What Is Muscle Fatigue?

Muscle fatigue is a lowered ability to produce force with your muscles. Your muscles feel weak and may even ache. This makes it harder to move and limits what you can do during exercise and daily life.

What Causes Muscle Fatigue?

Muscle fatigue is usually short-lasting (acute) and reversible. But it can also be long-lasting (chronic). How long muscle fatigue lasts depends on the cause.  

Short-Term Muscle Fatigue

Muscle fatigue is a common short-term side effect of exercise. It occurs when one or more body systems that aid muscle contraction—including your nervous, vascular (blood vessels), electrical, and energy systems—can’t meet the supply and demand.

You may be more prone to muscle fatigue if you’re just starting an exercise routine after being inactive or if you’re exercising a muscle that’s injured or newly recovered. Muscle fatigue can also build up over multiple workout sessions if you don’t give your body enough time to recover in between, which is called overtraining.

Short-term muscle fatigue is different from delayed-onset muscle soreness (DOMS). DOMS is the muscle tenderness and pain you start to feel after 12 to 24 hours have passed since completing a strenuous workout or a particular movement you don’t normally do. DOMS is a common side effect, happening as a repair response to the micro-damage your muscles experience during exercise. DOMS is usually at its worst within one to three days and gone within a week.

Chronic Muscle Fatigue

Long-lasting muscle fatigue can result from diseases, aging, and immobility.

Chronic muscle fatigue is a symptom of the following conditions:

• Arthritis
• Heart failure
• Multiple sclerosis (MS)
• Chronic obstructive pulmonary disease (COPD)
• COVID-19
• Chronic kidney failure
• Muscular dystrophies (a group of genetic diseases that cause progressive muscle weakening) 

Several factors go into how muscle fatigue develops in these health conditions, but muscle loss is usually involved. For instance, the chronic inflammation in conditions like arthritis and COPD lead to the wasting of muscles and, in turn, muscle fatigue.

Similarly, muscle loss that often happens with age, a condition known as sarcopenia, can also lead to muscle fatigue.

Muscle can waste away and become fatigued after you become immobile, too.

What Does Muscle Fatigue Feel Like?

Muscle fatigue may feel different depending on whether it’s short term or chronic.

Short-term muscle fatigue may feel like tiredness or a lack of energy during or after a workout.

With chronic muscle fatigue, the muscle feels floppy. The muscle can only generate low force, causing you to feel constantly frail.

How Can You Treat Muscle Fatigue?

The best way to fix short-term muscle fatigue, whether from overtraining or an intense workout, is to rest. Your muscles need time to recover from exercise.

How long you rest depends on the duration and intensity of the workout. In general, your muscles should be fully recovered within three to five days. Seek medical attention if your muscle fatigue lasts longer than two weeks.

Specific techniques may help your muscles recover faster and feel less tired. A 2018 review and meta-analysis found that massage was the most effective method. However, compression garments (special clothing that fits tightly around the skin) and water therapy were also found to lower the perception of muscle fatigue.

Treating chronic muscle fatigue is more complicated. But as chronic muscle fatigue is often linked to muscle loss, building muscle may help. In particular, pairing a resistance exercise program with a protein-rich diet could be beneficial.

However, the exact treatment depends on the underlying health condition. For example, physical inactivity can worsen muscle stiffness, weakness, pain, and fatigue in people with MS. Water therapy, yoga, and physical therapy are often recommended to help manage these symptoms.

It’s best to consult your healthcare provider if you have muscle fatigue from a chronic disease. They can make recommendations tailored to your specific needs and medical history.

Can You Prevent Muscle Fatigue?

There are steps you can take to prevent muscle fatigue during exercise and everyday life.

Hydrate

Your heart needs water to push blood throughout the body. If you’re dehydrated, your muscles won’t get the needed oxygen or nutrients. Dehydration also means your muscles can’t remove waste products efficiently. When waste products build up, muscles become weak and fatigued.

Generally, women should aim for nine cups and men should try to get 13 cups of fluid per day to stay hydrated. Your urine color should be pale yellow.

Maintain a Regular Exercise Routine

Consistent physical activity strengthens your muscles so they can support everyday movements. This enables you to complete essential functions like carrying groceries and climbing stairs without your muscles tiring.

Strive for 150 minutes of moderate-intensity aerobic exercise and two full-body strength workouts per week. This is the minimum amount of exercise needed for general health, per the U.S. Physical Activity Guidelines for Americans.

Let Your Body Recover From Exercise

The best way to prevent muscle fatigue from exercise is to give your body time to recover afterward. Muscles need 24 to 48 hours to fully heal. If the workout was particularly intense, muscles may need 72 hours. 

Try Supplements

Some natural products and nutritional supplements may help your muscles go longer before reaching fatigue during exercise. Two popular options include caffeine and creatine.

Thanks to its stimulating effect, caffeine may boost muscular endurance and strength when consumed before exercise. According to the International Society of Sports Nutrition, caffeine may be effective in doses of 3 to 6 milligrams per kilogram of body mass.

Creatine is an amino acid stored in muscles for energy. It’s also one of the most popular performance-enhancing supplements on the market. Supplementing with creatine (typically 3 grams daily) may help your muscles create more energy for high-intensity exercise, potentially preventing or delaying muscle fatigue.

A Quick Review

Muscle fatigue is a lowered ability to produce force with your muscles. Whether you experience short- or long-term muscle fatigue depends on the cause. Short-term fatigue is typically exercise-related; disease, immobility, or aging can lead to chronic muscle fatigue. If your muscle fatigue is short term, your muscles may feel temporarily tired. If you have chronic muscle fatigue, your muscle may feel floppy and you may feel frail. Usually, muscle fatigue is only short term. Especially with short-term muscle fatigue, there are steps you can take to manage muscle fatigue and prevent it from happening in the first place.