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Central Nervous System (CNS) Fatigue & Recovery – Are you getting on your nerves?

Have you ever gone through a long, challenging training program over many weeks and felt entirely drained at the end?

A few days of diligent workout leaves you at the edge of the constant struggle between the mind and body. Despite all intentions of keeping jumps and sprints at a steady pace, you find it hard enough to keep up.

I got you; it is mental exhaustion or central nervous system (CNS) fatigue. Stay connected and read to know the causes and treatment.

Does CNS Fatigue exist? 

The brain and spinal cord are the central nervous system (CNS).

CNS regulates most of the mental and physical processes. Since the human brain is thirty times faster than the best supercomputers, do you think it can be ever fatigued? The answer is YES.

Consistent or chronic sessions of intense workouts drain the muscles. As a result, motor neurons (nerve cells that carry the message to the brain) send messages to brain cells to shut down. Hence, the brain stops sending signals to the tired muscles, and fitness fanatics suddenly feel out of energy and stop doing sprints — this halt of signals is CNS fatigue.

So, there exists constant communication between brain and body actions. Muscles responsible for movements can’t move without receiving a permit from the brain. The brain’s area controlling the whole game is the ‘Motor Cortex’ located in the frontal lobe. It generates orders for all moves; no muscle can move in isolation if the order is not generated from there. 

During strength training, trainers want to avoid central nervous system (CNS) fatigue because it keeps them from recruiting the highest threshold motor units, which control the most responsive muscle fibres.

Mechanism of Central Nervous System Fatigue: 

In case muscles are at risk of damage and the motor cortex is not pausing. The controlling mechanism comes into action to control the system.

Given below are three famous mechanisms of CNS fatigue:

  1. Activation of inhibitory feedback loop:

Afferent nerve fibres (ascending nerve endings) signal the brain to cease activating motor fibres that activate muscle contractions. Afferent nerve fibres originate from mechanoreceptors (receptors that sense mechanical loading) and possess accessible nerve endings that feel the pain when muscles get damaged or hyper-extended. The activation of afferent nerve fibres is linked to the activation of pressure and pain-sensitive receptors. Inflammation further lowers the threshold of pain sensitisation.

  1. Increased production of free circulating tryptophan: 

According to research, when the energy depot goes down (reserved ATP), stressed muscles start rapid uptake of Branched Chain Amino Acids (BCAA). This voracious consumption of BCAA increases the concentration of free circulating tryptophan in the blood. Tryptophan, a serotonin precursor, increases the production of Serotonin inside the CNS. Serotonin is linked to fatigue, lethargy, depression and declining motivation. Hence, with the entrance of Serotonin, neurons stop, signals are paused, and muscles stop contracting. Gym goers feel that CNS is fatigued.

  1. Neurotransmitters involved in CNS Fatigue: 

Neurotransmitters are messengers that convey the message of one neuron to another and develop a transmission network for bringing communication and coordination into play inside the CNS. They decide when signals must go down and when not. For example, Serotonin is the inhibitory neurotransmitter that breaks the activation loop, as discussed above, whereas dopamine is an excitatory one that brings forth the activation, motivation, and movements.

In 1997, JM Davis wrote: “Good evidence suggests that increase or decrease in brain serotonin activity during prolonged exercise hasten and delay the fatigue.” Hence, it’s admitted that the play of messengers in the brain rule over the dreams of the muscle gainers



The Presence of Serotonin attracts fatigue more quickly, compromises athletic spirit, and lessens exercise endurance. During strenuous exercise, Serotonin gets elevated, and it’s due to the rise in free tryptophan concentration that crosses the blood-brain barrier and sparks neurotransmission.


It works contrary to Serotonin since it tapered the perception of effort needed for weightlifting. It strengthens the sense of competition, brings new waves of excitement, and closes the doors of associated fatigue. Sadly, its level goes down during rigorous exercises, and weightlifters feel weary.


Signs and Symptoms of Central Nervous Fatigue:


Disturbed Appetite: 

Any athlete who feels nauseated while looking at food indicates that CNS is slightly extended. The rest or break would be needed to return to the normal phase.

Troubled or Difficult Sleep: 

Sleep deprivation is not uncommon among fitness enthusiasts. When CNS of them get hit or ransacked, they find it extremely difficult to sleep.

Physical Appearance: 

CNS takes time to develop harmony and coordination with the build-up muscles. Hence, many newbies get unwell after strenuous training sessions and express clear signs of fever, diarrhoea, and inflammation.

Mood Fluctuations: 

When the emotional situation of anyone among trainees/trainers goes beyond conscious control, and they feel overwhelmed or a bit anxious most of the time, it’s a gesture that CNS is clouded. Recovery break of a few months to compensate for the loss of emotional health.

Central Nervous System Fatigue Recovery

Central Nervous System recovery time can take less than 20 minutes to several days and weeks. It depends on how adequately trainees maintain themselves during fatiguing training regimens (two to twelve/ fourteen weeks training sessions). Suppose optimum sleep, appropriate nutrition, and ideal rest days are held during training fellowships. In that case, the risks of getting CNS fatigue are reduced, and one can enjoy prolonged and strenuous sessions with merriment and jubilation.

However, if one performs high-intensity workouts over days with no breakouts, chronic CNS fatigue quickly becomes its way, and it takes days to get rid of it completely.

Some tips below are shared that one may consider as per choice.

Sleep Until Sufficient Strength is Regained:

Sleep is a natural way to heal from chronic illnesses. However, mental fatigue is not typically seen as an illness; it’s a symptom of lifting a bar without optimal preparedness. Going through extended workouts with continual skipping of naps exhausts the communication network inside. To keep the person healthy, auto-regulated pathways inside the human body take charge and don’t allow the next move until the loss is recovered. Hence, sleep is inevitable if doers aspire to emerge again.

Essential Nutrients in CNS recovery:

According to Meeusen and Decroix, the necessary intake of proteins and fats is needed to build muscles. Lipids help in recovering the repairable strength. If consuming carbs galvanise, take more of them. Do favour a diet fortified with zinc, manganese, and magnesium since minerals in combination with essential vitamins diminish fatigue and help the developing muscles to grow smoothly.

Removing all Triggers of External Stress:

Despite retaining adequate nutrition, and proper rest, many folks struggle with attaining recovery. If present in family or surroundings, disturbing elements keep the person stressed. Worries and grieves attract cortisol, further aggravate CNS fatigue, and let the body feels that it’s under attack. Such scenarios, if existing, instead of bringing recovery, begets lethargy and deprives the person of both physical and mental wellness.

Lifestyle changes to improve recovery:

Vary your routine from sport and exercise to include outside hobbies and interests. A brisk walk with little cardio involved improves circulation and assists in shedding mental fog. Realise what works for you and what does not: which food your body demands and which drinks you must avoid. Supplements are almost certainly required. Most people are deficient in magnesium and iodine; these shortages mess with the body’s cellular transactions and hormone functions and the body’s little general – the thyroid. This goes undetected mainly and requires specific blood tests. Avoid toxic people with bad habits and unhealthy environments.

Stretch and foam roll exercise

May 30 mins a day with a goal of foam rolling and stretching to help your body remove trapped energy and toxins and to assist in cell and nerve recovery.

Step-by-step guide on foam rolling and stretching: link

Complementary therapies for faster healing

Physical therapy, also known as physiotherapy, is a complementary treatment that reduces recovery time and helps the body heal faster. Pulsed Electro-Magnetic Field (PEMF) and Far Infrared are therapies that help in CNS fatigue recovery.

Pulsed Electro-Magnetic Field (PEMF) treatment employs technology to stimulate and train cells to help correct cellular malfunction and enhance overall health. Dr. Christopher Williams, who works at Interventional Orthopedics of Atlanta, recommends it to many of his patients in Atlanta, GA, because it makes them feel better.

Pulsed electromagnetic field therapy with a device that can reach deep enough into the body’s tissues is a promising way to deal with workability, fatigue, mental health and quality of life.

Another famous alternative treatment is far infrared ray therapy. The infrared treatment uses rays to alleviate pain and inflammation.

The primary quality of infrared light is its capacity to reach even the deepest layers of skin, which results in more effective pain alleviation. Infrared light is painless, natural, safe, and non-invasive. Infrared treatment increases cell mitochondrial function, prompting new muscle cell and tissue development. In other words, infrared light speeds up the healing process following muscle damage.

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Myths about CNS Fatigue:

Several myths regarding CNS fatigue are believed to be true without any documented evidence: It’s generally accepted that the heavier the training intensitythe higher the CNS fatigue would be. In 2007, Tejin Yoon published a study concluding the fact:

‘the low-force task induced more significant central fatigue than the high-force contraction for both men and women. 

Another common notion that people believe is that it takes 48-72 hours for the CNS to recover entirely from fatigue. In 2012, M Behrens showed via a study conducted on trained athletes:

It took just 20 minutes for the CNS to be recovered completely, and in competitive athletes, it was not obvious as such.’

So, CNS fatigue is just for a while; however, certain aspects of CNS functioning stay compromised until and unless muscles fully recover and inhibitory feedback stops.


Strength and tolerance can’t be developed overnight. It takes days to weeks for the brain to align in coordination with developing muscles, so patience is the key. CNS fatigue is too minimal for experienced and professional athletes, but beginners must work with patience if they want to gain their competence; otherwise, they can harm themselves by not taking proper measures.

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Recovery Systems