Muscle Twitching After Workout? 5 Potential Causes + Solutions

When most of us finish our workout, we grab a drink from our water bottle, do some stretching or foam rolling, hopefully, get in a good high-protein post-workout snack, and then hit the shower before moving on to the next part of the day.

As you’re stretching out on your mat, sipping your water, sports drink, or protein shake, there are a few predictable things you’re probably so accustomed to after exercise that they hardly even register in your mind: you’re likely sweaty, still breathing a bit hard, and your muscles probably feel spent.

But, what if your muscles are twitching after working out? Is muscle twitching after workouts concerning? Does muscle twitching after workouts mean muscle growth?

In this article, we will discuss the causes of muscle twitching after working out, getting a muscle spasm after workouts, and how to prevent a muscle spasm after workouts.

We will cover: 

  • What Are Muscle Twitches?
  • Does Muscle Twitching Mean Growth?
  • What Causes Muscle Twitching After Working Out?

Let’s get started!

A runner holding their hamstring.

What Are Muscle Twitches?

Muscle twitches, which are medically known as fasciculations, can feel concerning, but the good news is that muscle twitching after working out is fairly common and typically innocuous. 

Muscle twitches are usually experienced as small flutters or vibrations in your muscles. Some or all of the muscle fibers in a given muscle might be twitching, and one or multiple muscles might be twitching after working out.

Muscle twitches may be rhythmic or more sporadic, and depending on which muscles are twitching after a workout, you may even be able to see the twitches in addition to just feeling them.

Muscle twitches are categorized as a type of muscle spasm. Both are types of involuntary contractions, but muscle spasms are often more painful than twitches.

Additionally, although muscle spasms can occur as brief twinges that do make the muscle visibly twitch, many muscle spasms are more along the lines of sustained cramps

These types of muscle spasms are often more painful, and the involuntary contractions are prolonged such that there isn’t visible twitching since there isn’t a contraction/release pattern. The contraction is sustained.

One of the common times that people experience muscle twitches and muscle cramps is fatigue after working out, but there are other potential occasions when these sorts of involuntary muscle contractions occur, such as neurological disorders, anxiety, pinched nerves, anxiety, and dehydration.

A woman on the sand holding a cramping muscle.

Does Muscle Twitching Mean Growth?

Although muscle twitching after exercise can be alarming if it’s never happened to you before, it’s typically not a cause for concern, but it also isn’t typically a sign that your muscles are growing.

Muscle twitching after working out is usually painless and resolves within an hour or so.

You may experience muscle twitching after working out in any or all of the muscles used during your workout, but depending on the primary cause of the twitches, it is also possible to experience twitching in muscle groups that were not used or targeted during your training session.

For example, if you are following an upper/lower body split routine and finished a hard leg workout, it’s not uncommon to experience muscle twitching in your quads after working out.

However, you may also experience twitching in your upper body or even face or eye muscles, depending on the root cause of the twitching. 

A person stretches another because of a muscle twitching after working out.

When just muscular fatigue is at play, you will typically only experience twitching in the muscles that you used, but if other causes of muscle twitching, such as dehydration or low blood sugar, are contributing to these involuntary muscle contractions, either systemic or uninvolved muscle groups may twitch.

Muscle spasms after workouts can be more variable in terms of how long they last and how intense and/or painful they are. They may feel like a mild seizing feeling, along the lines of a tic, or more of a sharp, stabbing feeling. 

The muscle spasm progresses to a muscle cramp when the twitching or contracting remains sustained, and the muscle fibers are unable to relax.

Muscle spasms after working out commonly occur in the calf muscles, which are termed a “charley horse,” but they can also occur in the biceps, feet, hands, chest muscles, back, quads, hamstrings, and glutes.

A person massage the muscles spasm out of their foot.

What Causes Muscle Twitching After Working Out?

Here are some of the common causes of muscle twitching after workouts: 

#1: Your Muscles and Nervous System Are Fatigued

More often than not, you are experiencing muscle twitching after working out simply due to muscle fatigue. 

Muscle fibers, as well as the motor neurons that control them, can fatigue after prolonged or intense use.

The central nervous system controls the contraction of muscle fibers through motor units, which consist of a motor neuron and one to several thousand muscle fibers that are innervated by the motor neuron.

When your brain receives a signal to voluntarily contract a muscle, an impulse is sent down a motor neuron to the muscle fibers.

When the motor unit fires, all of the muscle fibers innervated by that motor neuron contract.

A runner bent over on a track, fatigued.

Essentially, there is an “all-or-nothing principle“ of muscle contraction that states that if a motor neuron successfully fires and sends a signal that exceeds the necessary threshold, termed the action potential, every single muscle fiber that the motor neuron innervates will contract. 

By the end of a long or vigorous workout, the neuromuscular system and the muscle fibers can be quite fatigued from all the repetitive and forceful contractions that they underwent throughout the course of the workout.

This can lead to some residual misfiring and rebound firing, where some of the motor units are still firing intermittently

This can cause muscle twitching after a workout. Not enough of the motor units in a given muscle are firing in a synchronized manner to have meaningful contractions that are producing force, which is why the twitches appear as little flutters or tics rather than full contractions that are moving your entire joint.

Muscle cramps after working out can also occur due to fatigue in these motor units. In the case of muscle cramps, neuromuscular exhaustion can lead to issues with the signals to relax the muscle fibers and release the contraction.

A person touching their toes.

#2: You Didn’t Warm Up

Warming up prior to engaging in more vigorous activity can help prevent muscle twitching and muscle cramps after working out, particularly if you include stretching. 

Dynamic stretches will increase blood flow, activate your muscle fibers and elongate them to repair your body from vigorous activity. 

By ensuring that the muscles are well perfused with oxygenated blood and nutrients before they are put under heavy workload and must contract forcefully and quickly can help prevent muscle spasms.

#3: You Are Dehydrated 

The other most common cause of muscle twitching after working out is dehydration or low electrolytes.

Electrolytes, such as sodium, potassium, magnesium, and calcium, are required to conduct normal neuromuscular signals and to contract and relax muscles. Therefore, if your electrolytes are imbalanced or become depleted during exercise, you may experience muscle twitching after workouts. 

Exercising in hot and humid conditions, particularly if you sweat a lot, can increase the risk of dehydration and electrolyte depletion. 

Other signs of dehydration after exercise include increased thirst, fatigue, dark urine, decreased urine output, dizziness, weakness, headaches, nausea, and confusion.

Two runners, hands on knees, fatigued.

#4: Your Blood Sugar Is Low

Hypoglycemia, or low blood sugar, can also cause muscle twitching or muscle spasms after workouts.

The muscles rely on glucose (blood sugar) for fuel to produce the energy they need to contract, particularly during high-intensity exercise.

If you performed a fasted workout or did not fuel properly with enough carbohydrates, or you did an extended endurance workout, your muscles may twitch after working out or may spasm due to insufficient energy availability in the form of blood sugar.

Other signs of low blood sugar after working out include headache, dizziness, weakness, fatigue, hunger, irritability, confusion, and an increased heart rate.

Try to eat 30-60 grams of carbohydrates an hour before your workout to prevent low blood sugar, and consider an electrolyte sports drink with glucose during long, high-intensity workouts.

A cup of black coffee.

#5: You Had Too Much Caffeine

Having too much caffeine in a pre-workout supplement, coffee, or another form before or during your workout can cause muscle twitching.

Caffeine is a stimulant and can cause jitteriness or trembling.

Other signs of caffeine overload include a rapid heartbeat, diarrhea, agitation, increased blood pressure, dizziness, nausea, and difficulty sleeping.

Generally speaking, muscle twitching is not a major cause for concern. Just ensure you are fueling and hydrating well before and after your workouts. 

If the twitches and spasms after exercise become habitual or concerning, speak with your doctor about other possible causes and treatments.

If you are often feeling lightheaded or dizzy after a workout and would like to search for the potential causes, you can check out our article for some answers: Lightheaded After A Workout? Here’s Why You Might Be Dizzy After Working Out.

A person sitting down at the gym, fatigued.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, and contributes to several fitness, health, and running websites and publications. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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