With many of us contemplating marathons or other prolonged endurance events in 2016, we, our spouses and other family members most likely have wondered whether such strenuous training could be harmful to our hearts. Could any of us, in making ambitious resolutions, exercise too much?
A newly published scientific review offers both reassurance and some caution. It found that while most athletes' hearts can withstand most exercise, there are exceptions. For some people in seemingly good health, heavy loads of exercise might be problematic. That's why all of us who work out should be as informed as possible about our family's cardiac history and our own potential genetic risks.
Exercise, of course, is in general extremely beneficial for heart health. Dozens of large-scale epidemiological studies have found that people who exercise in any amount, whether five minutes a day or two hours a day or more, are much less likely to develop or die from heart disease than people who are sedentary.
But these studies, while encouraging, contain a disquieting subtext. Their plotted data typically shows some type of bell curve to the heart benefits from exercise, meaning that the more people work out, the less they are at risk of cardiac problems — up to a point, and then the benefits plateau or decline.
To some scientists, that finding made little intuitive sense. If a little exercise is good for the heart, why shouldn't more be continually better?
Dr. Paul Thompson, the chief of cardiology at Hartford Hospital in Connecticut and for years a dedicated marathon runner, was particularly drawn to that issue. He and his colleagues at Hartford Hospital, along with scientists at the Radboud University Medical Center in Nijmegen, the Netherlands, recently decided to delve more comprehensively than had yet been done into the available data on the topic.
Many past studies have looked at individual aspects of prolonged exercise and heart health. But no past review had comprehensively examined all of the ways in which prolonged endurance exercise might affect the heart and whether, on aggregate, those studies indicated that we should — or should not — worry about the effects of heavy training.
So for the new study, being published next month in Physiological Reviews, Dr. Thompson and his collaborators gathered all of the studies they could find from the past 30 or more years related to exercise and heart health, and parsed their findings both singly and collectively.
Their findings should reassure most of us and our concerned loved ones.
"There is no evidence that there is a level of exercise that is dangerous or too much for a normal, healthy person," Dr. Thompson told me.
At the same time, those of us who work out should understand that frequent exercise training causes "profound changes in cardiac physiology and structure," as Dr. Thompson and his colleagues write in their review.
In the short term, these changes can mimic heart damage, they point out, with cardiac cells often becoming "leaky" after strenuous workouts or events, releasing proteins into the bloodstream that, in other circumstances, could indicate a heart attack. These proteins usually disappear within a few days, and the heart seems to recover fully, Dr. Thompson said.
But in the process, the heart adapts and changes. Its left and right ventricles enlarge. It begins to look quite different than a non-athlete's heart.
For most people, these changes are beneficial and also necessary for successful athletic performance. But, as Dr. Thompson and his colleagues write, their review of the studies indicates that there are outliers, seemingly healthy people for whom strenuous exercise holds unexpected dangers.
Perhaps most surprising, older marathon runners can be just as susceptible as their sedentary counterparts to atherosclerosis, or the buildup of dangerous plaques in the arteries, the studies show. Strenuous exercise does not prevent these plaques in people who are predisposed by heredity or lifestyle to the condition.
The act of exercising, however, may increase the risk that the plaques will rupture, precipitating a heart attack. Someone with atherosclerosis is more likely, studies show, to have a heart attack while running than while sitting quietly.
But many older athletes with atherosclerosis have no idea they suffer from the condition, which often causes few symptoms.
Similarly, according to the new review, people with certain inherited heart abnormalities, such as cardiomyopathy (an enlarged heart) or long QT syndrome, a disorder of the heart's electrical activity, may exacerbate their conditions with strenuous exercise. The cardiac remodeling that is beneficial for most exercisers, the reviewers write, is undesirable for them and could lead to premature death, possibly contributing to the statistical downturn in health benefits from extreme exercise seen in some studies.
The best response to this information is not, however, to panic and avoid strenuous exercise, Dr. Thompson said. The best response is "to know your family history of sudden death," he said. If a close family member has died unexpectedly of heart problems, talk to your doctor about whether you need to be tested for conditions such as atherosclerosis or cardiomyopathy.
The rest of us should pay attention to symptoms such as unusual fatigue, shortness of breath or chest pain during exercise, he said, but are much more likely to strengthen our hearts with exercise than harm them.
(Reuters Health) -- In a 10-year U.S. study, people who drank coffee regularly were less likely to die of many causes, including heart disease and diabetes, than those who didn't drink coffee at all.
The more coffee study participants consumed, the lower their risk of dying, and decaf drinkers showed a similar pattern.
"Coffee contains numerous biologically active compounds, including phenolic acids, potassium, and caffeine," said lead author Dr. Erikka Loftfield of the National Cancer Institute in Rockville, Maryland.
Many studies have found that coffee consumption is associated with lower risk of overall and heart-related mortality, Loftfield told Reuters Health by email.
The researchers used data from a previous study on 90,317 adults without cancer or history of cardiovascular disease who were followed from 1998 through 2009. They had reported their coffee intake, along with other dietary and health details, at the start of the study.
By 2009, about 8,700 people had died. After accounting for other factors like smoking, the researchers found that coffee drinkers were less likely to have died during the study than nondrinkers.
The risk of death was lowest for those who drank four to five cups of coffee per day. A similar association was seen among drinkers of decaffeinated coffee as well, according to the results online now in American Journal of Epidemiology.
Coffee drinkers had a reduced risk of death from heart disease, chronic respiratory diseases, diabetes, pneumonia and influenza, and suicide, but not cancer, the researchers found.
"Although coffee drinking has also been inversely associated with incidence of certain cancers, like liver, in epidemiological studies, we did not observe an association between coffee and overall cancer mortality," Loftfield said. "This may be because coffee reduces mortality risk for some cancers but not others."
People who consumed two to three cups of coffee per day had approximately an 18% lower risk death during follow-up compared to those who reported drinking no coffee, she said. Drinking up to five cups per day, or 400 mg of caffeine per day, is not associated with any long-term health risks, Loftfield added.
Moderate caffeine intake, up to 200 mg per day, is even safe for pregnant women, according to a statement by the American College of Obstetricians and Gynecologists.
"There is an accumulating number of studies of very high quality that show that people who drink more coffee tend to have better health outcomes," said Dr. Marc J. Gunter of Imperial College London, who was not part of the new study.
"Coffee drinking is correlated with other health behaviors," and those who drink it regularly may have other healthy habits, like exercising and keeping to a healthier diet, though the researchers tried to account for those other factors, Gunter told Reuters Health.
The study doesn't prove that coffee extends life.
"You could argue that people who are already sick might not be drinking as much coffee," Gunter said. But coffee may also have a direct effect on inflammation or cardiovascular health, he said. "It doesn't seem to do you any harm, if you like drinking coffee then carry on," Gunter said.
Coffee can be part of a healthy, balanced lifestyle, and it may even do some good, though we can't yet recommend than nondrinkers adopt the habit for health reasons, he said.
Only half who should are using medications to help prevent heart disease
WebMD News from HealthDay
By Robert Preidt
HealthDay Reporter
THURSDAY, Dec. 3, 2015 (HealthDay News) -- Nearly half of American adults who should be taking cholesterol-lowering drugs don't, federal government researchers report.
They also found that blacks and Hispanics were less likely than whites to take medications that lower levels of "bad" LDL cholesterol.
"Nearly 800,000 people die in the U.S. each year from cardiovascular diseases -- that's one in every three deaths -- and high cholesterol continues to be a major risk factor," said Carla Mercado, a scientist in the division for heart disease and stroke prevention at the U.S. Centers for Disease Control and Prevention.
"This study reveals opportunities to reduce existing [racial] disparities through targeted patient education and cholesterol management programs," she said in a CDC news release.
The CDC study team analyzed national data from 2005 to 2014 and found that nearly 37 percent of U.S. adults -- more than 78 million people aged 21 and older -- were eligible to take cholesterol-lowering medications or were already taking them.
Among these people, 55.5 percent were taking cholesterol-lowering medication, almost 47 percent were making lifestyle changes to lower cholesterol, 37 percent were taking medication and making lifestyle changes, and 35.5 percent were doing neither.
The study included all types of cholesterol-lowering drugs, but nearly 90 percent of those on medication were taking a statin, the researchers noted.
Of the almost 41 percent of men eligible for or already on cholesterol medication, close to 53 percent were taking them. Among women, the figures were almost 33 percent and more than 58 percent, respectively.
Of the roughly 24 percent of Mexican-Americans eligible for or already on cholesterol medication, 47 percent were taking medications. The figures were 39.5 percent and 46 percent, respectively, among blacks, and more than 38 percent and 58 percent, respectively, among whites.
The lowest rate of taking recommended cholesterol medication (close to 6 percent) was among blacks who did not have a regular place for health care. The highest rate (80 percent) was among people who said they already adopted a heart-healthy lifestyle.
The study appears in the Dec. 4 issue of the CDC's Morbidity and Mortality Weekly Report.
