RE: Re: Exercise versus mortality

[Guest guest]

Thanks, Dr Forshey,

for that data.

Playing with the numbers, If I do 10 mins, I have a 79% reduction. Just kidding.

I guess that's per day.

The question is what level?

And if I average 30 mins per day, how much does 60 mins improve mortality?

And let me change the heading to exercise versus mortality, since the issue is mortality, not LE or immunity.

Perhaps of interest:

2000 American Heart Association, Inc. Volume 102(20), 14 November 2000, p e168

Can Aerobic Exercise Training Be Hazardous to Human Vessels?

Response

Regular physical exercise reduces cardiovascular morbidity and mortality in the general population. Exercise-induced augmentation of endothelium-dependent vasodilation through an increase in nitric oxide may, at least in part, contribute to antiatherogenic and antihypertensive mechanisms of exercise. 1 However, we agree with Dr Abraham and colleagues that we must keep in mind the intensity, duration, frequency, and kind of exercise and that intense exercise training should be avoided because excess exercise can be hazardous to human vessels.

Bergholm et al 2 reported that 12 weeks of intense physical training, consisting of four 1-hour running sessions per week at an intensity of 70% to 80% of maximal oxygen consumption, decreased circulating antioxidants, such as uric acid, sulfhydryl groups, [alpha]-tocopherol, beta carotene, and retinol and decreased acetylcholine-induced vasodilation in forearm vessels in normal men. If the same exercise regimen is performed by hypertensive patients, their blood pressure may be elevated in association with these unfavorable effects. In addition, we also think that endofibrosis is a unique clinical model of vascular impairment resulting from excess exercise training, although the physiopathology of this disease and its possible relationship with endothelial function are unknown. 3

These findings suggest that long-term high-intensity exercise training may impair endothelial function through a decrease in antioxidants, an increase in free radicals, and a change in vascular structure, resulting in a reduction in nitric oxide release. Thus, we recommend a moderately intense exercise training program consisting of 30 to 60 minutes of walking, swimming, or bicycling, performed >=3 times per week at an intensity of 50% to 60% of maximal oxygen consumption. Most individuals can safely and regularly perform such a level of physical activity.

A special committee on hypertension has confirmed the beneficial effects of moderate-intensity exercise. 4 It has also been shown that high-intensity exercise generally does not alter blood pressure or cause blood pressure elevation. 5

Further investigation should be performed to determine the grade dependence of intensity and duration of exercise on endothelial function and blood pressure in individuals, including patients with essential hypertension.

Yukihito Higashi MD, PhD

Shota Sasaki MD

Satoshi Kurisu MD

Atsunori Yoshimizu MD

Nobuo Sasaki MD

Hideo Matsuura MD, PhD

Goro Kajiyama MD, PhD

Tetsuya Oshima MD, PhD

1. Higashi Y, Sasaki S, Kurisu S,et al. Regular aerobic exercise augments endothelium-dependent vascular relaxation in normotensive as well as hypertensive subjects: role of endothelium-derived nitric oxide. Circulation. 1999; 100: 1194–1202

Discussion

In the present study, 12 weeks of moderate exercise, but not mild- or high-intensity exercise, augmented endothelium-dependent vasodilation through increased NO production in healthy subjects. High-intensity exercise increased plasma concentrations of 8-OHdG and serum concentrations of MDA-LDL, which are indices of oxidative stress.

Conclusions: These findings suggest that long-term physical exercise improves endothelium-dependent vasorelaxation through an increase in the release of nitric oxide in normotensive as well as hypertensive subjects.

2. Bergholm R, Makinmattila S, Valkonen M,et al. Intense physical training decreases circulating antioxidants and endothelium-dependent vasodilation in vivo. Atherosclerosis. 1999; 145: 341–349.

Atherosclerosis. 1999 Aug;145(2):341-9.

Intense physical training decreases circulating antioxidants and endothelium-dependent vasodilatation in vivo.Bergholm R, Makimattila S, Valkonen M, Liu ML, Lahdenpera S, Taskinen MR, Sovijarvi A, Malmberg P, Yki-Jarvinen H.Department of Medicine, University of Helsinki, Finland.Physical training increases free radical production and consumes antioxidants. It has previously been shown that acute exercise markedly increases the susceptibility of LDL to oxidation but whether such changes are observed during physical training is unknown. We measured circulating antioxidants, lipids and lipoproteins, and blood flow responses to intrabrachial infusions of endothelium-dependent (acetylcholine, ACh, L-N-monomethyl-arginine, L-NMMA) and -independent (sodium nitroprusside, SNP) vasoactive agents, before and after 3 months of running in 9 fit male subjects. Maximal aerobic power increased from 53 +/- 1 to 58 +/- 2 ml/kg min (P < 0.02). All circulating antioxidants (uric acid, SH-groups, alpha-tocopherol, beta-carotene, retinol) except ascorbate decreased significantly during training. Endothelium-dependent vasodilatation in forearm vessels decreased by 32-35% (P < 0.05), as determined from blood flow responses to both a low (10.8 +/- 2.1 vs. 7.3 +/- 1.5 ml/dl min, 0 vs. 3 months) and a high (14.8 +/- 2.6 vs. 9.6 +/- 1.8) ACh dose. The % endothelium-dependent blood flow (% decrease in basal flow by L-NMMA), decreased through training from 37 +/- 3 to 22 +/- 7% (P < 0.05). Blood flow responses to SNP remained unchanged. The decrease in uric acid was significantly correlated with the change in the % decrease in blood flow by L-NMMA (r = 0.74, P < 0.05). The lag time for the susceptibility of plasma LDL to oxidation in vitro, LDL size and the concentration of LDL cholestetol remained unchanged. We conclude that relatively intense aerobic training decreases circulating antioxidant concentrations and impairs endothelial function in forearm vessels. PMID: 10488962

3. Abraham P, Saumet JL, Chevalier JM. External iliac artery endofibrosis in athletes. Sport Med. 1997; 24: 221–226.

Sports Med. 1997 Oct;24(4):221-6.

External iliac artery endofibrosis in athletes.Abraham P, Saumet JL, Chevalier JM.Laboratoire d'Explorations Vasculaire et de Medecine du Sport, C.H.U. d'Angers, France.Atherosclerosis and inflammatory arterial diseases are rare in young people. Since the early 1980s, an increasing incidence of iliac arterial stenosis in competition cyclists has been reported. Histological findings in these individuals are specific, with fibrosis of the intimal wall on histology and no atherosclerotic or inflammatory lesions. Clinical consequences of this arterial endofibrosis are usually described as an exercise-related subjective sensation of swollen thigh in one or both (15%) legs, with normal clinical and Doppler investigations at rest. Following maximal exercise, ankle-to-brachial systolic pressure index is lower than 0.5 in 85% of individuals with disease and is used as a key argument for diagnosis before deciding upon arteriography. Surgery (recalibrated saphenous grafts or angioplasty-endofibrosectomy) seems to be efficient to allow an early return to competition, but its long term results are still to be evaluated. The physiopathology of this disease and its possible relationship with atherosclerosis are unknown. PMID: 9339491

4. Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. The sixth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VI). Arch Intern Med. 1997;157:2413–2446.

5. Roman O, Camuzzi AL, Villalon E,et al. Physical training programs in arterial hypertension: a long-term prospective follow-up. Cardiology. 1981; 67: 230–243.

Cardiology. 1981;67(4):230-43.

Physical training program in arterial hypertension. A long-term prospective follow-up.Roman O, Camuzzi AL, Villalon E, Klenner C.A long-term training program was performed on 30 chronic hypertensive female patients, stages I-II, WHO criteria. The effect on blood pressure (BP) and other physiological parameters, as exercise BP, heart rate, physical working capacity, VO2max, double product, were studied. Four phases were outlined throughout the trial: (1) 3 months training at 70% of the maximal heart rate; (2) 3 months without training; (3) 1 year training at the same level as phase I, and (4) 12 or more months with increasing intensity training over 70% of the maximal heart rate. Serial ergometric work tests were performed every 3 months. We observed a close relationship between physical working capacity and VO2max increases with training intensity. Resting BP fell significantly with training (182/114-161/97 mm Hg; p less than 0.001) but increased again when training was discontinued (161/97-179/115 mm Hg; p less than 0.001). BP persisted low throughout the trial, but there was a tendency to a further but not significant decrease when training intensity was raised over 70% of the maximal heart rate. Both the submaximal and maximal exercise BP showed similar changes to those found in the resting BP throughout the trial. The submaximal heart rate and the double product (BP X heart rate) also fell significantly with training but with maximal values not changing significantly throughout the whole follow-up period. PMID: 7248998

Regards.

----- Original Message -----

From: drsusanforshey

Sent: Saturday, July 23, 2005 8:39 AM

Subject: [ ] Re: Exercise >>> Immunity

"For each minute increase in maximal treadmill time betweenexaminations, there was a corresponding 7.9% (P = .001) decrease inrisk of mortality."

[Guest guest]

I have avoided proffering any advice to this thread despite being convinced of the value and

a regular exerciser. I believe just like so much else we are individuals and will respond

differently to variations in diet and exercise.

The number of apparently contradictory results should show the risk of taking any one

study and literally "running" with it (sorry I couldn't resist the pun).

Eating less and exercise both appear to provide health benefits. As with all things

moderation is prudent until we understand more and are able to apply that understanding

to our specific situation. Micromanagement based on any one study may be suspect.

I've got to go mow my lawn, I think that's too much exercise :-) but if I don't cut it, it don't get cut.....

Be well .

JR

-----Original Message-----From: [mailto: ]On Behalf Of jwwrightSent: Saturday, July 23, 2005 10:17 AM Subject: Re: [ ] Re: Exercise versus mortality

Thanks, Dr Forshey,

for that data.