leetbulldog
08-08-2013, 03:56 AM
Most of the time, you’re probably blissfully unaware of your heart's ceaseless activity -- nearly 100,000 beats per day, or about 37 million beats per year and 3 billion in an average lifetime. But not always. Maybe your pulse suddenly races for no apparent reason. Maybe your heart throbs. Maybe it flutters or seems to skip a beat. When it does, you wonder: Is this normal? That can be a tricky question, especially if you don't know the facts about heart rate and rhythm. Here are five common myths -- and the truth about each one.
Myth #1: An erratic heartbeat means you’re having a heart attack. Almost never. It's fairly common to feel your heart flutter, flip-flop, or skip a beat from time to time. If you monitor the heart rhythm of any person long enough, almost everyone will display the occasional skipped or extra beat. It is very unusual for these sensations (without accompanying chest pain or shortness of breath) to indicate the occurrence of a heart attack. If the feelings of skipping or flip-flopping are new or frequent, or if the sensation is more of a fluttering, the sensations may suggest the presence of an abnormal heart rhytm(arrhythmia).
"The vast majority of arrhythmias are benign," says Gordon F. Tomaselli, MD, professor of medicine at Johns Hopkins University School of Medicine in Baltimore. But that doesn't mean you should ignore arrhythmias. Some arrhythmias raise the risk of a stroke, heart failure, and sudden death. So it’s prudent to alert a doctor about any erratic beats (especially if new or frequent) -- even in the absence of bothersome symptoms.
Arrhythmias can affect the heart’s upper chambers (atria) or -- more ominously, but much less frequently -- the lower chambers (ventricles). The most common atrial arrhythmia, atrial fibrillation (often called "AFib," for short), causes the heart to beat irregularly and makes stroke more likely. More than 2 million Americans have AFib.
AFib often causes a rapid heart rate, but it can also cause a slow heart rate or have no effect on heart rate. An ECG can help diagnose AFib.
Myth #2: A fast pulse means you’re stressed out.
Stress can spike your resting heart rate, sometimes nudging it to beat more than 100 times per minute, a condition called tachycardia. But smoking or consuming lots of caffeine can also do the trick. So can dehydration, fever, anemia, and thyroid disease.
In the absence of an obvious cause, anyone who experiences tachycardia at rest should consult a doctor. Even heart rates in the upper range of normal may signal a health issue. "If you don’t have a good explanation for a [resting heart] rate above 85, that should dictate a search for something else," Tomaselli says. "Most of the time, tachycardia is caused by an abnormal heart rhythm," says Joseph E. Marine, MD, associate professor of cardiology at Johns Hopkins University School of Medicine in Baltimore.
Some cases of tachycardia send the heart rate soaring – to well over 200 beats per minute -- bringing on symptoms including shortness of breath, chest pain, dizziness, and fainting.
"Over a long period of time, a [resting heart] rate of 130 or higher can cause the heart’s squeezing function to weaken," says Richard L. Page, MD, chairman of the department of medicine at the University of Wisconsin School of Medicine and Public Health in Madison, Wis. and president of the Heart Rhythm Society. "The good news is that that weakening can resolve when you get heart rate under control." Often that’s accomplished via drug therapy or procedures that deliver an electrical shock to the heart. Some patients require targeted destruction of the tiny areas of heart tissue in which the arrhythmias originate to fix the problem.
Myth #3: A healthy resting heart rate is between 50 and 90 beats per minute.
True, that's a normal heart rate range for adults. But the upper end of that range may mean a greater chance of serious health problems.
"A number of studies have shown that, even within the normal range, a high resting heart rate is associated with an increased risk for ischemic heart disease, stroke, and sudden cardiac death," Tomaselli says.
Norwegian researchers recently reported that for every 10-beat rise in resting heart rate, the risk of dying from a heart attack rose by 18% in women and by 10% in men. And a recent Japanese study showed that a resting heart rate higher than 80 beats per minute was associated with a greater risk of becoming obese or developing heart disease decades later. Diabetes and obesity are both risky for the heart.
Those studies don't prove that a high resting heart rate caused heart attacks, obesity, or diabetes. But the findings held when the researchers considered other risk factors.
So how high is too high for a resting heart rate? There’s no absolute consensus about this, but most doctors agree that resting heart rates consistently in the upper range are not ideal.
"It is hard to set a precise cutoff for this risk factor, but usually a heart rate of 90 or above is considered abnormal and potentially deleterious," Javaid Nauman, a research fellow at the Norwegian University of Science and Technology in Trondheim, Norway, tells WebMD in an email. Nauman headed the Norwegian heart rate study, published online in the Journal of Epidemiology and Public Health on Jan. 11, 2010.
To find your resting heart rate, press the index and middle fingers over the underside of the opposite wrist, just below the thumb. Press down gently until you feel your pulse. Count the beats for one minute, or count for 30 seconds and multiply by two. To ensure an accurate reading, sit quietly for at least 10 minutes before taking your pulse.
Myth #4: A slow heart rate means a weak heart.
"People often think that if their resting heart rate is too slow, they are on the precipice of having their heart stop completely," Tomaselli says.
Infact, it tends to be just the opposite.hThe heart is a muscle, and, like all muscles, it grows stronger with exercise. The stronger it is, the more efficient it is, taking fewer beats to pump blood throughout the body. So a heart with a resting heart rate under 50 (a condition known as bradycardia) is likely to be especially strong and healthy. That’s why highly conditioned athletes often have resting heart rates of 40 to 60 beats per minute. Famously fit bicycle racer Lance Armstrong, for example, reportedly has a resting heart rate of 32. (For more information on heart rate and fitness, read "The Truth About Heart Rate and Exercise.")
"In general, a slow heart rate that is [not causing any symptoms] is not cause for concern," Marine says. This is particularly true in younger individuals.
In the elderly, bradycardia (even if asymptomatic) might actually signal that heart disease is present. Certain medications, including beta-blockers and other heart drugs, can also cause bradycardia.
Myth #5: Since my heart rate is normal, my blood pressure must be normal too.
There's no simple relationship between heart rate (which is measured in beats per minute) and blood pressure (measured in millimeters of mercury, or mmHg).
A person can have a normal resting heart rate and still have high blood pressure. And someone whose heart rate is abnormal can have normal blood pressure. Strenuous exertion sharply raises heart rate, but it may only modestly increase blood pressure.
The bottom line? Heart rate and blood pressure are not the same. The only way to know your blood pressure is to measure it with a blood pressure cuff.
www.m.webmd.com/heart-disease/features/5-heart-rate-myths-debunked?page=7
include fatigue, dizziness, and fainting.
Myth #1: An erratic heartbeat means you’re having a heart attack. Almost never. It's fairly common to feel your heart flutter, flip-flop, or skip a beat from time to time. If you monitor the heart rhythm of any person long enough, almost everyone will display the occasional skipped or extra beat. It is very unusual for these sensations (without accompanying chest pain or shortness of breath) to indicate the occurrence of a heart attack. If the feelings of skipping or flip-flopping are new or frequent, or if the sensation is more of a fluttering, the sensations may suggest the presence of an abnormal heart rhytm(arrhythmia).
"The vast majority of arrhythmias are benign," says Gordon F. Tomaselli, MD, professor of medicine at Johns Hopkins University School of Medicine in Baltimore. But that doesn't mean you should ignore arrhythmias. Some arrhythmias raise the risk of a stroke, heart failure, and sudden death. So it’s prudent to alert a doctor about any erratic beats (especially if new or frequent) -- even in the absence of bothersome symptoms.
Arrhythmias can affect the heart’s upper chambers (atria) or -- more ominously, but much less frequently -- the lower chambers (ventricles). The most common atrial arrhythmia, atrial fibrillation (often called "AFib," for short), causes the heart to beat irregularly and makes stroke more likely. More than 2 million Americans have AFib.
AFib often causes a rapid heart rate, but it can also cause a slow heart rate or have no effect on heart rate. An ECG can help diagnose AFib.
Myth #2: A fast pulse means you’re stressed out.
Stress can spike your resting heart rate, sometimes nudging it to beat more than 100 times per minute, a condition called tachycardia. But smoking or consuming lots of caffeine can also do the trick. So can dehydration, fever, anemia, and thyroid disease.
In the absence of an obvious cause, anyone who experiences tachycardia at rest should consult a doctor. Even heart rates in the upper range of normal may signal a health issue. "If you don’t have a good explanation for a [resting heart] rate above 85, that should dictate a search for something else," Tomaselli says. "Most of the time, tachycardia is caused by an abnormal heart rhythm," says Joseph E. Marine, MD, associate professor of cardiology at Johns Hopkins University School of Medicine in Baltimore.
Some cases of tachycardia send the heart rate soaring – to well over 200 beats per minute -- bringing on symptoms including shortness of breath, chest pain, dizziness, and fainting.
"Over a long period of time, a [resting heart] rate of 130 or higher can cause the heart’s squeezing function to weaken," says Richard L. Page, MD, chairman of the department of medicine at the University of Wisconsin School of Medicine and Public Health in Madison, Wis. and president of the Heart Rhythm Society. "The good news is that that weakening can resolve when you get heart rate under control." Often that’s accomplished via drug therapy or procedures that deliver an electrical shock to the heart. Some patients require targeted destruction of the tiny areas of heart tissue in which the arrhythmias originate to fix the problem.
Myth #3: A healthy resting heart rate is between 50 and 90 beats per minute.
True, that's a normal heart rate range for adults. But the upper end of that range may mean a greater chance of serious health problems.
"A number of studies have shown that, even within the normal range, a high resting heart rate is associated with an increased risk for ischemic heart disease, stroke, and sudden cardiac death," Tomaselli says.
Norwegian researchers recently reported that for every 10-beat rise in resting heart rate, the risk of dying from a heart attack rose by 18% in women and by 10% in men. And a recent Japanese study showed that a resting heart rate higher than 80 beats per minute was associated with a greater risk of becoming obese or developing heart disease decades later. Diabetes and obesity are both risky for the heart.
Those studies don't prove that a high resting heart rate caused heart attacks, obesity, or diabetes. But the findings held when the researchers considered other risk factors.
So how high is too high for a resting heart rate? There’s no absolute consensus about this, but most doctors agree that resting heart rates consistently in the upper range are not ideal.
"It is hard to set a precise cutoff for this risk factor, but usually a heart rate of 90 or above is considered abnormal and potentially deleterious," Javaid Nauman, a research fellow at the Norwegian University of Science and Technology in Trondheim, Norway, tells WebMD in an email. Nauman headed the Norwegian heart rate study, published online in the Journal of Epidemiology and Public Health on Jan. 11, 2010.
To find your resting heart rate, press the index and middle fingers over the underside of the opposite wrist, just below the thumb. Press down gently until you feel your pulse. Count the beats for one minute, or count for 30 seconds and multiply by two. To ensure an accurate reading, sit quietly for at least 10 minutes before taking your pulse.
Myth #4: A slow heart rate means a weak heart.
"People often think that if their resting heart rate is too slow, they are on the precipice of having their heart stop completely," Tomaselli says.
Infact, it tends to be just the opposite.hThe heart is a muscle, and, like all muscles, it grows stronger with exercise. The stronger it is, the more efficient it is, taking fewer beats to pump blood throughout the body. So a heart with a resting heart rate under 50 (a condition known as bradycardia) is likely to be especially strong and healthy. That’s why highly conditioned athletes often have resting heart rates of 40 to 60 beats per minute. Famously fit bicycle racer Lance Armstrong, for example, reportedly has a resting heart rate of 32. (For more information on heart rate and fitness, read "The Truth About Heart Rate and Exercise.")
"In general, a slow heart rate that is [not causing any symptoms] is not cause for concern," Marine says. This is particularly true in younger individuals.
In the elderly, bradycardia (even if asymptomatic) might actually signal that heart disease is present. Certain medications, including beta-blockers and other heart drugs, can also cause bradycardia.
Myth #5: Since my heart rate is normal, my blood pressure must be normal too.
There's no simple relationship between heart rate (which is measured in beats per minute) and blood pressure (measured in millimeters of mercury, or mmHg).
A person can have a normal resting heart rate and still have high blood pressure. And someone whose heart rate is abnormal can have normal blood pressure. Strenuous exertion sharply raises heart rate, but it may only modestly increase blood pressure.
The bottom line? Heart rate and blood pressure are not the same. The only way to know your blood pressure is to measure it with a blood pressure cuff.
www.m.webmd.com/heart-disease/features/5-heart-rate-myths-debunked?page=7
include fatigue, dizziness, and fainting.