Re: Duration of Exercise and CHD Risk Reduction

[Guest guest]

Barry Vaughn wrote:

<<<Could any of the members direct me to any scientific papers that deal with

the duration of exercise necessary to increase cardiovascular HEALTH, eg. CHD

risk?>>>

***

Barry, some recent studies have suggested that high-intensity training may

substitute for longer duration lower intensity training in reducing

cardiovascular morbidiity/mortality. For example:

Eur J Cardiovasc Prev Rehabil. 2006 Oct;13(5):798-804.

A single weekly bout of exercise may reduce cardiovascular mortality: how little

pain for cardiac gain? 'The HUNT study, Norway'

Wisloff U et al.

" A single weekly bout of exercise of high intensity reduced the risk of

cardiovascular death, both in men [relative risk (RR) 0.61, 95% confidence

interval (CI) 0.49-0.75], and women (RR 0.49, 95% CI 0.27-0.89), compared with

those who reported no activity. There was no additional benefit from increasing

the duration or the number of exercise sessions per week. "

One would need to read this study carefully to see what energy was expended in

the single session. (I have not.)

See also:

Heart. 2003 May;89(5):502-6.

What level of physical activity protects against premature cardiovascular death?

The Caerphilly study.

Yu S et al

" CONCLUSIONS: These data suggest that, in a population of men without evidence

of CHD at baseline, only leisure exercise classified as heavy or vigorous was

independently associated with reduced risk of premature death from CVD. "

Again, one would need to determine the MET level of 'vigorous', 'heavy' etc in

this study.

Even so, rather than just consider duration or intensity of exercise, the

over-arching determinant of cardiovascular health in relation to physical

activity is cardiorespiratory or aerobic 'fitness' (CRF), more or less measured

by VO2, heart rate reserve (max minus resting HR) or recovery time. It does not

seem to matter how one gets fit, high-intensity, low-intensity or anything in

between, it's mainly 'CR fitness' that matters -- as a general principle. (Bear

in mind as well that CVD for most people will be a multi-factorial disease

involving genetics, lifestyle -- diet etc -- as well as fitness.)

Whether, as suggested by the above studies, one can substitute intensity for

duration or energy expended needs to be tested further in my view.

In this Institute study below, heart rate reserve (HRR) was inversely

associated with CVD mortality in younger men, whereas in older men, HRR and

cardiorespiratory fitness reduced CVD mortality.

Med Sci Sports Exerc. 2002 Dec;34(12):1873-8.

Heart rate reserve as a predictor of cardiovascular and all-cause mortality in

men.

Cheng YJ et al

" CONCLUSIONS HRR,independent from CRF, was inversely associated with CVD

mortality among men in this study. HRR may be an important exercise test

parameter to predict CVD mortality in younger men, whereas CRF and other

established risk factors are better predictors of CVD and all-cause mortality in

older men. "

It is possible that heart rate reserve may be the best all round indicator of a

protective fitness.

See also:

Church TS, Kampert JB, Gibbons LW, Barlow CE, Blair SN.

Usefulness of cardiorespiratory fitness as a predictor of all-cause and

cardiovascular disease mortality in men with systemic hypertension.

Am J Cardiol. 2001 Sep 15;88(6):651-6.

Laukkanen JA, Lakka TA, Rauramaa R, Kuhanen R, Venalainen JM, Salonen R,

Salonen JT.

Cardiovascular fitness as a predictor of mortality in men.

Arch Intern Med. 2001 Mar 26;161(6):825-31.

Blair SN, Kampert JB, Kohl HW 3rd, Barlow CE, Macera CA, Paffenbarger RS

Jr, Gibbons LW.

Influences of cardiorespiratory fitness and other precursors on cardiovascular

disease and all-cause mortality in men and women.

JAMA. 1996 Jul 17;276(3):205-10.

Laukkanen JA, Kurl S, Salonen R, Rauramaa R, Salonen JT.

The predictive value of cardiorespiratory fitness for cardiovascular events in

men with various risk profiles: a prospective population-based cohort study.

Eur Heart J. 2004 Aug;25(16):1428-37.

" CONCLUSIONS: VO2peak can be used as a very powerful predictor of future fatal

cardiac events beyond that predicted by many conventional risk factors. On the

prognostic consideration, unfit men with unfavourable risk profiles or

underlying chronic disease are the risk groups that will benefit most from

preventive measures. "

Morshedi-Meibodi A, Larson MG, Levy D, O'Donnell CJ, Vasan RS.

Heart rate recovery after treadmill exercise testing and risk of cardiovascular

disease events (The Framingham Heart Study).

Am J Cardiol. 2002 Oct 15;90(8):848-52.

Fitnesse Health and Fitness

Gympie, Australia

[Guest guest]

Barry,

There is direct relationship between intensity and duration. For heart

conditioning minimum requirement is-

- continuous exercise at 70% of maximum heart rate (HR max) for 30- 40

minutes, 4-5 days a week or

- continuous exercise at 85% of HR max for 20 minutes, 3 days a week.

In both the cases cardiovascular fitness will be same.

Mayo clinic experts state even if you do 10 mts in two sessions at 85%HR max

effect will be the same. But if you do for less than 10 minutes in a single

session there will be no conditioning.

BUT even if you do far below this but for long duration, there will be

cardiovascular benefits even if there is no heart conditioning or loss of

weight, because of following positive health effects--

1- Increase fitness level- increase VO2 max, time of exhaustion.

2- metabolic changes like- reduced cholestrol, LDL and trigleceride : increase

HDL.Further there wikk be increase sensitivity for insulin.

3- Decrease body weight.

4- the result of such fitness have also direct positive effects on muscular

endurance and indirect effect on strength and flexibility.

All these effects translates into reduced risk of heart diseases, heart attack

and even strokes. Truth is you can improve your cardiovascular fitness and

reduce risk of heart diseases even by moderate exercise without loosing weight

and strenghtening the heart.

Ajai Tomar

Khartoum, Sudan

ajai_53@...

[Guest guest]

The article posted by Dr. Giarnella is great news for folks like me

who want to maintain or improve cardiovascular health without

spending a lot of time or effort. The message I get from this study

is that it requires a very small volume of aerobic exercise at very

low intensity to improve cardiovascular health. Here's the info I'm

basing my opinion upon:

> The exercise groups were as follows:

>

> (1) low amount/ moderate intensity (LAMI, n =25), the

> caloric equivalent of walking 19 kilometers (km)/wk at

> 40 to 55%of peak vO2 ;

>

> (2) low amount/high intensity (LAHI, n = 36), the

> equivalent of jogging 19 km/wk at 65 to 80%of peak ?O2

>

> (3) high amount/high intensity (HAHI, n = 35), the

> equivalent of jogging 32 km/wk at 65 to 80%of peak ?O2

An intensity of 40-55% of peak vO2 is only a warm up for a

runner, cyclist, rower, XC skiier, or swimmer. (For those who

aren't familiar with endurance sports, that's not an exaggeration or

boast--it's a fact.) At that level of intensity, you may not even

be perspiring or breathing hard. Even the " high intensity " used in

this study (65-80% of peak vO2) isn't considered high for endurance

athletes.

The volumes ( " amounts " ) used in this study are very low

compared to the volumes used by recreational endurance athletes.

Nineteen kilometers is about 12 miles. I know a lot of runners, but

I don't know any who only run twelve miles per week. At a slow pace

of ten minutes per mile, that's only two hours of exercise per

week. At a pace of eight minutes per mile, that's only slightly

more than 1 1/2 hours per week. The " high amount " was only 32

kilometers, or about 20 miles per week. At ten minutes per mile,

that's three hours and twenty minutes of excercise. At eight

minutes per mile, it's two hours and forty minutes.

For endurance athletes who aren't limited by impact (e.g., swimmers,

XC skiiers, rowers, cyclists), these hourly volumes are tiny.

Consider an endurance athlete who works out once a day, six days per

week, and takes one day off. The athlete will spend at least five

minutes warming up and another five minutes cooling down at exercise

intensities >40% of peak vO2. That's already a minimum of sixty

minutes, just for the warm up and cool down.

Many thanks to Dr. Giarnella for this great news!

Regards,

s

Ardmore PA

[Guest guest]

The following artticle may also shed some light on

physical activity and CHD risk reduction:

Ralph Giarnella MD

Southington, CT

AHA: The Heart Failure Waltz Leads to Improved

Function

By Peggy Peck, Senior Editor, MedPage Today

Reviewed by Jasmer, MD; Associate Clinical

Professor of Medicine, University of California, San

Francisco

November 12, 2006

MedPage Today Action Points

Explain to interested patients that cardiac

rehabilitation is known to improve function in

patients with mild to moderate heart failure. This

report suggests that a nontraditional exercise such as

dancing may be a rehabilitation option.

This report is based on abstracts presented at a

meeting. These data and conclusions should be

considered preliminary as they have not yet been

reviewed and published in a peer-reviewed publication.

Review

CHICAGO, Nov. 12 -- Heart failure patients can waltz

their way to improved function, and dancing made them

much happier than cardiac rehabilitation that relied

on treadmills and exercise bikes.

Patients randomized to waltz classes significantly

improved functional measures (P<0.001) compared with

controls in traditional exercise training, Romualdo

Belardinelli, M.D., of Lancisi Heart Institute in

Ancona, Italy, reported today at the American Heart

Association meeting here.

What's more, the dancing patients posted significantly

better quality-of life scores than the traditional

exercise group (P<0.05),

Dr. Belardinelli said

Nieca Goldberg, M.D., chief of women's cardiac care at

Lenox Hill Hospital in New York, said the results are

important because it is difficult to get patients to

complete cardiac rehabilitation faithfully, so a

program that patients consider " fun and enjoyable is

likely to make rehabilitation more palatable. "

Dr. Belardinelli said he and his colleagues " chose

waltz because it is a universal dance, which means

that the findings can be generalized to other

countries. " He said, however, that other slow dances

might be just as effective.

He and his colleagues studied 110 patients with stable

congestive heart failure and a left ejection fraction

of less than 40%. Eighty-nine of the patients were men

and the mean age was 59 ± 11 years.

Forty-four patients were randomized to supervised

exercise training on cycles and treadmills at 70% of

peak oxygen consumption (VO2) three times a week for

eight weeks and 44 to a dance protocol of alternate

slow-five minutes--and fast-21 minutes-- waltz three

times a week for eight weeks.

Twenty-two patients served as a control group.

Both exercise training and dance classes were

conducted at the hospital and heart rate was monitored

during the sessions. At baseline and at eight weeks

all patients underwent cardiopulmonary exercise

testing until volitional fatigue as well as

two-dimensional echocardiography with Doppler, and

endothelium-dependent dilation of the brachial artery.

Quality of life was assessed by the Minnesota Heart

Failure Living Questionnaire.

Among the findings:

Heart rate during exercise training was 110± 15

beats/min and during dancing it was 113±19 beats/min

(NS)

Peak VO2, anaerobic threshold, minute ventilation

(VE)CO2 production /(VCO2) and VO2/Workload (W) slope

were all similarly improved in both the dance and

exercise arms (NS, P<0.001 versus controls).

Ejection fraction was not significant changed by

either exercise or dancing, but E-wave to A-wave ratio

was decreased in both the exercise and dance groups

compared with controls (P<0.05).

" As might be expected, the real difference between the

two groups was in quality-of- life scores, " he said.

Noting that a higher score indicated a worse quality

of life, he said the patients randomized to the dance

class improved scores from an average of 56±18 years

at baseline to 41±16 after completing the study versus

58±20 to 48±21 in the exercise group (P<0.05), he

said.

Dr. Belardinelli concluded, " Dancing should be

considered an alternative to traditional cardiac

rehabilitation for patients with heart failure. "

Primary source: American Heart Association Scientific

Sessions

Source reference:

Belardinelli R et al " Dancing in Patients with Chronic

Heart Failure : A new Form of Exercise Training "

Abstract 3957

--- s wrote:

> The article posted by Dr. Giarnella is great news

> for folks like me

> who want to maintain or improve cardiovascular

> health without

> spending a lot of time or effort. The message I get

> from this study

> is that it requires a very small volume of aerobic

> exercise at very

> low intensity to improve cardiovascular health.

> Here's the info I'm

> basing my opinion upon:

>

> > The exercise groups were as follows:

> >

> > (1) low amount/ moderate intensity (LAMI, n =25),

> the

> > caloric equivalent of walking 19 kilometers

> (km)/wk at

> > 40 to 55%of peak vO2 ;

> >

> > (2) low amount/high intensity (LAHI, n = 36), the

> > equivalent of jogging 19 km/wk at 65 to 80%of peak

> ?O2

> >

> > (3) high amount/high intensity (HAHI, n = 35), the

> > equivalent of jogging 32 km/wk at 65 to 80%of peak

> ?O2

>

> An intensity of 40-55% of peak vO2 is only a warm up

> for a

> runner, cyclist, rower, XC skiier, or swimmer. (For

> those who

> aren't familiar with endurance sports, that's not an

> exaggeration or

> boast--it's a fact.) At that level of intensity,

> you may not even

> be perspiring or breathing hard. Even the " high

> intensity " used in

> this study (65-80% of peak vO2) isn't considered

> high for endurance

> athletes.

>

> The volumes ( " amounts " ) used in this study are very

> low

> compared to the volumes used by recreational

> endurance athletes.

> Nineteen kilometers is about 12 miles. I know a lot

> of runners, but

> I don't know any who only run twelve miles per week.

> At a slow pace

> of ten minutes per mile, that's only two hours of

> exercise per

> week. At a pace of eight minutes per mile, that's

> only slightly

> more than 1 1/2 hours per week. The " high amount "

> was only 32

> kilometers, or about 20 miles per week. At ten

> minutes per mile,

> that's three hours and twenty minutes of excercise.

> At eight

> minutes per mile, it's two hours and forty minutes.

>

> For endurance athletes who aren't limited by impact

> (e.g., swimmers,

> XC skiiers, rowers, cyclists), these hourly volumes

> are tiny.

> Consider an endurance athlete who works out once a

> day, six days per

> week, and takes one day off. The athlete will spend

> at least five

> minutes warming up and another five minutes cooling

> down at exercise

> intensities >40% of peak vO2. That's already a

> minimum of sixty

> minutes, just for the warm up and cool down.

>

> Many thanks to Dr. Giarnella for this great news!

>

> Regards,

>

> s

> Ardmore PA

>

>

>

>

[Guest guest]

The following may be of interest and on topic

Ralph Giarnella MD

Southington, CT

Original page:

http://www.webmd.com/content/Article/129/117324.htm

Obese Kids Getting Hardened Arteries

Exercise -- If Kept Up -- Can Undo Damage to Blood

Vessels

By DeNoon

WebMD Medical News Reviewed By Louise Chang, MD

on Tuesday, October 31, 2006

Oct. 31, 2006 -- Obese 14-year-olds already have

hardening of the arteries, an early warning of heart

disease risk.

That finding comes from German researchers looking

deep into the Pandora's box of childhood obesity. The

latest bad news is that by the time they reach their

teens, obese children's blood vessels already are

hardening on the outside and thickening on the inside.

However, the study holds hope. It shows that when

obese teens undergo an aggressive, six-month exercise

program, they can undo the damage to their arteries.

They also lose weight, cut their cholesterol and blood

fat levels, and lower their blood pressure.

" Atherosclerosis -- hardening of the arteries --

starts during childhood in the presence of such risk

factors as obesity and sedentary lifestyle, " the

study's lead researcher, s Meyer, MD,

says in a news release.

" We think that 90 minutes of exercise, three times per

week, is the minimum children need to reduce their

[heart disease] risk, " he adds.

Swimming, Sports, and Walking

Meyer, a pediatric heart specialist at the University

of Rostock Children's Hospital in Rostock, Germany,

enrolled 96 obese boys and girls in the study.

The kids ranged in age from 11 to 16, with an average

age of 14. None got even a half hour of exercise per

week.

Compared with 35 normal-weight kids, the obese kids

showed alarming warning signs. Most dramatically,

their blood vessels were stiffening and getting

narrow.

Unless something changed, these kids were on their way

to short, unhealthy lives.

A Solution

A Solution

For six months, 50 of the obese kids were assigned to

a structured exercise program.

They did 60 minutes of swimming and water aerobics on

Mondays. They played team sports for 90 minutes on

Wednesdays. And they walked for 60 minutes on Fridays.

Under the observation of coaches and physical

therapists, the exercises intensified to the degree

individual teens could tolerate them.

Only about two-thirds of the kids made it through the

exercise program.

But those who did saw encouraging changes:

The kids' arteries became more flexible, allowing them

to carry more oxygen-rich blood throughout the body --

and making exercise easier.

The inner layer of their arteries shrank, allowing

increased blood flow and lowering the chance of plaque

buildup.

They lost weight.

They cut their high blood levels of cholesterol and

fats.

They lowered their blood pressure.

The study's findings appear in the Nov. 7 issue of the

Journal of the American College of Cardiology.

The Trick: Motivating Kids

Meyer warns, however, that these benefits will

disappear if the kids don't keep up regular exercise.

Obese kids, he notes, lack motivation to exercise and

tend not to persevere once exercise becomes strenuous.

" It's important that children enjoy exercise, so we

recommend games like soccer, football, basketball, and

swimming -- especially for obese children, " Meyer

says.

Fun or not, it takes time to get obese children to

want to exercise, says Albert P. Rocchini, MD, a

pediatric heart specialist the University of

Michigan's C.S. Mott Children's Hospital. Rocchini was

not involved in the German study.

" We want young people to understand that now is the

time to start dealing with health issues before they

become permanent, " Rocchini says in a news release.

" But it takes time to get through to them. "

SOURCES: Meyer, A. Journal of the American College of

Cardiology, Nov. 7, 2006; vol 9: pp 1865-1870. News

release, American College of Cardiology.

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