Use a balloon to estimate RV
So it's been awhile since I estimated my residual lung volume (RV), and I figured it was time to do it again.
I'm a big guy, so my lungs hold a lot of air. When you're blowing all your air into containers in the bathtub, and you're ⅔ or more exhaled, is not the best time for pausing to move your straw to another container—or worse, refilling the container. This time I decided to use a balloon.
I took a deep breath, exhaled maxmially into the balloon, then blew the rest into the container through a straw. (Wait, did he just say "the rest" after "maximally exhaled"?) I heard that. Yes, you can't exhale all of your air because the pressure in the balloon is higher than atmospheric pressure. In my case, I had another 400ml of air.
Then I emptied the air out of the balloon into the container. This is easy and leisurely once you figure out the trick, but it can seem next to impossible at first. Hint: don't try to submerge the balloon. If you grab the lip of the balloon mouth only, and avoid pinching the neck, you can control the air flow very well. There, I had measured my vital lung capacity (VC).
It worked great, and compared with the last circus event when I measured VC it was much easier.
Now I had to figure out how to get from VC to RV. The clown who wrote http://hans.fugal.net/density kind of left this step vague. I've remedied that and added a page to my spreadsheet. For the curious, my RV is up from 2.0 liters to 2.2 liters, and a total lung capacity of 8.2 liters.
%BF Nomogram
Remember that system I came up with for calculating body fat percentage using a gallon jug in a swimming pool? I always let the computer do the calculations for me—I have a little script that I run that updates my weight graph. But not everyone is as geeky as that, and formula is not that simple, and when you add units conversion in it gets downright hairy.
I finally figured out how to generate a nomogram. Now you have no excuses.
Fat Loss Progress
Back in October I talked about my fat loss plan, which boiled down to this: exercise 30 minutes a week and live a 1.5 lb-per-week feedback diet.
Here's a snapshot of the graph on the sidebar:
The red dots are my daily weigh-in, the blue dots are my water jug body fat measurement (aka the days I go swimming). The green and blue lines are trend lines. I've lost about 25 pounds. There are some notable features here.
First, notice how my body fat was plummeting compared to my weight when I was actively swimming and doing some minimal strength training. I got out of the habit, and haven't really reestablished it yet. Also, note that the body fat measurement is consistently lower than the BMI number.
Second, notice that my trend is most consistent when I was swimming regularly. Seems like that exercise thing is a good thing to do.
Third, and you'll have to take my word for it on this, when I was following my feedback diet it worked flawlessly. The humps are when I got rebellious and didn't follow the diet even though the feedback said I should.
Let's review the diet. It's really really easy. Get a piece of graph paper and mark today's weight. Draw a line that goes down 1 lb every 5 days (this is the rate I chose, you may want to choose 1 lb per 7 days or whatever). Now, if your weight is over the line, you eat smaller portions, drink more water, and skip dessert. If it's under the line, you don't fret it. Eat what you want (without gorging yourself).
Ok, this works really good, but there's bound to be hiccups. You're only human. So when you get a hiccup like I had in January/February, the feedback system breaks down. It only takes a week or so of disobedience for you to be completely unable to get back down to the line you charted without a sharp dive. But a sharp dive is exactly the thing you are not prepared to do. So you continue to float too high. Maybe you start a new chart (a wholly demoralizing thing to have to do), and then another hiccup begins and you lose heart even sooner. What I'm getting at is that line is just too rigid. The whole point is a sustainable rate of loss.
So I modified the mechanism slightly, and hence this blog post (no, it's not so I can brag about losing 25 pounds—that comes when I get to my target weight).
Take a piece of graph paper and draw a line with the slope you want as before, starting in the corner. Now, that line starts 5 lb or so above where you are now. This is to emphasize that the line is only a slope reference, not the actual line. Now mark your weight every day, and then decide if it's a diet day or not. Do this by estimating with your pencil, finger, or just your eyes, what the slope of the line that best fits the last 5 measurements is. If it's pointing down as much or more than your reference slope, it's not a diet day. If it's flatter (or pointing up), then it is a diet day.
I've been trying this new system for a few weeks and I have found it much more adaptive and encouraging. If you have a bad couple of days, you can be back on track within a few days, no problem. You don't need to make a new graph. You can see the progress of the past and recognize that while it's not a perfect line it's still very good progress. All the good kinds of feedback.
So go give it a try. It can fit in with whatever other exercise/diet plan you have. It can work if you are just maintaining your perfect weight, or even if you're trying to gain weight. It's easy (just a piece of graph paper on the fridge). You've got nothing to lose. At least, nothing you don't want to lose.
Measure body fat with only a gallon jug (and a couple thousand tons of water)
I finally got around to uploading the PDF version of my body fat measurement quest, and also a simplified one-page PDF for those of you that just want to try it out and don't want to wade through all the physics and my ramblings. While I was at it I threw together an OpenOffice.org spreadsheet to do all the heavy math for you too. Now the only difficulty is finding a couple thousand tons of water laying around. I put together a simple page with links to all that stuff I just mentioned (except the water).
Total Immersion
I've always loved to swim. Or, more accurately, I've always loved to play in, and especially under the water. I went to the pool as often as I could as a kid, and then when I was old enough I became a lifeguard. I did not, however, join a swim team. I'll never know if that would have been good for me, or if it would have destroyed my enjoyment of swimming. Still, as a lifeguard I watched and studied a lot of very good swimmers from my perch. I also watched and studied a lot of very bad swimmers. To this day I am utterly amazed that crazy triathlete lady managed to make it from one end of the pool even once, let alone for an hour and a half straight day after day.
So when I decided it was time to get in shape, I knew I wanted to do it by swimming. My stroke is decent, because of the tips I've picked up and things I've learned by observation over the lifeguarding years of my youth, but I knew I had a lot to learn. If I was going to swim at least 3 times a week, it wasn't going to be like crazy triathlete lady, but like the human fish who swam so elegantly and effortlessly. Crazy triathlete lady always left (and arrived, for that matter) with a frown. The human fish was happy, not to mention strong and elegant in and out of the pool. I would need this kind of swimming if I was going to muster up the motivation day after day to get out of bed early and go climb in a pool. Google helped me find out about Total Immersion Swimming, and the book reviews and excerpts and video snippets looked gold, so I ordered the TI book.
The basic philosophy behind TI is one I like to apply in everything: work smarter not harder. The nature of swimming—pushing our bodies through water—demands efficiency. If you run inefficiently, you are just a bit inefficient. If you swim inefficiently, drag will kill you. TI is all about minimizing drag and maximizing the efficiency of the movements that you make. The other half of TI is using your core body strength instead of your arms and legs to do the work. Weight shifting and rotation, not kicking and pulling. Other sports use this secret, we swimmers can too.
I waited to write this review until I had worked through the TI drills and put together at least a rudimentary version of the "TI stroke", so I could evaluate it better. After ½–¾ hour sessions 3 times a week for 2 months, I have what I would call a basic "TI stroke". The first couple of drills took a lot of patience and practice, but I feel they paid off. When floating on my back, I went from sinking legs and no forward motion to the balanced and effortless cruise. My kick necessarily improved (by learning kick technique, not kicking harder), as did my balance. The next few drills were also difficult but rewarding in time. Once I got to the rolling drills I found my childhood play instincts contributing greatly and I moved quickly through the last half of the drills.
My freestyle stroke now is more relaxed and efficient. I've known that stretching out is important, but now that I know why and better how (by rolling to the side) I get a much better glide. I'm still not completely comfortable with the integration of breathing into the stroke, but it's getting better every time. My stroke isn't quite effortless enough (and I'm not yet fit enough) for me to swim along without stopping for hundreds of meters, but I can feel it coming. Like when I'm learning a hard piece on the piano or organ—one that I know I can learn—I can almost see and feel myself in the final result and the practice sessions in between are just figuring out the details.
I would definitely recommend this book to anyone looking to either improve their stroke (e.g. for racing) or just looking to make swimming as fun as it was when you were a kid and you didn't have to go in a straight line or do specific strokes.
My next step, aside from continous improvement, is to apply the same principles to the other strokes, especially breaststroke (my favorite, and the one for which my body was built). I'll probably enlist the help of this newer TI book, which covers all four strokes, and looks like an excellent follow-up to the first.
Total Fitness in 30 Minutes a Week
Sorry, one more post on the topic of fitness and fat loss. I picked up ($4 with shipping) and reread Total Fitness in 30 Minutes a Week by Laurence Morehouse, Ph.D. and Leonard Gross, and it's as good as I remembered. For various reasons I didn't follow through with the plan laid out in this book last time I read it years back, but the principles I picked up stuck with me, and influenced my search for my custom and sustainable fitness program. I had a question that I thought was answered in this book, and so I picked up a copy and started reading. I'll give you a synopsis and review, then I'll divulge my (finally) finished custom plan.
First, this book is older than I am (1975). Naturally, that means we've learned some things that Dr. Morehouse (a Ph.D. in exercise physiology at UCLA) didn't know. On the other hand, most of what he did know back then, especially the basic foundation on which the program is based, is just as true now as the law of gravity remains. The book shows its age, but in ways inconsequential to successfully losing fat and/or gaining fitness. Indeed, it worked for people in the 50s, 60s, and 70s and there's no reason why we should be any different now.
And not just any people. Dr. Morehouse worked for NASA on exercise programs for the astronauts. Thanks to him astronauts on extended missions were able to walk (if a little shakily) rather than be carried on stretcher when returning to Earth. Low gravity is worse than sitting in front of a computer when it comes to atrophying muscle.
If I had to boil this whole book down into one paragraph, this would be it: Eat balanced meals, exercise with a balance of simple equipment-free strength training and aerobic exercise 3 times a week for a total of 30 minutes a week, live a bit more actively (take the stairs, etc.), and take note of and respond to feedback to stay on track. To get into shape (generic good shape, not athletic shape), that's all you need. To lose fat, you chart your course of 1 lb a week on a piece of graph paper. If you're above the line that day, you eat a little less (skip that piece of pie or extra helping). If you're below, you eat normally.
The book and method are very straightforward. There's no gimmicks here. It won't get you ready to run a race or climb Mount Everest. There's no confusion here between being an athlete and just plain getting in shape. The book is a little wordy, and could be half as long and just as informative. But that may be because I'd already convinced myself of most of the points he drives home in this book and didn't need the persuasive arguments.
This book is very much along the same lines as the Hacker's Diet I reviewed the other day, except it emphasizes exercise much more (for its own sake, primarily, not as a primary means for losing weight). Both use the simple view: calories in and calories out. Both emphasize the importance of feedback and the realities of measurement. Both give you a sustainable and easy-to-follow program (this one is easier than hacker's diet since you don't have to count calories).
So combining these two books and everything I've read from the web (everything from fat-loss zone heart rate cardio training to the bodybuilder mantra "cardio is useless for fat loss"), I have come up with my own personal plan. Time will tell if it works.
If I'm going to exercise, it's going to be swimming. I told myself that many many times over the years, and I meant every word. So I go swimming 3 days a week. There's my cardio. It's also part of my strength training, when doing intervals. The other part is on the other 3 days when I do some simple equipment-free strength training (5-10 minutes). I'm basing my exertion on the combination of perceived exertion (primarily how hard I'm breathing) and heart rate. I aim for staying aerobic and jumping the lactate threshhold on the hard intervals.
I'm convinced you can't lose weight in a reasonable amount of time without adjusting your diet, unfortunately. The numbers just don't add up otherwise. Every pound of lean mass you add burns some 10-20 kcal a day, and you're a lucky bodybuilder if you can add 1-2 pounds a week. That gets you no closer to burning off that extra pair of twinkies than the hour of jogging. Exercise alone, in the sense of that thing you do for an hour in the morning, is not enough to raise your energy usage enough to create a calorie deficit without adjusting your diet (especially since if you have too much fat you've probably been eating a calorie surplus). No, you have to adjust your diet. That doesn't mean you have to starve, it just means you need to be conscious.
Exercise does, however, apparently act as an appetite suppressant, and it will make you feel better and so you'll be a hair more willing to walk instead of ride, stand instead of sit, etc. Water is apparently another appetite suppressant, and it is important to drink plenty for other reasons especially when losing fat, so drink plenty. If for no other reason than because it fills your stomach partially, water can suppress your appetite if you drink it before a meal. So on my above-line days I'll be drinking a couple glasses before meals.
Dr. Morehouse says not to lose more than 1 lb a week. The consensus on the web is similar, but says 1-2 lb a week. I'm a little too impatient for 1 lb a week, but probably too lazy for 2 lb a week, so I'm aiming for 1.5 lb a week. I shall have lost my goal 40 lb by mid April.
To recap, I'm watching feedback (heart rate and weight) to fine-tune my eating and exercising in order to stay on track for a reasonable goal. No starving. Only the exercise I like. Reasonable and sustainable. Why don't you play along at home?
The Hacker's Diet
I came across this blog post while googling an unrelated gnuplot problem, of all things. The post talks about The Hacker's Diet. Duly intrigued, I whipped out my razor and plowed through the book. I like it.
The book is well-written, doesn't take itself too seriously, takes the subject matter seriously, and takes the audience seriously, i.e. you aren't expected to be Superman—the program is very down-to-earth and achievable. It is slightly aged (he mentions at one point that you need a color monitor to really appreciate the color graphs), but this isn't a problem.
The best part about the book (besides being free) is that he takes the problem of weight loss and attacks it as an engineering problem. He comes up with an understanding and a plan and implements it, and loses some 70 pounds. This book definitely appeals to every inner geek.
The worst part about the book is that his solution involves calorie counting. That makes me sick on so many levels, but I'll just rant on two of them. First of all, a calorie is not a calorie. I don't know if this is new knowledge or not, but we see it in all the latest fad diets. Atkins, GI, etc. are all based on the fact that a calorie is not a calorie. Second, I am not going to spend my life counting calories, thank you very much. I'd rather drink oil.
Speaking of drinking oil, this book has a very interesting parallel to the Shangri-La diet. They both use the thermostat analogy, but Shangri-La aims to adjust your off-kilter internal thermostat and this book aims to replace your broken thermostat with record keeping and conscious decision. Certainly, one could apply both at the same time.
In spite of me not wanting to count calories, I do intend to put a modified version of this plan into practice. Since I don't want to count calories, I am going to have to rely on some other feedback. Since most of us eat a relatively manageable variety of foods, we should be able to get an instinctive feel for "how much" we are consuming on a meal-by-meal and/or day-by-day basis. Indeed, he talks about getting to this point, by accident. I intend to get there much sooner, on purpose. By keeping a food log and comparing it to weight loss/gain over the period of a month or two or three, and studying it in hindsight, I should be able to get a feel for three "thermostat settings": lose weight, maintain weight, gain weight. It may be a bang-bang approach, but there's also the minute automatic adjustments and body's metabolism adjustment working in your favor while trying to stay stable.
I have adjusted my weight graph to include a trend plot as described in the book. While I was at it, I added the plot for measured body fat percentage (which I need to start doing more frequently). BMI is a linear relationship with weight, so the kg on the left correspond with the BMI on the right. So, by graphing measured body fat percentage you can see whether I am above/below the BMI for my given weight, plus see that otherwise invisble chasm between losing fat and losing weight. If you'd like to set up your own such graphs, I'm happy to share my code with you. Just drop me a line.
Total Heart Rate Training
I’m still swimming. This may be the longest I’ve stuck with any exercise program (excluding things thrust upon me like basketball practice or getting out of bed). Naturally, being the technical sort that I am, I want to make sure I’m using this exercise time efficiently, so I picked up Total Heart Rate Training by Joe Friel at the bookstore (and put it down before I left—reading it over several visits while my son played with the Thomas trains). This is an informative book with lots of information, but it’s not for the weak of heart—literally or figuratively. The book is written by and for obsessive-compulsive athletes (the most common variety is known as triathlete). You have to be absolutely bonkers to follow this book religiously. But it can be useful to the thinking fitness swimmer, with a grain of salt.
The first problem with this book is precision. Not a lack thereof but an overabundance and misunderstanding of it. In physics, or any practical math, you can get in trouble by giving more significant digits than your measurements warrant. You can fool yourself and others into thinking you have more precision than you do, which leads people to jump to incorrect conclusions and make silly and/or dangerous decisions. Heart rate monitors will give you absurdly accurate heart rate measurements. But I posit that you can’t measure how that maps to your body’s metabolism (the zones) with anywhere near that accuracy, at least not while exercising. What’s more, as a swimmer anyway, you can only check the monitor during rests at the end of the pool, where it’s just as convenient to take your pulse with the pace clock (it takes 6 seconds to get ±5 bpm). The heart rate charts in the appencides are what really give it away, though. Running, Biking, Swimming, etc. each have their own 2-page chart with some 60-odd entries on where the zones begin and end, to the nearest bpm. If that doesn’t sound absurd by itself, take a look at this graph I made from the swimming chart:
They say a picture is worth a thousand words. Notice how the relationship is almost completely linear. I’m no exercise scientist, but how much do you want to bet the body is not so perfectly conformant? I bet it varies depending on the day, conditions, what you ate, etc. There might even be some nonlinearities. So we have a chart with a bunch of numbers and no graph, that is overly precise.
That wouldn’t be so bad on its own, but the author actively disparages traditional measures and formulas for being too inaccurate, when of course the reason they are too inaccurate is that they are too precise. The most obvious example is that your maximum heart rate is 220 minus your age. This gives you a bpm, but really it’s only good to within 10 or 20 bpm. He rightly says that this is not accurate. But he says it’s as likely to be way wrong as not, because it’s a statistical measurement. i.e. it’s a bell curve. Hello, 95% confidence of being within 2 standard deviations hardly qualifies as “as likely as not” to be outside. If he really wanted to convince me he would have stated the confidence intervals and said just how far off from that number you are likely to be. Then he would have compared that error with the error in pinpointing the zones in exercise. I think we’d find that maximum heart rate, while not perfect, isn’t as bad as all that.
While being absurdly precise and complicated (to the delight of obsessive compulsive triathletes everywhere), this book is also somewhat lacking in rigor and logic. Besides the examples above, there’s an issue I blogged about previously: the so-called fat-burning zone. As you may recall, the fact is that your body burns more fat per calorie when in an aerobic metabolism. This leads people to call the aerobic zone the fat-burning zone. People get lazy and forget to put in the disclaimer that you have to work longer to burn as many calories, which leads to confusion. Trainers and self-righteous OC athletes retaliate by pointing out that you burn more calories per time unit by working out harder—up into anaerobic, and so “the fat-burning zone is a myth”. Well it’s not a myth, it’s perfectly valid if you’re willing to work out longer. Instead of elucidating the topic with clarity and stating both sides of the issue without bias, the author falls squarely, if not extremely, on the myth side.
Still, there is a lot of good information in here on how the body works, what’s going on in the various zones, in which zones you can best spend your exercise time in order to achieve your goals (the information for a fitness swimmer is in there, if a bit hidden behind the triathlete-like goals). Numbers that are useful if you take into account that they are too precise, etc.
I’ll give you an oversimplified summary of what I learned in the book. Referring to that graph above (by the way, I had no control on which colors were used—they’re just GNUPlot’s default colors), notice that the x axis is the lactate threshold. He claims that LT is a better base point than maximum heart rate, because you can directly observe it without killing yourself. Sounds good to me.
At the border of zones 1 and 2, aerobic respiration accounts for almost all of the energy produced. Aerobic respiration primarily uses fat and is much more efficient, but less powerful, than anaerobic respiration. If you’re fit you can stay in zone 2 all day long.
At the border of zones 4 and 5, enough anaerobic respiration is happening that various easily-observable changes occur, and the exercise benefits change too (especially those related to heart). Oversimply put, training above LT will train for speed in shorter (non-endurance) races, and also do various good things for your heart.
At the border of zones 5b and 5c, almost no aerobic respiration is occuring—it’s all anaerobic. This is because you’re demanding more power than aerobic respiration can keep up with. Anaerobic respiration is done not from fat stores but from stuff stored in the muscles themselves (for immediate access and powerful energy). There’s only so much of this fuel, so you run out of steam quickly above LT, but especially up here. This is sprinting stuff, and you can rarely keep it up long enough to even measure heart rates much into zone 5c.
For me, I am going to aim at increasing my LT and staying mostly in zones 2 and 4, (apparently zone 3 is a waste—little more benefit than zone 2 but requiring a lot more recovery) but doing interval training shooting up into the above-LT zones, mostly for the heart benefits. I figure that will meet my goals best, i.e. I will enjoy the exercise more and not leave the pool exhausted, I will burn more fat per calorie, and the interval training will give me enough edge to keep things interesting and improve my cardiovascular health (not to mention increase LT—doing intervals with sufficient rest to “cycle” the heart rate from low to high and back to low is one good way to do that). And I’m going to do it by taking my pulse with the pace clock periodically, and paying attention to how my body feels and how hard I’m breathing.
Of course, the most important thing is to keep on just doing it, and that’s going well because I’m enjoying learning the Total Immersion swimming method, and I’m finaly getting into the more interesting drills. It won’t be too long until I graduate to swimming again, at which point I’ll review that book. I’m looking forward to seeing if I can swim a 500m in under 10 minutes with ease. That’s something I had to do regularly as a lifeguard and even though I was more fit then (or at least less fat) I always struggled with swimming 500m non-stop, and my times were usually 10-12 minutes. If I can swim a 500m with ease in under 10 minutes in my current shape, it will be a testament to the TI method. Stay tuned!
Posted in life | 2 comments |
Body Density Measurement Uncertainty
A couple days back I posted my idea for measuring body density and estimating body fat. Dad, who has a set of skinfold calipers gave it a try and gave me comparative results, and asked the question on everbody's mind: just how accurate is it, especially with that pretty blatant guess at residual lung volume?
So I took some time to learn how to account for uncertainty and take a stab at pinning a confidence interval on the technique. First of all, I didn't realize how complicated uncertainty propogation is. Partial derivatives, squares and square roots, etc. Luckily, I came across some lecture or presentation notes detailing a sequential perturbation method (instead of an analytical method). I could have talked Jacob into walking me through the partial derivatives, but this method is easy to code and a find in and of itself. Read about it in this PDF.
I coded up the formula and ran some test data through it. Here's the equation again for review: ρ = m / ((m + mc)/ρw - (va + vc + vr)) Here's the values and uncertainty I attribute to each variable:
- m = 121.29 ±0.02 kg
- ρw = 0.997 ±0.001 kg/l
- va = 1.13 ±ٍ0.01 l
- vr = 1.87 ±0.5 l
- mc = 0 ±0.02 kg
- vc = 0 ±0.01 l
I didn't actually use a counterbalance, but I included the uncertainty in measuring its mass and volume as if I had, just for completeness. As suspected, vr has the largest uncertainty. I calculated the uncertainty if vr were magically accurate, and found that the uncertainty was 0.0014 kg/l. This translates to about 0.65% body fat with Siri's equation (ignoring the uncertainty inherent in that equation, which is a constant bias accross measurements for one person on any given day).
Note that I give ρw this time, instead of whisking it away with a magical 1 kg/l. I picked an average value between 72°F and 84°F (most pools are in this range), with an uncertainty (due to water temperature) of about 0.001 kg/l. If you use 1 kg/l instead you are introducing a bias of about 0.9% body fat. So I was wrong about that being insignificant.
Now, I found a better estimate
(why better? because it seems to come from a more reputable source than
Wikipedia) for residual lung volume: vr = RV = 0.24 VC. So I may
have overestimated my RV last time by ½ liter.
(Update: I think that must be a typo on that page, they probably mean 24% or 28% of total capacity instead. This fits in much better with the rest of the literature that I have found, e.g. Quanjer and Paoletti.) That seems like a generous
uncertainty measure for RV, too. With that uncertainty factored in, we get an
uncertainty of about 2.1% body fat, or about 5% is you are on the slight side of average (the less you weigh, the more difference that 1/2 liter makes).
So, Dad, let's bump your score up by about 1% for the density of water and then tack an uncertainty of 2% onto it, you have a body fat of 26.3% ±2%. I'm no expert on using calipers, but one paper's abstract indicates that the skinfold method uncertainty is about 3%. I've seen 10% tossed around casually too, but have no reliable source to back that up. That puts the two methods within the appropriate reach of eachother, which is heartening. It's interesting to note that BMI is overestimating Dad's fat, because he's more lean than the average couch potato. Imagine the difference if the subject were someone completely nuts, like a young triathlete, who has body fat of about 15%. Even better, if you are such a nut you could do the experiment and post your results (and BMI) here as a comment for us to see.