What Is CNS Fatigue?
CNS fatigue is a phenomenon in which the central nervous system becomes exhausted. CNS fatigue can be caused by intense physical activity, lack of sleep or high stress levels. It can lead to decreased athletic performance, impaired cognitive function a general feeling of tiredness.
CNS fatigue is also sometimes referred to as central fatigue. It is a complex multidimensional syndrome that is associated with neurological diseases, specifically conditions affected by the nervous system (CNS) [1,2]. Individual experiencing this feels an overwhelming sense of tiredness, lack of energy, or a need for increased effort. This can be perceived as pervasive and disabling [3].
Not only does central fatigue encompass physical sensation, but it also involves mental exhaustion. Individuals experiencing this have reduced working efficiency and affect concentration. In addition to this, it may lead to an indictment of chronic diseases [4].
However, CNS is not the same as peripheral neuromuscular fatigue. On the contrary, that is characterised by the failure to sustain the force of muscle contraction [5].
CNS fatigue has been associated with conditions like multiple sclerosis, Parkinson’s disease, traumatic brain injuries and others [2, 6, 7]. The onset of CNS fatigue can vary from the early stages of a certain condition or injury and may persist over time, or it may appear later in the disease[2].
Although the symptoms of CNS fatigue are not known exactly, it has been associated with conditions such as multiple sclerosis, Parkinson's disease, and traumatic brain injuries, among others [2, 6, 7]. It can present from the early stages after an injury or onset of disease and may persist over time, regardless of whether other symptoms have resolved [2]. In addition, it is believed that CNS fatigue is related to dysfunction of circuits involving the thalamus, basal ganglia and frontal cortex [6].
It's also worth noting that CNS fatigue can be measured and assessed using tools such as transcranial magnetic stimulation and the Fatigue Severity Scale (FSS) [1, 2].
CNS Fatigue Symptoms
Symptoms of CNS fatigue can manifest in a variety of ways. To start with, one of the most common symptoms of CNS fatigue is extreme exhaustion after physical or mental exercise. It is not the typical tiredness that comes after such activities, as you might have wrongly assumed. Rather, it is a profound lack of energy, which does not improve with rest and which can significantly impact daily activities [8]
Another symptom can be having problems with memory or thinking skills. This might entail difficulties with concentrating, forgetfulness and a general sense of mental fog [8].
Further, dizziness is also commonly accompanied by muscle or joint pain [8]. Improper sleep or high sensitivity to light, sound, smells, food or medicines. For instance, despite getting adequate hours of sleep, individuals may wake up feeling just as tired as when they went to bed [8].
All of these may fluctuate from person to person and from day to day [8]
How Can I Recover From CNS Fatigue?
Recovering from CNS fatigue involves a combination of therapeutic strategies and lifestyle modifications.
What is typically recommended for CNS fatigue recovery are neurorehabilitation therapies, which are bright light therapy, neurofeedback, electrical stimulation and transcranial magnetic stimulation. All of these have shown positive results in reducing fatigue symptoms in patients with acquired brain damage [2]. Another approach which can be considered is transcranial direct current stimulation. This approach has shown improvements in fatigue symptoms of stroke survivors [8].
Further, mindfulness-based interventions are also recommended. They have shown positive results in relieving fatigue symptoms across different neurological conditions and also in improving the quality of life of the patients [9].
However, lifestyle modifications are also essential. These include organising daily activities, making dietary changes, and finding forms of rest that work best for the individual [10].
However, symptoms of CNS fatigue are very individual and it is always for the best to consult with your medical provider to obtain personalised advice.