Why do my muscles fatigue so quickly during workout

Most people feel fatigued and tired while performing exercise. It is normal to be sore, sweaty, and tired after you exercise. Feeling ill or weak after exercising is not normal. You may be feeling exhausted after a workout and even the next day, but you should recover quickly. If you are not recovering or are more tired than normal, this could be a sign that your workout was too intense and demanding on your body. This may be a sign of exercise fatigue syndrome. 

Exercise Fatigue Symptoms

Exercise fatigue syndrome is characterized by constant and excessive: 

• tiredness
• fatigue and loss of energy
• pain and stiffness in the muscles & joints used during exercise
• nausea 
• vomiting
• headaches
• dizziness
• unusual or unexpected breathlessness 
• high heart rate

Syndromes can vary from moderate to debilitating. 

Fatigue is often restricted to larger muscles in arms, legs, and core body, but can affect smaller muscles in feet and hands. This can be called exercise intolerance which is the inability to maintain a certain level of performance during exercise. It is not an illness or disease, but it can cause other health issues with cardiac, pulmonary, and other underlying medical issues. It is recommended that you consult your doctor if fatigue continues longer than normal recovery from exercise.

What Causes Exercise Fatigue?

The following issues may contribute to exercise fatigue. Improving these areas can minimize fatigue after exercise.

1. Dehydration - When you sweat, you lose water and electrolytes. Less than optimum levels of fluid and electrolytes lead to exhaustion during and after workouts and affects your physical and cognitive performance. Recommended daily amounts of water are thirteen glasses of water for men and nine glasses of water for women. When working out, you need about 2.5 extra glasses for each hour of exercise. Taking plain water is recommended, but if you work out for more than one hour, an electrolyte-rich sports drink is also necessary to replace electrolytes lost in the sweat. Drinking water also helps flush out metabolic waste.
2. Diet - Your body needs fuel to complete daily tasks and exercise which comes from the food you eat. The food is broken down into glucose for use throughout the body. Any extra glucose is converted to glycogen which is stored in the liver and muscles. When you start working out, your body uses glucose first. When this is depleted, glycogen is converted back to glucose for energy supply and once your glycogen stores are used up, you will get exhaustion after exercise. 
   1. The amount of glycogen in muscles can be used quickly with high intensity exercise and depleted slower with low intensity exercise. Eating a snack that contains protein and carbohydrate within 30 minutes of exercise can decrease fatigue. For longer workouts, eat a snack that takes longer to digest such as a banana. During the thirty minutes after your workout, snack on something containing carbs and protein such as yogurt and fruit to help you recover and rebuild your glycogen stores. Some individuals take pre-workout and post-workout supplements to help with their recovery. 
3. Overheating - Your body temperature rises with exercise and may reach 104 degrees. This happens because blood is directed to the skin to help cool down the body. But when you are still working out, the circulatory system can be overwhelmed. This causes the temperature to rise even higher, which leads to fatigue and lowered performance. Make sure you are hydrated before and during exercise and dress appropriately for exercise to help cool your body. 
4. Lack of Muscular Endurance - Starting with a strenuous exercise routine such as weightlifting without warming up can cause fatigue. Your gym trainer will assist you to work on building your muscle endurance by designing tailored training program which will improve muscle strength and endurance. 
5. Training Techniques - Poor training techniques, such as incorrect breathing, can cause many problems and lead to exhaustion after exercise. Another poor technique is excessive swaying of arms which wastes energy and leads to poor performance and tiredness. Be aware of your breathing during exercise and make adjustments so that it is smooth and stable. If this is difficult for you, talk to your doctor or trainer.  
6. Overexertion - Overexertion is a common problem for athletes in endurance exercises, such as marathons, and leads to the breakdown of muscle fibers. This can stress the kidneys. Signs of overexertion include exhaustion, nausea, vomiting, decreased urine output and fever. Recovery from these endurance events can take days or even weeks. 
7. Stress & Quality of Sleep - Physical, emotional, and psychological stress can make you feel tired or exhausted. And when you do not sleep well, your body and mind do not properly recharge. You may feel like you do not have the energy to face another day. There is a correlation between sleeping 8+ hours each night and lower levels of body fat, higher muscle tone and improved health. 
8. Allergies & Asthma - If you have asthma or allergies, your body has a hard time getting the oxygen it needs to exercise. Working out when your body has decreased oxygen levels causes exhaustion in your body cells, including those in your muscles and other organs. Contact your doctor if you experience wheezing, coughing, shortness of breath or tightness in the chest during or after working out. These could be signs of exercise-induced asthma whereby airways in the lungs constrict due to strenuous physical activity. 
9. Anemia - If you have anemia, your body does not get sufficient oxygen from red blood cells. Anemia results from low iron levels in the body which may be due to diet. It may also be a result of heavy periods in women. Signs include pale skin, dizziness, insomnia, easy bruising, and leg cramps. Following up with a doctor is recommended. You will need to eat an iron-rich diet that includes fresh green vegetables, poultry, and meat, and possibly take iron supplements.
10. Thyroid Issues - The thyroid hormone is a critical player in energy metabolism. When the thyroid gland does not produce enough thyroid hormone it can result in low energy and exhaustion. Exercise can increase the fatigue. Signs of low thyroid hormone include low energy, weight gain, muscle pain and depression. If you experience persistent fatigue and muscle pain, follow up with your doctor for a thyroid test. Medication may be needed to correct the deficiency.
11. Poor Cardiovascular Fitness - Exhaustion after workout can be the result of poor cardiovascular fitness. Working out without breaks or working out beyond your current fitness level can strain your heart and circulation system, leaving you exhausted. Take a five-minute break to lower the heart rate and rehydrate by taking some water. Rehydration will reduce blood thickness, resulting in improved circulation. Click to Learn 4 Cardio Exercises You Can Do With An Injured Leg.
12. Illness - If you are recovering from an illness, you may feel fine doing your normal activities, but exercising is more demanding on your body and can lead to exhaustion. Do not engage in exercise until you are fully recovered then start back on your training program slowly and gradually increase the intensity. 

How Often Should You Exercise? Is it Ok to Work Out Every Day Without Rest?

The Department of Health and Human Services recommend that healthy adults get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week, or a combination of moderate and vigorous activity. It is recommended that people get at least 30 minutes per day of moderate exercise, for five days per week. This may be translated into two and a half hours of moderate physical activity per week.

When Should I See a Physician if I am Experiencing Fatigue during Exercise?

Exercise fatigue syndrome affects a small number of people in the United States. Extreme fatigue or exhaustion after workouts may be caused by intense physical exertion or an underlying medical condition. If this becomes persistent such that you are always fatigued, it could signify a serious underlying condition that requires immediate medical attention.

By: Terri Ahren, OTR/L

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