Weekly Blog

Oct 30

This summer, our Carolina-based team was asked to build on a project we first explored a few years prior: to quantify and help manage the spike in physiological load that occurs when extreme temperatures layer onto a baseline of heavy physical work. There's no mystery why a project like this is important: anything that accelerates fatigue also accelerates risk - incidents, injuries, or worse. Therefore, finding ways to identify changes early and implement strategies that help individuals stay below the risk threshold is critical. 

We love projects like these because they push us to find new limits in the hope of gaining a performance edge. We dig deeper, become more creative, and ultimately embrace the challenge of unlocking the little victories and improvements that add up into meaningful benefit. And while we can't share all the findings and details, after tracking this group of industrial-athletes' physiological loads 24/7 for weeks using wearable tech, two things became abundantly clear:

First, our physiology prefers moderate temperatures: Adding heat and humidity to already heavy work creates a significant spike in load (and thus risk), which can be oppressive if not well managed. Second, as we all inherently know, but the data make plain to see: it's never "just" about the loads; working equally hard to RECOVER might be even more important.

Two new studies lend support to these ideas. The first, an ergonomic study on construction workers in Korea, found that while spikes in load were never ideal, the accumulation or layering of load - specifically, duration of work in awkward postures, time spent working in high temperatures, or efforts requiring handling of heavy materials - carried the greatest risks associated with pain and injury. Similar to overall physical capacity, the risk/performance threshold dropped as age increased. The second, a look at injury prevention in competitive sports, found (as we did) that impaired recovery was more strongly associated with injury risk than heavy training loads alone. In plain English, while there definitely is a line that represents "too much", seasoned athletes - whether traditional, tactical, or industrial - have built-in reserves, a robustness through experience which allows them to absorb temporary increases in load. However, the old adage about burning the candle at both ends appears equally true. Anything that harms rest ultimately adds risk, so prioritizing and protecting sleep remains critical, as reviewed here and here.

Yet 2 open questions remain: (1) Just how hard can we humans push without risking injury? (2) Are there any new tactics shown to increase the odds of optimal recovery?

While some machine learning models have found ways to use load spikes up to 50% above baseline and still increase performance without injury, coaches and professionals more widely use the traditionally accepted ramp of up to 30% beyond what we've adapted to over time. In a work setting, this means that if we typically clock 8 hours at an average perceived exertion level of 6 (out of 10), or 48 "load points" per day (8 x 6), we risk overuse around 62 "load points" (8 x 6 x 1.3). Therefore, if we perform those same 8 hours at an exertion of 8 (extreme temps, emergency work, etc.) or extend our typical "level 6" exertion to a block greater than 10.5 hours, we are hovering very near the risk threshold and, if nothing else, are likely to have pushed our systems beyond RECOVER and into "repair". We might notice an elevated resting heart rate, an irritable mood, or even signs of overuse like localized inflammation, night sweats, or a body that is barking back. This brings us to question 2.

While it's hard to call it a new idea, a recent animal study may provide new proof of why an old idea should be near the top of any list: whether you call it a ramp-down, slowing before stopping, or "active recovery", light aerobic efforts after overuse-level loads may help reset the nervous and immune system pathways that disrupt recovery when irritated and tend to leave us with pain. Not only did performance metrics return to baseline when light exercise was added, some metrics actually exceeded baseline levels, but they also bounced back stronger, even when sleep was disrupted. More work is definitely needed to determine if the effect is equally strong in humans, but it's a promising start.

Our physiology has limits. It needs both stimulation and high-quality recovery - enough but not too much of both - in order to grow and stay strong. We continue to learn that these aren't distinct and different, but overlapping and inseparable. We need to RECOVER to MOVE and MOVE to RECOVER...which makes now (and always) a great time to get out there.

Have a great weekend,

Mike E.