cardio before weights or after?

If you are doing both in one workout, there is no question that doing one first will leave the muscles more fatigued for the second.

You should know that the elevated heart rate you experience during strength training is not the same as an elevated heart rate during cardiovascular exercise. The underlying physiological mechanisms are different. During strength training (traditional resistance weight lifting to voluntary fatigue in less than 15 reps), even if heart rate is elevated, cardio training (i.e. increased VO2) is not taking place.

If resistance is low enough that cardio training IS occurring, then you are probably not experiencing much increase in strength or muscle mass.

It's not an "off/on" switch--but you cannot really achieve cardio and strength training simultaneously. (Circuit training alternates).

This is interesting - I didn't know this!

So, for example, when I am doing P90X and my heart rate monitor is reading an average of a 70% MHR, and at the end says "700 calories burned" should I trust that number? I have been enterting that number into MFP. Is that not accurate?

Thanks in advance for any info!

Sorry, my router went out this morning and Comcast has been playing with the network, so I have spent the entire day trying to diagnose my internet connection problems--and It appears that I still need to go out and get a new router--and waste tomorrow hooking it up.

Good thing I don't have a job--I don't have time for work ;-P

So, here is my answer to your question, "Is that accurate?":

Yes, no, maybe. What I was referring to was "traditional" weight lifting, e.g. 1-3 sets, up to 15 reps working to "failure". P90x is a combination of moves that will incorporate more "cardio" type movements as well as strength.

As I mentioned before, the body is not a series of "on/off" switches--everything works in unison. When Nautilus selectorized strength machines became popular in the late 1970s, the company made 2 specific benefit claims. One was that the unique design of the cam resulted in a constant resistance force vector throughout the entire range of motion, thus 1 set of exercises using Nautilus machines was equivalent to doing multiple sets of conventional strength exercises or machines.

Two, Nautilus claimed that doing the circuit with ligher levels of resistance (12-15 RM) with no rest between exercises would elevate heart rate and result in simltaneous cardiovascular and strength training, thus removing the need to do separate cardio. Pretty cool, huh? No wonder many clubs installed the Nautilus circuit in a separate room and required you to pay extra for a "Nautilus" membership.

In the mid-1980s, a study was done to directly investigate claim #2. Participants trained on a Nautilus circuit, following the exact directions from Nautilus. The study looked at what progress was made during a 12-week program. Based on stress tests and VO2 analysis, it was determined that, while participants had maintained a 75%-80% heart rate level throughout the workout, there was no improvement in cardiovascular fitness after 12 weeks of Nautilus training.

Hmm....in order to investigate further, they actually did some VO2 studies on subjects during the workout itself. What they discovered was that, while heart rate increased during the exercise, oxygen uptake did not. When you do cardio exercise, the increase in heart rate reflects an increase in oxygen uptake, or aerobic intensity. During strength training, that association does not exist.

(It was a great study, well constructed with clear results. Along with other studies that showed no particular advantage for Nautilus training over other types of strength training, it pretty much started the decline of Nautilus as a company, a decline from which they never recovered.)

Now a combo workout, like P90X, or even a circuit training workout, is going to be more difficult to analyze. First of all, there will be a "carryover" from the cardio intervals, esp if you push at a high intensity--VO2 will remain elevated while the other noncardio movements are performed. Secondly, I suspect that many of the "strength" type movements are not performed at a 12-15 RM resistance level or less.

I suspect that if you analyzed a lot of P90X workouts, you would find results similar to most circuit-training programs--there are increases in both muscle strength and aerobic fitness, but not to the same extent as if you were doing dedicated programs. As far as calorie burn? Harder to say, without knowing your weight, the length of the workout, and the specific movements. For a 1 hour workout, it's not out of the question.

Hope this makes sense. I knew this would come up, since so many people here do these types of classes. I am more concerned with the folks who are doing traditional weight lifting routines and thinking they are getting cardio training too, because HR is elevated or who are using HRMs to track calories during this part of their workouts and assuming they are actually burning those calories.

You should know that the elevated heart rate you experience during strength training is not the same as an elevated heart rate during cardiovascular exercise. The underlying physiological mechanisms are different. During strength training (traditional resistance weight lifting to voluntary fatigue in less than 15 reps), even if heart rate is elevated, cardio training (i.e. increased VO2) is not taking place.

If resistance is low enough that cardio training IS occurring, then you are probably not experiencing much increase in strength or muscle mass.

It's not an "off/on" switch--but you cannot really achieve cardio and strength training simultaneously. (Circuit training alternates).

This is interesting - I didn't know this!

So, for example, when I am doing P90X and my heart rate monitor is reading an average of a 70% MHR, and at the end says "700 calories burned" should I trust that number? I have been enterting that number into MFP. Is that not accurate?

Thanks in advance for any info!

Sorry, my router went out this morning and Comcast has been playing with the network, so I have spent the entire day trying to diagnose my internet connection problems--and It appears that I still need to go out and get a new router--and waste tomorrow hooking it up.

Good thing I don't have a job--I don't have time for work ;-P

So, here is my answer to your question, "Is that accurate?":

Yes, no, maybe. What I was referring to was "traditional" weight lifting, e.g. 1-3 sets, up to 15 reps working to "failure". P90x is a combination of moves that will incorporate more "cardio" type movements as well as strength.

As I mentioned before, the body is not a series of "on/off" switches--everything works in unison. When Nautilus selectorized strength machines became popular in the late 1970s, the company made 2 specific benefit claims. One was that the unique design of the cam resulted in a constant resistance force vector throughout the entire range of motion, thus 1 set of exercises using Nautilus machines was equivalent to doing multiple sets of conventional strength exercises or machines.

Two, Nautilus claimed that doing the circuit with ligher levels of resistance (12-15 RM) with no rest between exercises would elevate heart rate and result in simltaneous cardiovascular and strength training, thus removing the need to do separate cardio. Pretty cool, huh? No wonder many clubs installed the Nautilus circuit in a separate room and required you to pay extra for a "Nautilus" membership.

In the mid-1980s, a study was done to directly investigate claim #2. Participants trained on a Nautilus circuit, following the exact directions from Nautilus. The study looked at what progress was made during a 12-week program. Based on stress tests and VO2 analysis, it was determined that, while participants had maintained a 75%-80% heart rate level throughout the workout, there was no improvement in cardiovascular fitness after 12 weeks of Nautilus training.

Hmm....in order to investigate further, they actually did some VO2 studies on subjects during the workout itself. What they discovered was that, while heart rate increased during the exercise, oxygen uptake did not. When you do cardio exercise, the increase in heart rate reflects an increase in oxygen uptake, or aerobic intensity. During strength training, that association does not exist.

(It was a great study, well constructed with clear results. Along with other studies that showed no particular advantage for Nautilus training over other types of strength training, it pretty much started the decline of Nautilus as a company, a decline from which they never recovered.)

Now a combo workout, like P90X, or even a circuit training workout, is going to be more difficult to analyze. First of all, there will be a "carryover" from the cardio intervals, esp if you push at a high intensity--VO2 will remain elevated while the other noncardio movements are performed. Secondly, I suspect that many of the "strength" type movements are not performed at a 12-15 RM resistance level or less.

I suspect that if you analyzed a lot of P90X workouts, you would find results similar to most circuit-training programs--there are increases in both muscle strength and aerobic fitness, but not to the same extent as if you were doing dedicated programs. As far as calorie burn? Harder to say, without knowing your weight, the length of the workout, and the specific movements. For a 1 hour workout, it's not out of the question.

Hope this makes sense. I knew this would come up, since so many people here do these types of classes. I am more concerned with the folks who are doing traditional weight lifting routines and thinking they are getting cardio training too, because HR is elevated or who are using HRMs to track calories during this part of their workouts and assuming they are actually burning those calories.

WOW! What a great answer - thanks for taking the time Azdak! Makes perfect sense.
:flowerforyou:

I figured P90X was no substitute for my running (I still run 3-4 times a week in addition to my daily P90X), but I hope I am accurately accounting for my calories (I use my HR monitor).

Have you read anything about heavy lifting being hard on the aorta? My dad is 65 and fit as a fiddle but has a congenital aorta defect and the cardiologist recommended he quit his heavy lifting (I am taking a shot in the dark here - but you seem to know a lot about a lot!).

Having spent most of my time as a fitness professional working within the medical world, I must be extremely cautious about providing any specific information. The load on the heart that occurs with heavier lifting is more of a pressure load (as opposed to aerobic exercise, which is a volume load); that is why the increase in heart rate that occurs with weight lifting is not the same as the increase that occurs during cardio.

For someone with an aortic defect, there could be concerns. As in any medical condition, it is important to make sure your father is communicating his desires clearly with his cardiologist and that the cardiologist is knowledgeable about the specfic demands of lifting and how they would affect your father's specific condition.

It is quite possible, perhaps even probable, that you father will have to restrict/modify his weight lifting activity. However, as a rule, cardiologists don't see a lot of 65 year old lifters, so it's worth pressing the point a little just to make sure.

It may also be possible to come up with a modified routine that allows your father to do some lifting while minimizing risk (things like different exercises, using dumbbells, independent single-arm movments). It wouldn't be quite the same, but it might be possible to come up with an acceptable substitute. Again, it really depends on the specifics of his condition.