Sunday, January 24, 2010

Using Indirect Measures -- Polar's OwnIndex

From the previous posts it's clear that my goal is to increase overall fitness, improve diet, continue to lose weight, and meet the lipid profile goals associated with my recent calcium heart scan. (LDL cholesterol below 70mg/dl -- now at 77mg/dl; HDL cholesterol > 60mg/dl -- only at 45 but possible if I can tolerate more Niaspan; triglycerides beloww 100mg/dl -- already achieved with Trilipix, hopefully sustainable.)

Fitness is a key, but isn't controlling by itself as I had thought (or hoped)during previous years. For this post I want to focus on fitness and a key indicator of fitness -- O2Max as yielded by Polar's program called "OwnIndex", a fascinating indirect measure of O2Max.

O2Max, of course, is a measure of how much oxygen you can burn at your peak performance level. The more the better. Lance Armstrong has one of the highest measures (he has been described as the "oxygen-burning machine"). The highest scores are in the 90's and are held by Norwegian cross-country skiers.

Interestingly, having among the highest O2Max scores does not guarantee a gold medal in track, but it certainly helps, and when combined with running efficiency, good stride, balance and all of the other good running characteristics, will make you a super competitor. It is regarded as the single best indicator of overall fitness. It is often called the "gold standard" of fitness indicators.

As with many other things, it tends to diminish with age. For my age category, an O2Max in the 40's is considered excellent. But I have not had my oxygen-burning capability directly tested in a lab. That is where they actually hook you up, put you on the treadmill, and measure the amount of oxygen you burn. But I have been tested by the Polar program, which has a .97 corrleation coefficient with direct O2Max testing. And it is done on a bed -- no oxygen mask or treadmill.

In fact, you may have this tool if you have a Polar monitor. It's on the Polar 725 or 810, for example, and probably on most new Polar monitors selling for above $150.

The test consists of wearing the Polar transmitter and setting the monitor on "fitness test". You lie quietly for about 5 minutes. Within that time the monitor reads your heart rate and your heart rate variability (HRM). HRM is an extremely intriguing measure -- the more variability, the greater the indication of fitness. More about this in future posts. You have also entered your age and weight and your current exercise level. On this basis, the Polar gives you a number (mine is currently 41) that is, essentially, the number you would get if you did a direct O2Max test. On the Polar web site, there are tables that intepret your score by age. Mine is shown as "excellent".

These scores are remarkably consistent. If I am a "41" on my 810, my 725 will typically also read "41". They improve slowly over time in accord with an exercise program. I made it to "43" after the last Cycle Oregon. Several years ago it was in the high 30's, so I have made some progress over the years.

According to the Polar literature, movement from an OwnIndex/O2Max score of 40, for example, to 45 would take about 3 months with a more rigorous program.

So I think it is realistic to shoot for an OwnIndex of 45 about 3 months from now, if I am able to ratchet up my weekly exercise level in the right way. If I can keep my weekly mileage within the 100 mile range and do some cross-training -- some running and some hiking, getting up to a 45 by April 24th is realistic.

Friday, January 22, 2010

The Next 18 Months

You've read about the current situation in the previous post. I had a thalium stress test this past week in order to assess further the results of the calcium heart scan. I'll be meeting with the specialist in early February. I'll likely schedule a second calcium heart scan in the summer of 1011 to see whether my efforts have stabilized calcium build up.

All of these tests are indirect measures used to determing heart risk. In fact, right now I am asymptomatic. My O2Max is excellent for my age (41); morning heart rate (52); good heart rate variability (HRM); no chest pains, shortness of breath; dizzyness, etc. The challenge is to make the most of these indicators and others to manage risk prudently. For example, I didn't train enough for the last Cycle Oregon and "blew it out" when I did the ride -- probably not the most prudent approach. At the very least I'll increase my training mileage before the race so that there is not a big discontinuity between the race milage and my average race mileage.

So it's helpful to know the real state of my vascular system before emabarking on some demanding exercise adventures (Cycle Oregon, hiking across England, doing the Grand Canyon Rim to Rim to Rim again).

None of the tests I've mentioned actually involve looking into my vascular system. So they are "indirect". (An angiogram would provide a view, but that is invasive and not without its own risk.)

The calcium heart scan can "slice" the heart into 60 cross-sections and build up a view of the calcium in your major heart arteries. You are not looking at the plaque directly, only the calcium which is very highly correllated with plaque. On this test it showed that I have a one in five chance of a major heart incident soon if no changes occur. Some studies show that I am 21 times more likely within a specified time (say a year) to have a major heart incident if I don't do anything. I take this seriously.

There are other indicators, blood pressure is a good one. 130/80 is the new standard (Pre-hypertension). Another is the CRP (C-Reactive Protein) test which tests for inflamation, where inflamation is highly correlated with plaque build up.

The thalium stress test is probably not going to tell me anything more than the calcium heart scan. I'll let you know about this when I see the specialist in February. It does show blood flow under modest stress. It compares, as I understand it, blood flow in a relaxed state with blood flow under modest exercise. A different color dye is injected when you are on the treadmill. The key is to see which arteries are totally blocked, or blocked in one state (relaxed) and not in another. The calcium heart scan theoretically can show this, but the "real-life" blood flow situation perhaps can show more. We'll see.

During my debriefing after the heart scan, the nurse said that "70% is in the genes." If change is to be made, it has to occur in the remaining 30%. There are two areas 1) Lifestyle and 2)Medication.

Lifestyle consists of diet and exercise. I'm working on the former and have lost about 4 pounds since the summer. I plan to continue losing slowly and have a goal of a total of 8 pounds by March when I take the next lipid panel.

In terms of exercise, I plan to up my mileage for the September, 2010, Cycle Oregon. Also it should be possible to do something each day, including stretching, some (new) elliptical work, and some running cross-training. These are "tweaks" that might help. It's possible I might be able to up my O2Max (Polar version) to 44 by March and perhaps higher in the summer as my bike milage rises.

But the re-take of the calcium heart scan wouldn't occur until a year from this summer, so I would not have a smaller scan number to reinforce my efforts (if it happens at all) until then. So I'll have to make do with weight loss, cycle and other miles, maybe calories, higher O2Max, etc.

Seeking the Perfect Lipid Profile -- The Situation Now

Friends have asked about the ups and downs of my attempts over the years to control cholesterol and thereby lessen the risk of heart attack and stroke from the build up of plaque in my circulatory system. I got a good report earlier this month on my "lipid profile" and thought this might be a time to put it in context. The next eighteen months will be a crucial time during which I'll be looking for indications that my plaque build-up is stabilized or perhaps (happy thought) reveresed slightly.

On January 8, I took at standard lipid panel (not a VAP or Berkeley Heart Labs panel). Total Cholesterol: 140 mg/dL. This is the second lowest score in the past five years, which is when I started following my lipids closely. In fact it has been nearly five years since I scored 132 in July of 05.

My LDL-Cholesterol is 77, is cut in half from my last test in March of this year. This is good news. LDL-Cholesterol is a better predictor of heart incident than Overall (or Total) cholesterol. My goal is to lower this to below 70. Important here is the fact that my recent HBCT heart scan showed considerable placque build-up in the heart and that without changes (lifestyle, medication) I have (or had at the time of the test) about a 1 in 5 risk of a heart attack soon. Also important here is that I have the dreaded "Small-LDL Trait" which is also closely correlated with heart attack and stroke.

I will be talking about this later, but this means that I have smaller, denser, grittier LDLs (Low Density Lipoproteins) than normal. These are well-adapted to create plaque build-up. They fit into crevices in your ateries and ratchet up the plaque like gangbusters. It is possible, however, to make them less dense and even bouyant through medication. Doing so means moving from "Type B" to "Type A" in this aspect of our lipid inventory. I've made it in the past almost to the "A" range of the spectrum. Typically, though, I've been mired in the gritty end ("B"). My last lipid panel was a standard one which doesn't test this. VAP or Berkeley Heart Labs panels do test this, so I will looking closely for results in this area when I take a VAP test in March. In fact, the size/bouyancy dimension extends over the range of lipids, including High-Density-Lipoproteins (HDL-the "good" cholesterol). Increasing the bouyancy of all lipids protects against heart incident.

My "good" cholesterol - HDL - is 45 on my last test. This is good for me, but because of a familial pre-disposition, not what it could/should be given my level of exercise. That is, all things considered, it should be about 70. My brother shares my anomalous tendency for 1) slightly elevated overall chosterol, 2) elevated triglycerides (typically >150 mg/dL standard), and 3) diminished HDL, often <>60"]

The final difference is taking Rx Omega3 consistently and in large quantities - 3 to 4 grams a day.

More about VAP tests and key indicators (CRP test, calcium heart-scan, thalium stress test, and others) in subsequent posts.