Signs of Overtraining: What Is CNS Fatigue?

Trainer using tablet in weights room at the gym

Signs of Overtraining: What Is CNS Fatigue?

Overtraining in athletes is a common issue that can lead to a decline in performance and even serious health consequences. While there are many signs of overtraining, recognising them early on is key to preventing any long-term damage. In this post, we’ll take a look at some of the most common symptoms of overtraining and offer tips for avoiding it. Stay safe and perform your best by keeping an eye out for these red flags!

What Is CNS Fatigue?

After any strenuous exercise, fatigue sets in. When we recognise our fatigue, we, at times, push ourselves harder and train more. A constant state of overtraining, however, can lead to a very serious condition called central nervous system (CNS) fatigue.

CNS fatigue is when overexertion wears out the nervous system. It’s characterised by the decreased performance of the brain area in charge of voluntary movement.

Among the leading causes of CNS fatigue is overtraining, although inadequate sleep and poor nutrition can also contribute to this condition. CNS fatigue is the inability to signal your muscles that it is time for exercise, which can significantly hinder your workout routine.

As a result of CNS fatigue, muscle activation declines, which means muscle growth is more difficult since you are not exercising at your maximum potential. Hence, exercising with a highly fatigued central nervous system is not the best way to build muscle mass.

Overtraining and CNS Fatigue

You can think of overtraining as a condition that precedes CNS fatigue. When your training load surpasses your body’s capacity to recover and replenish, you become overtrained. Most of the time, it can be treated with rest and adequate nutrition over a few days.

Meanwhile, CNS fatigue manifests itself in a complex physical manner due to overtraining. It can halt muscle development, causing you to hit a fitness plateau. With CNS fatigue, the ability to move and perform is impaired.

10 Signs of Overtraining

1.  Fatigue

Some tiredness can be expected from time to time. However, fatigue builds when the body is unable to successfully recover. You may experience extreme exhaustion when you’re overtrained, particularly after or during exercise.

2.  Workouts seem more challenging

With overtraining, your workouts may seem harder, and you may have to put more effort into them. As a result, you may feel you are exerting more effort than usual while unable to reach your personal best times or weights

3.  Performance decline

Performance can stagnate or decline if you overtrain. You might notice very little improvement although you are training consistently. You might have diminished strength, stamina and agility, making achieving your training goals more challenging.

4.  Muscle soreness

A sore muscle that persists for a day or two after a workout is normal. However, if you are still sore after 72 hours, you should schedule a rest period. An extended period of soreness is an indication that your muscles have not recovered, which can negatively affect your efforts to build muscle. One of the causes of poor muscle recovery and growth is overtraining.

5.  Injuries

Exercise leads to inflammation. Without a healing period, there is a greater chance you’ll experience injury, constant aches and dull pain.

6.  Irritability

Are you feeling overstressed, overwhelmed, moody, sad or depressed? Overtraining is a common cause of these symptoms. When you’re overtrained, your mental health typically suffers. You may begin to get irritated by the little things. You may grow frustrated and annoyed without even knowing why.

7.  Poor sleep

Overtraining can lead to higher levels of stress hormones. It can be challenging to relax at bedtime when your hormones are out of whack. Consequently, you lose out on the crucial rest, repair and restoration time your body requires during sleep.

8.  Decreased immunity

Sometimes, feeling unwell is your body’s way of communicating that your immune system is weak from overtraining. Excessive training adds extra stress on the body and makes it harder to fight infections. Your immunity is then lowered, making you more susceptible to illnesses. Reducing workout time is thus necessary, as pushing yourself through illness can exacerbate the situation.

9.  Eating too little

There’s a link between undereating and overtraining. While working out typically increases appetite, excessively doing rigorous, intense workouts may result in hormonal imbalances that can affect your hunger. With overtraining, you not only experience exhaustion but also reduced appetite.

10.  Motivational slump

It’s common to skip a workout from time to time. However, if you’re generally passionate about fitness, but then start losing interest, chances are you’re overworking yourself. If you feel more apprehensive than excited at the thought of working out, this is a telling sign of overtraining. Whenever exercise no longer feels fun, take it as a sign from your body that you need to slow down and decrease your workouts.

CNS Fatigue Symptoms

There are overlaps between signs of CNS fatigue and signs of overtraining. The difference is you’re more likely to experience flu-like symptoms with the former. Here are some of the CNS fatigue signs you have to watch out for:

  •       Poor sleep and appetite
  •       Fever and other flu-like symptoms
  •       Mental fog
  •       Lack of energy
  •       Mood changes
  •       Joint aches and pains
  •       Headaches
  •       An inability to perform easy tasks
  •       Loss of motivation

How to Avoid Overtraining?

Make your training less monotonous. Plan active rest days that include low-impact exercises like jogging, yoga and swimming. Switching up your exercises strengthens your entire body.

Avoid abrupt increases in workout times or intensities. Give your body time to recover by implementing gradual increases.

Train with appropriate rest periods. Give yourself regular breaks after tough workouts.

Reduce your stress levels. Meditate or practise yoga to relax.

Get 7-8 hours of sleep each night. The more intense your training becomes, the more time you need to sleep.

Stay fuelled. Make sure you eat plenty of carbohydrates, protein and healthy fats in addition to fresh fruits and vegetables.

Take heed of your body’s signals. A tired, sore and cranky body indicates something is wrong. Take a break for a little while, and you’ll return healthier, stronger and more fulfilled.


To prevent overtraining and CNS fatigue, keep recovery at the forefront of your fitness regimen. You should also get proper nutrition, sleep well and incorporate various exercises into your routine.

If you’re looking for a training programme unique to your fitness level, needs and goals, consider reaching out to VH&F’s Personal Trainers. Our team offers expert guidance and 24/7 support. Contact us now to learn more.