Central and peripheral fatigue: differences, symptoms, causes and solutions

Why do you suddenly lose all motivation during a session, even though your muscles still seem capable of producing force? Why do your legs "give out" after twenty minutes of intense running, only to partially regain their efficiency after a few minutes of rest?

These situations illustrate two very distinct forms of fatigue: central fatigue and peripheral fatigue. Understanding this difference allows for adapting training, recovery, and nutrition to better manage effort and maintain performance.

Important: This article is for informational purposes only. In case of unusual or persistent fatigue, medical advice is recommended.

1. Definition: central fatigue and peripheral fatigue

1.1 What is central fatigue?

According to a landmark scientific review published in Physiological Reviews, central fatigue refers to a reduction in the capacity of the central nervous system (brain and spinal cord) to maximally activate muscles.

1.2 What is peripheral fatigue?

Peripheral fatigue corresponds to a localized failure at the muscle level or at the neuromuscular junction (the contact area between nerve and muscle). It results from a disruption of biochemical and electrophysiological processes (electrical signals in the muscle) responsible for muscle contraction.

1.3 Key differences between central and peripheral fatigue

1.4 Vocabulary and synonyms

Central fatigue is sometimes described as neural fatigue or supraspinal fatigue, depending on the level of central nervous system involvement.

Peripheral fatigue is also called local muscle fatigue or contractile fatigue.

2. Peripheral fatigue: mechanisms, symptoms, and triggers

2.1 Physiological mechanisms

As Westerblad et al. (2002) point out, muscle acidification associated with lactate accumulation (a glucose metabolite produced by body tissues when oxygen supply is insufficient) is not the primary cause of local muscle fatigue. Instead, it results from multiple mechanisms involving ions, calcium, and metabolites (organic substances involved in the metabolic process).

Mechanism 1: Inorganic phosphate, a metabolite produced during exercise, accumulates in the muscle and disrupts the action of calcium, which is essential for muscle contraction (a waste product produced by the muscle during exercise). This results in a reduction in the activation of contractile proteins such as actin and myosin (proteins that allow the muscle to contract).

Mechanism 2: Excitation-contraction coupling, the process by which an electrical signal triggers calcium release, can progressively deteriorate during sustained efforts (Cheng, A. J., et al., 2015). This is the transmission of the nerve signal to muscle contraction.

Mechanism 3: After repeated stimulation, the neuromuscular junction can, in certain contexts, lose efficiency, limiting the transmission of nerve impulses (Arnold & Clark, 2023).

2.2 Symptoms of peripheral fatigue

This fatigue is recognized by typically local signs:

• burning sensation in the solicited muscle;
• progressive decrease in strength;
• difficulty completing repetitions despite strong will;
• localized pain, sometimes sensitivity to touch;
• insufficient recovery between sets despite prolonged rest.

These symptoms appear during sustained isometric contraction or high-intensity sets.

2.3 Causes and aggravating factors

High-volume sessions and dehydration promote the onset of peripheral fatigue, by altering the contractile and metabolic capacities of the muscle.

Insufficient carbohydrate intake and a lack of sleep are aggravating factors. They reduce energy availability and neuromuscular recovery.

3. Central fatigue: mechanisms, symptoms, and influences

3.1 Neurological mechanisms

Central fatigue results from a complex interaction between several neurotransmitters and physiological factors that influence motivation and the perception of effort, without a single mechanism being able to explain it alone.

Another mechanism: fatigued muscle fibers send more stress signals to the brain. The brain then adjusts the intensity of motor commands to protect your body.

3.2 Symptoms of central fatigue

This type of fatigue generally manifests as:

• a loss of motivation and a desire to end the session quickly;
• a decrease in concentration and an exaggerated perception of difficulty;
• a decrease in maximal voluntary force;
• a sensation of general heaviness or lethargy.

These symptoms can persist even if you take breaks that are normally sufficient for recovery.

3.3 Triggering factors

Central fatigue is promoted by:

• long efforts at moderate intensity;
• heat and dehydration;
• psychological stress;
• chronic sleep deprivation;
• overtraining (consecutive loads without recovery).

This is why athletes who engage in endurance sports (trail running, marathon, long-distance cycling) are the most vulnerable.

4. Diagnosis: how to distinguish central and peripheral fatigue?

4.1 Self-assessment

Ask yourself these questions:

• Does your strength decrease specifically in one muscle? (more peripheral)
• Do you feel a general lack of will and concentration? (more central)
• Do your performance improve after a short rest? (more peripheral)
• Do you feel "drained" even without strong muscle pain? (more central)

4.2 Specialist evaluation

In the laboratory, techniques such as transcranial magnetic stimulation or motor nerve electrical stimulation are used to measure voluntary activation.

These methods are used to analyze the mechanisms of fatigue in patients or athletes who experience a decrease in performance.

A decrease in voluntary force without alteration of the muscle response to stimulation suggests central fatigue. Conversely, a decrease in the muscle response itself points more towards peripheral fatigue (Taylor et al., 2016).

4.3 Signs indicating mixed fatigue

In reality, central and peripheral fatigue often coexist. A fatigued muscle sends signals to the nervous system, which then voluntarily reduces motor command. This explains why peripheral fatigue can progressively trigger central fatigue.

5. Solutions to reduce peripheral fatigue

5.1 Training optimization

Reduce the volume of repetitions over several consecutive sessions.

Lengthen rest periods between sets (3 to 5 minutes for strength exercises).

Integrate deload weeks every 4 to 6 weeks for complete recovery.

Gradually vary intensities and exercises to avoid excessive accumulation of muscle stress.

5.2 Improved muscle recovery

Sleep is a central factor: aim for 7 to 9 hours per night to promote muscle tissue repair.

Active recovery (walking, light cycling) can help reduce muscle stiffness and accelerate metabolite elimination.

Regular hydration is essential to maintain plasma volume and optimize metabolic exchanges.

5.3 Nutrition and supplements

Consume carbohydrates before and during prolonged sessions (30 to 60 g per hour of effort) to maintain energy availability.

Maintain sufficient protein intake (1.6 to 2.2 g/kg of body weight).

Drink hydration solutions containing electrolytes (sodium, potassium, magnesium) to preserve hydro-electrolyte balance, essential for neuromuscular function.

6. Solutions to reduce central fatigue

6.1 Mental stress management

Use relaxation techniques (deep breathing, meditation) to reduce mental load.

Do not overtrain and respect periods of complete recovery.

Vary sessions, change format or objective to maintain motivation and limit monotony.

6.2 Improved sleep

Sleep plays a key role in central nervous system recovery. It helps restore neurochemical balance and optimize the brain's ability to produce effective motor commands.

To improve your sleep quality:

• go to bed at a fixed time;
• create a conducive environment (darkness, cool temperature, calm);
• limit screen time in the evening;
• Reduce caffeine consumption at the end of the day.

6.3 Psychophysiological strategies

Certain simple strategies can delay the perception of exhaustion:

• breaking down the final goal into intermediate goals;
• using music as motivational support;
• practicing positive self-talk as suggested by some studies in sports psychology and neuroscience.

These techniques improve effort tolerance, especially in endurance.

6.4 Scientific data on central fatigue

Research suggests that certain neurotransmitters, notably dopamine and serotonin, influence the perception of effort and motivation during exercise. A scientific review emphasizes that the dopaminergic and serotoninergic systems play a key role in exercise-induced fatigue, particularly prolonged physical activity (Cordeiro et al., 2017).

7. Preventing central and peripheral fatigue

7.1 Effort planning

Structure your training cycles by alternating intensity phases and recovery phases. Respect the principle of progression by gradually increasing volume and intensity. Avoid brutal load peaks that simultaneously saturate neuromuscular systems.

7.2 Lifestyle

Maintain a balanced diet rich in essential nutrients (B vitamins, magnesium, iron) that support nerve and muscle function.

Limit alcohol consumption and substances that disrupt sleep.

Manage daily stress through recreational activities.

7.3 Monitor warning signs

Be attentive to an unexplained drop in performance, unusual irritability, or persistent sleep disturbances. Use a journal to track the evolution of your sensations.

Medical advice becomes a priority if fatigue:

• lasts more than 2 to 3 weeks despite rest and correct diet;
• is accompanied by unusual shortness of breath;
• causes dizziness, discomfort, or palpitations;
• is accompanied by unexplained weight loss;
• is associated with chest pain or abnormal weakness.

In this context, it may be a manifestation of a health problem (anemia, infection, thyroid disorder, nutritional deficiencies, chronic diseases, etc.).

FAQ

What is the difference between central and peripheral fatigue?

Central fatigue originates in the nervous system (brain, spinal cord), while peripheral fatigue originates in the muscle itself.

What are the symptoms of peripheral fatigue?

Local muscle burning, rapid decrease in strength, pain to the touch of the muscle, and slow recovery between sets.

What are the symptoms of central fatigue?

Loss of concentration, decreased motivation, exaggerated perception of effort, and general lethargy despite preserved muscular capacity.

How to detect central or peripheral fatigue?

Local fatigue with burning indicates a peripheral origin. Generalized fatigue with loss of will suggests a central origin. Laboratory tests use electrical stimulation to precisely differentiate between the two.

How to reduce peripheral muscle fatigue?

Increase rest times, optimize carbohydrate intake, maintain adequate hydration, and incorporate regular deload weeks.

How to reduce central fatigue?

Sleep more, manage stress, vary training stimuli, and avoid chronic overload.

Central fatigue and overtraining: what's the link?

Chronic overtraining disrupts the balance of the nervous system and neurotransmitters involved in motivation and perceived effort, amplifying central fatigue and sustainably reducing performance.

Can nutrition reduce peripheral fatigue?

Yes. Sufficient carbohydrate and protein intake supports muscle energy availability and limits exhaustion.

Conclusion

Fatigue in strength training and endurance results from an interaction between central mechanisms (nervous system) and peripheral mechanisms. Recognizing the specific symptoms of each type allows for adapted recovery, nutrition, and training planning.

Peripheral fatigue primarily responds to optimal management of intensity, volume, and energy intake. Central fatigue requires particular attention to sleep, stress, and motivation.

By monitoring these parameters and adjusting your approach, you maintain your performance while preserving your long-term health.

 

Bibliography

Gandevia S. C. (2001). Spinal and supraspinal factors in human muscle fatigue. Physiological reviews, 81(4), 1725–1789. https://doi.org/10.1152/physrev.2001.81.4.1725

Allen, D. G., Lamb, G. D., & Westerblad, H. (2008). Skeletal muscle fatigue: cellular mechanisms. Physiological reviews, 88(1), 287–332. https://doi.org/10.1152/physrev.00015.2007

Meeusen, R., & Roelands, B. (2010). Central fatigue and neurotransmitters, can thermoregulation be manipulated?. Scandinavian journal of medicine & science in sports, 20 Suppl 3, 19–28. https://doi.org/10.1111/j.1600-0838.2010.01205.x

Westerblad, H., Allen, D. G., & Lännergren, J. (2002). Muscle fatigue: lactic acid or inorganic phosphate the major cause?. News in physiological sciences : an international journal of physiology produced jointly by the International Union of Physiological Sciences and the American Physiological Society, 17, 17–21. https://doi.org/10.1152/physiologyonline.2002.17.1.17

Arnold, W. D., & Clark, B. C. (2023). Neuromuscular junction transmission failure in aging and sarcopenia: The nexus of the neurological and muscular systems. Ageing research reviews, 89, 101966. https://doi.org/10.1016/j.arr.2023.101966

Place, N., Ivarsson, N., Venckunas, T., Neyroud, D., Brazaitis, M., Cheng, A. J.,... & Westerblad, H. (2015). Ryanodine receptor fragmentation and sarcoplasmic reticulum Ca2+ leak after one session of high-intensity interval exercise. *Proceedings of the National Academy of Sciences*, 112(50), 15492-15497. https://doi.org/10.1073/pnas.1507176112

Taylor, J. L., Amann, M., Duchateau, J., Meeusen, R., & Rice, C. L. (2016). Neural Contributions to Muscle Fatigue: From the Brain to the Muscle and Back Again. Medicine and science in sports and exercise, 48(11), 2294–2306. https://doi.org/10.1249/MSS.0000000000000923

Cordeiro, L. M. S., Rabelo, P. C. R., Moraes, M. M., Teixeira-Coelho, F., Coimbra, C. C., Wanner, S. P., & Soares, D. D. (2017). Physical exercise-induced fatigue: the role of serotonergic and dopaminergic systems. *Brazilian Journal of Medical and Biological Research*, 50(12), e6432. https://doi.org/10.1590/1414-431X2017643