CNS, Insulin Sensitivity Cortisol

Over the last several years, Ellington and I have discussed the “going to failure” issue. The bottom line is, training to failure is a mistake and limits growth. We mistakenly contributed to this mythos, and we want to set the record straight. Our goal is to help HITters (and all trainees) understand the reality of the growth-stimulating-gains-realized mystery.

Here’s what I wrote in another post:

Overtaxing the CNS increases cortisol and decreases insulin sensitivity (both are very negative and opposite of what you want). Training one set to failure serves no beneficial purpose. It overtaxes the nervous system and isn’t required for muscle growth. (Muscle tissue recovers relatively quickly, whereas the nervous system takes much longer.)

Our goal is to stimulate the most muscle growth with the least CNS stress. Training three times per week – layering specialized techniques for each body part – is ideal for beginner and advanced trainees. Pump a muscle with performance-enhancing, buffering, and growth-stimulating nutrients, then train on the pump.

I think there may be some misunderstanding.

Muscles being trained (aka ‘stress’) creates a cascade of events (that includes both hormones via the pituitary gland and enzymes) and the nervous system (the CNS) – two interrelated yet separate paths.

But, pushing your training into the realm of overtraining actually becomes catabolic going beyond normal tissue damage to include the stimulation of cortisol. Think hard core endurance athletes, Crossfit.

Yes, cortisol does have a negative impact on insulin sensitivity, but a trainee has to be in a chronic state of overtraining or have some other issue (or ingesting cortisone) for this to take and impact recovery, growth, performance. Think about chronic cardio trainees like triathletes or marathoners who are out hammering it day in, day out and there’s no real recovery resulting in things like endurance athletes being more susceptable to colds due to issues with their immune systems or AFIB as the heart muscle never rests and recovers, etc.

With an HIT trainee following a 2x/week or 3x every three weeks, just my humble opinion but I doubt an HIT’er with two or there days of recovery is going to encounter true “CNS” issues. Remember the P90X trainees? Those folks were training 6x/week, sometimes over an hour yet many put on some lean body mass and looked terrific. (Disclaimer: I am sure this isn’t 100%.) Or Vic Holtreman? Kettlebell, Warrior Diet and 90 days later lost bodyfat, added LBM yet he trained seven days/week including mountain biking.

Or simply look at the before/after pictures in Darden’s books.

So at the end of the day, with all due respect I don’t think we’re looking at an overtrained CNS, etc., with an HIT trainee. At the end of the day, it comes down to training hard but not too hard, recovering, eating clean, getting enough water and enjoy your life.



Good post.

Anyone stating facts about Central Nervous System fatigue should be checked for credentials. We know little chemistry about the CNS. Are the depressed readily treated efficaciously? Most mass killings are done by the mentally challenged. When fatigue of the CNS is discussed, few facts and measurements are forthcoming. So pardon me, if I am highly skeptical of CNS fatigue within resistance training.

On the other hand, non-failure training (alactic training) is refreshing. Alactic training targets fast twitch muscle, the very fibers mature trainees lose due to aging. SuperSlow recommends unfettered breathing, which hinders fast twitch muscle recruitment . The stability of the spine from intra-abdominal pressure is known and measureable. Alactic sets are short, thus learning to control breathing during these sets enables one to maximize stability. The resultant retarding of inhibition of the nervous system will maximize performance.

Alactic sets are theoretical and people lose fast twitch due to saropenia. Science. Strength training slows the process but you can’t stop it and it makes no difference what form you use…breathing has little to do with muscle recruitment. A muscle contracts based on the stimulus.

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