moving** BETTER -> LONGER


Chad Southwick

Karen Southwick