June 2, 2020
9 Biomarkers to Track If You Want to Live Well and Prosper
WRITTEN BY Jesse O'Brien

People are used to going to the doctor for their annual physicals and getting routine lab tests performed. Those will give you some information about your health, however, tracking some more specific values over time can be a great tool for understanding the road to longevity and any interventions that may need to be established.

One pertinent point is that what is “normal” is not necessarily optimal when it comes to health. Typically standard labs aggregate the data from patients who have utilized that testing facility and whoever fits between 2.5 standard deviations (95% of the patients) are considered “normal”. One thing I have personally observed over the five years when my clients have labs drawn are biomarkers such as ALT and AST, which measures an enzyme that indicates damage at the liver, where what is considered the “normal” reference ranges has widened over the years. For example, the old reference ranges were:


0 – 35 U/L Males

0 – 20 U/L Females


0 – 37 U/L Males

0 – 31 U/L Females

The new reference ranges I have observed are around:


0 – 41 U/L Males

0 – 33 U/L Females


0 – 40 U/L Males

0 – 32 U/L Females

If you had a lab test that indicated 40 U/L as a male today, that is considered “normal” which people assume is healthy and ideal. However, if this test had been performed in 2010, it would have been flagged as an abnormal test result and the doctor would have likely discussed this with the patient. 40 U/L is still a departure from what is optimal:


0 – 30 U/L Males

0 – 20 U/L Females


0 – 30 U/L Males

0 – 30 U/L Females

Health should be less about statistics and more about understanding optimal values that are associated with health. Our bias at Central Athlete is that health is not merely the absence of disease, but an optimal expression of physical, emotional, and mental well-being. That’s why we feel strongly that using a functional perspective for clinical laboratory testing is the highest form of care to optimize health and longevity. Below are the 9 biomarkers you should be paying attention to in order to live a long, fulfilling life. This post is longer than our usual ones but provides a wealth of good information.

Vitamin D

Optimal range = 50 - 100 ng/dl

The literature on Vitamin D has established the supplement as a major factor in preventing stress factors and optimizing bone health. Rates of vitamin D insufficiency in humans vary among studies, but most researchers agree that people should be evaluated regarding vitamin D status and given intake recommendations to maintain optimal 25(OH)D levels >40 ng/mL. Some studies estimate as many as 80% of the population lacks optimal vitamin D status.

Not only does vitamin D assist in the growth and maintenance of bones, but it also aids in the regulation of electrolyte metabolism, protein synthesis, gene expression, and immune function. These vital functions are essential for all individuals, especially elite and recreational athletes. Therefore, regardless of the limited literature available in support of a positive effect from vitamin D on performance, obtaining optimal 25(OH)D levels should be a goal for all people.

The data is not conclusive to support vitamin D supplementation as a direct performance enhancer, however, research supports the role of vitamin D in the prevention of chronic and acute diseases, such as cancer, cardiovascular disease, type 2 diabetes, autoimmune diseases, and infectious diseases. Athlete or not, optimal vitamin D status is essential for countless fundamental bodily functions, making it important for all individuals to obtain appropriate levels. Further research is warranted to define optimal supplementation regimes for specific populations (the elderly, athletes, those who are deficient/altering levels for the seasons), establish definite serum 25(OH)D goals, and investigate the effect of vitamin D on physical performance.

Epidemiological studies indicate all-cause mortality drops as vitamin D levels increase:

Central Athlete’s recommendation is to get 20-60 minutes of unprotected sun exposure daily on at least 40% of your body to increase serum vitamin D levels. Additionally, testing vitamin D levels with the goal of establishing a minimum of 50 ng/dl. is recommended. In our experience, we have never tested one client who has had optimal vitamin D levels without supplementation likely due to a lack of an optimal amount of sun exposure.

In our opinion, with the support of the literature referenced, we feel that Vitamin D supplementation is one of the cheapest and most effective interventions to support living a long prosperous life.

High-Sensitivity C-Reactive Protein

Optimal range < .5 mg/L

Over two dozen research studies have proven that baseline levels of the inflammatory marker C-reactive protein (CRP) in healthy men and women are highly predictive of future risk of cardiovascular ailments, including heart attack, diabetes, stroke, sudden cardiac death, and peripheral arterial disease. It has also been shown that CRP levels predict repeat coronary events among patients who already suffer from heart disease and that the outcome of patients immediately after a heart attack is tightly linked to CRP levels.

Ultimately, individuals with excessive levels of CRP have a risk of about two to three times higher than the risk of those with low optimal levels.

In our opinion, a CRP test for inflammation, combined with a basic lipid panel, is the single best way to evaluate your risk for heart disease. we personally recommend that individuals keep their CRP below 0.5 mg/L, and preferably below 0.2mg/L. Some ways to do that include eating an anti-inflammatory diet and avoiding overtraining, excessive stress, and toxin exposure.


Optimal range = 4.6 - 5.5%

HbA1C is roughly a 90-day average of your blood glucose levels. We prefer A1C to fasting blood glucose levels because it speaks to a larger time frame and paints a more accurate picture of the metabolic health of an individual.

Over 50% of the population is prediabetic and about $1 our of every $7 spent on healthcare is spent on diabetes. This equates to $327B in the United States per year spent on managing and treating diabetes.

Type-2 diabetes can literally be removed from society if consumers change their food profile. While some people will be more carbohydrate sensitive than the next person due to genetic factors (single-nucleotide polymorphism), everyone can benefit from knowing their A1C values and how that is affected by their patterns of behavior around food. Addressing blood sugar regulation in our opinion offers the single-handed biggest ROI to the global society measured by the economics of the issue along with societal suffering.


Optimal value = 2 - 5 μIU/ml

Low fasting insulin can be an excellent market for assessing longevity, correlating to glycemic variability—essentially how often your blood sugar is elevated. A high fasting insulin level is associated with a greater risk of cancer mortality.

In addition, cancer patients who eat the highest amount of insulin-producing foods experience worsened cancer and increased overall mortality. Furthermore, high insulin levels can predict cancer mortality, even when controlling for variables such as diabetes, obesity and metabolic syndrome. In older adults with type 2 diabetes, the level of insulin use also predicts mortality.

The trick is not to eliminate insulin altogether, but to keep insulin levels within certain limits. Dr. Joseph Mercola recommends “a normal fasting blood insulin level…below 5 [uIU/ml], but ideally… below 3.”

Some non-pharmaceutical interventions include lowering your carbohydrate intake, particularly processed foods, along with managing stress. Both a high intake of carbohydrates with not enough energy expenditure along with a stressful lifestyle, connect with increased levels of insulin.

An interesting fact is that hypertension is an early indicator of insulin resistance. As insulin levels increase, a hormone called aldosterone also increases. Aldosterone causes us to retain sodium, which causes us to retain water. Reducing dietary sodium has a modest effect on hypertension but does not address the root cause of elevated insulin levels. It only works for a small subset of people.

RBC Magnesium

Optimal range = 6.0 - 6.5 mg/dl

“Magnesium is central to all of our energy-forming reactions in every cell in the human body, and there are over 300 enzyme pathways in humans that are dependent on magnesium.” -Dr. Amy Neuzil

Accurately measuring magnesium levels can be difficult. Magnesium is found primarily within your cells (intracellular), however, most blood tests for magnesium do not detect a significant deficiency because they measure what is outside the cells (extracellular).

Despite this fact, most physicians measure magnesium with a simple blood test, and many people are then informed that their levels are normal. But to get an accurate reading, you need to measure intracellular magnesium levels, which can be done by testing red blood cells.

Red blood cell (RBC) magnesium measurements can help predict important longevity markers such as insulin sensitivity and the likelihood of being hospitalized. High levels of RBC magnesium can predict physical performance and potential for sarcopenia (muscle deterioration) as you age.

Magnesium is one of those miracle supplements if you are deficient. It is estimated that over three-quarters of Americans don’t even meet the RDA for magnesium (400mg for men and 320mg for women) and for most, magnesium tends to help tremendously with bowel movements, energy, and sleep. Also, if you are a heavy exerciser or under high stress, say goodbye to the RDA and start increasing your intake via foods or supplementation. This is because you need magnesium to run the enzymes that make energy and also clear adrenaline.

We get magnesium from eating green plants. A cup of raw spinach has about 25 mg of magnesium and one cup cooked has about 150 mg. Yet, the magnesium content of food has diminished drastically over the last 100 years because of soil depletion and big agriculture. For example, the average magnesium content across all fruits and vegetables has declined 21% since the 1960s: a typical apple is down 82% since 1914, and swiss chard is down 84% since 1963. Thus, it is a toss-up on how much you are actually getting through food alone.

As mentioned above, an RBC magnesium test can provide an earlier indication of magnesium deficiency than a standard magnesium blood test. This is because when levels are low, the body will pull magnesium from the red blood cells to keep blood levels normal. In this case, a magnesium blood test may show normal levels while an RBC magnesium test will give a far more accurate result.

Total and Free Testosterone

Optimal range:

Males = 700-900 ng/dl (total testosterone) 150-224 pg/ml (free testosterone)

Females = 35-45 ng/dl (total testosterone) 3.25 - 6.4 pg/ml (free testosterone)

Imagine you have a pool filled with water, and within that water, you have a single innertube. This is analogous to total and free testosterone where the water in the pool represents your total testosterone and your free testosterone the pool float.

Total testosterone is what your body has available while free testosterone is unbound and available for use within the body.

Several reports published in the related medical literature have proven that low testosterone (“low T”) is associated with increased mortality.

One study demonstrated that men with low T had a 33% greater death risk over the next 18 years of life compared to men with higher T. The study tracked nearly 800 men, 50 to 91 years old, living in California. Their T levels were measured at the beginning of the study, and their health was then tracked over the next 20 years. In addition, low T can drastically affect the quality of your life as you age, as symptoms reported by these men included decreased drive, erectile dysfunction, fatigue, loss of strength, decrease in bone density, and decreased muscle mass. These men tended to be overweight or obese and had higher risks for cardiovascular disease and diabetes. Indeed, men with the lowest T, below 241 total serum level, were 40% more likely to die!

When it comes to T deficiencies, it is important to understand that having high total T levels does not mean that you will also have high, bioavailable free T levels. Some men have total T levels ranging from 300 to 800 ng/dl, but their free T levels are often as low as 2, 3, and 4 ng/dl (often less than 1% of total T!). This can occur because some of the 2% of your T that remains in a free form can be converted into hormones like estradiol and DHT.

So what ratio of free T to total T should you aim for?

Ideally, you want at least 2% of your T to be free. If you are testing your testosterone levels, it can be insightful also to test DHEA. The largest amount of hormone produced by the adrenal glands is actually in the form of DHEA, which is a precursor to estrogen, progesterone, and testosterone. Symptoms of DHEA deficiency usually include fatigue, cognitive impairment, depression, decreased drive, and risk of recurrent infections.

Fortunately, DHEA is relatively easy to measure. But when DHEA is measured, the results should be correlated to age to be meaningful. Males around the age of twenty should have high levels of DHEA (around 1,200 ng/dL). By age ninety, the level is usually closer to 180 ng/dL. A thirty-year-old male with a DHEA level of 250 ng/dL would technically fall “within the normal range” of 180 to 1,200, but as you can imagine, this is a problem, since it’s nowhere near optimal levels and can actually indicate adrenal insufficiency and significant hormone imbalances.

Similarly to estradiol and estrogen testing, the best way to test testosterone levels is not via a blood test or salivary test (although salivary tests are more accurate than blood tests if performed 4 to 5 times throughout the day), but via a comprehensive DUTCH test.

Triglyceride-to-HDL Ratio

Optimal range < 2

Otherwise known as the atherogenic index of plasma, a high triglyceride-to-HDL ratio is also one of the best indicators of your risk for heart disease and suggests cardiovascular inflammation.

One study in elderly women, the triglyceride-to-HDL ratio predicted all-cause mortality, meaning it predicted the risk of not only cardiovascular mortality but also the overall risk of dying from anything. There is, of course, a host of additional studies on this ratio, including a study that shows that the triglyceride-to-HDL ratio predicts coronary heart disease and cardiovascular disease mortality risk as well as or better than a full-blown metabolic syndrome. A ratio of 2 or under is good for a triglyceride-to-HDL ratio, and most of my healthiest individuals strive for under 1, which demonstrates very little inflammation. Above 4 is typically a very unfavorable scenario.

Basic Lipid Panel and OmegaCheck

Total cholesterol = 160 - 180 mg/dL

Triglycerides = 70 - 80 mg/dL

LDL = 80 - 100 mg/dL

HDL = 55 - 70 mg/dL

Cholesterol:HDL = 0 - 3

Non-HDL cholesterol < 130 mg/dL

Omega 6:3 < 4:1

A basic lipid panel helps to uncover early risk factors for heart disease and measures fats and fatty substances in the blood, such as LDL, HDL, triglycerides, and total cholesterol—which indicates current and potential heart health.

In most cases, a doctor or medical textbook will give you the usual advice for cholesterol ranges, such as the following:

Lipidologists typically look at a basic lipid panel and go after poor ratios (Triglyceride-to-HDL Ratio and Cholesterol-to-HDL), high LDL, and cholesterol. One thing to note is that LDL can actually be a poor measurement of risk when compared to two other important lipid markers: HDL and triglycerides. In studies that stratify all three, HDL and triglycerides appear as the clear risk indicators, with LDL becoming nearly irrelevant. When HDL is high and triglycerides are low, the risk for cardiovascular disease is very low, regardless of LDL levels.

In contrast, the more omega-3 fatty acid in the red blood cells, the lower your risk for colon cancer (and the higher the omega-6, the higher the risk for colon cancer). Older individuals with low levels of omega-3 fatty acids decline physically more quickly than older adults with higher levels. A low omega-3 fatty acid count also predicts smaller brain volume and cognitive decline, even in older adults who don’t possess any other symptoms of dementia. The ideal dietary ratio of omega-6-to-omega-3 fatty acids is 4-to-1, although many anti-aging and functional medicine practitioners suggest consuming a 1-to-1 ratio or higher in favor of omega-3 (the average American eats a ratio ranging from 12:1 to 25:1 omega-6-to-omega-3!).

Complete Blood Count with Differential

White Blood Count = 5.0 - 7.5

Neutrophils = 40-60%. Higher = viruses, autoimmunity, or detoxification challenges

Monocytes = 0-7%. Higher = liver dysfunction, prostate problems, or recovering from infection (or Epstein Barr virus)

Eosinophils = 0-3%. Higher = food sensitivities, environmental allergies, or parasites

Basophils = 0-1%. Higher = tissue inflammation

A complete blood count with differential, also known as a CBC, is often used as a broad screening test to determine an individual’s general health status. It can be used to screen for a wide range of conditions and diseases and to help diagnose various conditions, such as anemia, infection, inflammation, bleeding disorder, or leukemia.

A CBC is a panel of tests that evaluate the three types of cells that circulate in the blood, including:

The evaluation of white blood cells, the cells that are part of the body’s defense system against infections and cancer, and also play a role in allergies and inflammation. White blood cell (WBC) count is a count of the total number of white blood cells in a person’s blood sample and identifies and counts the number of the various types of white blood cells present (the five types include neutrophils, lymphocytes, monocytes, eosinophils, and basophils).

The evaluation of red blood cells, the cells that transport oxygen throughout the body. Red blood cell (RBC) count is a count of the actual number of red blood cells in a person’s blood sample. Other factors in this part of the panel include hemoglobin, MCV, MCH, MCHC, RDW, MPV, and RDW. Hemoglobin measures the total amount of the oxygen-carrying protein in the blood, which generally reflects the number of red blood cells in the blood. Hematocrit measures the percentage of a person’s total blood volume that consists of red blood cells. Mean corpuscular volume (MCV) is a measurement of the average size of a single red blood cell. Mean corpuscular hemoglobin (MCH) is a calculation of the average amount of hemoglobin inside a single red blood cell. Mean corpuscular hemoglobin concentration (MCHC) is a calculation of the average concentration of hemoglobin inside a single red blood cell. Red cell distribution width (RDW) is a calculation of the variation in the size of RBCs. The mean platelet volume (MPV) is a calculation of the average size of platelets. Platelet distribution width (PDW) reflects how uniform platelets are in size.

In addition, one study reports that men and women with above-normal WBC counts could face an increased risk of death at an earlier age, particularly from cardiovascular disease. People with normal WBC counts may not be out of danger since individuals on the high end of the normal range are also at increased risk of illness and death. Basically, the risk of cardiovascular mortality increases progressively with increasing WBC counts, and the increased risk of mortality associated with high WBC counts is maintained over 40 years of follow-up!

For WBC counts, a healthy blood functional range is between 5 and 8 cells per liter. Higher often indicates a possible infection and lower often indicates a depressed or suppressed immune system. As mentioned above, consistently high WBC counts translate to an increased risk of death at an earlier age, particularly from cardiovascular disease.

One of the best things I can suggest to be an advocate for your health is to gain a better understanding of these biomarkers. They will help you be an informed patient and make critical decisions about your health. Additionally, track your results (or hire a coach who will) and connect any changes that you notice to behaviors you have consistently adjusted for that time frame. For all of my clients who get bloodwork, which Central Athlete has arranged to have run through their insurance, I track these results and make personalized recommendations based upon their physiology in the context of health and fitness.

To learn more, schedule a free strategy session at the link below!

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