Why Do Muscles Shake After Exercise?

muscles shake after exercise

It’s not uncommon to see the tremor in your hands or legs after vigorous exercise. While you may think of it as a badge of honor for building strength, it may be a sign that you should go easy. 

Muscles shake after exercise mostly due to muscle fatigue and low blood sugar. When you overtrain or exercise on an empty stomach, you’ll feel these shakes.

Lack of sleep, dehydration, caffeine, and keeping your muscles in the same position for too long are other reasons that cause shaky muscles.

This post will elaborate on different reasons why you get muscle tremors after exercise. You’ll also learn how to make these shakes go away.

7 Reasons Why Your Muscles Shake After Exercise

1. Muscle fatigue

A very common reason for muscle shakes is muscle fatigue. It means your muscles are tired because you’ve worked them too hard. 

The underlying cause has something to do with how muscles contract, which requires the nervous system to send messages from the brain to the working muscle fibers. 

However, not all muscle fibers in the target muscles contract at the same time. They divide the labor: some work while others rest.

When you work out for a long time, these signals become less efficient. So, the fibers alternate more quickly between contraction and relaxation, leading to fatigue and tremor. That’s when you should reduce the intensity of your workout or stop it.

Muscle fatigue can occur when you’re working more than what you’re used to doing. The key is to avoid pushing yourself too hard.

Go easy when your body sends you these signals. If you keep doing the exercise despite the tremors, you’ll put too much pressure on other body parts to make up for the weakness in your muscles. Make sure you have good control to avoid injury.

The more you exercise, the stronger you get and lesser chances for muscle shaking. That’s because they get more efficient at contraction and relaxation. They become more coordinated, leading to fewer shakes due to fatigue.

2. Dehydrated muscles

As you exercise, it’s easy to quickly get dehydrated through sweating. Dehydration can affect your performance in different ways. 

Your blood flow is responsible for taking electrolytes and other nutrients to your muscles. When you’re dehydrated, there won’t be enough blood flowing to your muscles, leading to quakes. Plus, your connective tissues can’t send signals from the brain to muscles. 

So, never work out without sipping water before, during, and after exercise. Besides, drink enough water during the day to stay hydrated. Sports drinks are also good options to restore the electrolytes, such as potassium and sodium, lost via sweating.

Look for dehydration signs, such as fatigue, dark urine, weakness, thirst, and headache.

3. Low blood sugar

Our muscles use glucose as fuel to function properly during a workout. That means you need to have a proper meal before exercise to make sure your muscles are well-fueled. 

Your glucose levels can drop if you exercise for a long time or work out vigorously. If you skip a meal before exercise, you may experience hypoglycemia, meaning your blood sugar level drops so much that your body starts to shake. 

Low blood sugar may also cause weakness, confusion, irritability, and dizziness. So, include enough carbohydrates in your diet and grab a small bite before working out.

4. Too much caffeine

muscles shake after exercise

If you’re into sports drinks before training, make sure you check caffeine content. Caffeine can give you enough energy and boost calorie burning. But it can leave you jittery if you take too much of it. 

Drinking coffee and taking pre-workout supplements could also cause muscle shakes, especially in your arms and legs. Other side effects of excessive caffeine include diarrhea, dizziness, and a fast heartbeat.  

5. Inadequate sleep

Working out when your body isn’t rested or hasn’t fully recovered from previous strenuous exercise is another reason for the shakes.

A good night’s sleep goes a long way in preparing your body for an intense session. The lethargy due to inadequate sleep is so important that you’d better skip the gym and catch up on your zzz’s.

So, if you lack enough sleep or don’t have rest days, you’ll experience exhaustion and tremor. Try to get enough sleep or rest your muscles during rest days by incorporating yoga, walking, or flexibility exercises. 

6. Working different muscles

You know how your body can adapt to various workouts with different difficulty levels. That’s why you should switch up the exercises to avoid getting stuck.

You may change the order of your workout days, cycle your weekly reps, or change the order of exercises to blast through plateaus.

All of these new challenges can make your muscles shake.

This kind of shaking is ok because it’s the result of adding variety to your routine. By introducing new moves and engaging new muscles, you prevent your muscles from getting overworked and balance out different muscle groups.

When you perform an exercise for the first time, your muscles may shake because they don’t know how to perform the move. But the shakiness will go away once you become good at the new moves. 

7. Keeping muscles in place longer than recommended

When you hold one muscle in the same position for too long, for example, when doing planks, you’re likely to experience muscle shakes.

Your muscles need motor units to provide them with force. They consist of motor neurons and muscle fibers. Some motor units only activate for doing powerful movements.  

Holding a muscle in one place for a long time means some motor units in the muscles have to stay engaged longer. Lifting or holding a dumbbell is a classic case of tremor due to this reason.

If you decide to rest between sets, don’t sit down. Instead, walk around or target a different muscle group with less intensity. This way, you let your muscles recover by getting oxygen circulating and reducing lactic acid concentration.

Ways to Prevent Muscle Shakes After Workouts 

During or after a workout, shaky muscles are nothing to be worried about as long as they’re limited to your training sessions and go away after leaving the gym. But you can make them stop more quickly by doing the following:

1. Stretch and cool down

Preparing your muscles before a workout is essential in preventing shaky muscles. Warmup exercises make sure your muscles are ready and don’t contract out of proportion.

Once you’re done, cooling down is a vital part of your workout, especially after high-intensity exercise.

It’ll bring your heart rate back to normal, removing lactic acid from muscles. Do light exercises for five to ten minutes slowly and without exerting much pressure.

This way, the blood running in working muscles will go back to the heart and core, and the shakes stop. 

Stretching also relaxes your muscles and boosts the range of motion. It’s particularly helpful if involuntary contractions cause your muscle shakes.

2. Refuel your body

muscles shake after exercise

You need to replenish your body by eating a small post-workout meal or snack. Make sure it contains carbs and protein to keep your energy up.

Sports drinks can also give you back the electrolytes you lost due to sweating and muscle contractions.

Make sure to drink lots of water to avoid dehydration by sipping slowly, not guzzling water.

Do You Need to Seek Medical Attention?

Muscle shakiness is completely normal since physical activities involve shortening and lengthening your muscles.

It normally goes away after a workout, but if it lingers or comes with dizziness, or difficulty breathing after leaving the gym, it can be alarming. Get medical help if you vomit, faint, or experience seizures.

Closing Thoughts 

It's quite normal if your muscles shake after exercise as long as they don't linger. If shaky muscles persist, it can be explained by several reasons, including:

  • Muscle fatigue
  • Low blood sugar
  • Too much caffeine
  • Dehydration
  • Inadequate sleep
  • Working different muscles
  • Keeping muscles in place for too long


To avoid shaky muscles, stay hydrated before, during, and after a workout. Never exercise on an empty stomach and skip the gym if you haven’t had a good night's sleep. Don’t overwork your muscles and refuel your body with a nutritious meal after the workout.

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Angel

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