9 health clichés decoded

If you believe a bird in the hand is worth two in the bush and a penny saved is a penny earned, you may also believe these popular health clichés. Experts unravel what's behind these common sayings – and their reality.

--By Linda Melone for MSN Healthy Living

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1. Butterflies in your stomach

The fluttery feeling in your stomach before a big presentation or special event may feel like butterflies, but it's actually your gut's response to your body's nervous system, says Gerard E. Mullin, M.D., associate professor of medicine at Johns Hopkins University School of Medicine in Maryland, and author of The Inside Tract: Your Good Gut Guide to Great Digestive Health (Rodale Press, July 2011).

"Under stress, the body activates the flight or fight response or sympathetic nervous system," Mullin says. "The butterfly feeling refers to fear and nervousness, part of the stress response." This also causes your pupils to dilate and increases your heart rate and blood pressure, preparing you for battle... or for a winning presentation.

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2. Cabin fever

Snowy days or an illness that keeps you stuck at home may start out cozy, but those cozy feelings may turn sour after a week or so. "Irritability, frustration and even paranoia may set in, which we refer to as 'cabin fever,'" says Elizabeth R. Lombardo, Ph.D., psychologist and author of A Happy You: Your Ultimate Prescription for Happiness (Morgan-James, 2009). "For some people, this feeling relates to claustrophobia (the fear of being stuck in a small space and unable to escape)." Physical health consequences such as increased muscle tension, headaches, gastrointestinal disturbances, insomnia and even forgetting to take medications or vitamins can occur.

Cabin fever can also refer to seasonal affective disorder (SAD), a mood disorder that includes depression. Try reaching out to a friend, watching funny movies, exercising or meditation. If symptoms worsen or you have thoughts of hurting yourself or others, make an appointment with a professional psychologist, Lombardo says.

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3. Lovesickness

Deep feelings toward another person that cause insomnia, rapid heart rate, weight loss and problems concentrating may be more than a mere crush, but rather symptoms of lovesickness. "Symptoms can occur whether you're happily in a relationship or you're sad because your feelings toward another person are not being reciprocated," Lombardo says. "In the first situation, also called 'lovestruck,' where you are deeply in love with someone, symptoms can include obsessive compulsive tendencies (such as checking and rechecking phone messages).

The feelings emerge due to a surge of certain neurotransmitters (brain chemicals) such as dopamine, norepinephrine and oxytocin. "If you develop chest pain, shortness of breath or overall weakness, see a doctor," Lombardo says.

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4. Runner's high

If you feel elated and exhilarated after a long run, you're familiar with the runner's high. Endurance training is known for causing many positive mental and physical changes, including stress reduction, decreased anxiety, enhanced mood and reduced pain perception, says Betul A. Hatipoglu, M.D., an endocrinologist with Cleveland Clinic. "The runner's high is described as feelings like pleasantness, inner harmony, boundless energy, or even drug-like 'orgiastic' sensations, although the degree of these exercise-induced mood changes differs considerably among individuals."

Chemicals called opioids produced by the brain as well as other brain chemicals such as dopamine and endocannabinoids (chemicals made by the brain that work on marijuana receptors) are believed responsible, Hatipoglu says. Fortunately, no dangerous side effects are known, other than some runners' desire to get "high" as often as possible.

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5. Beauty sleep

If you've ever excused yourself from a boring event because you needed your "beauty sleep," you were not telling a complete falsehood. "While solid evidence linking skin health to sleep is lacking, we do know that cells rejuvenate themselves while we sleep," says Alice Hoagland, Ph.D., director of the Insomnia Clinic at the Unity Sleep Disorders Clinic in Rochester, N.Y. Therefore, getting adequate sleep boosts the rate at which your cells turn over, a process required for skin health and appearance.

In addition, sleep deprivation and insomnia are linked to increased stress hormones, which reduce the functioning of the immune system and increase the potential for skin inflammations, Hoagland says. "Perhaps most importantly, sleep is a time of no sun exposure and UVA/UVB exposure, which is clearly beneficial to skin health." Sleep requirements vary individually and can range from five to 10 hours a night, Hoagland says. In general, an individual’s sleep requirement is defined by the amount of sleep required to eliminate excessive daytime sleepiness.

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6. Foot falls asleep

Sitting in the same position for too long can create a tingly "pins and needles" feeling when you try to stand up, a sensation referred to as your foot "falling asleep." In reality, slumber plays no part in this event. "This sensation happens from prolonged pressure on the legs," says Gary A. Pichney, DPM, a board certified podiatrist with Mercy Medical Center in Baltimore. "It's basically due to restriction of blood flow to the nerves, causing them to function improperly."

The arteries that supply blood and nutrients to the nerves of the foot become compressed. When that happens, the nerve cells cannot function properly, Pichney explains. Impulses from the nerves to the brain will then misfire, sending mixed signals to the brain resulting in the sensation of burning, prickling, pins and needles or tingling feelings. The solution? "Vary the position of your foot periodically to avoid putting constant pressure on any one part," Pichney says.

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7. Broken heart

Beyond normal grieving over a lost love, severe emotional stress such as the death of a spouse can trigger a serious medical condition known as a "broken" heart, says Andrew M. Freeman, M.D., a cardiologist with National Jewish Health in Denver. It's also called "takotsubo cardiomyopathy" (takotsubo is a Japanese name for an octopus trap, so the name relates to a ballooning out of the tip of the heart) or stress cardiomyopathy.

The syndrome occurs much more often in women than men (for unknown reasons) and also occurs in other stressful situations, such as a catastrophic medical diagnosis, devastating financial loss or natural disasters. "It is often associated with marked depression and can mimic a heart attack, although the coronary arteries remain unaffected," Freeman says. Scientists believe catecholamines (chemicals in the body such as norepinephrine known as "stress hormones") play a role in broken heart syndrome. "Most people recover over time," says Freeman, who recommends 30 minutes each of exercise and meditation or peaceful time each day to reduce the risk of a broken heart.

8. Scared to death

Can your prankster friend who pops out from behind a door and yells "boo!" cause your heart to literally stop? Not likely, Freeman says. "No data supports someone being scared to death, although it's theoretically possible."

Periodically, however, people can become extremely frightened and then suffer an acute heart attack due to the tremendous release of adrenaline from the fright. "The adrenaline release can cause a heart arrhythmia (abnormal heart beat)," Freeman says. "This arrhythmia may trigger coronary heart disease to 'erupt.' So a person can die from a heart attack as a result of a sudden fright, but not likely directly from the scare itself."

9. White as a sheet

You may appear "white as a sheet" or very pale when you're either sick or frightened. When this occurs, the skin is shunting blood away from it for various reasons, Freeman says. "When you're ill, your body may be doing things to regulate your body temperature, which can cause a pale look."

If you're frightened, the release of stress hormones during a scare causes a constriction of the blood vessels of the face, Freeman says. It then sends blood to the muscles in other parts of your body that may be necessary for survival, such as your legs, which may be needed to help you run to escape danger.

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