Do Compression Sleeves Help With Muscle Recovery? - NYTimes.com

http://mobile.nytimes.com/blogs/well/2016/07/29/do-compression-sleeves-help-with-muscle-recovery/?partner=rss&emc=rss&referer=

Do Compression Sleeves Help With Muscle Recovery?

Question:

Do compression sleeves help with muscle recovery?

Answer:

Compression sleeves and garments probably do help muscles recover after exhausting exercise, new research suggests. But they also have certain downsides that may discourage some of us from wearing them.

When the Summer Olympics start this week, viewers will see many track-and-field and other athletes sporting stretchy tubes of fabric on their arms, thighs or calves. These garments fit like sausage casings and are said to increase the flow of blood through muscles, potentially improving athletic performance and speeding recovery after workouts.

The evidence to support some of the claims for compression sleeves is scant, however. Most recent studies indicate that compression sleeves do not boost blood flow through muscles during exercise, probably because the movement of blood when we are exercising is already at its peak.

Similarly, while many athletes report that exercise feels easier when they wear compression clothing, those athletes perform about the same whether they wear the garments or not, according to a new review of studies of compression clothing and running that was published in April in Sports Medicine.

On the other hand, compression garments do seem to significantly aid muscles' recovery once strenuous exercise is over, says Billy Sperlich, a professor of sport science at the University of Würzburg in Germany who was a co-author of the new review. The garments can augment the movement of blood through muscles after exercising, when blood flow would otherwise slow, he says. This increase in circulation may help flush away some of the biochemical byproducts of hard workouts, like lactate, he says, reducing inflammation and muscle aches.

But to provide these benefits, compression clothing must be quite tight, which some people find uncomfortable, Dr. Sperlich says. The garments must also be worn for several hours after a workout, even if they become clammy and malodorous.

The upside is that when finally freed from these casings, he says, your muscles should "have less pain" than if they had not been squeezed at all.

Can Statins Cause Diabetes? - NYTimes.com

http://mobile.nytimes.com/blogs/well/2016/07/22/can-statins-cause-diabetes/?partner=rss&emc=rss&referer=

Can Statins Cause Diabetes?

Question:

Is it true that prolonged use of Lipitor-type drugs can cause diabetes?

Answer:

It's true. All medications have side effects, and numerous studies have shown that cholesterol-lowering statin drugs are linked to a small increase in the risk of Type 2 diabetes, even as they reduce the risk of heart attacks.

The higher the dose of a statin, the greater the diabetes risk, said Dr. Eric Topol, director of the Scripps Translational Science Institute and chief academic officer at Scripps Health. But many heart doctors, including Dr. Mary Norine Walsh, president-elect of the American College of Cardiology, say concern about diabetes should not deter patients from taking statins "if you fall into the higher risk category" for heart disease.

On the other hand, someone who has never had heart disease and who has high cholesterol but no other risk factors is less likely to derive benefit from a statin drug while still facing the risk of diabetes, Dr. Topol said, adding, "There you have a very tight benefit-to-risk ratio."

The Food and Drug Administration updated its advisory about statins in 2012 to include warnings about the slightly increased risk of higher blood sugars and Type 2 diabetes, based in part on two large analyses of earlier studies that controlled for diabetes risk factors like being overweight or being older. One found a 9 percent increase in the risk of diabetes among statin users, and the other a 12 percent increase, with a greater risk for those on intensive rather than moderate doses of the drugs.

The 2012 F.D.A. advisory also warns of other side effects of statins, such as muscle injury, rare cases of liver damage and reports of memory loss and confusion.

"You and your physician need to be aware of risks," said Dr. Walsh, and you may want to be assessed for diabetes. But she said, "It is not a reason not to take a statin if you fall into the higher risk category. The overall benefit of statins for people who need them because of their cardiovascular risk far exceeds the risk of diabetes."

http://www.medscape.com/viewarticle/866436?src=rss

Dissolving Coronary Stents: The Fog of Hype

The recent approval by the US Food and Drug Administration (FDA) of the Absorb GT1 bioresorbable vascular scaffold (BVS) system (Abbott Vascular) got me thinking about a modern-day medical problem: the tension between progress and safety.

Precarious is the balance between embracing the new and sticking with the tried and tested—pioneer vs Luddite. Interventional cardiologists are known for their pioneering spirit. By definition, a pioneer takes risks and sometimes suffers consequences.

We allow novel devices leeway because future iterations of a new device often prove beneficial. In general, current-generation drug-eluting stents (DES) perform better than the original versions.

But newer is not always better. The heart-rhythm community, including me, in my gullible days, accepted low-profile implantable cardioverter-defibrillator (ICD) leads, such as Medtronic's Sprint Fidelis. This embrace had disastrous consequences for patients.

Hindsight is sharp, but in the case of low-profile ICD leads, I assign some of the blame for this mistake on our susceptibility to industry marketing. We let our guard down. The bulkier ICD leads we were using at the time (and now) were performing well.

Do We Need a New Stent?

Performing well is how most interventional cardiologists would describe current-generation DES. Sure, the problem of neoatherosclerosis at the site of metal stent deployment continues to dog long-term results of PCI. But less than one in 500 patients suffers from late-stent thrombosis with standard DES. That makes for a tough comparison of any new stent—dissolving or not.

Approval of a disappearing stent has created great excitement—among both patients and doctors. The Wall Street Journal covered the first US implant of BVS. The patient said he "really liked the idea that the stent was going to dissolve and be out of there." He and his doctor were drawn to the potential benefit of this new technology. The keyword in that sentence—and in the entire BVS story—is potential.

Before delving into the actual BVS evidence, let's review the case for placing any coronary stent in patients with stable coronary artery disease. It is a short story. The highest-quality evidence shows that PCI in this setting does not reduce the chance of MI or death, and, by 3 years, there's no advantage in relief of angina.

BVS vs DES Evidence

ABSORB III : Approval of BVS hinged on this large US study. In this multicenter (193 sites) randomized trial, more than 2000 patients with stable or unstable angina received either a BVS (n=1322) or standard DES (n=686). The primary end point was target-lesion failure, defined by cardiac death, target-vessel infarction, or ischemia-driven target lesion revascularization at 1 year.

ABSORB III limited enrollment to patients with relatively stable symptoms and uncomplicated coronary lesions. It also used an arguably lenient noninferiority margin of 4.5 percentage points for the risk difference between the two stents.

Numerically more target lesion failure occurred in the BVS group (7.8%) vs the DES group (6.1%). This delta of 1.7% fell within the 95% confidence interval [CI] for noninferiority (−0.5 to 3.9, P=0.007).

Stent thrombosis occurred in 1.5% of patients in the BVS group vs 0.7% in the DES group. The authors note that the study was underpowered for low-frequency events such as stent thrombosis, but their observation of a higher risk of subacute scaffold thrombosis (>24 hours <30 days) has been seen in other data sets (0.9 vs 0.1, P=0.04).

Lancet Meta-analysis: German and Japanese investigators performed a meta-analysis of six trials of 3738 patients who underwent PCI with either the BVS or DES. They found similar rates of target lesion failure, revascularization, and death. The most concerning observation was a near-doubling of the risk of stent thrombosis and a tripling in subacute stent thrombosis (OR 3.11; 95% CI 1.24–7.82, P=0.02).

Systematic Review and Meta-analysis: Investigators from the Medstar Cardiovascular Research Network performed a systematic review and meta-analysis of patients treated with the BVS for various indications including ACS. This larger study also included registry and retrospective studies for a total of more than 10,500 patients (8351 treated with BVS and 2159 with DES). Similar to the Lancet meta-analysis, treatment with the BVS resulted in a doubling of the rate of stent thrombosis (OR 2.06; 95% CI 1.07–3.98).

In the real world, BVS is even less impressive.

ISAR-ABSORB Registry: Clinicians from Munich, Germany studied 419 consecutive patients who had BVS implanted at two high-volume centers. At 12 months, they found that the rate of death, MI, or target lesion revascularization was 13.1%. Definite stent thrombosis occurred in 2.6%—almost twice that observed in the clinical trials. Their conclusions exude wisdom: "Further study with longer-term follow-up and larger numbers of treated patients is required before we can be sure of the role of these devices in clinical practice."

German/Swiss Registry: At two German and two Swiss hospitals, 1305 consecutive patients received 1870 BVS devices. Investigators observed stent thrombosis in 42 patients, 40 of whom presented with ACS or sudden death. The incidence for stent thrombosis was 1.8% at 30 days and 3% at 12 months.

A novel part of this case-control study was adoption of a BVS-specific implant strategy partway through the series to address the issue of incomplete scaffold expansion. This adjustment led to a decrease in stent thrombosis from 3% to 1%; however, the authors acknowledge the limits of this implant-technique analysis, including the possibility of confounding and imbalances of clinical characteristics in the groups.

Comments

Proponents of BVS technology cite potential benefits. A disappearing stent could reduce neovascularization at the stent site and restore normal artery motion. These good things might translate to improved clinical outcomes. Animal models suggest complete resorption occurs at 36 months. The problem is that we don't have clinical data (published in peer-reviewed journals) with much more than 1-year follow-up. This, despite the fact that BVS has been approved in Europe since 2011.

The other argument BVS proponents make is that it is an early-generation device. It will improve. Maybe. Maybe not.

The reasons for concern are many.

First is the published evidence. Every study I read shows numerically more complications with BVS, including a higher incidence of myocardial infarction. Although, technically, the BVS system will be called "noninferior" to DES, the pattern is striking. And, if you add its "noninferiorness" to the lack of compelling evidence for PCI in stable CAD, any increase in complications is significant.

Then there is the matter of stent thrombosis. The combination of intense marketing, therapeutic optimism, and the pioneering spirit of cardiologists tempts one to skim over the words "stent thrombosis." This is medical speak for creating an acute heart injury in a patient with a chronic disease. You can accuse me of hyperbole, but the authors of the German/Swiss registry called stent thrombosis a "particularly malignant" condition.

The second problem with BVS is that it's a more complicated implant procedure. Patient and lesion selection will be key—as will staying true to inclusion criteria from the clinical trials. The fact that registry studies of real-world data show higher complication rates than clinical trials is ominous.

The third problem is cost. This is 2016; like it or not, new devices and drugs will have to "cross the fourth hurdle" of cost-effectiveness. Not only is BVS priced higher than regular DES, but a more complicated implant procedure, combined with the likely need for advanced imaging, such as optical coherence tomography, will further increase cost.

Finally, a comment on device approval in the US: I'm not sure we are doing it right. The FDA advisory committee was highly supportive of BVS. Some of these supposedly impartial judges even made enthusiastic comments. I'm baffled; how could they look at the data and be so positive? Enthusiasm is fine when the data show superiority.

I am not against innovation. I understand that pioneering means making miscues. BVS has immense potential. But it's unproven and thus far does not look especially good.

To me, a middle ground between progress and safety is possible. I'd propose that until novel devices like BVS are shown to deliver better outcomes, approval should come with three requirements: a controlled prospective registry, a full informed consent about the uncertainty, and discount (not premium) pricing.

JMM

http://www.m.webmd.com/fitness-exercise/news/20160727/hour-of-exercise-a-day-may-offset-sittings-toll-on-health?src=RSS_PUBLIC

Hour of Exercise a Day May Offset Sitting's Toll

By Steven Reinberg

HealthDay Reporter

WEDNESDAY, July 27, 2016 (HealthDay News) -- Just one hour of physical activity a day -- something as simple as a brisk walk or a bicycle ride -- may undo the increased risk of early death that comes with sitting eight hours or more on a daily basis, a new study suggests.

"These results provide further evidence on the benefits of physical activity, particularly in societies where increasing numbers of people have to sit for long hours for work or commuting," said lead researcher Ulf Ekelund. He is a professor in physical activity and health at the Norwegian School of Sport Sciences in Oslo, Norway.

"Unfortunately, only 25 percent of our sample exercised an hour a day or more," he said.

The study also found that watching TV for three hours or more a day was linked with an increased risk of early death, regardless of physical activity -- except among those who were the most physically active.

However, even among those who exercised the most, the risk of premature death was significantly increased if they watched five hours of TV a day or more, the researchers added.

It's not TV, per se, that is associated with an increased risk of dying early; rather, TV is a marker for sitting and not being active, Ekelund said.

In their review of 16 previously published studies that included more than one million people, the researchers divided the participants into four groups: those who got about 5 minutes of moderate-intensity exercise a day; 25 to 35 minutes a day; 50 to 65 minutes day; and 60 to 75 minutes a day.

The increased risk of early death ranged from 12 percent to 59 percent, depending on how much exercise the participants got, the findings showed.

"Indeed, those belonging to the most active group, and who are active about 60 to 75 minutes per day, seem to have no increased risk of mortality, even if they sit for more than eight hours a day," Ekelund said.

"Sit less, move more, and the more you move the better," he suggested.

The report, which did not prove that inactivity caused early death, was published online July 27 in The Lancet.

According to Dr. David Katz, president of the American College of Lifestyle Medicine, "This important analysis fortifies the increasingly clear verdict from a large and growing body of evidence addressing physical activity and health: all movement is good movement."

Evidence is clear that moderately vigorous exercise has an array of health benefits, Katz said.

"If you don't exercise but can stand often, do. If you can't stand often but can exercise, do," he added. "Better still, do both. It's clear: all movement is good movement."

Not only does physical inactivity increase the risk of early death, it's expensive, according to another study published in the same journal issue.

In that study, researchers estimated the cost of being physically inactive based on the increased risk for type 2 diabetes, heart disease, stroke, and breast and colon cancer. In 2013 dollars, the study authors estimated that inactivity costs the United States about $28 billion annually.

"The current economic cost of physical inactivity is borne mainly by high-income countries. However, as low- and middle-income countries develop, and if the current trajectory of inactivity continues, so too will the economic burden in low- and middle-income countries who are currently poorly equipped to deal with chronic diseases linked to physical inactivity," study author Dr. Melody Ding, of the University of Sydney in Australia, said in a statement.

Even a Little Exercise May Help Younger Women's Hearts – WebMD

http://www.m.webmd.com/women/news/20160725/even-a-little-exercise-may-help-younger-womens-hearts?src=RSS_PUBLIC

Even a Little Exercise May Help Younger Women's Hearts

By Steven Reinberg

HealthDay Reporter

MONDAY, July 25, 2016 (HealthDay News) -- Younger women who exercise just 2.5 hours a week may cut their risk for heart disease by up to 25 percent, a new study suggests.

"The habits and the choices we make in the first half of our life determine our well-being and freedom from chronic disease in the second half of our lives," said Dr. Erin Michos, an associate professor of medicine and epidemiology at Johns Hopkins School of Medicine in Baltimore.

"Importantly, higher levels of physical activity have been shown to be associated with reduction in rates of heart disease, stroke, cancers, diabetes and many other chronic health conditions," said Michos.

She co-authored an editorial accompanying the study, which was published online July 25 in the journal Circulation.

Lead researcher Andrea Chomistek said women can achieve the recommended 150 minutes of moderate-to-vigorous physical activity per week in as many or as few sessions as they wish.

Joining a gym or walking or bicycling, or any other moderate activity that one enjoys, can be enough to reduce your risk of heart disease, she said.

Chomistek, an assistant professor of epidemiology and biostatistics at Indiana University's School of Public Health, thinks that men, too, can achieve a similar benefit with a few hours a week of moderate exercise. But, further research would be needed.

"It is important for normal-weight, overweight and obese women to be physically active," she said. "For people who are currently inactive and find joining a gym intimidating, emphasizing the benefits of walking may help them get active."

For the study, Chomistek and her colleagues collected data on more than 97,000 women, aged 27 to 44, who took part in the Nurses' Health Study 2.

Specifically, the researchers looked at the frequency, amount of time, intensity and type of preferred physical activity in which the women participated. During 20 years of follow-up, 544 women developed heart disease.

The researchers found that women who were the most physically active during their leisure time had the lowest risk for heart disease -- 25 percent lower than women who exercised the least.

Exercise didn't have to be strenuous. In fact, moderate exercise, such as taking a brisk walk, was associated with a lower risk of heart disease, the researchers found.

But the study did not prove a cause-and-effect link between the two.

The women who seemed to benefit the most exercised the most, at least 150 minutes a week.

And, it didn't matter what weight a woman was when she started exercising to lower her risk for heart disease, Chomistek said.

However, Chomistek acknowledged that the study has two limitations. First, the women in the study were mostly white, so it can't be assumed that these results apply to other racial or ethnic groups. Second, the data from the participants were self-reported, so it's possible that the figures were less than accurate.

Young women are so busy being caretakers of others -- their young children, their spouses, their aging parents, their friends and neighbors -- that they can neglect their own health, Michos said.

"Young women, however, are often the gatekeepers of health for their families. If we can encourage young women to make better food choices and be more active, often their spouses, children and other members of their social network will benefit, too," Michos said.

Flu Shot May Help Protect Diabetics From CV Hospitalization

http://www.medscape.com/viewarticle/866657?src=rss

Flu Shot Seen to Help Protect Diabetics From CV Hospitalizations

LONDON, UK — In a population of adults with type 2 diabetes seen in UK primary-care clinics, those who received the influenza shot had lower rates of hospitalization for flu and pneumonia, major cardiovascular diseases, and death during the following flu season compared with their unvaccinated peers.

The study by Dr Eszter P Vamos (Imperial College London, UK) and colleagues examined data from seven flu seasons from 2003–2004 to 2009–2010 and was published online July 25, 2016 in CMAJ.

The diabetic patients who received the flu shot had 15% to 30% lower rates of death or hospital admission for stroke, heart failure, pneumonia, or influenza (P <0.05) during the subsequent flu season.

Although many countries strongly recommend annual flu shots for older adults and patients with chronic conditions such as diabetes, evidence from small, less rigorous trials has not been compelling. This is the first study to look at specific cardiovascular outcomes in diabetic patients who did or did not receive a flu shot.

Influenza vaccine is largely underused among people with chronic diseases such as diabetes, Vamos told heartwire from Medscape. This study shows that it may significantly reduce cardiovascular illness and death during flu season, and thus it is very important for this high-risk population to get vaccinated, she stressed.

Dr Jacob A Udell (Peter Munk Cardiac Centre and Cardiovascular Division, University Health Network, and University of Toronto, ON), who was not involved with this study, agrees. These observational data provide "positive reinforcement of why we should be getting patients vaccinated, particularly patients who aren't over 65 but have diabetes," he told heartwire .

Before flu season starts, cardiologists, internists, and endocrinologists should ask their patients if they have received a flu shot, and if not, should offer it at their local sites. "I strongly believe it should be considered a performance measure in our system," similar to screening for high cholesterol, he added. This study shows "no harm and certainly potential benefit" if all adult diabetic patients get a flu shot. Moreover, "we shouldn't be satisfied with just a 65% vaccination rate," he said.

Udell is an investigator in the Influenza Vaccine to Effectively Stop Cardio Thoracic Events and Decompensated Heart Failure (INVESTED), which is just getting under way and will compare two newer types of influenza vaccines for protection from major heart and respiratory illness..

124,000 Diabetic Patients, Seven Flu Seasons

Vamos and colleagues aimed to compare the risk of hospitalization for major cardiovascular outcomes and death in flu season in patients with type 2 diabetes who did or did not receive a flu shot.

They also looked at influenza or pneumonia as a combined outcome, which is common in clinical trials since "influenza is often not detected or recognized as a trigger of severe events and remains profoundly underrecorded as a primary cause of illness on hospital admission records and mortality files," Vamos explained.

The researchers analyzed data from 300 primary-care practices in England that are part of a Clinical Practice Research Datalink. They identified 124,503 patients with type 2 diabetes over a 7-year period between 2003–2004 and 2009–2010.

The patients' vaccination uptake ranged from 63% in 2008–2009 to 69% in 2006–2007.

Compared with the other patients, those who received the flu shot were generally older, sicker, and taking more medications, but they had lower HbA_1c and cholesterol levels.

Across these study years, there were 5142 hospital admissions for acute MI, 4515 admissions for stroke, 14,154 admissions for pneumonia or influenza, 12,915 admissions for heart failure, and 21,070 deaths.

After adjusting for covariates (age, sex, diabetes duration, number of comorbid conditions, smoking status, medications, blood pressure, body-mass index, HbA_1c, cholesterol, hospital admissions, past influenza vaccination, pneumococcal vaccination, and cohort year) and residual confounding (calculated from the summer period when the vaccine should not provide benefit), they found that patients who had received the flu vaccination had significantly lower rates of all studied outcomes during the flu season, except for risk of acute MI.

Cardiovascular and Mortality Outcomes in Flu Season, Vaccinated vs Unvaccinated Diabetic Patients

Flu season outcome	IRR (95% CI)	P
Hospitalization for acute MI	0.81 (0.62–1.04)	NS
Hospitalization for stroke	0.70 (0.53–0.91)	<0.05
Hospitalization for heart failure	0.78 (0.65–0.92)	<0.05
Hospitalization for pneumonia or influenza	0.85 (0.74–0.99)	<0.05
All-cause death	0.76 (0.65–0.83)	<0.05

IRR=incidence rate ratio, adjusted for multiple covariables and residual confounding

NS=not significant

The findings were similar after they excluded the 2 study years when there was not a good match between the vaccine and the circulating virus.

"Patients with diabetes . . . have a relatively suppressed immune system," so their immune system doesn't generate as good a response when they are infected with influenza, Udell noted, and the lower response in younger people with diabetes is similar to the age-associated decline in immune response.

The current study reinforces the importance of a flu shot in all patients with diabetes, he reiterated.

INVESTED Will Compare Trivalent vs Quadrivalent Vaccine, Two Doses

The current standard of care in the US and Canada is a trivalent vaccine with two strains of influenza A and one strain of influenza B, with 15 µg of each strain, Udell explained.

A quadrivalent vaccine with two strains of influenza A and two of influenza B, with 15 µg, has been approved by Health Canada and by the US Food and Drug Administration (FDA), and it is starting to come into use in the US and more slowly in Canada.

Moreover, he said, a high-dose trivalent vaccine with two influenza A strains and one influenza B strain with 60 µg of each strain has also been approved by the FDA and Health Canada, largely based on a recent trial, but it is not approved for adults under 65; in this age group, its use is investigational.

INVESTED will shed light on these two newer forms of flu vaccines in the general population, including diabetic patients, according to Udell. It will test the hypothesis that Fluzone (Sanofi Pasteur) high-dose trivalent influenza vaccine will reduce cardiopulmonary events to a greater extent than Fluzone standard-dose quadrivalent influenza vaccine in high-risk cardiovascular patients with a recent history of MI or heart failure.

The trial plans to enroll 9300 participants over a pilot season and three additional influenza seasons, and the primary end point will be a composite of all-cause mortality or cardiopulmonary hospitalization. Enrollment for the pilot phase will start in September 2016 at 40 sites across North America (about 15 sites in Canada), and the final results are expected in February 2021.

The study authors and Udell have no relevant financial relationships.

For more from theheart.org, follow us on Twitter and Facebook.

Being Unfit May Be Almost as Bad for You as Smoking - NYTimes.com

http://mobile.nytimes.com/blogs/well/2016/07/27/being-unfit-may-be-almost-as-bad-for-you-as-smoking/?partner=rss&emc=rss&referer=

Being Unfit May Be Almost as Bad for You as Smoking

By GRETCHEN REYNOLDS

July 27, 2016

Being out of shape could be more harmful to health and longevity than most people expect, according to a new, long-term study of middle-aged men. The study finds that poor physical fitness may be second only to smoking as a risk factor for premature death.

It is not news that aerobic capacity can influence lifespan. Many past epidemiological studies have found that people with low physical fitness tend to be at high risk of premature death. Conversely, people with robust aerobic capacity are likely to have long lives.

But most of those studies followed people for about 10 to 20 years, which is a lengthy period of time for science but nowhere near most of our actual lifespans. Some of those studies also enrolled people who already were elderly or infirm, making it difficult to extrapolate the findings to younger, healthier people.

So for the new study, which was published this week in the European Journal of Preventive Cardiology, researchers from the University of Gothenburg in Sweden and other institutions turned to an impressively large and long-term database of information about Swedish men.

The data set, prosaically named the Study of Men Born in 1913, involved exactly that. In 1963, almost 1,000 healthy 50-year-old men in Gothenburg who had been born in 1913 agreed to be studied for the rest of their lives, in order to help scientists better understand lifetime risks for disease, especially heart disease.

The men completed baseline health testing in 1963, including measures of their blood pressure, weight and cholesterol, and whether they exercised and smoked. Four years later, when the volunteers were 54, some underwent more extensive testing, including an exercise stress test designed to precisely determine their maximum aerobic capacity, or VO2 max. Using the results, the scientists developed a mathematical formula that allowed them to estimate the aerobic capacity of the rest of the participants.

Aerobic capacity is an interesting measure for scientists to study, because it is affected by both genetics and lifestyle. Some portion of our VO2 max is innate; we inherit it from our parents. But much of our endurance capacity is determined by our lifestyle. Being sedentary lowers VO2 max, as does being overweight. Exercise raises it.

Among this group of middle-aged men, aerobic capacities ranged from slight to impressively high, and generally reflected the men's self-reported exercise habits. Men who said that they seldom worked out tended to have a low VO2 max. (Because VO2 max is more objective than self-reports about exercise, the researchers focused on it.)

To determine what impact fitness might have on lifespan, the scientists grouped the men into three categories: those with low, medium or high aerobic capacity at age 54.

Then they followed the men for almost 50 years. During that time, the surviving volunteers completed follow-up health testing about once each decade. The scientists also tracked deaths among the men, based on a national registry.

Then they compared the risk of relatively early death to a variety of health parameters, particularly each man's VO2 max, blood pressure, cholesterol profile and history of smoking. (They did not include body weight as a separate measure, because it was indirectly reflected by VO2 max.)

Not surprisingly, smoking had the greatest impact on lifespan. It substantially shortened lives.

But low aerobic capacity wasn't far behind. The men in the group with the lowest VO2 max had a 21 percent higher risk of dying prematurely than those with middling aerobic capacity, and about a 42 percent higher risk of early death than the men who were the most fit.

Poor fitness turned out to be unhealthier even than high blood pressure or poor cholesterol profiles, the researchers found. Highly fit men with elevated blood pressure or relatively unhealthy cholesterol profiles tended to live longer than out-of-shape men with good blood pressure and cholesterol levels.

Of course, this study found links between poor fitness and shortened lifespans. It cannot prove that one caused the other, or explain how VO2 max might affect lifespan. However, the findings raise the possibility, as the scientists speculate, that by strengthening the body, better fitness may lower the risk of a variety of chronic diseases.

This study also involved men — and Swedish men at that. So whether the findings are applicable to other people, particularly women, is uncertain.

But "there is no reason not to think" that the rest of us would also share any beneficial associations between fitness and longevity, said Per Ladenvall, a researcher at the Sahlgrenska Academy at the University of Gothenburg, who led the study. Past studies involving women have found such links, he said.

Encouragingly, if you now are concerned about the state of your particular aerobic capacity, you most likely can increase it just by getting up and moving. "Even small amounts of physical activity," Dr. Ladenvall said, "may have positive effects on fitness."