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A Life Time team member working with a member who's using the InBody scale in the club.

Over my last 15 years of working with clients, I’ve found that many of them assume trainers and nutrition coaches address only workout regimens and diet choices. Most are surprised when the initial consultation and regular progress check-ins turn into conversations about symptoms that may seem unrelated to fitness (such as digestion, PMS-type symptoms, and hair loss), blood markers, and lab testing.

Why would a fitness trainer worry about these in-depth aspects of health? After all, they’re not doctors.

While no coach is qualified to diagnose and treat you based on results, here are the top reasons why your coach knowing them is useful:

Preventing or Delaying Chronic Disease

An effective trainer is not simply a luxury — it is one of the secret weapons for unlocking your optimal health for the long haul. And if you’re health-conscious, having a tuned-in understanding of what’s going on under the hood is essential. Proactively and regularly assessing trends of certain metrics can help catch metabolic imbalances before they become a full-blown chronic disease.

When addressed early, it’s much more likely that interventions with specific, tailored nutrition, exercise, lifestyle, and supplement strategies can help bring the system back to optimal balance. When left unchecked, imbalances likely evolve into an issue that requires pharmaceuticals or more aggressive medical interventions.

Longer-Term Results

There’s a misconception out there that assumes weight loss automatically means improved health. Unfortunately, there are plenty of popular ways to shed pounds on the scale in an unhealthy way, which sets you up for a quick rebound and loss of results, no matter how strong your willpower.

If you’ve been around Life Time for a while, you know that we believe in driving your results from the inside-out. The healthier you are on the inside, the more effectively your results show up externally. Tracking the right data ensures that you’re seeing desired changes as one of many positive results of getting objectively healthier. The impact is more lasting and sustainable change.

Program Customization

There are plenty of cookie-cutter programs out there to follow. Even if you find one that is perfectly designed, it’s unlikely that it’s perfectly designed for you. Your unique metabolic needs — which are dynamic and change over time — determine the specific exercise and nutrition approaches that will best work for you right now.

For example, there are times when heavier weights with fewer repetitions can be a game-changer, while there are other times (based on what’s going on with you metabolically) when a focus on moderate-intensity cardiovascular training and functional stability movements will deliver the best outcomes.

Markers to Track

We always recommend tracking a full gamut of health markers including nutrient levels, food sensitivities, inflammatory markers, and hormones on at least an annual basis. Doing so can help you proactively take better control of your health and effectively monitor trends or concerns over time to promptly address them and make sure you feel your best with each passing year.

At minimum, however, we believe you should know and keep trend of these five key metrics, testing typically every three to six months — and more often if you uncover markers that are notably out of range.

Note: The ranges below may indicate narrower or more conservative target ranges than many traditional medical reference ranges that are in place for diagnostics and treatment with your healthcare team. These suggested targets are intended to empower those who are focused on optimizing their health, who view wellness as more than simply the absence of disease, and who are aiming to be in a low-risk category for each metric. Being outside of the suggested target ranges is not a cause for fear and panic, and we always recommend sharing all lab data with your doctor to determine your best way forward.

1. Fasting Blood Glucose

Also known as “blood sugar,” glucose levels are required for our cells to function and for us to have energy. However, it’s important that these levels stay within a specific range throughout the day, including when you wake up fasting and within one to two hours after eating. While there are different methods to testing your glucose patterns, regularly testing fasting glucose upon waking is one strategy to assess trends over time and under similar conditions.

Blood glucose levels are determined by a variety of factors, but the most prevalent (and controllable) one is your dietary carbohydrate intake (e.g., sugar, bread, starches, potatoes, etc.). Additionally, your stress levels and sleep quantity and quality are significant determinants as well.

When blood sugar is too high or if it’s fluctuating erratically, it results in chronic inflammation, hormone issues, cravings, sleep woes, and difficulty losing body fat.

Read more: “The Ultimate Guide to Healthy Blood Sugar

Life Time target range: 82–88 mg/dL

2. Hemoglobin A1C

One in three U.S. adults have impaired blood-sugar control, yet only 8 percent of those affected are aware of it.

Since fasting blood glucose can fluctuate quite a bit based on stress levels, recent nutrition choices, and even how you slept the night before testing, it can be helpful to assess it in context with hemoglobin A1C, or glycosylated hemoglobin. This metric helps estimate your average blood-glucose levels over the previous three months.

Comparing the two can be especially helpful. For example, I’ve seen people who have seemingly normal hemoglobin A1C levels, but their fasting blood-sugar trend is concerning — which can indicate that their blood-sugar levels are actually erratic (which is problematic) but just happen to average out over time. On the flip side, I’ve seen people who happen to catch a fasting blood-sugar sample that looks perfectly in range, but discover that their average blood sugar as assessed through hemoglobin A1C reveals there’s an underlying issue.

In either case, seeing both metrics together provides the necessary hard data to take appropriate action.

As mentioned in the previous point, imbalanced blood sugar can be destructive to your overall health. It’s associated with an increased risk of diabetes, cardiovascular disease, and an array of other conditions.

Learn more: “How to Balance Your Blood Sugar

Life Time target range: Less than 5.3 percent

3. Total Cholesterol/HDL Ratio

There seems to be a lot of confusion about cholesterol and heart disease — and it’s rarely as simple as “high cholesterol levels mean bad heart health and normal cholesterol levels mean good heart health.”

Blood lipidology (the study and understanding of lipids and cholesterol) is complex. It’s entirely possible to have above-range total cholesterol and be healthy. It’s also possible to have within-range total cholesterol and be at a high risk for a heart attack. While a full assessment with a cardiologist that includes a coronary calcium scan, cardiac ultrasound, stress test, advanced blood work including looking at lipoprotein particle size and counts, and a battery of other tests would be the most eye-opening, it’s not always in-reach — or necessary — to do.

Instead, most of us can use a standard lipid panel (total cholesterol, HDL, LDL, and triglycerides) to glean some higher-level insights. Specifically, keeping close tabs on the relationship between HDL cholesterol (often referred to as the “healthy” or “protective” cholesterol) and total cholesterol levels is especially useful.

The higher the ratio between the two, the greater the risk of cardiovascular disease. An elevated ratio can be caused by a variety of factors, including chronic inflammation, poor blood-sugar control (which is often modifiable), altered thyroid function, a lack of exercise, or gall bladder issues, to name a few.

Life Time target range: Less than 3

4. Triglycerides

This is another type of blood fat or lipid that is tied to your heart health and to your blood-sugar control.

Excess calories are first stored as triglycerides, then as body fat. Elevated triglyceride levels are most often due to an excess of sugar, starch, or alcohol intake. They also can rise in those with impaired blood-sugar control, slow thyroid function, or high estrogen levels.

For some, rising triglycerides can be an early warning sign that the body is losing control of its blood glucose levels.

Life Time target range: 50–90 mg/dL

5. Body-Fat Percentage

From my experience, using scale weight alone as a marker to track health and progress is incredibly misleading. What’s more revealing and impactful and enables you to truly understand your body composition is to fully realize and monitor body fat and lean mass. In other words, your body-fat percentage, or the percentage of your total body weight that is made up of fat.

The beauty of assessing this metric is that it more accurately represents what most people are looking for when they say they want to be leaner and more fit. For example, if someone loses weight by eating in an extreme calorie deficit and a lack of protein, it’s likely that a lot of what was lost is from fluid and lean muscle. The result typically will be loss of tightness and tone (even with a decreased scale weight), along with fatigue, weakness, and general malaise.

Everyone who wants to feel leaner and look toned could benefit instead by dropping their body-fat percentage by prioritizing loss of body fat specifically (not just “weight”) and a proportional gain of muscle.

Read more: “Measuring Body Weight” and “Why This Scale is the Best Way to Measure Progress

Life Time target ranges:

Age Low Risk Borderline High Risk
20–29 <19% 19–26% >32%
30–39 <22% 22–27% >33%
40–49 <24% 24–29% >35%
50–59 <26% 26–30% >30%
60+ <27% 27–31% >31% 
Age Low Risk Borderline High Risk
20–29 <22% 22–32% >32%
30–39 <23% 23–33% >33%
40–49 <26% 26–35% >35%
50–59 <30% 30–38% >38%
60+ <31% 31–39% >39%


Keep the conversation going.

Leave a comment, ask a question, or see what others are talking about in the Life Time Health Facebook group.

Samantha McKinney, RD, CPT

Samantha McKinney has been a dietitian, trainer and coach for over 10 years. At first, her interests and experience were in a highly clinical setting in the medical field, which ended up laying a strong foundation for understanding metabolism as her true passion evolved: wellness and prevention. She hasn’t looked back since and has had the honor of supporting Life Time’s members and nutrition programs in various roles since 2011.

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