You Get Light-Headed When You Stand Up Quickly
The explanation: You could be mildly dehydrated. Or you might have orthostatic hypotension (a.k.a. postural hypotension), which occurs when blood rushes to your feet and away from your head as you stand up suddenly. (People with low blood pressure can be especially prone to this phenomenon.)
The fix: Drink plenty of fluids and be sure that when you stand up, you do it slowly, says Donnica Moore, a physician in Far Hills, New Jersey. If you see stars anyway, grab a table or a chair to stabilize yourself or sit back down.
When to see a doctor: If the light-headedness persists or if you actually faint.
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You Sometimes Get a Painful Swelling Under Your Arm
The explanation: It could be due to a plugged hair follicle or an ingrown hair in your armpit (from shaving, for example) or a swollen lymph node (from an infection).
The fix: Try putting a warm compress on it several times a day and see if it goes away within a week, says Teng.
When to see a doctor: If it lasts longer or if it worsens (and gets red or irritated). "It could be a sign of a breast infection, a cyst, or a tumor," says Teng.
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Your Hands Get Sweaty in Certain Situations
The explanation: Sweaty palms happen to everyone now and then, and they're a normal response to stress or a case of the jitters.
The fix: Taking a few minutes to try to relax—by breathing deeply, meditating, or visualizing a tranquil place—may help prevent or relieve the sweatiness, says Teng.
When to see a doctor: If your hands are constantly sweaty. You could have hyperhidrosis, a disorder involving excessive sweating of the hands, feet, or underarms. Applying an antiperspirant on the palms can treat the condition, says Roshini Raj, an assistant professor of medicine at New York University and the author of What the Yuck?! The Freaky & Fabulous Truth About Your Body ($20; amazon.com). So can a medication prescribed by your doctor. In very serious cases, surgery can remove the part of the nerve that's stimulating the sweat glands to become overactive.
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You Get Foot Cramps at Night
The explanation: A subtle electrolyte imbalance (involving potassium, magnesium, or calcium) or mild dehydration may be triggering these cramps, says Teng.
The fix: Get up and walk around, then massage the muscle to help it relax.
When to see a doctor: If you get them nightly or during the day when you walk. A condition such as a blood-clotting disorder or nerve damage could be to blame.
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Your Foot Goes Numb When You're on the Stair Master
The explanation: When you move your feet in a repetitive way during a workout, or if your shoes or laces are too tight, the "tiny nerves between your toes can get pinched as you put pressure on your foot," says Sabrina Strickland, an orthopedic surgeon at the Hospital for Special Surgery, in New York City, and that can make it feel uncomfortably numb.
The fix: During your workout, wiggle your toes in your shoes a few times—and loosen your laces if they're too tight.
When to see a doctor: If numbness happens during other activities or you can't make it go away. You could have a nerve problem in your foot.
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Your Body Jerks as You Fall Asleep
The explanation: These hypnic jerks, or sleep starts, probably stem from nerves misfiring as your brain and body downshift into sleep mode. "An interruption in your brain's signal to your body to relax can cause the limbs and head to jerk," says Clete A. Kushida, M.D., the medical director of the Stanford Sleep Medicine Center, in Redwood City, California.
The fix: There's nothing you can do to prevent these harmless jerks. Fortunately, they last only a few seconds.
When to see a doctor: If they happen frequently or disturb your sleep, as they might be a sign of sleep apnea or periodic limb movement disorder.
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You Hear Ringing in Your Ears
The explanation: It's probably tinnitus, a perceived buzzing or whooshing sound commonly caused by partial hearing loss, says Cristina Cabrera-Muffly, an otolaryngologist at the Cleveland Clinic. Medications, including aspirin and some antibiotics; allergies; and earwax buildup can be to blame.
The fix: There's no cure for tinnitus caused by hearing loss, but "stress-reduction techniques, such as biofeedback, may be useful to decrease your brain's perception of the sound," says Cabrera-Muffly.
When to see a doctor: If the ringing is only in one ear or is accompanied by vertigo, balance problems, or facial weakness. These symptoms could indicate an acoustic-nerve tumor.
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Your Jaw Cracks
The explanation: The temporomandibular (jaw) joint that's in front of your ear is most likely to blame. "It cracks when the joint isn't moving correctly or fitting back into the socket properly," says Raj.
The fix: It should self-correct.
When to see a doctor: If it's accompanied by pain, headaches, or locking of the jaw. These symptoms could point to temporomandibular joint disorder, arthritis, or some other kind of joint damage that requires treatment (like wearing a mouth guard at night).
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You Have Floaters in Your Eyes
The explanation: Those little white specks that drift across your field of vision are probably just tiny pieces of tissue that stray into the vitreous, the jelly-filled chamber of each eye, says Ruth D. Williams, M.D., a spokesperson for the American Academy of Ophthalmology.
The fix: Your eye will probably reabsorb them (or you'll just stop noticing them).
When to see a doctor: If the floaters are black or are accompanied by flashing lights, which can signal a retinal tear.
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You Always Sneeze in Threes
The explanation: "Sneezing is a protective reflex," says Nathanael Horne, a physician in New York City. "There's something irritating in the nasal passages, and your nose wants to get rid of it." So you'll sneeze until the job gets done.
The fix: Sneeze! Once, twice, or four or more times—all are perfectly normal.
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Your Heart Races When You Wake Up Suddenly
The explanation: "When you're startled, adrenaline kicks in, and your body's fight-or-flight response is suddenly turned on," says Moore. And, says Teng, if you wake up abruptly from REM sleep, when vivid dreams occur, your heart rate may be naturally elevated.
The fix: In either case, your heart rate should return to normal within a few minutes.
When to see a doctor: If you also have chest pain or dizziness.
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You Get Full-Body Shivers
The explanation: "It's probably a momentary glitch in the body's ability to regulate its temperature," says Raj, especially if it lasts mere seconds. (This happens more during the menopausal transition, since "hormonal changes can make body-temperature regulation go haywire," says Raj.)
The fix: A shiver should go away on its own in a minute or two.
When to see a doctor: If a shiver lingers for days, which could signal an infection. "Just like a fever occurs with some illnesses," says Raj, "you can get chills when your immune cells release chemicals to fight off bugs." Treating the underlying infection should stop the shivers.