Most lab tests and blood tests are designed to diagnose and treat illness and disease with medications or surgery. Strength and power athletes present a unique blood profile that most physicians will simply write off as "normal", even though performance is declining and the athlete is unsure why. Lab tests that come back as normal may still be problematic for a healthy athlete and may indicate some deficiencies that could be causing decreases in performance. The standard reference ranges for "normal" are compiled based on average of individuals ranging in age from 18-80 that had their lab tested by the organization that drew them. One lab panel from company A may have different reference ranges than company B, and this poses a problem for physicians and athletes alike.

In this article we will cover some lab metrics that can be useful for an active exerciser looking to increase their performance or ensure they are not at risk for developing any nutritional, recovery, or health deficiencies. We are going to look at Optimal Reference ranges as a way to interpret results, which can outline parameters of good health and performance. Since the body and its systems are interconnected, we are going to look for patterns and correlations between lab markers that show more of an overall look at how the body is responding to its environment currently (stress, sleep, nutrition, exercise, etc.) Using the optimal reference ranges, we can address some metrics before they become a big problem. We can start to see trends and see a composite of connected lab metrics that rise together, address them, and get everything working at peak capacity before any performance slow-down occurs. These labs can also help us determine if further testing is needed for certain conditions or problems.

Throughout this three-part series, we will cover labs that are commonly done as part of an annual checkup at the doctor's office and some other more specific labs done to get a larger picture of body functions. There are a multitude of available lab metrics to have tracked by your doctor, so we will cover some labs that you might have had done but never had explained before. We will also cover some labs that could be particularly useful for performance athletes. By going over these labs and giving you a little bit of background on what they are used for and what contributes to higher or lower levels, we hope to give you clues as to what diet or exercise changes to make to your programs to help you function at your best.

In the first part of this series we cover labs dealing with blood sugar regulation, blood cells and composition, electrolytes, male and female sex hormones, bone and muscle health, digestion and lipid levels. Part two of this series covers oxygen deliverability, liver function, and kidney function. The third and final part of this series covers the NMR lipoprofile test and an insulin resistance score. This last test goes more in depth as to cholesterol, lipid management and risk for insulin resistance and diabetes. It can also tell us more information about inflammation and give us clues as to what is driving inflammation in the body. These labs would normally be indicated on lab slips as a Complete Blood Count (CBC), Comprehensive Metabolic Panel (CMP), Male hormones, female hormones, and NMR Lipoprofile.


Energy and Metabolism

Glucose

Fasting blood glucose should be measured on a regular basis for the purpose of assessing how one's body is responding to sleep, stress, macronutrient intake, circulating insulin levels, stress hormone (cortisol) release and a host of other factors. This number by itself doesn't mean much, but when looked at with other biomarkers, it can start to paint a picture of what is going on in the body in relation to training and recovery. Fasting glucose can be paradoxically elevated in the morning after a several hour fast through a process often referred to as the "dawn phenomenon" when the blood glucose levels fall, the body sense it is in danger and secretes cortisol which frees up amino acids from muscle tissue to be turned into glucose molecules. Glucagon breaks glycogen down to glucose in the liver and glucose levels rise, and if fasting continues for longer than protein and fatty acids are broken down under glucagon stimulation and blood glucose levels continue to rise. This single measurement can alarm some that aren't aware of the dawn phenomenon and who are following a relatively low-carb diet and have been clean with their dietary intake. Since many medications and stress all affect glucose levels, it is difficult to pinpoint an exact cause for someone's elevation in glucose without more metrics to get the whole picture. Optimal levels of glucose should be 75-90mg/dL.

Insulin

Insulin levels are often checked to evaluate abnormal lipid and carbohydrate metabolism. It is often used in patients with an elevated fasting glucose or patients that have difficulty losing weight despite having a good diet and exercise program. Insulin regulates blood glucose levels by helping glucose to move out of the bloodstream and into the cells. Insulin secretion is primarily reactive to blood glucose levels, so as blood glucose rises, so does insulin, and then when blood glucose levels fall, insulin release stops. This test can be used to help determine insulin resistance and changes in lifestyle needed to address it. Since there are many different factors involved in insulin resistance, it is best to look at this metric in combination with other glucose, lipid and inflammation metrics to determine the therapy to address it. Optimal levels of insulin should be below 8.4 uIU/mL.

Hemoglobin A1c

The hemoglobin A1c test is used to determine a 3-month average of fasting glucose levels. This test is mainly used for assessing diabetic control and diabetic medication changes. We use this test to determine insulin resistance, stress induced elevations in blood glucose levels, overall glycemic control, composition of the diet, etc. It is not uncommon for someone following a low carbohydrate diet for this number to be slightly elevated for a few months following the initiation of a low carb diet due to the increased lifespan of Red Blood Cells. If an HbA1c level is slightly elevated, and the individual has been following a low carbohydrate diet for awhile, their elevation on blood glucose over the past few months may be due to stress induced elevations in blood glucose levels. If this is the case, then training may need to change, more emphasis on post-workout nutrition, BCAA supplementation, adequate rest and recovery, and stress reducing activities. Optimal levels of hemoglobin A1c should be between 4 percent - 5.7 percent.

Cholesterol

Cholesterol testing is used to determine the risk for coronary heart disease. It is also used for evaluation of dietary intake. The total cholesterol number is composed of a combination of HDL and non-HDL with a calculated LDL-C level. This number doesn't mean much by itself unless levels are over 250. In which case, levels over 250 could be caused by a high LDL-C level or an abnormally high HDL level. Since cholesterol is required for the production of steroids, sex hormones, bile acids, and cellular membranes, we want to make sure that our levels are optimal to keep us hormonally balanced, strong in the gym and resilient to injuries and ability to digest and absorb fats (bile acids help with this). In exercising populations, it's typical to see cholesterol range from 100-220 depending on other factors too lengthy for an article on biomarkers for performance. Optimal ranges for total cholesterol should be between 150-200 mg/dL.

LDL-C

The LDL-C measurement is calculated from Total Cholesterol and HDL. This number generally falls between 50-200 with numbers exceeding 150 being indicative of a few factors. LDL-C and total cholesterol can be elevated during the weight loss process because circulating fatty acids being used as precursors to energy can be measured during a serum test. If weight is stable, and LDL-C levels are elevated above 100, diet can be to blame. The recent trend of putting butter and coconut oil in coffee has caused many LDL-C numbers to be over 150, and this isn't necessarily a large problem by itself, but it definitely does not improve performance for strength and power athletes, nor does it tell us if our diet is deficient in other macronutrients or vitamins/minerals. This number is often raised in response to stress hormones, and a lower LDL-C number is generally found in individuals who are recovered well, respond to stress well, and train hard in the gym, but don't break themselves. Optimal levels of LDL should be <99mg/dL.

HDL

This is a measurement of the "so-called good cholesterol" but it's not really a cholesterol measurement at all, it's a lipoprotein that carrier cholesterol from the body back to the liver. HDL has often been referred to as the body's garbage collector that takes cholesterol distributed in peripheral tissues back to the liver. HDL has also been considered a negative risk factor for heart disease when this number is higher than 60 mg/dL. When it comes to looking at this lab for performance metrics, it helps us to consider the type of training we are doing and the goals of the training. In endurance exercisers it is not uncommon for HDL to be relatively low and higher for strength and power athletes. Some of the differences come from exercise intensity, and diet. Since most endurance exercisers think they need to "carb load" and super-compensate with tons of sugars that often aren't needed, this raises triglycerides and decreases HDL, especially when the exercise intensity falls below 6 METs or 75% of Heart Rate Max. When we look at this number in combination with triglycerides we can evaluate our training and our dietary intake to maximize benefits based on how our body is responding to the stimulus of the diet, exercise and recovery aspects. The dietary influences on this number are; fasting, saturated fat intake, and a reduced or appropriate carbohydrate intake based on training volume and intensity. Optimal levels of HDL are >55 mg/dL.

Triglycerides

Triglycerides are chemical components in the body composed of 3 glycerol molecules and 1 lipid backbone. When these numbers are elevated over 150 mg/dL it often indicates that there is an excess of alcohol, high fructose corn syrup, or carbohydrates in the diet. It could also indicate a deficiency in omega-3 fatty acids, choline, or ample exercise designed to burn glycogen stores. Triglycerides tend to be lower in strength athletes, bodybuilders, and individuals doing some form of high intensity circuits with appropriate resistance training and weight lifting exercises. When triglycerides are high, HDL is usually low and vice versa. If triglycerides are elevated and alcohol, carbs, omega 3's and choline are sufficient then training might need to change to include more heavy lifting or time under tension to deplete glycogen stores. Triglycerides can be artificially elevated on a blood test if someone did not fast properly or if someone is actively losing a lot of body fat. Optimal levels for triglycerides are <100 mg/dL.

Bone and Muscle Health

Calcium

Calcium is not usually tested for in most lab panels but it can be a diagnostic tool to help make sure our bases are covered nutritionally. Even though calcium is involved in muscle contractions a deficiency of calcium in the blood is unlikely. The body will take calcium from the bones to bump up levels of calcium for muscles in the body including the heart, smooth muscles, intestines and skeletal muscle. However, some have noticed an acute instance of muscle cramping when calcium is depleted, and has been addressed using calcium carbonate tablets (but this usually only happens with endurance athletes). Calcium in the body is regulated by parathyroid hormone, vitamin D and vitamin K2 but low levels of serum calcium can be due to vitamin and mineral deficiencies caused by inadequate diet or insufficient absorption of nutrients. High calcium levels should be looked at by a qualified physician because it could indicate a significant health challenge or illness. Optimal levels of calcium should be 9.2 - 10.1 mg/dL.

Vitamin D

No other nutrient, drug, or hormone has gained more scientific credibility than vitamin D. By now, most people should be familiar with Vitamin D and it's significant importance in our lives. Insufficient vitamin D is linked to virtually every age-related disorder and chronic inflammation. Vitamin D is very important for immune support, addressing chronic inflammation, protection from infections, osteoarthritis pain and functional performance. It is very important to get this metric tested annually or every 6 months. Some individuals are inefficient at synthesizing vitamin D from the sun even if they have enough precursors (cholesterol) in their diet. Supplementation may be needed for most people getting minimal sun exposure of sensitive to the sun, and getting your levels checked can ensure you are taking the proper dosage. I recommend getting levels checked in the middle of winter and the middle of summer when sun exposure is vastly different because it may mean that you don't have to supplement in the summer, and need upwards of 50,000 IU per week in the winter. Optimal levels 50-100ng/mL.

Magnesium

Magnesium is an electrolyte that is found mostly intracellularly in the body and is critical in nearly all metabolic processes. Magnesium acts as a cofactor in many different activities of enzymes and affects carbohydrate, protein synthesis and metabolism. Magnesium is also important in calcium metabolism because magnesium increases the intestinal absorption of calcium and low levels of calcium will respond to magnesium supplementation. Magnesium deficiency is very common, and is seen in individuals who have food malabsorption issues, alcohol abuse, diabetes, and excessive exercise. Optimal levels of magnesium should be 2.0 - 2.5 mg/dL.

Folic Acid

Folic acid (folate) is also called Vitamin B9. The body needs folic acid to make red blood cells (RBC), white blood cells (WBC), and platelets, and for normal growth. It is also needed for the synthesis of precursors to DNA, some amino acids, and relies on Vitamin B12 for conversion from the inactive to the active form of folate. Low levels of folate indicate nutritional deficiencies or malabsorption issues. This test is often used with a RBC test to identify a potential cause of low RBCs. High levels of folate are found with inadequate vitamin B12 and vegetarianism, and thus a Vitamin B12 test should be performed to check levels to isolate the deficiency. Optimal levels of folic acid should be 5-25 ng/mL.

Vitamin B12

Vitamin B12 is used to evaluate malnourished patients and evaluate the cause of some type of anemias. Vitamin B12 deficiency causes anemia but it may take up to 6-18 months of deficiency before anemia develops. Deficiency of intrinsic factor (made in the stomach), and lack of gastric acid in the stomach are the two primary causes for B12 deficiency. Serum B12 is a measurement of recent B12 ingestion, and if long-term B12 deficiency is suspected a urinary methylmalonic acid measurement may be recommended. Correcting a B12 deficiency involves eating more foods with B12 and addressing lack of stomach acid. Optimal levels of B12 should be 600-950 pg/mL.

Digestion

Total Protein

This metric (together with globulin) can be used to assess protein intake, digestion, and absorption. This metric doesn’t correlate strongly with muscle mass accretion but it does correspond with hydrochloric acid (HCL) produced by the stomach. Numbers outside of optimal reference ranges can indicate a HCL deficiency that impairs your ability to digest and absorb proteins from foods. This shouldn’t be used as a definitive marker for assessing HCL deficiency but that it could indicate an issue that warrants further investigation with a professional. Total protein should be between 6.9-7.4 G/L

Albumin

Albumin is an acute phase protein that shifts relatively quickly based on health status. Albumin levels should always be above 4.0 unless admitted to the hospital or have a significant nutritional deficiency. The albumin levels fall in response to inflammation in the body due to rising amounts of cytokines into the bloodstream. Albumin is thus called a “negative acute phase protein” because of the inverse correlation they have. Albumin is synthesized in the liver and can indicate some liver deficiencies also. Albumin's main role is to maintain fluid in the circulatory system and prevent excessive fluid buildup in tissues called edema. Optimal levels of albumin should be 4.0 - 5.0 g/dL

Globulin

This metric is often used with Total Protein levels to assess a possible deficiency in HCL production, which leads to a decrease in protein digestion and absorption. It is not uncommon for someone following a moderate to high protein diet to have insufficient levels of HCL. “Hard gainers” and individuals who have a really hard time putting on muscle may want to have their HCL levels tested professionally, because even though they may be eating sufficient protein, their body is not able to digest or use it properly for muscle mass gain. Optimal levels of Globulin should be between 2.4 – 2.8 G/100mL.

Minerals

Potassium

This is a measure of the electrolyte potassium in the body and since the kidneys don't reabsorb potassium once excreted by the kidneys, then serum levels can drop rapidly if not adequately supplied by diet. The level of potassium in the blood is regulated by a hormone produced by the adrenal glands called aldosterone. This serum marker is often used to look at electrolyte balance in the system and if this number is too low than there might be a serious problem because hypokalemia (not enough potassium in the blood) can lead to cardiac arrhythmias. Serum potassium levels are also affected by acid-base balance. Alkaline states lower potassium levels and acidic states raise potassium levels. This number is often used in conjunction with sodium to begin to assess adrenal health. However, if these numbers are within normal ranges, it doesn’t mean there isn’t an issue, it just means that these numbers don’t indicate there is an issue. We can find elevated Adrenal Stress Index tests but normal potassium and sodium levels in the blood. If these numbers are outside of the reference range, it doesn’t indicate if the adrenals are hyperactive or underactive and therefore and adrenal stress index test would give more information and help guide treatment. An optimal amount of potassium in serum is: 4.0-4.5 mmol/L.

Sodium

Sodium levels in the blood are also controlled by the hormone aldosterone made by the adrenal glands. A high sodium count on the labwork may indicate dehydration or an adrenal imbalance. A high sodium content diet does not contribute to a high level of sodium on the blood test, but is the result of a balance between dietary sodium intake and removal by the kidneys. I often hear from individuals that eat a lot of sodium from junk food that even though they eat a lot of junk food, their sodium is never high. This gives the individual a false sense of security and they can continue to eat salt in unlimited quantities without any negative effects. Since salt deficiencies are rare and one of the first symptoms of hyponatremia (low salt in the body) is weakness, we should strive to try and maintain a good balance between salt intake and water intake for optimal performance. An optimal amount of sodium in serum is: 135-140 mmol/L.

Inflammation/Food reactivity

High Sensitivity C-Reactive Protein

This is an acute-phase reactant protein used to indicate an inflammatory illness. Hs-CRP is often used to predict cardiovascular events, but standing alone, it shows little value without a number of repeat tests, or a lipid panel to accompany it. I have found that hs-CRP levels are high in patients with injuries, lack of sleep, lack of proper recovery, or people who are mentally stressed most of the time. These are all forms of inflammation in the body, so it makes sense that hs-CRP would rise due to these events. Optimal ranges for hs-CRP <1.0 mg/L

White Blood Cell Count WBC

White Blood Cells are important immune system cells that are composed of many different types of cells. White blood cells can rise in response to inflammation in the GI system, an infection or possible food sensitivity. If WBCs are low, it sometimes indicates a zinc deficiency, but if coupled with low globulin and a low total protein, the zinc deficiency might be caused from inadequate breakdown of proteins from low HCL production. High levels of WBCs can indicate a food intolerance or sensitivity in the absence of any other illness or infection during the time of testing. If levels are high and no illness or infection is present, starting with an elimination diet may help to improve performance provided that the diet is adequate in vitamins, minerals, macronutrients and total calories. Optimal range for WBCs is 5.0 - 8.0 x 109 /L

Eosinophils

Eosinophils are involved in allergic reactions. As the allergic response diminishes, the eosinophil count decreases. Eosinophils do not respond to bacterial infections or viral infections but can rise in a parasitic infestation. From my personal, clinical experience, I have found that eosinophils are relatively short lived, and if these numbers are high, but the WBCs are low, then the person recently encountered an acute agent that caused the body to mount an allergic response and can be useful if a diet log was assessed prior to blood sample collection. Optimal range is 0-3%

Strength and Endurance

Creatine Kinase

Creatine kinase is often used to measure cardiac events. The levels of creatine kinase in the blood are elevated following damage to muscle tissue. Too high levels of creatine kinase are not beneficial and may be indicative of some form of muscle wasting. Exercise and muscle trauma (contact sports, traffic accidents, intramuscular injections, surgery, convulsions, wasp or bee stings, and burns) can elevate serum creatine kinase values. Creatine supplementation may help to decrease serum creatine kinase levels if there is excessive muscle damage to an area as seen in endurance type activities. Creatine kinase levels should be between 52-336 U/L for males and 38-176 U/L for females.

Total Testosterone

Total testosterone is tested because of its relationship with stress, exercise, and the various lifestyle components that can be altered in order to improve it. If someone is an active exerciser, lifting heavier than 70% of their 1RM for the majority of their training, consuming enough saturated animal fats and cholesterol but doesn’t recover well, then their total testosterone could be low or low-normal. Alcohol dependence and acute alcohol toxicity can impair testosterone production and care should be used when consuming alcoholic beverages for anabolic purposes. Lifestyle modifications to improve testosterone should be focused on rest/recovery, consuming adequate precursors to steroid hormones in the body (cholesterol), heavy resistance training that is properly periodized and a moderate amount of alcohol consumption (1-3 drinks per day.) Most often, stress, and lack of sleep are a prime culprit for low testosterone production, except in people who eat severely restrictive low fat diets. Optimal levels for males should be between 500-950 ng/dL and females should be between 20-60 ng/dL.

Free Testosterone

Free testosterone measures the amount of testosterone that is not bound to Sex Hormone Binding Globulin (SHBG). Free testosterone is often measured in conjunction with total testosterone and can help to identify a primary causative factor in low total testosterone. Most of the time, men are placed on hormone replacement therapy when their levels are low but are not questioned about their lifestyle factors that may contribute to their low levels. Low levels can be due to liver detoxification issues, thyroid issues, zinc deficiency, increased cortisol levels, imbalances with insulin and blood sugar, increased activation of aromatization hormones caused by excessive body fat, etc. In order to get a thorough review of lab values for hormones and lifestyle factors, many patients have sought the help of Naturopathic physicians and Chiropractors who do saliva testing. Saliva testing can be beneficial but it’s often more expensive and the information and therapy given depends on the practitioner. Optimal levels of free testosterone should be for Males: 9-30 ng/dL and Females: 0.3-1.9 ng/dL.

DHEAS

A DHEA-Sulfate test may be ordered whenever excess/deficient androgen production is suspected and/or when someone wants to evaluate their adrenal gland function. If someone is having a hard time gaining muscle mass and issues with weight gain around their midsection while following a good nutrition and exercise plan, they might have low levels of DHEAS. Low levels of DHEAS might be caused by an adrenal gland dysfunction, or insufficiency or a pituitary problem. I use this lab marker to set a baseline for an individual and ensure that these levels aren’t going to affect their long-term training goals.

Typical normal ranges for females are:

Ages 18 - 19: 145 - 395 micrograms per deciliter (ug/dL)
Ages 20 - 29: 65 - 380 ug/dL
Ages 30 - 39: 45 - 270 ug/dL
Ages 40 - 49: 32 - 240 ug/dL
Ages 50 - 59: 26 - 200 ug/dL
Ages 60 - 69: 13 - 130 ug/dL
Ages 69 and older: 17 - 90 ug/dL

Typical normal ranges for males are:

Ages 18 - 19: 108 - 441 ug/dL
Ages 20 - 29: 280 - 640 ug/dL
Ages 30 - 39: 120 - 520 ug/dL
Ages 40 - 49: 95 - 530 ug/dL
Ages 50 - 59: 70 - 310 ug/dL
Ages 60 - 69: 42 - 290 ug/dL
Ages 69 and older: 28 - 175 ug/dL

You can see more on DHEA here.

Cortisol

Cortisol is the main glucocorticoid in the body and it plays a central role in glucose metabolism and in the body's response to stress. Cortisol rises in response to stress to prepare the body to “fight or flight”. Cortisol peaks in the morning between 8am and 10am and falls gradually throughout the day and levels off around the time the sun goes down. This is particularly important to know when the labs are taken because the cortisol number on the labs should correspond with the time of day. If you have your labs drawn around 10 am, you’re your plasma cortisol level should be elevated, and if you have your labs drawn later in the day (around 4pm) then those numbers are going to be significantly lower. It is often better to get a Salivary Cortisol Test done because cortisol is measured 4 times throughout the day by spitting in a tube at the prescribed times to check for peaks and valleys throughout the day. Decreasing cortisol levels allow the release of melatonin and increase the levels of growth and repair hormones. The signs and symptoms of chronically elevated cortisol are common (e.g., obesity, high blood pressure, increased blood glucose concentration). The most common cause of increased plasma cortisol levels in women is a high circulating concentration of estrogen (e.g., estrogen therapy, pregnancy). Many drugs, and significantly stressful events can falsely elevate cortisol levels, so it’s best to have this tested when you are relatively free from stress and not taking any prednisone or steroidal anti-inflammatories. This test can be used to decide when it is time to cycle off of a heavy lifting cycle and do more rest and recovery type activities. Serum cortisol levels should be 7-25 mcg/dL in the morning and 2-14 mcg/dL in the afternoon/evening.

SHBG

Sex Hormone Binding Globulin has profound effects on the balance between bioavailable androgens and estrogens. Increased levels of SHBG in men means there is less free testosterone that can be bound to albumin and used for performance and reproductive purposes. Increased levels of SHBG in men may manifest in enlarged breast tissue, fat gain around mid-section, and insulin resistance. Decreased levels of SHBG in women may lead to a deepening of the voice, reproductive difficulties and insulin resistance/Polycystic Ovarian Syndrome (PCOS). Patients with anorexia, on thyroid medication, or taking synthetic estrogens may also have elevated SHBG levels. SHBG starts to normalize for these patients when diet is adequate in calories, carbohydrates, proteins and fats. This marker can be used for diagnostic purposes to see if low testosterone symptoms are caused by too much SHBG if total testosterone is within optimal ranges.

Levels of SHBG should be:

Males: 10-57 nmol/L
Females (non-pregnant): 18-144 nmol/L