Data To Live By (Part I: Baseline Biometrics)

In God we trust. All others must bring data.
— W. Edwards Deming

The Prostate Specific Antigen (or PSA) test is a popular though imperfect marker for prostate cancer. Measured via a blood test, PSA is a protein produced by cells in the prostate gland. A high PSA (anything over 4.0 ng/mL is cause for concern) is correlated with prostate cancer risk but does not mean the patient has prostate cancer; it could also be an indicator of Benign Prostate Hyperplasia (or BPH), a form of non-malignant prostate disease commonly referred to as an enlarged or inflamed prostate. It is estimated that 80-90% of men over the age of 70 suffer from symptoms of BPH.

Imperfect as it may be, my PSA score was the one piece of data that my urologist, Dr. Geo Espinosa, and I used to determine whether the lifestyle interventions – the Health Warrior Way – I adopted after my diagnosis were effectively containing my prostate cancer. As long as my PSA remained stable we could be reasonably assured (without the need for another invasive, painful and risky biopsy) that my prostate cancer was being managed, that it wasn’t growing or spreading (metastasizing) outside the prostate capsule.

I had a lot riding on the status of my PSA test results and had blood drawn every three months, like clockwork, to monitor my PSA. My PSA, which was 9.36 in January 2014 (which is when my second urologist recommended surgery), fell to 5.41 within three months of adopting the Health Warrior Way. And that’s pretty much where it stayed for the two years between my first and second biopsy, the latter of which showed, conclusively, that I no longer had any detectable trace of cancer in my prostate.

While my PSA was the primary (if imperfect) indicator I used to track the health of my prostate, I soon began tracking other biometrics to keep (objective, measurable) tabs on the status of the rest of my physical and emotional health. This data orientation became, for me, the roadmap for my journey to wellness and remission. By regularly measuring things like Basal Metabolic Rate and Lean Body Mass, for example, I could reassure myself that I was at least maintaining if not improving my overall health.

To do this, I made an investment in two pieces of hardware: a biometric or "smart" scale (the one I chose was the Tanita Ironman) that measures several body composition factors, and a Garmin vivoactive HR, a GPS-enabled smartwatch that tracks metrics like heart rate, steps, activity intensity, sleep and calories burned. If you’re serious about your health I recommend starting with a biometric scale and an activity tracker, though not necessarily these two models. You can find recent, comprehensive reviews of activity trackers here and “smart scales” here, but first it would be a good idea to figure out what you want to measure and why. Here’s what's important to me:

Basal Metabolic Rate

Basal Metabolic Rate (or BMR) is the hypothetical number of calories your body would need to sustain its basic functions (e.g., respiration, blood circulation, brain function) during a theoretical 24-hour day at rest. If you don’t have a biometric scale which measures BMR then you could use an online BMR calculator or you could ask a rocket scientist to calculate it for you, using the following formula:


Alternatively, you could invest in a biometric scale which measures BMR, among other health metrics.

BMR is an important metric because it’s variable; you can elevate your BMR, which naturally decreases with age, by becoming more active. The more active you are, the higher your BMR will be (i.e., the more calories you will burn at rest). Burning calories passively is a good thing.

But BMR only tells you half the story. Your BMR is the minimum number of calories you will burn in any given day. The calories you burn above and beyond your BMR are considered active calories, which can be tracked via an activity tracker. My goal, as a reasonably active 54-year old male, is to burn, on average, between 800 and 1,000 active calories per day; that is, if my Basal Metabolic Rate, according to my biometric scale, is 2,161 calories, then my total daily calorie output goal is around 3,000 calories (for what it’s worth, my average daily calorie output for the past 6 months has been 3,262 calories).

Lean Body Mass

Lean Body Mass is the weight of the parts of your body that aren’t fat; it can be reflected in both absolute terms (in pounds or kilograms) and in relative terms (as a percentage of your weight, with the other side of the ratio being your body fat percentage). While a smart scale, which measures body composition by bioelectrical impedance, is not as accurate as some other body mass measurement techniques (such as calipers to measure skin folds or hydrostatic weighing) it is a good enough way to track your relative lean body mass over time.

Lean Body Mass is an important metric to track because we lose muscle mass as we age (up to 3-5% per decade after the age of 30) due to a process called sarcopenia, which is essentially age-related muscle loss. Losing muscle as we age causes all sorts of bad outcomes, including frailty and loss of balance and a diminishment of our ability to stay active (which then leads to more muscle loss).

The best way to combat sarcopenia is strength or resistance training. There’s no silver bullet, only hard work. And monitoring Lean Body Mass (and its co-pilot, body fat) can help ensure that you’re maintaining healthy muscle mass and carrying minimal body fat. This is why I prioritize the tracking of Lean Muscle Mass instead of body weight; I don’t really care how much I weigh so long as my Lean Muscle Mass and body fat are in healthy proportion.

Resting Heart Rate

A lower heart rate at rest is usually correlated with more efficient heart function and better cardiovascular fitness. While a normal adult has a resting heart rate anywhere between 60-100 beats per minute (bpm), a seasoned athlete might have a resting heart rate closer to 40 bpm.

You can measure your resting heart rate by taking your pulse either at your neck or your wrist. I prefer the convenience of a wrist-based activity tracker, however, which enables me to track my heart rate trends (resting and active) over time, something that wouldn’t be convenient to do otherwise.

A resting heart rate at the lower end of the scale (my resting heart rate has been an average of 56 bpm over the past 12 months) lets me know that I’m taking care of my heart by exercising regularly and consciously managing my stress through meditation and other forms of stress relief, including yoga.

Intensity Minutes

Most health guidelines recommend that adults get at least thirty minutes of exercise five days per week, or 150 minutes in any given week. This could be a combination of moderate exercise (between 55-69% of your maximum heart rate; you can maintain a conversation during moderate exercise) or vigorous exercise (between 70-89% of your maximum heart rate; you can no longer talk while exercising). A minute of vigorous exercise counts for two minutes of moderate exercise, so 75 minutes of vigorous movement will get you there just as effectively as 150 minutes of moderate activity..

Thirty minutes of activity per day might be good enough for some people, but not someone’s that trying to recover from a chronic illness (like prostate cancer or heart disease) or stave off age-related decline. That’s why my goal has been to average 150 minutes of exercise per day, every day, or at least 7x the recommended weekly guideline (my weekly average over the past six months, as measured by my activity tracker, is 1,310 intensity minutes, or roughly 187 intensity minutes per day. I never said being a Health Warrior would be easy!).

Now, this may sound like a lot, but remember that one minute of vigorous exercise (like riding a bike or hiking up a mountain or throwing around some heavy kettlebells) counts double. And I prioritize high intensity exercise for several reasons: I’m looking to build muscle and shed fat; it’s a more efficient use of my time; and I like the buzz I get from an intense, heavy workout, which seems to soothe my nervous system for the rest of the day (and helps me sleep well at night).

Metabolic Age

Metabolic age is a comparison of your BMR (Basal Metabolic Rate) against the average BMR of different age groups. For example, if you’re 54 years old but you have the BMR of a 42-year old (because you’re very fit and have a low percentage of body fat), your metabolic age would be 42. A metabolic age lower than your chronological age is good; a metabolic age higher than your chronological age means you have some work to do.

I love tracking my metabolic age because it makes me feel like I’m aging backwards. At least it provides me with a metric that gives me tangible proof that aligns with my perception that I’m slowing down the aging process. It doesn’t mean much, objectively (I’m not actually 33 years old), but it provides me with great incentive to keep doing what I’m doing.

This data orientation is a key HWW enabler. It's how Health Warrior's track progress against the goals we establish, both at the beginning of the journey and again, later, when we've surpassed our initial goals and set new ones. Every time I step on my scale I'm reminded of where I stand relative to my health goals; every time I look down at my wrist I get instant feedback on how hard I've been working -- today -- and how much more work I need to do to be the healthiest, most illness-proof, youngest, most vital version of myself that I can be.

We all get old, eventually. Accidents happen. Then there's just plain old shitty luck. But there's a lot that's within our control. We control our mindset, whether we view external events positively or negatively and how they effect us. We control what we ingest into our bodies, which can sometimes be delicate little ecosystems. We control whether we sit around on our asses all day or whether we get up and head out for an adventure.

Data enables us to measure how well we're managing the variables that are within our control. It shouldn't be some hysterical numerical obsession. It's not (or at least shouldn't be) about slaking one's ego ("winning!"). And it should be a contest with only one contestant: you.