Rehab and METS

[Doug]

As I have mentioned in other posts, rehab has changed over the years. My first go around with cardiac rehab was in 1996 and it was pretty much a joke. They put a 3 wire monitor on and told you to go exercise on the treadmill and then on the stationary bike. That was it.

Now, it is a lot different. The hospital where I am attending my rehab is very small so the rehab program is not huge, but it is well run. There are two nurses who run the program. They develop an exercise prescription for each patient and modify it as the patient progresses. One of the nurses leads us through a 10 minute warm-up and checks on us as we exercise. The other nurse monitors the telemetry through out the session and a doctor stops in about half way through.

They monitor our weekly progress via METS and METS are described as:
* 1 MET is equivalent to a metabolic rate consuming 3.5 milliliters of oxygen per kilogram of body weight per minute.
* 1 MET is equivalent to a metabolic rate consuming 1 kilocalorie per kilogram of body weight per hour.
Here is a link to the definition: http://www.sizes.com/units/metequiv.htm
And here is a link to a description and a compendium of exercises and METS : http://prevention.sph.sc.edu/tools/compendium.htm

1 MET is about the equivalent to sitting still and growing moss.

My nurses told me that they try to get the patients to around 5 METs before the end of rehab. I get to see my chart each time I go in and I started to pay more attention to the METs, I am due to end my rehab in 2 weeks. The software they use shows that I am over 4 METs for the treadmill, 3.6 for the Sci-fit Rex and about 3.6 for the NuStep. I am asked them about that because I am not exerting myself as hard on the treadmill as I am on the other machines. We use the RPE scale and on the treadmill at 3 mph and 2 % elevation I am feel I am exerting about 12, but on the other 2 machines I am really pushing it and I feel that I am hitting over 13 on the scale.

If I am breathing a lot harder and sweating more then you think the METs would be higher. I am going to keep asking the nurses to explain the difference.

BTW, if you don't remember the scale, here is a chart - http://www.advancedhrm.com/index.php?option=com_content&view=article&id=85&Itemid=93&limitstart=3

 

[JeffM]

Hey Doug - There may be a few factors at work here. I am not familiar with the two machines you mentioned, but a quick google search shows they are recumbent training devices. I know these are designed to allow a greater number of people to more comfortably and safely position themselves to get a good cardiovascular workout and that they work different muscles than a regular bike or treadmill in simulating cycling or running. I'm pretty (99.999%) sure running, especially on a grade, treadmill or outside, is going to jack your heart rate, wattage, METS, RPE (however one measures energy output) higher than any recumbent device; same with traditional cycling. Walking, on the other hand, unless one is really pushing, does not require as much effort. And it's an activity and a motion most people are used to and comfortable with compared to running. However, as one walks uphill, the level of effort becomes exponentially harder with each grade increase.

We're all different and a person's physical stature and exercise experience may actually allow him/her to work harder in a recumbent position. So if one walks on a treadmill then gets on one of these recumbent devices, it's conceivable to me that he/she might in fact be able to put out a greater level of effort on the latter. At 3 MPH, even at a 2% grade, you're probably not working as hard on the treadmill.

My explanation for the higher METS burn on the treadmill versus the recumbents despite your RPE is this: Since you're oxygen usage is not actually being measured, the only way to estimate your METS (never heard this term before BTW) is based on a chart that someone put together that says activity X burns n METS; activity Y burns z METS, etc. The chart probably recognizes that running on a treadmill as an activity, generally burns more calories than exercising on a recumbent device. But like these machines that tell you how many calories you burn based on some overly simple algorhythm, they just aren't capable of factoring in all the variables that would reflect individual differences. Any time a chart or a machine tells us what we burned or how many miles we ran/cycled, we need to remember it's just a rough estimate that's very often way off. If I can use a food analogy: an 8oz piece of (chicken, fish, beef, pork) has x amount of fat. A good friend of mine and I both like rib eye steak. If you're familiar with a rib eye, you know it's a pretty fatty cut. When he grills it, he leaves all the fat on it and melts butter on top before eating it, which is a common way to prepare it. I sacreligously trim every little piece of visible fat to the point of changing the nice attractive shape of the steak. I don't add butter either. If my piece has n grams of fat my friend's steak probably n+y to the 2nd power more fat. My point again is we're working with guidelines based on rough estimates. I just happened to be craving a steak at the moment.

I'm betting you are actually burning more METS on the Sci Fi Rex and the NuStep than on the treadmill, consistent with how you feel, but the chart doesn't reflect reality. Are you monitoring your heart rate during all of these activities? I'd definitely keep track of that and see if the level of effort expressed as heart rate corresponds with the METS burned. And, if you have clearance to do so, see if you can increase the grade while maintaining your pace. I'm betting your HR and RPE will spike. But the key will be whether you can increase it slowly enough and just enough so that you can hold that level of exersion. Not everyone can because you're using the largest muscle groups in your body to support and move the entire weight of your body. If that's not something you're accustomed to doing, it'll be hard to maintain the effort. And that's why some (probably rich) genius came up with the concept of recumbents. I'll be interested to know what you find out about this.

Jeff

 

[Doug]

My max heart rate is captured on each machine. I do have a higher heart rate on the recumbant machines, when the nurses print the telemetry it has max heart rate for that activity. On the treadmill I hit about 110, on the Rex I hit 119 and the NuStep is about 114.
The resistance has been set to about the middle of the range on both of the recumbant machines.

Another difference I came up with is I do 15 minutes on the treadmill and 10 on the other 2. I may try switching it around and do 15 on the Rex. I just have to figure out how to switch my program around without getting interrupted.

I like to start with the treadmill, it warms me up. The nurses take my BP (after 15 minutes) and I hit the Rex. If I do 10 minutes on the treadmill, and start the Rex they will interrupt me, after 5 minutes on the Rex, to get my BP. I may talk to them and see if we can change some things around with the BP and the machines.

 

[JeffM]

Doug - you seem like a very detail oriented guy. When I work with engineers or finance/accounting people in my real estate business, I have to give them lots of data to analyze. I tend not to look at a lot of data, but I like to ponder questions about "why things are the way they are" so this is just the kind of thing that interests me. But the bottom line is you're exercising. And that's good stuff. And you've got people monitoring you to make sure you're doing it safely. And that's really good stuff. You'll have plenty of opportunity to tinker with your workouts and equipment down the road. Right now, you're probably better off going with the flow, recognizing that charts are just estimates and continuing to enjoy the benefits you're receiving. Keep up the good work!

 

[Doug]

Jeff,
I appreciate your insight and this is a topic that interests me. You did pick up on the detail and analysis part of it. I have been dealing with heart issues for many years (not as long as some, but longer than most) and have been through rehab before. So in addition to the physical exercise this is a mental exercise as well.

I don't do "go with the flow".

 

[Jeanie]

I am in a similar program, and the METS directed for each patient is based upon the nature of their heart problems, per the case manager who explained it to me at the outset. Some people for example may not have enlarged left ventricles, and I believe that category can tolerate higher METS and higher RPE. In my situation, I not only had AVR plus repair of Tricuspid, but also have LVH, left ventricle hypertrophy and am taking a Beta Blocker. Per my research into that class of drug, apparently it presents additional risk factors for exercise, making cool down, rather than abrupt cessation of exercise, very important.

It was explained to me that they purposely want lower heart rate (and the Beta Blocker I am on supposedly helps that), and do not want my RPE to go above 13 because of the LVH. My target RPE, per the rehab folks is 11 - 13 however when I am not feeling as if I am in that range, I tell them and they tell me to bump up the treadmill speed, for example. We only have BP checked before and after, plus once during exercise. They do the during exercise one usually on the bicycle, just saying to keep pedaling but not to do the arm motions while it is checked.

Basically, IMO, although you may feel capable of doing more and surely will later on whilst monitoring your own target heart rate, trust the protocols they recommend. In addition to wanting me to be at RPE 11 - 13, my METS is supposedly 2 - 4. Thus, I am guessing that METS level = RPE projected. Every day of the class (3 days a week), we are given our 'exercise prescription' which can vary, but includes the sequence and length of time on various machines. The speeds of the treadmill start lower for the warmup, usually 3 minutes, then faster for the actual exercise part. Those continually are being bumped up in length or intensity based upon our reported RPE for the previous session. Although I am not totally clear on how they calculate these things, I am sure the underlying heart issue being rehabbed is a factor, as I said above. I hope my perspective helps, even though mostly guessing!

 

[Doug]

Jeanie,
My nurses check the RPE for each machine and that is used for part of the prescription. If I am working at 11, they typically ask if I am ready for the next level. For example, one of the nurses asked if I was ready for the 2.5% elevation on the treadmill. I bumped it up and told her we will see.

My rehab ends next week so that will probably kill my METS exploration so I will have to find something else to fixate on. Maybe I will go back and fixate on resistance training.

 

[Jeanie]

Doug, you have a great sense of humor, which when combined with your obvious intelligence and attention to detail will probably result in you being able to write an article on the subject! At the very least, I hope you will keep posting in this message thread about what-all you are observing about your continued exercise tolerance and progress! Congrats on being almost done with the rehab program.

 

[realkarl]

I can relate to being able to exert yourself at very different levels with different activities.
According to the METS chart http://prevention.sph.sc.edu/tools/docs/documents_compendium.pdf, I can bicycle outdoors at 16-19MPH, that's 12.0 METS. But at the same time, I can only do a "jog/walk combination" at 6.0 METS. For me I know it has something to do with breathing while running - I've never been able to breathe very well while running, so even just walking uphill, I am sure I can do more METS than running, but bicycling has always been my favorite activity.

My rehab ends next week so that will probably kill my METS exploration so I will have to find something else to fixate on.

I would recommend a Garmin Forerunner 310XT GPS, with a heart rate monitor, and cadence, speed monitor for your bicycle... It keeps track of everything you can imagine, auto-calibrates wheel size using GPS data, and downloads it all to your computer and/or your own pages at connect.garmin.com. It doesn't know about METS, but based on your heart rate (and the max/rest heart rates you have given it) estimates kcals spent. I don't look much at that number myself, it never matches the number from stationary equipment, of course, since both are rough estimates. But I love the Forerunner and its data gathering capabilities. It's a great aid to keep track of progress, as well as walking trails, bike routes, etc.

Also, I just got a set of Kreitler indoor rollers, and based on their chart http://kreitler.com/wattage.php?section=wattage, when I am bicycling continuously at 18mph on my 3.0 drums with no extra equipment, at the same exertion level as outdoors same speed, it's equivalent to 148Watts, measured using Power Meter Cranks. According to the chart referred to in the beginning of my post, 150Watts on an indoor stationary, is only moderate effort and 7.0 METS, only a little over half of the 12.0 METS the same chart gave for the same exertion level (for me) Outdoor bicycling. Go figure!

Karl.

 

[Doug]

Thanks Karl, I will check it out. I don't ride a bike, we can't where we live. Our roads are made more for motocross. Next week I will be in a Hilton in San Francisco so I will have access to half way decent equipment, but the week after I am on my own.

From what I understand, the Y in this town is very old, but I plan to check out their equipment. I could pay to use the rehab center at the hospital, but I don't know if I want to get up that early. I would have to be there by 5:30 am. A bit early even by my standards (I am a firm believer in getting the day started before 7.)

The breathing while running is what always got me. When it was real cold I had a hard time finishing a race. When it was warm, I was tough to beat. It's kind of funny, when I was in high school and college I was a very good distance runner.