Tracking them might help you live longer, too.
Elite athletes leverage every available tool to enhance performance and increase their odds of remaining competitive for longer. Lab tests to determine lactate threshold and VO2 max have become quintessential parts of athletes’ routines. Increasingly, tracking metabolic, inflammatory, and hormonal biomarkers are also part of their arsenal.
Take U.S. ultrarunner Crystal Seaver, who used blood tests to pinpoint the cause of her crippling fatigue—low iron. Or sports scientist Dylan Lindsey, who guided triathlete Sarah Gigante to an Australian National Time Trial Championship win using a targeted lactate recovery protocol.
But this isn’t just for the pros. Whether you’re gearing up for your next 10K or simply looking to stay fit, tracking your key biomarkers could be the secret to a longer, healthier life.
Think of it as a roadmap for long-term wellness. “The more biomarkers you can evaluate and track over time, the better your chances are for a smarter and longer health span,” says Laura Kunces, PhD, RD, CSSD, a physiologist and registered dietitian at Human Powered Health. By monitoring these metrics, you establish a baseline to understand how your workouts, nutrition, sleep, and recovery stack up—and how to optimize them.
We asked top researchers, coaches, and longevity experts about the specific metrics pro athletes rely on to win championships and increase their health and lifespan—and how they could help you boost performance and longevity, too.
About the Experts
Laura Kunces, Ph.D., R.D., C.S.S.D., is a physiologist and registered dietitian at Human Powered Health.
John Thomas Smith, MBChB, FRCS, is the chief medical officer at RejuveAI.
Jena Brown, R.D., C.S.S.D., ISAK-1, is a performance dietitian for endurance athletes at Victorem Nutrition.
Michael Cockrum, C.P.T., is a certified personal trainer and education manager at Fitness SF.
Short-term inflammation is a normal response to exercise, especially in high-intensity training. But chronic low-grade inflammation messes with recovery and performance, which can leave you prone to injuries and burnout, says John Thomas Smith, chief medical officer at RejuveAI.
“Chronic inflammation is a hallmark of aging. It’s implicated in the development of numerous age-related diseases, including cardiovascular disease, cancer, Alzheimer’s disease, and metabolic disorders,” Smith explains. So, keeping chronic inflammation in check can help you recover faster and extend your healthspan—the number of healthy years in your life (1).
Here are a few of the best ways to track it:
Your liver cranks up the production of this protein when inflammation increases (2). CRP levels can rise and fall rapidly depending on how much inflammation is in your body.
Athletes monitor CRP to understand if their bodies are responding appropriately to their training—or if it’s time for a break. Regular exercise tends to lower resting CRP, so if yours is high even after resting, it may mean you need to take a deload week (or two) or see your doctor to check for any underlying health issues (3).
Like CRP, IL-6 is another protein that signals inflammation. Specifically, inflammation from injury and illness, including chronic illnesses like type 2 diabetes and rheumatoid arthritis.
Regular exercise can help keep IL-6 levels low. People who work out regularly tend to have lower resting IL-6 levels than inactive folks. Meaning: Sudden spikes (especially on rest days) or chronically elevated levels could indicate an underlying health issue, which may require training and/or nutrition adjustments, or medical intervention, to correct (4).
Measuring CRP and IL-6 can give real-time feedback on tissue damage and immune responses, says Smith. “In athletic contexts, these markers can predict injury risks by revealing low-grade inflammation before it becomes symptomatic. This allows coaches and medical teams to modify training or recovery protocols to prevent long-term damage.”
For the regular health-conscious person, monitoring CRP and IL-6 still offers insights that can help you manage your training load, understand your biological age and disease risk, and more. Still, it’s important to determine your baseline and watch how these markers evolve over time since they can shoot up for a variety of reasons that cause inflammation, not always related to training. They can also stay elevated for a while after an intense workout or long-duration event like a marathon or triathlon.
This biomarker measures polyunsaturated fatty acids (EPA and DHA) in the red blood cell membrane (5). Jena Brown, R.D., C.S.S.D., ISAK-1, tests her athletes for the omega-3 index. Why? “The cell membrane is crucial for cell signaling and cell function, which impacts athlete health, recovery, immunity, and performance,” says Brown.
Studies also suggest omega-3’s role in reducing inflammation may improve endurance and reduce muscle soreness after a workout (6, 7). Brown adds that an omega-3 index level of greater than 8 percent has been shown to offer the most health protection, whether you’re an athlete or not (8).
Metabolic biomarkers give you a snapshot of your blood sugar, cholesterol, and overall metabolic health—areas where even the fittest athletes can slip up. “Athletes or individuals focusing on short-term performance gains can unknowingly push these markers into unhealthy ranges, such as experiencing high cholesterol or insulin resistance,” Smith says.
According to Kunces, it’s not unusual for athletes’ fueling strategies to cause short-term health issues. Kunces, who has been a part of studies that have looked at ultra-marathon runners and many of their metabolic processes, says, “while these athletes are lean and usually metabolically efficient, dietary intakes like how many carbohydrates they consume (and in some cases, it’s a lot of carbs) plays a large role in metrics like triglyceride levels, HDL, LDL, and total cholesterol as well as things like glucose, insulin, and HbA1c.”
Monitoring your metabolic biomarkers can help you catch warning signs early so your peak performance doesn’t come at the cost of serious issues like type 2 diabetes or heart disease. Here’s what to look for:
Fasting glucose is your blood sugar level after at least eight hours of fasting. Insulin sensitivity shows how well your body responds to the hormone insulin, which is released and lowers your blood sugar when you eat or drink carbs.
“Chronic elevation of blood glucose levels and insulin resistance (poor insulin sensitivity) are linked to conditions such as type 2 diabetes and cardiovascular disease,” says Smith. On the flip side, stable blood glucose and high insulin sensitivity help you crush endurance workouts and recover faster. Keeping blood sugar in check also reduces oxidative stress and inflammation (9), both of which are key factors in aging and longevity, Smith adds.
A lipid profile measures cholesterol and fats in your blood, including total cholesterol, HDL (the good cholesterol), LDL (the bad one), VLDL (another bad type), and triglycerides. According to Smith, a healthy lipid profile is linked to a lower risk of chronic diseases, cardiovascular disease, and stroke, which are major killers. So, maintaining balanced cholesterol and triglyceride levels promotes heart health and may help you live longer (10).
Even though staying active generally leads to better cholesterol levels, studies have found that a surprising number (around 17 percent) of elite athletes are still at medium-to-high risk for heart disease. That’s why tracking cholesterol and other lipids is crucial—even if you’re in top shape (11).
An optimal hormonal balance improves strength, endurance, and recovery. “Hormonal imbalances, such as low testosterone or chronic cortisol elevation, are linked to aging, muscle loss, and metabolic dysfunction (12, 13),” says Smith. Keeping these hormones in check is essential for performance and longevity.
While keeping all of the 50-plus hormones in check is essential for optimal wellness, cortisol is a top offender when it comes to poor health. Cortisol isn’t always bad, but chronically high levels can cause extreme fatigue, irritability, and drops in athletic performance (14).
Athletes often overtrain without giving their bodies enough time to recover, which drives cortisol levels through the roof, says Michael Cockrum, certified personal trainer and education manager at Fitness SF.
Tracking cortisol is a simple way to fine-tune your training, he says. For instance, if your blood work consistently shows high cortisol, you might have an underlying medical condition. Or it could be a sign to dial back the intensity or volume of your workouts until your levels even out, especially if you do multiple sessions per week of high-intensity workouts, heavy lifting, and/or high-volume running.
There’s a reason testosterone gets so much attention. When your levels are optimal, both men and women benefit from better muscle growth, recovery, and athletic performance, says Smith. When it drops, you could be looking at weight gain, loss of muscle and bone mineral density, fatigue, depression, and more—all things that can tank performance and health (15). By keeping testosterone levels in the sweet spot, you’ll stay strong, lean, and ready to perform at your peak.
Cardiovascular biomarkers are among the most important metrics that pro athletes track, especially endurance athletes. “They’re strongly correlated with improved cardiovascular health and a reduced risk of heart disease, which is a major contributor to longevity,” says Smith.
Perhaps the most buzzed-about physiological biomarker, VO2 max, or maximal oxygen consumption, measures how much oxygen your body can use during exercise. Represented in milliliters of oxygen consumed per kilogram of body weight per minute (mL/kg/min), VO2 max has become a quintessential marker of fitness and performance.
It’s not just a fitness indicator, though, says Smith. A better VO2 max is linked to improved
overall health (16): “Higher VO2 max levels are strongly associated with lower all-cause mortality and a reduced risk of cardiovascular diseases. Better overall cardiovascular health directly contributes to longevity.” How’s that for a one-two punch?
Heart rate variability is a hot topic in elite sports. This biomarker measures the variation in time between your heartbeats. It reflects how well your autonomic nervous system handles stress, including physical stress from training, explains Smith (17).
“Athletes with higher HRV tend to have better recovery, adaptability, and resilience to physical stress, which contributes to enhanced performance,” says Smith. It’s also a strong predictor of overall cardiovascular health and longevity. Higher HRV can be a sign of better heart health, lower stress levels, and reduced inflammation, Smith adds.
As a regular person—read: not a pro athlete who’s paid to be healthy and perform—keeping track of all of this may seem like overkill. In truth, staying healthy doesn’t necessarily require tracking all of these biomarkers.
Optimizing your health is a different story. It’s nearly impossible to improve unless you understand your foundation. As the saying goes, knowledge is power.
If you want to learn more about your body and how well—or not—it’s operating, the biomarkers listed above are a good place to start. Working with a qualified health professional to interpret test results is also key to making the educated tweaks to your routine that actually boost performance and longevity.
For a more comprehensive picture of your biological age and health, Kunces suggests also tracking markers of blood and bone health, hormones, metabolism, chronic disease risk, inflammation, stress, and injury, as well as vitamin and mineral status.
Doing so can shed light on seemingly unexplained symptoms that interfere with athletic performance, such as fatigue, weakness, poor sleep, and more. Plus, biomarker testing helps manage your risk for illness and injury, both acute and long-term.
Kunces recommends getting blood work done at least once a year, ideally quarterly, as things change (including sun exposure with the seasons, diet fluctuations, training program evolution, and life stages).
It also depends on what you’re testing. For example, the lifecycle of red blood cells is around three months, which is why it’s not usually worth retesting blood more than once a quarter. However, CRP tests are often taken a few weeks apart to monitor risk. And you’ll want to track HRV daily since the overall trend is what’s most important for spotting signs of stress.
“The point is to not necessarily uncover something that’s going bad,” she says, “but to check that what you have been doing is working for you and fine-tune any changes to diet or exercise as necessary.”
Ready to dial in your essential biomarkers? Below are the defined healthy or normal ranges to keep an eye on. Keep in mind, “normal” doesn’t always mean “optimal,” and working with a qualified healthcare provider is the best way to interpret your results.
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