Central Nervous System Fatigue - Ultimate Limiting Factor of Progress

As sportspeople, we desire to master our craft and improve with each and every training session; preferably in a linear trajectory. Therefore, we train more often and harder, forcing the body to exceed its limits daily - and here's a trap. Paradoxically, the saying "give 100% or don't give at all" is wrong and mistaken in sports.

Workout is the same important as recovery, and it's crucial to regularly give half as much or skip a training session when you feel like "it's not your day" and clearly notice that, for some reason, your performance isn't as good as the week before. If this delicate balance becomes disrupted, long-lasting, nasty adverse effects may follow, thus not only preventing your progress but also pull back the work you've done on a gym or playing field.

Speaking about progress in physical performance, we always mean anabolism (- in short: growth and building), which can not efficiently occur when one of the following factors is neglected: physical stimuli, dieting, or recovery. Today, we'll focus on the most common pathology of the latter factor, known as central nervous system fatigue.

[Complementary article: How to recover the most efficiently?]
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1. CNS fatigue symptoms
2. The detailed mechanism behind PNS and CNS fatigue
3. When CNS fatigue occur?
4. How to recover from CNS fatigue?
5. How to prevent & spot CNS fatigue?

1. The three primary functions of the Central Nervous System (CNS) are to take in sensory information, process it, and finally send out motor signals.

CNS fatigue is a nearly "mythical" phenomenon that concerns every athlete around the globe. No matter how potent AAS you take and how much growth hormone you inject, it will always be the ultimate limiting factor of progress that you have to consider with the utmost seriousness. At the end of the line waits the tormentor - chronic CNS fatigue, which can be easily mistaken for, e.g., the first symptoms of the seasonal flu.

The most common symptoms of CNS fatigue are:

• reduced sleep quality or insomnia

• loss of appetite

• mental fog

• mood swings

• increased body temperature

• restlessness

• increased resting heartbeat rate

• lack of motivation

• feeling as if being sick - poor well-being

• prolonged muscle soreness

Other side effects:

• hormonal disturbances

• excessive stress levels

• adrenals fatigue

• disturbances in neurotransmission

2. The detailed mechanism behind physical fatigue

Whenever an athlete exercises intensively, muscle fibers get torn bit by bit, and lactic acid accumulates in the skeletal muscles, which directly leads to a decrease in strength and endurance during as the sets continue.

The onward mechanism of fatigue control is mediated by the PNS (peripheral nervous system), which is directly connected to muscle fibers through the neuromuscular junction. It plays two primary roles - mediating between muscles and CNS and controlling involuntary reflexes.

During and after a regular training session, first occurs peripheral fatigue (muscles and PNS), by the "extremum" leading to muscle collapse when you're unable to engage more of motor units due to this local fatigue.


Finally, on top is located the CNS, which regulates the maximal force that can be produced by the fatiguing muscles, so a safe and economic pattern of muscle activation can occur. The whole process is controlled by neurotransmitters such as dopamine, serotonin, and acetylcholine.

If inflammations and stress levels arise afterward PNS fatigue occurred, so the more often and the stronger signals the CNS receives, the stronger load on the CNS, which is like a king in chess. You can't play further when it's in check until you take special care of it.

When CNS becomes fatigued due to prolonged & continuous stimulation, we're no longer capable of recruiting high threshold muscle fibers, first reducing our strength and training effectiveness (even though you took a longer break). After finishing a workout, manifests itself as the classic mental & physical symptoms, I listed in the first subsection.

Side note. Intense CNS stimulation by the extremum can lead to seizures or fainting (Eddie Hall didn't faint due to disturbances in oxygenation only).

3. When CNS fatigue is most likely to occur?

We distinct CNS fatigue arose due to the short & long-lasting overstimulation:

1) Classic CNS fatigue (arose in the long-term / chronic) results from working out intensely without sufficient recovery between workouts (not after a single training session). You should carefully watch out for CNS fatigue symptoms if you're:

• performing heavy exercises which are engaging muscles of the whole body, e.g., deadlifts, squats

• practicing any sports discipline that engages the whole body, e.g., American football, basketball, climbing, etc., regardless of what respiratory threshold they rely upon. Interestingly, data revealed that extended aerobic respiration-based exercises can be more CNS fatiguing than aerobic-anaerobic or anaerobic ones

• exercising with high intensity (short breaks between sets, heavy weight, etc.)

• on a caloric deficit

• excessively using CNS stimulants (i.a., pre-workouts)

• lacking sleep

2) CNS fatigue arose in the short-term
Unlike long-term fatigue, it can occur straight after extremely intense physical exertion. Always take extra care of recovery if you're:

• taking part in a tournament

• beating your personal records

4. Recovering from CNS fatigue

Recovering is a long process; therefore, preventing the occurrence or a build-up to a severe stadium is the key; but we all how reality is. If can confidently say that you're at the threshold of CNS fatigue, it will be essential to:

• get enough sleep (in such a case, 7h can be insufficient. Best 9h+)

• increase caloric intake for at least 5 days (refeed - step off from caloric deficit, and eat a lot of proteins and carbohydrates. Your organism will be grateful)

• discontinue intensive training. Instead, recover actively by performing low-intensity exercises and stretching

• all GH secretagogues will come in handy whether these are binaural beats or actual compounds such as MK-677

• reduce stress levels. Consider Ashwagandha, Rhodiola Rosea, and taurine, which will work synergistically against CNS fatigue

• restrain from using stronger stimulants (preferably also including caffeine)

• increase your testosterone and DHT levels

• Invincible and Bulletproof Nervous System are your friends

Diet & supplementation tips to maximize recovery: https://www.patreon.com/posts/29753620

5. How to prevent & spot CNS fatigue?

Of course, it's always crucial to properly plan diet, recovery, and workout plan so it's not overloaded, and to carefully observe your body if none of the symptoms I listed above occur.

Still, the easiest method to control CNS fatigue is by measuring your heartbeat rate every day right after you wake up in the morning (before you stand up!). By this time, your heartbeat rate should be the slowest of all the waking time (typically 40-55). If you notice any deviations from your everyday norm (rate is higher than usual, by approx. 15), it's a great indicator to know that you should take your training session more easily that day or schedule it entirely and fully focus on recovering.

Optionally, and even easier, invest in a hand grip dynamometer. Any reduction in strength greater than ~8% will clearly indicate that you should take it easy on your next session.