Study: Strength Training to Failure Improves Cardio Function

It sounds like it is a review of existing literature?

"Anything that raises your heart rate is overall good for cardiovascular function. News at 11"

I do agree that weight training intensely can stress the cardio vascular system, which is good for overall health. It will not improve your running or biking. this is more muscle specific training. For general fitness if you hate cardio, this would be a good option. Exercising intensely with weights to help increase cardio function.

Of course it improves running and biking. We used to lift when I was in cross country in high school. Stronger muscles = more power to drive you forward = better run times. And if your heart is pumping stronger as a result of lifting (to supplement your cardio), that's an extra bonus because you're meeting the oxygen needs of your muscles.

Except that's not what happens. I agree with a lot of what was said, but the increased heart rate that occurs during weight training is not associated with an increase in cardiac output. So while it may "meet the oxygen needs of the muscles", that's only because the oxygen needs are not all that great.

And the thickening of the cardiac muscle that occurs from strength training (if any does occur) is different from the "enlarged heart" that occurs from endurance cardio training.

Studies have shown that the oxygen uptake during heavy squats (e.g. 2-4 RM) is about equal to taking a mild stroll at the shopping mall.

Just as an untrained person who starts doing cardio will see a statistically significant--but modest--increase in muscle strength, someone starting a strength program will see similar cardio increases due to initial adaptation to the workout stresses.

For an untrained person, anything that causes an increase in blood flow will initially result in some cardiovascular improvement. This includes not only weight training, but things like saunas as well. The effect, as I said, in part of the initial adaptation and any increase is transient.

Now, strength training can result in an increase in cardio PERFORMANCE, because of increased power and muscle efficiency. So one might see an increase in a 5K time when adding weight lifting, but that is not the same as increasing cardiac function--it just means you can run faster with the same level of cardiac conditioning.

By definition, as the body weight increases, VO2max decreases proportionately.

VO2 max refers to the maximum amount of oxygen that an individual can utilize during intense or maximal exercise. It is measured as "milliliters of oxygen used in one minute per kilogram of body weight.". Ref: http://sportsmedicine.about.com/od/anatomyandphysiology/a/VO2_max.htm

By definition, as the body weight increases, VO2max decreases proportionately.

VO2 max refers to the maximum amount of oxygen that an individual can utilize during intense or maximal exercise. It is measured as "milliliters of oxygen used in one minute per kilogram of body weight.". Ref: http://sportsmedicine.about.com/od/anatomyandphysiology/a/VO2_max.htm

Agreed. But... VO2 max isn't really a measure of cardiovascular health, is it? Or maybe it's one measure? I admit, I'm not too knowledgeable about exercise science. *I* think of cardiovascular health as normal blood pressure, lowish resting heart rate, ability to breath steadily, evenly when exercising (as opposed to the desperate gasping after an all-out sprint), the ability to run at a reasonably good clip for an extended period of time...

It should also be noted that not everyone is going for increased muscle mass when they weight lift. Many (like me) want to maintain the mass we have while dieting... in which case, I don't think our VO2 max is going to change much. Then again, it might... if muscles convert to fast-twitch, then VO2 might change without a change of mass.

more important than cardio function, it is my belief that training til failure increases muscle size the quickest.. drop sets, negatives, forced reps, etc.

Well, I've only gotten through the first couple of pages but here is one interesting divergence:

Here is a statement from the authors:

Where studies have appropriately controlled for intensity (as defined in this way), by having
participants perform RT to momentary muscular failure, the results indicate improvements in both
predicted VO2 max (112,130) and measured VO2 max in both young (69,99) and older adults (67).

Note the emphasis on MEASURED VO2 MAX. I looked up just one reference (69). Let's compare the study's conclusions with those of the people writing this review (also note they are citing a 30+ year old study):

Strength training effects on aerobic power and short-term endurance.
Hickson RC, Rosenkoetter MA, Brown MM.
Abstract
Nine men participated in an exercise program (five days a week for 10 weeks) that was designed to strengthen the quadriceps muscles. This study was undertaken to determine if heavy resistance training results in an increase in endurance, Vo2max and whether the differences that are normally observed during bicycle and treadmill Vo2max measurements in the same individuals are strength-related. Following training, endurance time to exhaustion significantly increased while cycling (47%) and while running (12%), when the subjects exercised at 100% of their pretraining Vo2max. There was a small increase in Vo2max (4%, P < 0.05) during bicycle exercise (3.40 l.min-1 to 3.54 l.min-1) after training, but no significant differences were observed when expressed in (ml.kg-1.min-1). Strength training had no effect on Vo2max when measured during treadmill exercise. Absolute differences between bicycle and treadmill Vo2max were essentially the same after training as before. Lactate concentration in blood after the bicycle and treadmill endurance tests were not elevated to a greater extent after training. Thigh girth increased significantly and muscle strength increased 40% with the training. These findings provide evidence that HRT is capable of dramatically increasing short-term endurance, when the muscles involved in the training are used almost exclusively during the testing without an accompanying increase in Vo2max. These data also suggest that the differences in Vo2max between bicycle and treadmill exercise are not the result of inadequate muscle strength.

Let me highlight: "There was a small increase in VO2 max (4%) during bicycle exercise after training, but no significant differences were observed when expressed in ml/kg/min....differences in between bicycle of VO2max were essentially the same after training as before".

And: "HRT is capable of dramatically increasing short-term endurance....without any accompanying increase in VO2 max."

So the authors claim an increase in "measured VO2 max", yet the study they cite specifically states there was no increase in VO2 max after HRT.

I did go a little further. It seems that the basic theme (at least in the initial literature review) is that "any study that disagrees with our idea is flawed".

This produces another gem:

Most studies have
reported that the average VO2 during RT is less than 50% of maximal whole body capacity
(17,20,28,35,43,74,117,118). Hence, in light of the recommendations for achieving particular levels of
VO2
for CV improvement, the average VO2 during RT data led Jung (80) to conclude that the VO2 of
RT is “…hardly a substantial stimulus for improving aerobic capacity in all but the most sedentary of
people.”

So first they state what most people already know and what has been confirmed by decades of research. Then they follow with this:

Despite the difficulties in determining VO2 during intense RT, it is reasonable to expect that as RT
intensity is increased a concomitant increase in VO2 occurs.

Well, no, it's not reasonable at all. You just cited a number of studies that show that the increased VO2 does not happen. But then claim that it must be true because it is "reasonable".

This type of shell game seems to occur in every section of this "review" that I read. A relentless list of minutiae that, due to its overwhelming volume, MUST prove the idea that HRT is equal to CV training. Yet most of the research cited either disagrees, or is not relevant. I can only imagine the ideological axe grinding that would motivate someone to produce such an incoherent mess.

BUMP

This is fantastic!! Thanks for sharing

Except that's not what happens. I agree with a lot of what was said, but the increased heart rate that occurs during weight training is not associated with an increase in cardiac output. So while it may "meet the oxygen needs of the muscles", that's only because the oxygen needs are not all that great.

And the thickening of the cardiac muscle that occurs from strength training (if any does occur) is different from the "enlarged heart" that occurs from endurance cardio training.

Studies have shown that the oxygen uptake during heavy squats (e.g. 2-4 RM) is about equal to taking a mild stroll at the shopping mall.

Just as an untrained person who starts doing cardio will see a statistically significant--but modest--increase in muscle strength, someone starting a strength program will see similar cardio increases due to initial adaptation to the workout stresses.

For an untrained person, anything that causes an increase in blood flow will initially result in some cardiovascular improvement. This includes not only weight training, but things like saunas as well. The effect, as I said, in part of the initial adaptation and any increase is transient.

Now, strength training can result in an increase in cardio PERFORMANCE, because of increased power and muscle efficiency. So one might see an increase in a 5K time when adding weight lifting, but that is not the same as increasing cardiac function--it just means you can run faster with the same level of cardiac conditioning.

I think we're talking about different things. Cardiovascular health, to me, means the whole kit and kaboodal. It's more than just thickness/strength of the heart wall. There are adaptive changes on a cellular level, there are hormonal changes, and so on that improve over-all fitness, including the ability of your heart to pump more blood when you run, the ability of your lungs to draw in air... and just in general your ability to handle the stress of exercise whether it's cardio or lifting.

Now yes, I agree that endurance exercise is going to have a larger effect than weight lifting on heart output and lung capacity. But that doesn't mean weight lifting can't have a substantial effect too. For me, personally, weight lifting has drastically improved my capacity to handle exercise. I can walk for miles, hike up hills, play floor hockey with a bunch of teenagers, and even run. I could not do those things before I started weight lifting. My weight hasn't changed but my physical health has changed a lot.

One last comment... this is my own personal experience and not science... but I disagree with the claim that weight lifting requires oxygen intake equivalent of a mild stroll. I am breathing HARD when I finish a set, and my heart is beating rapidly. I am still breathing harder than normal when I start the next set (though not as hard as right after finishing the set). That's not shopping mall stroll. That's an hour of breathing faster than normal. It's probably closer to intervals than to endurance... but it's still getting my respiratory rate and pulse rate up.

It's mostly an academic difference, but you are confusing anatomy/physiology with performance. That's the only point I was trying to make.

As you state, in real life, it doesn't make any difference HOW you feel better--just that you feel better and can do more things. That's the essence, and the rest of this is just amusement.

But, if you want to get into the actual physical/physiological mechanisms of how this stuff works, then I was providing the scientific explanation. You can take as much out of it (or as little) as you want ;-)

Very interesting. Saw several references to those already with improved VO2max from traditional means would not see much improvement, from any type of training.

So this is indeed the normal aspect of if you are new to exercise in general, Resistance Training to failure can improve your Running Economy and your VO2max.

Same way certain types of interval training can improve your endurance at same VO2 level to failure, actually doubling endurance time. So doesn't surprise me really, same concept, improving the anaerobic system can improve the aerobic system.

Interesting that the research didn't find or measure improvements to Lactate Threshold. Since the normal training to get that up is to do intervals near that limit, and RT to failure many times has you to that line or above too. Very similar in that regards.

The only thing I'd question and like to see the study of that is not mentioned there.

What type of activity will truly benefit from this.

Will a study group that only did RT and a group that only did Cardio, after the end of the study, go do a 5K or 10K run, or 100K bike ride?

This is where I think the neuro aspect of muscle use would come into play. Just as people starting weight lifting can increase strength merely by training nerves how to handle the load and lift better.

I dare say the RT group is going to cramp up, run differently, not have their fat-burning trained for the longer events, ect.

Short sprints and hard efforts, perhaps up to 3000m would be fine and probably benefit the RT group.

So I think in the context of weight loss, and people improving their bodies, this would indeed help with idea that you could get by with just RT to failure to help lose weight, and see great improvements to Cardiovascular system.

But for those that want to make perhaps doing a marathon or century ride or triathlon part of their goals, or really enjoy a certain cardio workout, RT can't replace the benefits you'd get from C workout.

But if you don't have those goals - stick to RT to failure for your limited time, and reap some great side benefits for your CV health.

I agree with this. I'm certainly not ready to go out there and run a 5k just because I weight lift. However, I can actually run now. I can run about a mile, and there's a high cost to that mile in terms of pain the day after, but I can still run and that's better than I could do prior to lifting.

So certainly, for those who want to run or bike, they're going to need to run or bike to train their system for that kind of stress.

It's mostly an academic difference, but you are confusing anatomy/physiology with performance. That's the only point I was trying to make.

As you state, in real life, it doesn't make any difference HOW you feel better--just that you feel better and can do more things. That's the essence, and the rest of this is just amusement.

But, if you want to get into the actual physical/physiological mechanisms of how this stuff works, then I was providing the scientific explanation. You can take as much out of it (or as little) as you want ;-)

I suppose you're right. Usually, I am all about physiology and mechanisms of action, but the cardiovascular system is pretty complex and not 'my thing'. My thing is brains. It's been a while since I've had to think about the cardiovascular, so its easier for me to be concerned about functional output than to dig up my text books and remind myself enough to go detailed.

I do appreciate your insight.

But I've got to ask... even if we're worrying about the physiological mechanisms... isn't there more to cardiovascular health than just size of the heart, thickness of the heart wall, and VO2 max? At the very least, you've got to worry about elasticity of the arteries, output from the vegas nerve, hormones released from the adrenal cortex... and so on.

Still, I do agree that cardio exercise is superior to weight training for improving cardiovascular health. It's just that I think weight training can help and for someone like me who's just not ready for/interested in a lot of cardio, that makes me happy.

I want to make it clear that I am not trying to push any type of training as "superior" to another. Anyone who reads my posts knows that my strongest comments tend to come for the opposite reason--debunking absolutist claims of "superiority" for whatever reason.

I do like to get kind of picky about defining terms--too often, the discussions get sidetracked when people think they are talking about the same thing, but in fact they are not.

So in my mind there is a difference between cardiovascular "performance" and cardiovascular "health". You don't have to be an athlete to have a healthy cardio system and being a top endurance athlete doesn't automatically mean you have good cardiovascular health.

And, again, I am not addressing the issue of "can resistance training enhance cardiovascular (aerobic) performance. Of course it can.

You also state correctly that what we refer to as the "cardiovascular system" includes all kinds of physiologic components--including hormonal and neurological.

However, the main purpose of all of those components (and I'm oversimplifying here) is to deliver oxygen to the tissues and use it, along with fuel, to create energy. So, the accepted measurement for determining cardiovascular (aerobic) capacity is: oxygen uptake.

So you can compare all of the minutiae and isolated effects you want, but the bottom line is: does training method "X" improve maximum oxygen uptake, and, if you are claiming that a certain training method is equivalent, does it improve maximum oxygen uptake to the same degree as what you are comparing it to.

It's not that hard to test. You take two groups--one does cardio training, one does resistance training and you compare them at the end. And the overwhelming body of research says that traditional weight lifting does not increase VO2max, except in untrained subjects as an initial adaptation to resistance training.

It doesn't matter if, on some microscopic level. heavy resistance training evokes similar responses as cardio training. At the end of the road, the results are different. It's like the whole "fat burning" discussion--you can look different workouts and empirically show that one "burns more fat" than the other; you can measure training effects that show an increase in fat-burning structures and hormones. But, ultimately, when you actually measure the overall effect, you find that "fat burning" exercise, well, it doesn't really burn all that much fat, and it burns less fat that other training methods.

So, that's just the academic part of the discussion. I will repeat, again, that in terms of real life, real health, resistance training plays an essential role and resistance training can enhance cardio performance--it just is not equal to cardio training, as the authors of the "review" are claiming.

more important than cardio function, it is my belief that training til failure increases muscle size the quickest.. drop sets, negatives, forced reps, etc.

Unless you want to have a heart attack in your twenties, I wouldn't put muscle mass above cardiovascular health (but that's beside the point).

Regularly training to failure reduces the production of the growth hormone IGF-1, while training without going to failure decreases cortisol and increases testosterone. Don't go to failure if your goal is adding mass.

http://www.jappl.org/content/100/5/1647.full#abstract-1
"Strength training leading to RF [rep failure] resulted in reductions in resting concentrations of IGF-1 and elevations in IGFBP-3, whereas NRF [non-rep failure] resulted in reduced resting cortisol concentrations and an elevation in resting serum total testosterone concentration. This investigation demonstrated a potential beneficial stimulus of NRF for improving strength and power, especially during the subsequent peaking training period, whereas performing sets to failure resulted in greater gains in local muscular endurance."