A common complaint that is heard
in the physicians office is why am I so weak and fatigued.
Weakness and fatigue are terms that are often used as if they
mean the same thing, but in fact they describe two different
symptoms. It is important to explain what you mean when your
concern is weakness or fatigue. This will help your health care
professional make a better assessment of your symptoms.
A feeling of weakness is a
sensation that you do not have adequate strength to perform
certain activities that involve the use of your arms, legs,
trunk, and other muscles. This may be demonstrated by difficulty
getting up from a chair, walking across the room, lifting
objects, and performing other activities of daily living that
require the use of your muscles.
Fatigue is a feeling of
tiredness, exhaustion, or lack of energy. Someone suffering from
fatigue may require frequent rest to complete a task. The
symptom frequently comes to attention because they are not able
to perform routine activities without stopping to rest.
General weakness often occurs
after you have done too much activity and simply need to allow
your muscles to rest. An example would be a long hike, running,
working out at the gym or other activity requiring a lot of
muscular exertion. Weakness related to these activities
usually improves after a short period of time.
If the weakness is not
improving, after a short period of time, it is important to see
your doctor for further evaluation. The following are
potentially serious health related problems that can cause
The thyroid gland is involved
in the bodies use of energy. An underactive thyroid or low
thyroid level (hypothyroidism) can cause fatigue, weakness,
lethargy, weight gain, depression, memory problems,
constipation, dry skin, intolerance to cold, coarse and thinning
hair, brittle nails and abnormalities in cholesterol and
triglycerides. Heart related problems such as low heart rate and
enlargement of the heart may occur.
An overactive thyroid or high
thyroid level (hyperthyroidism) can cause fatigue, weight loss,
increased heart rate, intolerance to heat, sweating, muscle
weakness, irritability, anxiety, and other mood disorders.
A problem with the bodies
minerals (electrolytes) can cause weakness of the muscles. Low
levels of potassium, sodium, calcium, and magnesium may all
contribute to muscular weakness and abnormalities in nerve
conduction. Individuals with very low sodium levels may
demonstrate mental status changes and seizures when levels
become dangerously low. Low levels of potassium may cause
weakness as well as heart rhythm irregularities. Electrolyte
abnormalities may be seen in patients that are taking diuretics
for blood pressure control or to help control problems with
fluid retention and swelling.
It is imperative that you see
your healthcare professional if you are experiencing muscle
weakness that is slowly getting worse or sudden in onset. Sudden
muscle weakness and loss of function in one area of the body can
indicate a serious problem within the brain such as a stroke or
transient ischemic attack (frequently referred to as mini
Spinal cord injury or pressure
on the nerves from disk herniation can also result in weakness
of the extremities that demands further evaluation.
Two less common serious medical
problems that cause weakness are Guillain-Barre syndrome and
Myasthenia gravis. Guillain-Barre syndrome is a rare nerve
disorder that causes weakness in the legs, arms, and other
muscles and can progress to complete paralysis.
Myasthenia gravis, is a rare,
chronic disorder that causes weakness and rapid muscle fatigue.
The symptoms of weakness and
fatigue are commonly experienced by all of us during our day to
day activities. Most of the time the cause will be easily
explained and nothing serious. However, when symptoms are of
sudden onset, progressive, or of duration greater than 1-2
weeks, further evaluation is warranted. It is important to be
proactive in seeking medical advice so that you can keep moving
forward with a healthy, and rewarding life.