We all know hard training is required to make significant improvements to our fitness, but now scientists at The Scripps Research Institute in Jupiter, Florida have discovered a new reason why.
It was previously believed the sympathetic nervous system (the part of your nervous system that famous for regulating the “flight or fight response”) had only short-term effects to exercise by mobilizing energy stores and heightening mental acuity. However, recent research has shown that the sympathetic nervous system (SNS) plays an important role in long-term adaptation to exercise as well. The stress hormones released by it in response to intense exercise appear to be critical to your body becoming stronger. The researchers summarized their research as follows.
Collectively these findings demonstrate that the SNS‐adrenergic signaling cascade coordinates a transient catabolic stress response during high‐intensity exercise, which is followed by transcriptional reprogramming that directs anabolic changes for recovery and that augments subsequent exercise performance.
The take home message is you need to train hard enough to stimulate the release of stress hormones to most efficiently improve fitness. This means you need to keep challenging yourself with progressively harder workouts for continual improvement. This part isn't groundbreaking news to any good coach, but the mechanism behind it certainly is.
Don’t get carried away and start hammering yourself into the ground during every workout, however. You still need to balance hard training with recovery. There's also good reason to have workouts of varying intensity as part of your training program. The key is to make your hard workouts count. Don't merely sleepwalk through intervals. Get out of the comfort zone and challenge yourself to improve each workout.