Exercise may cause weakness if environmental and physiological conditions are not optimal. Weakness is often associated with muscle cramping, fainting, confusion and dizziness. Weakness when exercising can result from a myriad of conditions and may occur suddenly. Monitor physiological signals to prevent progression of weakness.
Hypothermia
Exercising in cold environments can cause individuals to develop hypothermia. Characteristics of hypothermia include muscle weakness, drowsiness, shivering and confusion. Individuals often wear more clothes than needed when exercising in a cold environment, as reported by the United States Military Academy. Excess clothing along with exercise causes sweating and heat loss. As an individual tires from exercising, the body motion slows down and produces less heat. The sweaty clothes, increased heat loss and decreased heat production can cause a speedy initiation of hypothermia.
Arrhythmias
A heart arrhythmia is an irregular rhythm of the heart, causing the heart to pump blood less efficiently. Sinus tachycardia, a type of arrhythmia, occurs when signals are sent to the heart from the sinus node, stimulating the heart to beat faster than normal. This condition is common among children when exercising vigorously. The heart will speed up to compensate for the increase in energy expenditure. If the heart speeds up too quickly to pump a sufficient supply of blood, weakness, dizziness, malaise and heart palpitations occur. Sinus tachycardia is often an acute problem and ameliorates when physical activity stops.
Glycogen Storage Disease
Glycogen is stored glucose or sugar. After exercising for five to 10 minutes, glycogen is the major energy source for the body. Individuals with glycogen storage diseases do not store glycogen properly and possess abnormal quantities of glycogen in their bodily tissues. Defects of glycogen storage become evident when an individual with McArdle's disease, a type of glycogen storage disease, starts engaging in exercise of moderate intensity. Extreme muscle weakness, low blood sugar, cramping and fatigue are likely to occur.
Hypoglycemia
Hypoglycemia, also known as low blood sugar, is common among individuals with diabetes and individuals who are fasting or skipping meals. When low blood-sugar levels are present, the body will express symptoms that include weakness, dizziness, confusion, shakiness, sweating and fatigue. Symptoms occur especially during exercise, when the body needs glucose for energy. The National Diabetes Information Clearinghouse recommends that individuals with hypoglycemia should check their blood-sugar levels and eat a snack prior to exercising.
References
- United States Military Academy: Exercising in Cold Environments
- University of Arkansas for Medical Sciences: Arrhythmias
- "Motor Disorders"; Chapter 10: Metabolic Myopathies; Michio Hirano and Salvatore DiMauro; 1999
- Children's Hospital of Pittsburgh; Glycogen Storage Diseases; November 2010
- National Diabetes Information Clearinghouse; Hypoglycemia; October 2008
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