What To Know About Muscle Fatigue

Muscle fatigue is a reduced ability to produce force with your muscles. Some of the most common causes of muscle fatigue include exercise, aging, and immobility. Conditions like arthritis and heart failure can also cause long-term muscle fatigue.

Your muscles may feel weak and even ache. Muscle fatigue makes it harder to move and limits what you can do during exercise and daily life.

What Causes Muscle Fatigue?

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

Acute

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

You may be more prone to muscle fatigue if you are new to exercise after being inactive or exercising a muscle that's injured or newly recovered. Muscle fatigue can build up over multiple workout sessions if you do not give your body enough time to recover in between. This is called overtraining.

Short-term muscle fatigue is different from delayed-onset muscle soreness (DOMS). DOMS is the muscle tenderness and pain you feel 12-24 hours after a strenuous workout or particular movement you do not normally do. It's a common side effect of a repair response to the micro-damage of your muscles that happens during exercise. DOMS is usually at its worst within one to three days and gone within one week.

Chronic

Long-lasting muscle fatigue can result from disease, aging, and immobility. Chronic muscle fatigue is a symptom of the following conditions:

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

Several factors affect how muscle fatigue develops in these conditions. Muscle loss is usually involved. Chronic inflammation in conditions like arthritis and COPD leads to the wasting of muscles and, in turn, muscle fatigue.

Muscle loss that happens with age, or sarcopenia, can also lead to muscle fatigue. Muscle can also waste away and become fatigued after you become immobile.

Symptoms

Short-term muscle fatigue may feel like tiredness or a lack of energy during or after a workout. Your muscles can feel floppy with chronic muscle fatigue. The muscle can only generate low force, which causes you to feel frail.

Treatments

Rest is one of the best ways to fix short-term muscle fatigue, whether from overtraining or an intense workout. Your muscles need time to recover from exercise. How long you rest depends on the duration and intensity of the workout. Muscles typically fully recover within three to five days.

Specific techniques may help your muscles recover faster and feel less tired:

• Compression garments (special clothing that fits tightly around the skin)
• Massage
• Water therapy

Treating chronic muscle fatigue is more complicated. It's often linked to muscle loss, so building muscle may help. Pairing a resistance exercise program with a protein-rich diet could be helpful.

The exact treatment depends on the underlying cause. Physical inactivity can worsen muscle stiffness, weakness, pain, and fatigue in people with MS. Water therapy, yoga, and physical therapy 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 based on your specific needs and health history.

How Can Muscle Fatigue Be Prevented?

Both acute and chronic muscle fatigue might keep you from meeting your fitness goals. There are steps you can take to prevent muscle fatigue during exercise and daily life.

Hydrate

Your heart needs water to push blood throughout your body. Your muscles will not get the needed oxygen or nutrients if you are dehydrated.

Experts generally advise women to drink 9 cups of fluids per day, while men need 13 cups of fluids 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. Exercising 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 muscle-strengthening workouts per week. This is the minimum amount of exercise needed for general health.

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 24-48 hours to fully heal. Muscles may need 72 hours if the workout is particularly intense.

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.

Caffeine is a stimulant that can boost muscular endurance and strength when you consume it before exercise. It may be effective in doses of 3-6 milligrams per kilogram of body mass.

Creatine is an amino acid stored in your 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.

When To Seek Care

Seek medical attention if your muscle fatigue lasts longer than two weeks. Persistent muscle pain can be a sign of a severe complication called rhabdomyolysis (rhabdo). It's the breakdown of muscle tissue, in which harmful chemicals get released into the bloodstream.

Get immediate medical attention if you have symptoms like:

• Dark, red, or brown urine
• Decreased urination
• Fatigue
• Joint pain
• Myalgia (achy or stiff muscles)
• Seizures
• Tender muscles
• Unintentional weight gain
• Weakness

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. 

Muscle fatigue is usually only short-term. There are steps you can take to manage muscle fatigue and prevent it from happening in the first place. Make sure you stay hydrated, maintain a regular exercise regimen, and let your body recover after physical activity.