What Causes Muscle Fatigue? Causes, Symptoms, and Prevention

The Answer Lies at the Beginning

Muscle fatigue – or should I say, being utterly drained, is really just your muscles giving up the ghost when it comes to putting in any real effort. You know, like when you’re in the middle of a killer workout and your legs feel like they’re made of lead and your arms are wobbling all over the place. It’s that moment when you try to push through but your muscles just wont budge. That’s muscle fatigue for you

Every athlete has been there, and every gym-goer knows it all too well. It’s your body’s way of saying, “Hey, something’s not right here… maybe you went a bit too hard, maybe you forgot to eat, or maybe you pulled an all nighter and forgot to drink a drop of water. Maybe you’re just plain dehydrated”

Key Takeaways to Keep in Mind

• Important difference: fatigue vs soreness. Soreness takes hours to appear, but fatigue hits you smack in the middle of a workout – you feel like you’ve lost all strength right then and there.
• The usual suspects are intense exercise, dehydration, not getting enough sleep, not eating properly, and overtraining.
• Symptoms include weakness, burning, or that odd trembling feeling, plus you just can’t seem to perform at your best
• Prevent this from happening by keeping hydrated, eating balanced meals, sleeping like a baby, and making sure you’re not trying to do too much, too soon
• Recovery is key: get some rest, refuel with some seriously good food, get some light movement in there to help get those endorphins going, and if all else fails, dont be afraid to seek some medical advice – muscle fatigue that lasts for days is a serious thing

Opening Up a Conversation

Muscle fatigue is a normal physiological response – its just the body’s way of saying slow down, mate. Figuring out whats going on will help you avoid it, and when it does come up, help you get back on track a heck of a lot sooner.

This guide is here to break it down for you – what is muscle fatigue, whats causes it, what symptoms to look out for, and most importantly, how to prevent it and get back on track when it does happen. Whether you’re a pro athlete or just a casual gym-goer, this is the lowdown on muscle fatigue

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What is Muscle Fatigue Anyway?

Muscle fatigue is the time when your muscles have had enough and can’t keep going. Muscle fatigue happens slowly and usually occurs when you are pushing yourself too hard or for a long time. Your muscles just cant muster up the energy to put in as much effort as they were at the beginning.

There are two types: central fatigue is when your brain decides its had enough, so it sends less signals to your muscles. Its like your brain is saying “stuff it, I’m outta here” Peripheral fatigue is when the muscle itself just cant perform as well as it used to. Your muscle fibres just cant contract like they used to.

Both happen, usually – and the result is the same: you start to feel weak, you slow down, and sometimes you just have to stop dead in your tracks.

What causes muscle fatigue?

There are a load of factors that can contribute to muscle fatigue and more often than not its a combination of the lot that causes the problem.

Intense Exercise

High-intensity exercise – the most obvious culprit- is where most people start. When you go all out, your muscles just can’t keep up with the demand for energy & it quickly gets out of balance.

You see, your muscles rely on a thing called adenosine triphosphate (ATP) for that energy. But when you’re doing something intensely, that ATP runs out pretty sharpish and your body has to shift to other energy systems – and they produce waste products. Lactic acid builds up in your muscles and this contributes to that nasty burning sensation you get.

Its the balance between how fast your muscles are using up energy versus how fast they can produce it that determines how long you can actually push on. And when that balance gets out of whack, fatigue kicks in.

Dehydration

And then theres dehydration. Now I know water might sound simple but your muscles are about 75% water so when you sweat you’re losing more than just water you’re losing important electrolytes. Even a mild case of dehydration can screw with your muscle performance.

Dehydration reduces the amount of blood in your system which means less oxygen is getting to your muscles. It also messes with the balance of electrolytes like sodium and potassium which are kinda critical for getting your muscles to contract.

Studies show that if you lose just 2% of your body weight through sweat you can expect a 10-20% reduction in performance. Not exactly what you want when you’re on the pitch or track – make sure to drink plenty of water before, during & after exercise.

Lack of Sleep

And then – as if we needed another one – theres sleep deprivation. Now your body is actually repairing and rebuilding muscle tissue when you’re sleeping – and your nervous system is recovering from the days antics.

Lack of sleep screws with your muscle recovery and your performance too. You’ll find your coordination and reaction time are all a bit shot and endurance just isn’t what it used to be. And lets not forget the fact that everything just feels that bit harder when you’re running on fumes.

You should aim for 7-9 hours of quality sleep per night – and thats just for starters. Athletes may need even more – so make sure you put sleep high on your priority list.

Poor Nutrition

And finally theres poor nutrition. You’re not going to be surprised to hear that what you eat is pretty important. Poor nutrition and you’ll be feeling the effects in no time.

• Carbohydrates are your muscles primary fuel source. If you’re on a low-carb diet you’re probably going to find yourself running out of fuel pretty sharpish.
• Protein is what helps your muscles repair and rebuild – but you need to be eating enough of the stuff.
• Iron is what carries oxygen to your muscles and you need to be eating enough of the stuff to avoid fatigue and weakness amongst other things.
• Vitamin B12 is important for red blood cell production and nerve function. If you’re deficient you can expect fatigue and weakness.
• Magnesium and potassium are electrolytes that are pretty essential for getting your muscles to contract. Don’t get enough of these and you can expect cramps and fatigue.

Eat a balanced diet full of whole foods and you’ll be giving your muscles the best chance to function properly.

Overtraining

And finally theres overtraining – a state of being where you’re exercising more than your body can actually recover from. And trust me this is no fun – your performance will decline, youre likely to find yourself getting sick a lot & you’ll be increasing your injury risk too.

If you find yourself feeling persistently fatigued, struggling to perform and getting a little down on yourself – take a step back and have a good think. Are you giving yourself time to recover? Are you eating the right foods? Are you getting enough sleep?

SYMPTOMS OF MUSCLE FATIGUE

Muscle fatigue produces several recognizable symptoms.

Weakness: Your muscles feel weak. You cannot lift the same weight or run at the same pace.

Burning sensation: A burning feeling in the muscles during intense exercise. This is caused by metabolic byproducts.

Trembling or shaking: Your muscles may shake when you try to maintain force.

Reduced coordination: Movements become clumsy. Your form breaks down.

Shortness of breath: You cannot catch your breath during activity.

Heaviness: Your limbs feel heavy and difficult to move.

Decreased power: You cannot jump as high, sprint as fast, or lift as much.

These symptoms appear during activity. They resolve with rest and recovery.

MUSCLE FATIGUE VS. MUSCLE SORENESS

People often confuse muscle fatigue with muscle soreness. They are different conditions.

Fatigue tends to resolve fairly quickly with some rest and decent nutrition. Soreness will likely peak 24-48 hours after exercise & it can take a while longer to start feeling back to normal – both are pretty common responses to an intense training session.

Preparing Yourself To Avoid Muscle Fatigue – The Essentials

You can’t really prevent muscle fatigue if you don’t try in the first place. By following these tips, you stand a better chance of avoiding it altogether.

Stay hydrated – a pretty simple thing to do. Drinking plenty of water is a must throughout the day, and during exercise you should try to knock back 7-10 ounces every 10-20 minutes or so. When you’re doing a long or intense session though, consider grabbing an electrolyte drink.

Eat a fairly balanced diet. Get a mix of carbs to fuel your workouts, and some protein to help your muscles recover afterwards. Fruits, veggies, whole grains and lean meats are all solid choices – just don’t forget a bit of healthy fat here & there. And for goodness sake, don’t skip meals before a workout.

Get enough sleep – don’t make it any harder than it has to be. Try to get between 7-9 hours a night – consistency is key, so try to stick to a regular sleep schedule. And if you’re a bit of a screen addict, try to avoid them before bed.

Train in a way that won’t leave you exhausted. You can’t just leap from being a beginner to an advanced athlete overnight. Ease yourself into more intense workouts gradually. Give your body time to adjust.

Don’t forget to schedule some proper rest days. By rest days, I mean actual days off from training. Let those tired muscles recover – try to fit at least one rest day per week in. Some light activity like a walk or swim is okay, but nothing too strenuous.

Warm up properly before a workout. Get those muscles ready for the hard stuff with some light cardio and dynamic stretching.

Listen to your body. If you’re feeling absolutely knackered, stop what you’re doing and take a break. Pushing through when you’re genuinely exhausted is just a recipe for disaster, and will likely lead to injury.

Reeling Back In When Fatigue Hits – Basic Recovery Strategies

When muscle fatigue does creep in, these tips should help you recover a bit faster.

Take a break and let your muscles recover. Stop pushing yourself and give your muscles some breathing space. It’s really not worth risking injury by pushing through fatigue.

Rehydrate – don’t try to do it all on your own. Drink plenty of water, or grab an electrolyte drink to replace what you’ve sweated off.

Refuel – you know, get some energy back in your system. Grab something with some carbs and protein within an hour or so of finishing your workout to help with energy and muscle repair.

Do some light stretching – don’t overdo it. Gentle stretching’s fine for getting the blood flowing again and reducing stiffness, but don’t go too crazy.

Get a good night’s sleep – do it for yourself. Sleep’s when your body does most of the recovery work, so make sure you’re prioritising it.

Do a bit of light activity – don’t try to tackle too much. You can still do some movement without stressing your muscles – a walk, swim or some yoga’s fine.

Consider getting a massage or some foam rolling if you feel like it. These can help reduce muscle tension and circulation, which should make you feel a bit better.

WHEN DO YOU NEED TO GET MEDICAL HELP?

Muscle fatigue is usually nothing to worry about but sometimes it can signal something more serious going on. If you have any of these symptoms, get some medical advice:

• The fatigue lasts for days or weeks & doesn’t go away with rest
• It happens even when you’re not doing anything strenuous
• You have severe muscle pain, swelling or dark urine
• You have weakness that persists
• You experience fatigue along with a fever, weight loss or other symptoms
• You suspect a nutritional deficiency (like iron, B12 or vitamin D)
• You have a medical condition like diabetes, thyroid disorder or heart disease

Medical conditions that can cause muscle fatigue include anaemia, hypothyroidism, chronic fatigue syndrome & fibromyalgia to name a few. A doctor can help work out what’s going on & recommend the right treatment.

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CONCLUSION

The cause of muscle fatigue is mainly just your body signaling its need for a break. It is simply your body reacting to too much physical exertion, lack of hydration, inadequate sleep, bad diet, or overtraining.

Prevention of muscle fatigue is not difficult – stay hydrated, have a good diet, get proper sleep, and listen to your body. Recovery from muscle fatigue is also easy – all you need to do is rest, get back some energy, drink water, sleep, and possibly take some low-level activities.

However, if muscle fatigue continues and causes you severe problems, it is best to visit a doctor. Your body is trying to tell you something. Listen to it.