Monday, September 16, 2013

Interesting Article About Aerobic Interval Training For Heart Failure Patients


Abstract
Background— Exercise training reduces the symptoms of chronic heart failure. Which exercise intensity yields maximal beneficial adaptations is controversial. Furthermore, the incidence of chronic heart failure increases with advanced age; it has been reported that 88% and 49% of patients with a first diagnosis of chronic heart failure are >65 and >80 years old, respectively. Despite this, most previous studies have excluded patients with an age >70 years. Our objective was to compare training programs with moderate versus high exercise intensity with regard to variables associated with cardiovascular function and prognosis in patients with postinfarction heart failure.
Methods and Results— Twenty-seven patients with stable postinfarction heart failure who were undergoing optimal medical treatment, including β-blockers and angiotensin-converting enzyme inhibitors (aged 75.5±11.1 years; left ventricular [LV] ejection fraction 29%; V̇O2peak 13 mL · kg−1 · min−1) were randomized to either moderate continuous training (70% of highest measured heart rate, ie, peak heart rate) or aerobic interval training (95% of peak heart rate) 3 times per week for 12 weeks or to a control group that received standard advice regarding physical activity. V̇O2peak increased more with aerobic interval training than moderate continuous training (46% versus 14%, ...
Conclusions— Exercise intensity was an important factor for reversing LV remodeling and improving aerobic capacity, endothelial function, and quality of life in patients with postinfarction heart failure. These findings may have important implications for exercise training in rehabilitation programs and future studies.
You can read the PDF of the whole article here.  I will be discussing this with my cardiologist today at 11:00 AM.
Also:

Abstract

Regular exercise training is recognized as a powerful tool to improve work capacity, endothelial function and the cardiovascular risk profile in obesity, but it is unknown which of high-intensity aerobic exercise, moderate-intensity aerobic exercise or strength training is the optimal mode of exercise. In the present study, a total of 40 subjects were randomized to high-intensity interval aerobic training, continuous moderate-intensity aerobic training or maximal strength training programmes for 12 weeks, three times/week. The high-intensity group performed aerobic interval walking/running at 85-95% of maximal heart rate, whereas the moderate-intensity group exercised continuously at 60-70% of maximal heart rate; protocols were isocaloric. The strength training group performed 'high-intensity' leg press, abdominal and back strength training. Maximal oxygen uptake and endothelial function improved in all groups; the greatest improvement was observed after high-intensity training, and an equal improvement was observed after moderate-intensity aerobic training and strength training. High-intensity aerobic training and strength training were associated with increased PGC-1alpha (peroxisome-proliferator-activated receptor gamma co-activator 1alpha) levels and improved Ca(2+) transport in the skeletal muscle, whereas only strength training improved antioxidant status. Both strength training and moderate-intensity aerobic training decreased oxidized LDL (low-density lipoprotein) levels. Only aerobic training decreased body weight and diastolic blood pressure. In conclusion, high-intensity aerobic interval training was better than moderate-intensity aerobic training in improving aerobic work capacity and endothelial function. An important contribution towards improved aerobic work capacity, endothelial function and cardiovascular health originates from strength training, which may serve as a substitute when whole-body aerobic exercise is contra-indicated or difficult to perform.
The full article is here. It appears that weight training is not the most effective strategy, but that both high-intensity and moderate-intensity aerobic training do a lot of good.  (All of them do some good.)

In case you don't know what "endothelial function" is (neither did I): it is a measure of how well the blood vessels handle the vasodilation and vasocontraction conflicts.  The better this works, the less likely you are to develop various problems:
Endothelial dysfunction is thought to be a key event in the development of atherosclerosis and has been reported to predate clinically obvious vascular pathology by many years[2]. However, the problem with this assertion in terms of the flow-mediated response indicator of endothelial dysfunction is that a morphological characteristic of atherosclerosis (baseline artery size) is inherent in the calculation of percentage flow-mediated dilation. Endothelial dysfunction is associated with reduced anticoagulant properties as well as increased adhesion molecule expression, chemokine and other cytokine release, as well as reactive oxygen species production from the endothelium. This leads to inflammation and myofibroblast migration and proliferation inside the vessel all of which play important roles in the development of atherosclerosis.
The introduction to Endothelial Dysfunction and Inflammation (2010) provides a bit more information on this.

UPDATE: My cardiologist agreed that the cardiac rehab program wasn't necessary with the level of exercise that I am getting, and with the health of my heart.  "Most of our patients we have trouble getting to walk to the corner and back."

1 comment:

jdege said...

You always have to look at the details.

Think about the many studies that have purported to show negative consequences of low-carb diets, where the diets in question were 40% carb.

In this case, the strength training regime chosen doesn't look anything like what I've seen recommended.