Shaking After a Workout: 4 Common Causes and How to Prevent It

Shaky, quivering muscles after a workout can feel strange or even worrisome. But it’s not usually a cause for concern. Typically, it’s your body’s natural response to the stress of vigorous exercise.

Here’s what you need to know about why shaking happens after a workout and how to prevent or avoid it.

What causes shaking after a workout?

Several things can cause shaking muscles after a workout, including the following common culprits.

1. Fatigue 

Muscle fatigue is the most common reason for feeling shaky after a workout. Your muscles are made up of motor units, or groups of cells controlled by a nerve. Motor units work together to make your muscles contract. When one unit fatigues during exercise, another replaces it. This allows your muscles to keep working.

“After strenuous exercise, so many motor units are fatigued that a smooth contraction isn’t possible,” said exercise physiologist and running biomechanist Kaleigh Ray. Shaking occurs because these units fire and turn off too quickly to be replaced, Ray said.

2. New or intense exercise 

If you’re new to exercise, you might be shaky after a workout because your muscles haven’t adapted to the strain of exercise. But even experienced exercisers can feel shaky after a new or higher-intensity workout. When you push your muscles to the limit during strenuous exercise, fatigue sets in. Your muscles may get shaky and sore as a result. You should feel less shaky postexercise as your body adjusts to the new activity or intensity. 

3. Dehydration

About 75% of your muscle tissue is water. Maintaining this volume is crucial for proper muscle function. Even minor fluid imbalances can tire your muscles and hurt your exercise performance.

Water also helps electrolytes, such as potassium, sodium, and calcium, reach your muscles. Dehydration slows the delivery of these nutrients to your muscles, Ray explained. “[This] upsets the electrolyte balance required for muscle contraction,” Ray said.

You lose electrolytes when you sweat –– the more you sweat, the more you lose. If you’re shaky after a strenuous workout, especially in a hot climate, then electrolyte loss and dehydration may be to blame.

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4. Low blood sugar 

Glucose, or blood sugar from food, is your body’s main source of energy. It supplies your muscles with energy to power through a workout. As you exercise, your muscles use up glucose. If you do long or high-intensity workouts, you may burn through your body’s supply, leading to low blood sugar, or hypoglycemia. 

You might feel shaky after a workout if you haven’t eaten and your blood sugar is low. Muscle tremors are a hallmark symptom of low blood sugar. Other symptoms include a racing heartbeat, sweating, and feeling dizzy, confused, irritable, and nervous or anxious. People with diabetes may have a higher risk of exercise-induced hypoglycemia. 

Can you prevent shaking after working out?

“Shaky muscles after a workout are normal, but there are ways to avoid this discomfort and increase performance,” Ray said. She suggests the following tips to prevent or stop shaking after a workout.

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Stay hydrated

Staying hydrated throughout the day, not just during your workout, is important. But there isn’t one set rule for how much water to drink. It depends on factors such as your exercise intensity, body weight, and the climate where you live. Active people and those in humid environments may need more water. 

Let your thirst be your guide. Carry a water bottle to stay hydrated throughout the day, including before, during, and after exercise.

Add electrolytes

Ray recommends drinking plain water for shorter exercise sessions. But she suggests adding electrolytes to your water if you’re doing longer, more strenuous workouts. For example, if you do endurance exercises like running or cycling for more than an hour, electrolyte drinks can help you stay hydrated. You can buy electrolyte water, powders, or single-serve packets to add to your water.

Eat a balanced preworkout meal or snack

Working out on an empty stomach can cause low blood sugar and postworkout shakiness. Make sure to have a balanced preworkout meal or snack with protein and carbohydrates so your muscles have what they need to make it through. Some ideas include:

• Oatmeal topped with fresh fruit

• Whole-wheat toast with nut butter

• Chicken breast with brown rice and salad

Ray recommends extra fuel during your workout if it’s long or intense. “Take a snack rich in carbohydrates and protein to the gym, or keep it nearby when exercising,” Ray said. “You can eat as needed or try to eat around 100 calories after every 45 minutes of exercise.”

Adjust workout intensity

Give your muscles time to adapt to new exercises and intensities. Gradually increase the amount of weight you lift or the speed and length of your run, swim, or other exercise of choice. Slow and steady progress will also lower your risk of injury and postworkout soreness.

But there may be times when you need to scale back your exercise intensity. Doing so can prevent overtraining, injuries, and shaky muscles from strain or fatigue. “There are benefits to training to failure and maxing out lifts, but they may not be worth it for all exercisers,” Ray said. Adjusting your workouts to suit your needs will keep your training plan challenging but sustainable.

Cool down properly

A 5- to 10-minute cooldown is essential after every workout. It returns your heart rate to baseline, reduces muscle soreness, and promotes recovery. If your muscles are tired and shaky at the end of a workout, make time for a brief rest period. Slowly reduce the intensity of your exercise. Then, finish with some gentle static stretches to relax the muscles you’ve just worked.

When should you see a doctor about shaking after a workout?

Muscle shakiness after exercise is usually nothing to worry about. But talk with a healthcare professional if you have prolonged muscle shakiness that doesn’t subside with rest, hydration, and proper nutrition.

In rare cases, shakiness could signal something more serious. “It could be a sign of a condition brought on by the exercise, like rhabdomyolysis, heat illness, or injury to the muscles or nerves,” Ray said. Rhabdomyolysis, a condition where muscles break down and release harmful substances into the bloodstream, can result from overexertion.

You should also see a healthcare professional if you have shakiness accompanied by any of the following symptoms:

• Dark urine

• Dizziness, lightheadedness, or confusion

• Tingling, numbness, or paralysis

• Chest pain

Why trust our experts?

Written by:

Jody Braverman, CPT, RYT

Jody Braverman has worked in the health and fitness industry –– as a trainer, yoga teacher, nutrition and lifestyle coach, writer, and editor –– for more than two decades. She graduated with a B.A. from the University of Maryland and maintains several accredited certifications.

Edited by:

Lauren Savage, MA

Lauren Savage, MA, is a health editor at GoodRx, where she focuses on movement, exercise, and healthy aging. She aims to provide readers with the information they need to live healthier, more active lifestyles.

Reviewed by:

Sanjai Sinha, MD

Sanjai Sinha, MD, is a board-certified physician with over 20 years of experience. He specializes in internal medicine.

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