Muscle Weakness

WHEN TO SEE YOUR DOCTOR

* You have unexplained muscle weakness that persists beyond a day or two.

* If you're suddenly unable to lift your limbs, see your doctor immediately.

What Your Symptom Is Telling You

The coffee pot feels like it weighs a ton. It takes two tries to heave-ho the trash. Even raising your arm to brush your hair takes effort.

It's no wonder your arms feel like someone pulled the plug on your power source. Yesterday, you pruned the shrubs in your front yard and hauled a half-dozen cartons of discarded junk from the basement. You didn't know it then, but your home maintenance marathon actually damaged your muscles.

Pushing out-of-shape muscles to the brink tears the proteins inside the muscle fibers, according to Priscilla Clarkson, Ph.D., professor of exercise science at the University of Massachusetts in Amherst. Normally, these proteins link up to make muscles flex. This allows you to lift, push and do countless other movements.

When proteins tear from overactivity, they can't link up properly. And you have less power to perform even simple movements. "Depending on the extent of damage, it can take up to five days for the proteins to repair and for muscles to regain strength," says Dr. Clarkson.

You don't have to be hauling heavy boxes for muscles to lose their steam. One of the hallmarks of the flu is weakness, often to the point where you can barely lift your head off the pillow. That's because the virus causes inflammation of the muscle fibers. This interferes with proper contraction, according to Irwin Siegel, M.D., associate professor of orthopedic surgery at the Rush Presbyterian-St. Luke's Medical Center in Chicago.

The longer you stay bedridden, however, the weaker you'll be. Just as overdoing it stresses the protein in muscles, "underdoing" it harms muscles in another way. Movement builds up the proteins needed for muscle contraction. If you're barely stirring, the proteins deteriorate. "After a week spent flat on your back with the flu, you'll be weak as a kitten for days afterward," says Dr. Siegel.

Fluid loss?from severe sweating, vomiting or diarrhea?can also cut off the power juice to muscles. When you lose fluid, you drain away salt and also trace amounts of potassium, magnesium and calcium. A delicate balance of these minerals?called electrolytes?allows electrical signals to travel through the nerves to the muscles. These signals from the brain tell the muscles when to flex. Losing fluid upsets the electrolyte balance, and the signals may get confused before contraction can occur.

But muscles can't live on fluid alone. They'll wimp out if they're starved of the nutrients they need to do their work?proteins and carbohydrates. Protein from food is converted into your body's muscle fiber protein. And carbohydrates, which is stored in the muscles as glycogen, or found in the blood as glucose (blood sugar) provide fuel for muscle activity.

Muscles that slowly become weaker for no apparent reason could indicate a disease or condition in the body. Possible disorders include: anemia, which shuts off oxygen to muscles; diabetes, which interferes with the body's use of blood sugar; a thyroid condition, which interferes with the body's use of protein; or a nerve injury, which interferes with the brain's signals to the muscles.

Muscle weakness that develops slowly and is accompanied by pain can indicate lupus (a severe disorder that causes the immune system to attack the body) or polymalgia rheumatica (a common source of muscle pain in middle-aged people). And sudden muscle weakness can indicate food poisoning or a medication overdose and requires immediate medical attention.

Symptom Relief

To overcome temporary muscle weakness from overactivity, flu, fluid loss or poor diet, try these self-help measures.

Lighten up. When you overdo it, you need to let your muscles rest, but it's important to give them some activity while they heal, says Dr. Clarkson. Continuing to perform light chores allows your damaged muscles to repair themselves without sustaining further damage, she explains. Give yourself a few days before doing any heavy lifting, she adds. If you push it, you'll further damage the fibers, and it may take longer to regain your strength.

Get back to exercise slowly. If you've been inactive because of sickness for a few days, it will take double your downtime before your muscles build back up to full steam, according to Dr. Siegel. If, for example, you've been in bed with the flu for three days and missed your daily walk, give yourself six days to work back up to top speed.

Replace lost fluids with sport drinks. Carbohydrate-electrolyte products can help recharge muscles weakened from severe vomiting, diarrhea or profuse sweating. "As a bonus, they also contain glucose, which can refuel muscles and speed fluid from your stomach to your bloodstream," says Robert Hackman, Ph.D., professor of nutrition at the University of Oregon in Eugene.

Eat a balanced diet. "Don't expect to have a lot of muscle stamina if you're restricting yourself to diet soda and rice cakes," says Dr. Clarkson. Your daily diet should include protein, which is found in red meat, milk, cheese, eggs, chicken, fish, lentils and soybeans. You should also have generous helpings of complex carbohydrates, found in pasta, breads, fruits and vegetables. Your body breaks down these foods to glucose, for muscle power. These foods also provide a mix of vitamins and minerals that assist in the chemical reaction needed to fuel muscles. "Think of vitamins and minerals as 'oil' for the muscle engine," says Dr. Clarkson.

Help from the Doctor

If your muscles suddenly become weak for no apparent reason, view the situation as a potentially life-threatening emergency and go to the nearest hospital for treatment. And if your muscles have slowly become weaker for unexplained reasons, see your doctor to get a handle on what's happening. He'll probably order a blood test to rule out anemia or other conditions, a urine test to detect diabetes and an electromyagram (EMG) to test if the muscles are receiving electrical signals from the nerves.