Shaking After Workout: Why Muscles Shake After Exercise - Healthline

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HealthlineSubscribeFitness5 Reasons You May Feel Shaky After Working Out

Medically reviewed by Daniel Bubnis, M.S., NASM-CPT, NASE Level II-CSS — Written by Kirsten Nunez on November 10, 2020

Causes
How to stop
Prevention
When to seek care
Bottom line

Two people, in an urban setting, stretch their quads after working out. — Westend61/Getty Images

It’s common to feel shaky after a vigorous workout. This can happen for several reasons, but it’s usually not a cause for concern.

Still, it’s important to know the difference between what’s normal and what’s not. In some cases, shaking after you’ve exercised might indicate a more serious problem. This is especially true if your tremors continue long after a workout.

If you’re prone to shaking after workouts, read on. We’ll explore the possible causes, plus ways you can prevent it from happening.

What can cause shaking after a workout?

Because there are several possible causes of shaking after exercise, it’s important to take note of any other symptoms. Pay attention to your habits before and during your workout, too. This may help you pinpoint the reason behind your post-exercise shakes.

Let’s take a closer look at five of the most common causes for shaking after you’ve worked out.

1. Muscle fatigue

Muscle fatigue is a common reason for tremors after exercise.

During physical activity, your central nervous system (CNS) fires motor units to contract your muscles. A motor unit consists of a motor neuron and muscle fibers.

The firing of motor units provides force for your muscles. But the longer you work out, the more these signals slow down and become less intense. These changes can make your muscles rapidly alternate between contractions and relaxations, resulting in tremors.

Your CNS can also lose its ability to forcefully move your muscles. This can lead to fatigue, which may cause shaking or twitching.

Other signs of muscle fatigue include:

weakness
soreness
low energy levels

If you have muscle fatigue, it usually means you’ve worked your muscles to their max. That’s why you’re more likely to develop fatigue if you’ve challenged yourself with a tougher workout.

But sometimes, it might mean you’ve pushed yourself too hard. If you’re in pain or unable to finish your workout, try reducing the intensity of your exercise.

2. Holding a muscle in one position

Shaking can happen when you keep a muscle in one position for a long time. You may have experienced this while doing planks or a barre workout.

This is due to the activity of motor units. Some motor units in your muscles are only used for powerful movements. When you hold a muscle in place for a long time, these motor units are activated to provide more force. This can result in shaking.

Typically, you’ll experience the tremors in the muscles being worked. For example, during or after planks, your arms and core may shake.

The same thing may happen when you lift and hold a heavy dumbbell.

3. Low blood sugar

Your muscles use glucose for fuel. When you work out, your glucose levels can become depleted, especially if you exercise at a vigorous pace or for a long period of time. This can lead to low blood sugar, also known as hypoglycemia.

Without enough fuel, your muscles may begin to shake. You might also experience:

fatigue
hunger
headache
dizziness
confusion
irritability
weakness
fast heartbeat

4. Dehydration

Staying hydrated is important for keeping your electrolyte levels balanced. Electrolytes control the function of your nerves and muscles.

However, doing an intense activity can make you sweat a lot and lose water. The same goes if you exercise outdoors on a hot day.

If you sweat too much and become dehydrated, you may experience muscle twitching and cramps. This can feel like shaking.

Other symptoms of dehydration can include:

fatigue
thirst
dark urine
reduced urination
headache
dizziness
weakness
confusion

5. High caffeine intake

Some people like to drink coffee, sports drinks, or pre-workout supplements before exercise. These beverages contain caffeine, which can help you power through your workout.

But if you consume too much, you may become jittery. The “high” you get from working out may make this even worse.

Shaking due to caffeine most often affects your hands and limbs, but it can involve other body parts. Excess caffeine intake may also cause:

a fast heartbeat
dizziness
insomnia
nausea
diarrhea
elevated blood pressure

Can you do anything to stop post-workout shaking?

Try these tips to reduce your shaking:

Rest. Muscles often shake because they’ve been overworked. If you feel shaky, avoid jumping into another workout and let your muscles rest instead.
Eat a healthy meal. Refuel your muscles by eating a post-workout meal. Focus on carbohydrates to replenish your glucose stores and protein to repair your muscles.
Drink water. Be sure to rehydrate as soon as possible to restore your electrolyte and fluid levels.
Stretch. Stretching after you’ve worked out may help loosen your muscles and reduce spasms, aches, and cramps.

How to avoid muscle shaking after a workout

It’s also possible to prevent post-exercise tremors before they happen. Here’s how:

Challenge yourself gradually. Increase the duration or intensity of your workout in small increments. This may help prevent shaking and injury.
Eat a pre-workout meal. Give your body enough fuel before you start exercising. Consume a pre-workout meal 2 to 3 hours before your workout.
Limit or avoid caffeine. If you’re sensitive to caffeine, reduce or avoid it before exercise.
Warm up and cool down. Before exercise, warm up to prepare your muscles for movement. Cool down when you’re done to promote recovery and reduce soreness and fatigue.
Prepare a post-workout meal in advance. If you have a meal prepared ahead of time, you can quickly and easily refuel your muscles once you’re done working out.
Hydrate before, during, and after exercise. Drinking fluids throughout the day can help reduce your risk of dehydration. Increase your fluid intake if you exercise outdoors in hot weather, or if you do a strenuous workout.

When to get medical attention

In most cases, post-workout shaking isn’t serious. But if you notice any of the following symptoms, get medical help:

prolonged shaking
difficulty breathing
dizziness
vomiting
fainting
seizures

The bottom line

Muscle fatigue, dehydration, and low blood sugar are common reasons for post-workout shaking. It can also happen when you hold a muscle in one position for a while, like during a plank. Drinking too much caffeine before working out may make you feel jittery or shaky, too.

To prevent tremors after exercise, avoid pushing yourself too hard. Stay hydrated throughout the day and eat a healthy post-workout meal. If you experience shaking long after exercise, or if you shake when you’re not exercising, it’s a good idea to follow up with your doctor or healthcare provider.

How we reviewed this article:

SourcesHealthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

Caffeine Q & A. (n.d.). https://uhs.umich.edu/caffeine
Dehydration. (2019). https://www.mayoclinic.org/diseases-conditions/dehydration/symptoms-causes/syc-20354086
Low blood glucose (hypoglycemia). (2016). https://www.niddk.nih.gov/health-information/diabetes/overview/preventing-problems/low-blood-glucose-hypoglycemia
Mathew P, et al. (2020). Hypoglycemia. https://www.ncbi.nlm.nih.gov/books/NBK534841/
McCall P. (2015). 10 things to know about muscle fibers. https://www.acefitness.org/education-and-resources/professional/expert-articles/5411/10-things-to-know-about-muscle-fibers/
Shaky hands – normal or not? (n.d.). https://www.piedmont.org/living-better/shaky-hands-%E2%80%94-normal-or-not
Son H, et al. (2019). Analyses of physiological wrist tremor with increased muscle activity during bench press exercise. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6477828/
Taylor JL, et al. (2017). Neural contributions to muscle fatigue: From the brain to the muscle and back again. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5033663/
Top 10 benefits of stretching. (2014). https://www.acefitness.org/education-and-resources/lifestyle/blog/5107/top-10-benefits-of-stretching/
Wan J, et al. (2017). Muscle fatigue: general understanding and treatment. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5668469/

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Medically reviewed by Daniel Bubnis, M.S., NASM-CPT, NASE Level II-CSS — Written by Kirsten Nunez on November 10, 2020

Shaking After Workout: Why Muscles Shake After Exercise - Healthline

What can cause shaking after a workout?

1. Muscle fatigue

2. Holding a muscle in one position

3. Low blood sugar

4. Dehydration

5. High caffeine intake

Can you do anything to stop post-workout shaking?

How to avoid muscle shaking after a workout

When to get medical attention

The bottom line

How we reviewed this article:

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