When it comes to fitness, I have become a little bit of a data nerd. I like having metrics that allow me to track changes. I have been curious for a while now about getting some testing done to supplement the data that I obtain from my fitness trackers. Among the information I have been curious about is VO2 Max, body composition, and resting metabolic rate. I found a company that offers these services, so I decided to get a battery of the tests done. (I went to DexaFit Madison, but DexaFit has many locations throughout the US. I have also been told that many universities have the ability to conduct some or all of these tests.) The DexaFit also offered 3D body scans as part of their testing package, so I did that as well. I felt that this may be of interest to others who are looking to dig into a bit more detail with their health and fitness, so I thought I would take some time to explain the test procedures, share some of my results, and explain what they mean and how I plan to use them. I should not need to say this, but just in case there is any question, I am not a health care professional.

But before I dive into the results, a few comments. As with any metric regarding health, these results are just a piece of the overall picture. They should not be taken in isolation and are not solely indicative of health. That being said, there is a lot of information that I received, and the test results have helped to round out my understanding of my health.

In the charts for many of the tests, I have the ability to see my results in comparison to optimal ranges or in comparison to my peer group. All of my results will be shown in comparison to optimum ranges. The results of my peers have very little bearing on how I want to conduct myself, so knowing where I am in relation to what is healthy is much more important for me and tells me where I have room for improvement. Likewise, others should not be measuring their results against mine. I am sharing my results because it is easier to talk about and show actual data than to discuss hypotheticals.

Additionally, since this was my first round of testing, some of the charts are a little bit bare. As more tests are completed, more data points are established, and trends can be seen over time. All results will be shown as screen captures from my phone. While there are accompanying PDF reports that have more nuanced data, the screen captures present a better visual depiction of the data for this purpose. If anybody is interested in the actual report formats, reach out to me and we can discuss.

3D Body Scan

I started with a 3D body scan. For this, I was told ahead of time to wear or bring some form-fitting clothing as baggy clothing would create an inaccurate model. I then stood on a rotating platform with my arms and legs spread apart. Spreading the limbs is important because, for example, if the arm was too close to the torso, the scanner may accidentally measure across the wrist and waist as one measurement instead of two. I was also told that I would need to stand with my head looking up otherwise my beard would interfere with the neck measurement. Once I was in position, the platform slowly rotated while a scanner created a 3D model.

From this model, measurements can be made for 20 different locations on the body. It also estimates lean mass, bone mass, and several body fat parameters. The mass values are estimates only, and I do not give much weight to them as a test I discuss later yields much more accurate results. However, the estimated parameters are good for relative comparison, that is the values may not be completely accurate, but if the reported body fat percentage goes down from one scan to the next, it indicates a decrease in body fat. As far as I am concerned this test is most useful for individuals who are trying to lose or gain weight. Body scans can be compared across time to chart progress and physically see changes. But for somebody like me who is only interested in maintaining my weight, scans across time should show relatively little difference. The model can also be downloaded and viewed on any computer or smartphone. Here is my 3D model showing one of the 20 measurements, 22.0 inch circumference taken mid-thigh on my right leg. There is also another viewing option that shows a silhouette of the body. That one would likely be the most useful in comparisons across time as one could see the body shrinking or growing in relation to previous scans.

DexaFit

The DEXA scanner is an impressive piece of machinery that goes far beyond my understanding, but suffice it to say that it works somewhat like an x-ray in that it images the body. However, DEXA also has the ability to measure mass and differentiate between different types such as lean mass and body fat. For the test, I was asked to wear clothing that was free of metal and remove all jewelry & electronics as they could interfere with the readings. I was then laid on the scanning bed and told that I must lay still. The scan takes about 5 minutes. They have some measures that they can use if people are afraid they may move too much, but I did not feel that I needed this option, so I don’t know what they entail. This test gives a lot of data, so I will do my best to break it up and hit all of the key details. For context in the results, my total mass on the day of the tests was 160 lb.

One last note to be aware of. DEXA was developed by two former NFL athletes. That being the case, some of the optimum parameters are skewed a bit away from the average person and toward elite athletes. This is a case where a bit of nuance must accompany the data interpretation.

Mass

Lean mass often gets confused with muscle mass, but they are not completely synonymous. Lean mass is muscle mass plus organs, water stores, and select other substances that compose the body. Thus, it is easiest to think of lean mass as everything except fat and bone. I had a result of 129 lb of lean mass which gives 81%. In relation to what is optimum (135 lb), I could work to increase my lean mass. As somebody who almost solely focuses on running, this is not much of a shock to me. For overall health, I know that I could spend a little bit more time focused on strength training. While strength training will never be my focus I am going to make a bit more of an effort to incorporate it into my routine, especially in the off-race season. I know that I have a heavy cardio base in my fitness, and adding some strength would help to balance my overall health.

However, this is only one piece of the equation. Lean mass cannot be looked at in isolation. Fat mass is another important parameter. I had a result of 23.3 lb of fat which gives 14.6%. This is over the optimum range of roughly 11 to 17 lb of body fat. This is where the nuance comes in because let’s remember this is skewed toward elite athletes. A standard range of body fat percentage for male athletes is 6 to 13% and a standard range for male fitness is 14 to 17%. So, given this information, I am in a suitable range. That being said, I do think that I could squeeze a few benefits from dropping my body fat percentage into that 6 to 13% range. However, I do not aim to cut any fat to achieve this. Instead, as I mentioned above, I would like to add a few pounds of lean mass. Doing this while keeping fat around 23 lb would increase my overall weight but drop my body fat percentage and give the strength benefits I mentioned.

The last mass parameter is bone mineral content. This is essentially the weight of my bones. This is interesting, and I wanted to show it. However, I don’t know what bone mass should be. This number alone has very little context for me to interpret. There is a different bone parameter that I will discuss below that is much more informative in my opinion.

Relative parameters

More raw data can be extrapolated from the DEXA results to give more insights. One formatting of the data can highlight differences between the right and left sides of the body. While small differences are to be expected, large differences can cause issues and should be addressed. For example, I am right-handed, so it is to be expected that I have a bit more mass (both muscle and fat) in my right arm. You can see that this is the case. However, for people who heavily use their dominant arm (think pitchers, quarterbacks, people who use hammers often, etc.), large differences may result. This causes an imbalance and can lead to issues. In this scenario, workouts specifically targeting the nondominant arm should be considered.

The next two figures relate to bone density. The second figure shows bone density in various areas of the body. Again, this is informative, but not particularly insightful. The third figure, however, is one that I can use. It is a depiction of a T-Score. Going back to stats class, a T-Score is developed by statistical analysis of bone density in relation to what can be expected in a healthy individual of a given age and sex. Any positive number is good whereas a negative indicates below-average bone density. As we age, we tend to lose bone density, so especially for younger individuals, a positive number should be targeted to stave off issues like osteoporosis. Should this number be negative, there are ways to increase it, strength training being a primary method. A T-Score of 1.0 is 1 standard deviation above the average.

The fourth figure is visceral fat, the fat that wraps around the organs in the abdomen. Of all fat, this is often considered the most dangerous and is most associated with health concerns. Anything under 1 lb is generally regarded as safe, but the optimal is given as 0 lb. For context 0.09 lb is roughly 2 AA batteries.

Resting Metabolic Rate

This test requires fasting and caffeine abstinence for an accurate result. My test was around 11:00 a.m., so I ate as normal the night prior but was not allowed to eat or have coffee the morning of the test. I don’t know what the necessary time windows are for accurate results, but I would anticipate not eating or consuming caffeine prior to the test. For obvious reasons, many people opt to have this test as early as possible in the day. For the test itself, I was fitted with a finger pulse oximeter and a respiratory mask. The pulse oximeter measures pulse and blood oxygen saturation. The respiratory mask measures oxygen consumption and the amount of carbon dioxide breathed out. I was then sat on a couch in a dark, quiet room and told to sit relatively still and relax for about 15 minutes. The only additional instruction was to try not to fall asleep. I’m guessing sleep may somehow have an adverse effect on readings.

A result of the test is resting heart rate. This is likely not to be 100% accurate due to the parameters of the test. The best time to take resting heart rate is immediately upon waking up before getting out of bed. Because I wear fitness trackers constantly, I know that this number is a bit high for me. I typically find my resting heart rate to be between 35 and 40 bpm and see jumps in the range of 50 to 60 bpm only when I am not recovering well or having an intense training week. Overall, this is a good indicator, but know that the actual resting heart rate is likely a bit lower than this test will yield.

The other results relate to the resting metabolic rate. Here you can see that my metabolism seems to be about average with a Calorie requirement of about 1,800. This means if I did not get out of bed on a given day, I would still need to consume 1,800 Calories to maintain normal body function. Any active Calorie burn needs to be added to this number to maintain a given weight. On an average day, I could easily burn an additional 1,000 Calories, meaning I should be targeting around 3,000 Caloires for maintenance. (Note in the USA we use Calories which are different than calories. A Calorie is equal to 1,000 calories. A Calorie equals a kilocalorie, the unit shown in the chart.)

The third result shows a breakdown of the Calories I burn at rest. You will see that there is a slight tendency for me to burn fats over sugars. This means that I could cater my diet to be a bit heavier on fats than carbs. Anecdotally, I have found this to be true. I have played with diets that range from high fat/low carb to high carb/low fat. I didn’t feel great at either extreme, but I do feel best near the middle with a slight shift toward fat. This result is validation of my intuition.

Vo2 Max

The VO2 Max is an indication of how much oxygen the body can utilize during exercise. A higher VO2 Max indicates that the body is able to more efficiently process and use the oxygen that is taken in through breathing. VO2 Max is a key indicator of cardiovascular fitness and endurance. As a runner, this is one metric that I am very interested in maximizing. The test also yields the most accurate result when fasting and abstaining from caffeine. The test uses the same mask as the resting metabolic rate as well as a chest strap heart rate monitor. The test can be performed on a treadmill or stationary bike; DexaFit Madison uses the treadmill test. An appropriate program is then selected based on fitness level and anticipated results. The programs differ in speed and intensity. Based on my running background, the advanced program was selected. The treadmill starts at a slow, walking pace and progressively speeds up and increases in incline. The objective is to reach a threshold that cannot be maintained. This is where picking the appropriate program is key. A program that is not rigorous enough will end before the individual has had a chance to reach that threshold. Obviously for safety purposes, the aim is to stop just short of that threshold. Pushing to the point where an individual falls onto or off of the treadmill may yield the highest VO2 Max but is going to come with some major repercussions. For that reason, I was instructed to push to a point where I felt that I could continue for only a couple seconds longer, then give the sign to end the test and slow the treadmill.

Respiration and heart rate are continuously monitored throughout the test and from this data, a number is derived which is the VO2 Max. The higher the number the better. Recent findings have indicated that VO2 Max is the best predictor of all-cause mortality. That means that statistically, the higher the VO2 Max, the less likely an individual is to die in a given time frame. This, more than other parameters like blood pressure or cholesterol, is indicative of longevity. But more immediately, this is a parameter that I can track and correlate to my races. Increasing my VO2 Max is one parameter to evaluate whether I am improving as a runner. I don’t have a target for my VO2 Max, but I would like to continue to monitor it and assess how it relates to my race times.

The other piece of this is finding heart rate data. When it is recommended that an individual get 30 minutes of moderate activity a day, this is what is being discussed. Heart rate should be in that moderate category, for me 164 - 174 bmp, to really be effective. While any activity is better than nothing, there is the most return on effort at or above that moderate category. But be aware that these categories do not directly correspond to the zones that are often discussed in training. The zones are commonly assessed as a percentage of maximum heart rate (MHR). Zone 1 is 50 - 60 % MHR, Zone 2 is 60 - 70% MHR, Zone 3 is 70 - 80% MRH, Zone 4 is 80 - 90% MHR, and Zone 5 is 90 - 100% MHR. These breakdowns are a bit different from what is given below. Although not a standard report, I was able to get a full spreadsheet of my test data. From here I easily found my MHR to be 198 bpm and can easily calculate my zones from this number.

In all, I really enjoyed the experience and found the data insightful. Full disclosure, I am writing this several months after my initial test and have since been back for additional tests. I wanted to keep this focused on the initial results as not to get too complex, but I have already been able to see some changes from the initial tests, some of which I discuss in my Mines of Spain Race Report. I am interested to continue tracking some of these metrics and evaluating trends and correlations with performance. I am sure that there will be a follow-up post in the future once I have been able to establish some trends. For now, though, I hope this information was insightful to anybody considering similar tests.