Shaky Legs After Working Out: Is It Really Dangerous?

If you’ve done strenuous exercise before, you’re likely familiar with the feeling of having jelly-like legs after a workout. Walking upstairs might feel unsteady, and squatting down to tie your shoes is out of the question! Sometimes the sensation of shaky legs after exercise worries people. They wonder if they’ve pushed themselves too far and done more harm than good.

The answer isn’t entirely clear-cut. Having shaky legs after a workout could be either a positive thing or a negative thing depending on your particular fitness goals, your ability to recover, and of course, the cause of the shaking muscles. Keep reading to find out what could be causing your shaky legs and whether it’s cause for concern.

The 3 Reasons Your Legs Could Be Shaky

Before beginning, it’s important to recognize that this isn’t a fully comprehensive list and that you should always consult with a trusted healthcare practitioner if you believe there could be a serious problem. This concern aside, there are a few likely reasons for shaky legs.

Fatigued Muscles

Probably the first explanation for shaky legs that comes to mind is simply fatigued muscles and many times, this is exactly the case. When you exert effort through continued physical activity, you’re contracting groups of muscle cells that attach to the spinal cord through a nerve cell. Together, these are called motor units.

A signal is emitted from the brain to the motor units with each physical movement during exercise through specific chemicals. These chemicals eventually get depleted during physical activity, so the brain can no longer effectively contract the motor units of muscles. This is exactly what leads to increasingly shaky movements, which may stay with the individual for several hours until they properly recover.

Fatigued muscles are generally considered to be a positive and normal part of working out. If you’re trying to make progress with your fitness levels, you’ll need to continually exert yourself past what you’ve achieved before. If you’re exercising at this intensity, it’s likely that you’ll experience shaky legs at some point.

The only times this should be avoided are if the intensity of your workouts is interfering with your ability to complete regular activities due to soreness and shakiness or if you’re unable to recover from your workouts. The more intense a workout is, the more time and rest you’ll need to recover, so take this into account when deciding how hard to push yourself with your physical activity.


The second most common cause of shaky muscles after a workout is dehydration. Unlike fatigued muscles, this isn’t a desirable outcome. The body needs water to operate properly for countless functions. Among them, water is an important component of energy metabolism pathways that are active during physical activity.

What this means in clearer terms is that you need adequate water in your system to create the energy needed to do your workout. Without it, you’ll become fatigued and may experience shakiness.

Another important component of hydration isn’t just water but also the essential minerals it contains. These minerals are what’s known as electrolytes, and they help with muscle contraction. Sodium, potassium, calcium, chloride, and magnesium are all essential minerals that your body requires in specific ratios for optimal nerve function.

Nerves play an important role in exercise since they signal to the muscles when to contract. With either an imbalance or a depletion of electrolytes, this signaling system can become temporarily weakened, and muscles may shake instead of smoothly contracting.

Dehydration is very clearly an undesirable outcome, and it’s sometimes dangerous. Mild dehydration is relatively common and can be quickly fixed with an electrolyte-containing sports drink without any ill effects, but more serious cases of dehydration can certainly be dangerous. Serious cases of dehydration can lead not only to shakiness but also weakness, confusion, and even organ failure if it continues for extended periods of time.

Always make sure to bring water to your workouts, and add in some electrolytes if you want to give yourself an additional hydration boost.

Low Blood Sugar

What’s likely the third most common reason for experiencing shakiness after a workout is low blood sugar. Though many people tend to think of blood sugar fluctuations as a concern exclusively for those with diabetes, low blood sugar can affect almost anyone.

The body relies on quick energy, mostly in the form of glucose, while exercising. This is derived from food and stored in small amounts in the blood and larger amounts in the liver. Issues arise, however, when the body cannot keep the level of glucose in the blood stable because the body is burning energy quickly or because it’s been a significant amount of time since you’ve eaten food.

This means during exercise, low blood sugar can occur, which leaves individuals feeling tired, shaky, weak, and maybe even anxious or light-headed.

Having severe fluctuations in blood sugar is dangerous, but the more regular slight fluctuations shouldn’t be anything to worry about. If you’re concerned about how significantly your blood sugar seems to dip, you could experiment with wearing a continuous glucose monitor or visit a physician to have your blood sugar response tested.

Otherwise, just make sure to have a filling snack before working out, and bring food with you to quickly bring your blood sugar back up if you’re prone to experience shakiness from low blood sugar during workouts.

General Tips to Avoid Unwanted Shakiness After Workouts

  • Eat a pre-workout snack 30 minutes to 1 hour before you exercise
  • Don’t over-exert yourself past the point you can recover properly from
  • Stay well hydrated before, during, and after your workout
  • Add electrolytes to your water at the gym, or bring an electrolyte drink
  • Get your blood sugar tested if you frequently experience low blood sugar symptoms


Overall, having shaky legs after the gym is par for the course and not something to usually worry about. If you find it to be a persistent problem and the tips listed above don’t seem to help, it’s best to talk with a healthcare practitioner to get to the bottom of your issue so you can get back to working out worry-free!