Exercise-related muscle shakiness can happen to anyone, no matter your fitness level, age or gender. It can be caused by a variety of factors and poor choices. Because it can sometimes signal a more serious underlying condition, it is important to understand why shaking muscles can occur during exercise and how it can be treated.
Muscles shake during intense exercise due to fatigue as you push your body during a workout. Dehydration and low blood sugar may also cause or increase the risk of muscle shaking.
Symptoms of Muscle Shaking
Shaking muscles during exercise can vary from a mild tremor to extreme shaking. Any muscle in the body can be affected, including the legs, abdominals and arms. Shaking can be uncontrollable and can occur when you are straining the muscles or even while they are at rest.
Additional symptoms can include tiredness, muscle cramps and a decrease in muscular performance. Your muscles may even give out if shaking is severe, causing you to collapse.
What Causes Muscle Shakes?
Exercise-related shakiness occurs as the muscles naturally shorten and lengthen with physical activity. These contractions normally happen smoothly, but during exercise, some muscles may become fatigued, causing trembling and shakiness.
Although this shaking action will become less noticeable as your muscles become stronger and can sustain exercise longer, it can develop if your muscles are not used to the type of exercise you are performing, if you increase the intensity of exercise or if work out for a long time without taking proper breaks and maintaining proper hydration.
Your body also releases metabolic byproducts, like lactic acid, when you exercise that can cause shakiness and fatigue. If lactic acid accumulates and your body is unable to clear it fast enough, it may result in lactic acidosis, which may cause muscle cramps and a burning sensation. This will resolve quickly with rest.
Improper nutrition, hypoglycemia or low blood sugar, and lack of hydration can also trigger shakiness.
Treating Exercise-Related Muscle Shaking
Decrease the intensity of your workout and take breaks as needed. Research published in 2016 in the journal Experimental Physiology suggests resting for two to three minutes between exercise sets.
Stay hydrated before, during and after your workout. Stop and drink a glass of water or have a carbohydrate-rich snack if you suspect shakiness due to dehydration or poor nutrition or low blood sugar.
How to Prevent Muscle Shaking
Breaking Muscle recommends moving while you rest between exercises or sets. For example, walk around or switch to a different muscle group rather than sitting down. This will help your muscles recover more easily from intense exercise. This can help get oxygen circulating in your system and lower lactic acid concentration and decrease fatigue.
Cool down by gradually decreasing your activity and allowing your heart rate to slowly return to normal over a five-minute period. This will help remove metabolic byproducts from your blood and muscles, helping to reduce shakiness and fatigue.
When to Seek Medical Attention
See a doctor if the shaking is severe or lingers long after exercise. It could be a symptom of an underlying medical condition such as Parkinson's disease or an essential tremor. According to MedLinePlus, these tremors may be caused by serious underlying conditions such as brain tumor, multiple sclerosis, overactive thyroid or stroke.
- Los Angeles Times: Muscles Aquiver
- Merck Manual: Professional Version: Approach to Sports Injuries
- Scientific American: Why Do Muscles Tremble After Strenuous Exercise?
- MedLinePlus: Tremor
- American Parkinson Disease Association: Tremor
- Breaking Muscle: Use Active Rest to Build More Muscle
- WebMD: Lactic Acidosis and Exercise: What You Need to Know
- The Physiological Society: Experimental Physiology: Short Inter‐Set Rest Blunts Resistance Exercise‐Induced Increases in Myofibrillar Protein Synthesis and Intracellular Signalling in Young Males