Overtraining and CNS Fatigue – Does it Really Exist?
Overtraining and CNS fatigue has been debated ever since I’ve been interested in health and fitness. The opinions on it are totally polarised.
In this article I’m going to look at overtraining and CNS fatigue to understand more about them both and provide information on what to look out for and how to avoid it.
One camp (usually the old-school powerlifters with more injuries than brain cells) vehemently argue that overtraining and CNS fatigue doesn’t exist. In their opinion, overtraining is something only pussies experience.
It’s funny – the people who sit in this camp often use performance enhancing drugs, so of course they’re less likely to suffer from it; they’re injecting chemicals with the sole aim of improving performance!
The other camp believe in it absolutely. These are people who seek to balance work with rest to improve health alongside performance.
Is overtraining and CNS fatigue simply a case of under-recovering?
Overtraining is relative to the individual – some people can cope with more than others.
Some people are born with a higher work capacity; there are schools of thought that suggest this is down to their mitochondrial (the energy factories in cells) density, or a higher red blood cell count, their hormone levels or their muscle make up (more fast twitch than slow twitch fibres for example). Whatever the reason, our work capacities vary across the board.
What is clear though is that work capacity is quite a fluid concept – it can be manipulated by training history, supplementation, rest, drug use etc. You can improve your work capacity through training and nutrition and you can reduce your work capacity through no training and poor nutrition.
Staying strictly legal, the best improver of work capacity (and therefore reducing the risk of overtraining) is to train correctly and frequently for a long period of time. Only at a point of around 9 months would I be comfortable upping the volume of a personal training clients programme, for example. Of course this rule isn’t set in stone, but it’s a solid guideline.
It largely depends on a persons training history – if they’re newer to exercise, their probably more susceptible overtraining.
So whats the mechanism – what is overtraining and Central nervous system fatigue (CNS fatigue)?
Overtraining: Training at a rate an intensity and volume that you can’t adequately recover from. Once your training load exceeds your body’s ability to replenish and recover from it, you enter a state of overtraining. It’s a burnout that’s often experienced via tiredness, decreased motivation to train, lower energy levels.
CNS Fatigue: A slightly more difficult phenomenon to describe, but essentially CNS fatigue occurs when progressive overload and training has led to a neurotransmitter release and use rate that your body can’t keep up with. It effects sports performance by compromising muscle firing patterns and movement quality, i.e. skills and movements are more difficult to execute. The effects are more flu-like.
What’s the difference?
Overtraining is actually a relatively simple thing to recover from. By resting and recovering, you should be able to repair and restore your body sufficiently enough to exercise again quickly. Most people will recover enough within 4-5 days of rest and better nutrition.
CNS fatigue is slightly different and may take more time to recover from. It’s usually caused by more complex movement exercises and is really common in strength sports where a lot of the training is done approaching maximum levels of strength, such as Weight Lifting and Power Lifting. In this case, recovery is best viewed as a resting and supplementation-based protocol and may take slightly longer, at around 7-10 days.
What are the symptoms of CNS Fatigue and Overtraining?
CNS Fatigue Symptoms
- Head aches
- Joint aches (specifically joints, not muscles)
- Poor skill execution – inconsistent execution of skills you can do
- Lower energy
- Poor sleep quality – disturbed sleep
- Lower motivation
- Flu-like feelings (without the blocked nose)
- Low concentration
- Prolonged muscle fatigue
- Reduced immunity
- Decreased workout performance
- Increased injury frequency
- Waking up feeling sleepy
- Craving high calorie foods
- Needing to snack often
- Slower illness/injury recovery
There will be commonalities between the two and you may be suffering from some of those symptoms despite not suffering from CNS fatigue or overtraining.
Diagnosing A Case…
One of the problems with (for want of a better word) ‘diagnosing’ overtraining and CNS fatigue is that they are situational, so a best guess is the best you can come up with for saying you’ve overtrained or your central nervous system is fatigued. You can be suffering from a number of these symptoms and trace the onset of them back to an extended period of particularly hard training.
There are basic indicators such as HRV (heart rate variability) monitors. Typically if you are still in a state of recovery, your heart rate will be higher than usual.
Some heart rate monitor apps with also tell you how long you should be resting post workout, so at a basic level that may be helpful – you’ll know if you’ve ignored the recovery suggestions for long enough you may be overtrained.
If you have the time or inclination, you can have blood work done to assess neurotransmitter levels and inflammatory blood markers such as CRP (C-Reactive Protein). These are the most accurate test, but are only really necessary in extreme cases. Almost any level of overtraining and CNS fatigue can be overcome with adequate recovery protocols.
It’s important to understand that if you are suffering from any of the symptoms listed above and you haven’t trained any harder than usual, you should explore those independently.
Recovering from Overtraining and CNS Fatigue
When you have established you have overtrained or have CNS fatigue, you need to take steps to address the problem from the ground up – begin by not making the problem worse.
Recovering from Overtraining
- Stop exercising. At most, go for a walk.
- Stretch – stay supple.
- Rest as much as you can – have early nights, sleep deeply – use herbal sleep aids if required.
- Take 1-2 weekly saunas – improves a number of processes, including circulation which is vital for recovery.
- Eat a high protein, clean (think natural – rice, potatoes) carbohydrate and vegetable rich diet.
- Take multivitamins.
- Drink lots of water – keep your urine clear.
What NOT to do
- Carry on training, just at a lower intensity (hello, injury)
- Take pre-workouts to get you through a session if you’re tired. If you’re too tired to train, listen to your body.
- Just eat more – this over-simplifies the problem and makes it seem as though it’s just a fuel issue. It’s not – this is about hormones, neurotransmitters, tissue health, energy AND nutrition.
Recovering from CNS Fatigue
From my experience, the symptoms of CNS fatigue are a little different to overtraining and need to be treated as such – I suffered from almost cold-like symptoms, without the streaming nose etc. I ached, had difficulty regulating body temperature etc.
- Stop exercising. Walk, but nothing more.
- Increase protein intake.
- Eat a little carbohydrate, but not too much – a palm-sized portion, twice per day.
- Take Omega 3’s. I use these – they are large dose so great for replenishment.
- Take ZMA before bed – it helps with deep, restful sleep. I’m currently on these.
- Stay hydrated.
- If possible, avoid (or at least reduce) caffeine intake.
What NOT to do
- Treat the aches and pains with paracetamol, thinking you’ve got a cold – if you can trace feeling like this to a heavy training programme, it’s unlikely to be a cold (especially if you’re not snotty etc).
- Eat a low protein diet.
- Drink alcohol and caffeine – you want to give your body the best chance of recovery and those substances can affect that.
How to avoid overtraining and CNS Fatigue
The first point to mention is that training is an art, not a science. Any training programme is a guideline – it’s not rigid, meaning you should always listen to your body. If you need to take a rest day, take a rest day. If you need to reduce the weights you lift or pick a slightly different exercise, do so.
When putting together your training programme, think about the following…
- Your goals – if your goals are big, give yourself longer to train for them and allow deload weeks and rest weeks.
- Your training history – if your training history is short, keep training cycles short (4-5 weeks) and include a rest or deload week then. If it’s longer, maybe go to 6 weeks.
- Exercise nature – if it’s strength based, you’ll do a lot of heavy lifting. In which case, you’ll need regular rest weeks. Ideally every 6 weeks. If it’s hypertrophy, you can push on longer without rest – maybe 8-10.
- Adaption – your body needs time to adjust and adapt to the demands of the training, so don’t try to improve every single session. Your aim is to be better by the end of the programme – think longer term.
Following a particularly intense programme, especially if it involves either heavy lifting or a lot of lifting, it’s a good idea to use some supplements. I don’t mean generic supplements, I mean specific supplements that will help you stay healthy.
- ZMA – helps restful sleep.
- Fish oil – helps look after joints, among other things.
- Amino Acids – help with neurotransmitter production (vital for muscle contraction, motivation, mood, concentration etc).
My Experience with CNS Fatigue
I’m writing this post now because I’ve just recovered from a pretty heavy case of CNS fatigue myself. It wasn’t overtraining and I’ll explain why below.
I have been following a weight lifting programme myself. It was 9 week programme, designed to improve weight lifting skill and strength.
It worked. I’m not only technically a better weight lifter, I’m also a stronger weight lifter. I managed PB’s in both of the major lifts, as well as many of the accessory lifts, so I’m happy with that.
The problem was, I did too much. I trained 5 days per week, I didn’t supplement properly, I didn’t rest enough.
First of all, on the 5 days per week thing. Yes, there are people who exercise more than 5 days per week. The difference here though, this was training, not exercising. The difference? Exercise can be non-specific, it’s without purpose. It’s great, but it’s self-limiting – you decide when to stop.
With this, I was training – I was following a plan. It was outcome-based. There was a prescribed number of sets and reps. I did them. On some days, I did more than I should. I now know that this was stupid.
The nature of a weight lifting programme also is that so much of the work is done at very heavy weights – around 75-95% of your 1 rep maximum. Working so close to your maximum capacity for so long is going to have an effect after a while, especially when you consider the exercises are not only heavy, they’re also very complex in terms of their movements, which places more demands on the CNS.
I’m experienced in weight training and I have a long training history behind me, but with weight lifting, I’m new.
I’m learning new skills and was asking my body to do things it hadn’t done before – or certainly not to that level or intensity. Learning new skills, working really hard and not taking adequate rest, it was a recipe for disaster!
When you spend such a long time working so close to your max, then not supplementing to help support it, you are going to stress the central nervous system.
The programme was as follows – 7 weeks of progressive strength training, a deload week where we reduced the weights right down (I didn’t), then a PB week where we maxed out and tried to set new personal best lifts.
I followed the programme (but didn’t deload – I just carried on lifting heavy), then a couple of days after stopping it hit me – the neck ache, the head ache, the joint aches, the hot/cold spells, the constant tiredness etc. I’d read about CNS fatigue, so I read up on it again – yup, I had it!
I wasn’t suffering from a muscle point of view and I had no high calorie food cravings, so I knew it wasn’t simply overtraining.
I checked my resting heart rate (usually mid 50’s) – it was nearly 80. I was tired, but not sleeping well at all. I knew what it was, so I knew what I had to do. I supplemented properly, I’ve been to the sauna twice, I’ve slept better and I haven’t trained.
It’s been 8 days and I’m about to do my first session back in the gym – even that will be basic.
A quick thought on the heart rate data…
The heart rate information is key actually – by keeping an eye on heart rate data you can see patterns, progressions and have a computer algorithm make suggestions as to how much rest and recovery you need. Of course you can always ignore it, but it’s a good idea to have a second pair of eyes on your performance – particularly one that is emotionless, unswayed by opinion and second-guessing. It’s very much a data-driven opinion that you get from a heart rate monitor with app support.
If you’re after a suggestion, I personally think Polar make the best monitors. I use the M400, but the M430 is the updated version. Personally, I love it – I’ve used it for 3 years and think the app support is top drawer…
What would I do differently?
How will I avoid falling into the CNS fatigue trap again? What did I learn and what would I do differently? Here are my thoughts on it…
- I’d follow the programme properly. If it called for lighter weights, I’d lift lighter weights. If it called for a deload week, I’d do a deload week.
- Now I know the true effects of the training, I’m supplementing regularly – Vitamin D, ZMA and Omega 3 oil before bed.
- I’d follow shorter cycles. At this stage of my weight lifting, a 9 week programme is perhaps too long. Perhaps 6-8 weeks may be more appropriate – I’ll have to experiment.
In hindsight, the warning signs were there. Towards the end of the programme, I had a session where I struggled a few times to hit a 70kg snatch (my PB at the time was 80kg). At that point, 70kg wasn’t a big deal to me, so I should have realised then that something wasn’t quite right. I also struggled with overhead squats, again something I’m very used to. My movement quality and muscle firing patterns were off – classic CNS fatigue symptoms.
Every now and then, we need a reminder to reinforce what we already know. Overtraining and CNS fatigue weren’t new to me, and in some ways I’m glad I’ve experienced it so I can avoid it in future and pass on what I’ve learned to you guys.
Remember – you aren’t superhuman. Punish your body for too long and you’ll pay for it. If you’re going to embark on an intense fitness programme, treat your body right. Exercise is supposed to help you, not punish you!
Some updated thinking on the subject…
This is an update to the article that discusses some of the more recent research and thinking around CNS fatigue. It also helps to explain my own symptoms when I suffered from a degree of CNS burnout.
Studies are now showing that short bursts of high intensity exercise aren’t as fatiguing neurally as workouts that last a longer period of time, during which people are expecting their bodies to perform optimally for upwards of an hour.
This is exactly what I was doing in the lead up to my CNS fatigue – I would complete my (sensibly) programmed workouts, then carry on and do more training. I’d do this day after day. My 45-60 minute workouts were becoming 70-90 minute strength training sessions, 5 times per week.
The research shows that training for longer sees muscles fatigue more generally, which in turn leads to a reduction in motor unit recruitment and function. This explains why we see technique and form drop off towards the end of a workout. We knew this anyway, but a little reminder every now and then is a good thing.
The CNS fatigue picture becomes a little more muddied when research is looked into further….
The 2016 study on the subject shows that the CNS can actually recover remarkably quickly to baseline levels post exercise (although its worth pointing out that only the biceps brachii was studied, which is a small muscle and would incur relatively little classic CNS fatigue symptoms), but the peripheral musculature takes a lot longer to recover.
Perhaps here lies the key to sensible training, avoiding CNS fatigue and ensuring adequate recovery.
Following on from the original article, here are a few extra tips to avoid CNS fatigue…
Keep your strength workouts short. Your body is unlikely to cope well with 60+ minutes of heavy strength training multiple times per week. Allow your muscles time to recover – give them a chance and feed them well. Sleep well.
Give yourself a break – your muscles take longer to recover than your CNS, so if you’ve been training hard recently, observe your body. How do exercises ‘feel’? Take heed of the signs and make sure you relax and recover when you need to.
Look to accelerate your recovery with supplemental help beyond the norm. I have experimented with CBD Balm with great success.
CNS fatigue, to whichever degree you understand and believe in it, can seriously affect your training and recovery. Don’t try to be a hero – it’ll cost you in the medium to longer term.
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