Hormone Lab Testing for Masters Athletes: What to Test and Why It Matters

If you've been following this series, you know that hormone suppression in masters endurance athletes isn't random — it follows a predictable cascade. Chronic training stress elevates cortisol, cortisol suppresses testosterone through two distinct mechanisms, DHEA declines, thyroid conversion gets impaired, and SHBG rises to bind whatever testosterone remains. The physiology is interconnected and the pattern is readable.

This article is about how to actually read it — what to test, why each marker matters specifically for athletes over 40, and how to interpret what you find as a system rather than a collection of isolated numbers.

Here's the framing that matters before any of the specifics: standard hormone testing was not designed for someone training 10 to 12 hours a week at this stage of life. Reference ranges are population averages. They're built to identify disease in sedentary or lightly active people — not to evaluate whether a masters athlete has the hormonal environment needed to perform, recover, and adapt. The gap between what gets flagged as abnormal and what's actually optimal for performance is where most masters athletes get lost — told their labs are fine while feeling progressively worse.

Prefer to watch? The full video is below — or keep reading for the expanded breakdown.

1. Testosterone: Total, Free, and SHBG — Always All Three

Total testosterone measures everything in circulation — bound and unbound. But most of that circulating testosterone is bound to proteins and biologically unavailable to tissue. What your cells actually use is free testosterone — the unbound fraction that can enter cells and bind to androgen receptors. Total testosterone alone doesn't tell you that.

The variable controlling how much is free versus bound is SHBG — sex hormone-binding globulin. SHBG binds testosterone tightly and renders it biologically inactive. And here's what's critical for masters athletes: SHBG naturally rises with age, which means free testosterone declines faster than total testosterone. An athlete in their late 40s or early 50s can have total testosterone that sits comfortably within the standard reference range while free testosterone is meaningfully suppressed — because SHBG has risen enough to bind a disproportionate share of what's circulating.

This is one of the most common patterns in masters athletes who've been told their testosterone is fine. The total number looked acceptable. Nobody measured free testosterone or SHBG. The actual functional availability was never evaluated, and the unresolved symptoms were attributed to something else.

What to order: Total testosterone, free testosterone, and SHBG — always together. The relationship between them is what tells you what's actually happening at the tissue level.

This applies equally to women. Because baseline female testosterone levels are lower, even modest reductions in the free fraction produce significant functional effects — on training tolerance, recovery, power output, and motivation. Women are not exempt from this testing picture; they're often the population where it matters most and gets evaluated least.

2. Cortisol Rhythm: Why a Single Blood Draw Misses the Point

Cortisol sits at the center of the hormonal suppression cascade in overtrained masters athletes. It suppresses GnRH, reduces LH output, competes for shared adrenal precursors with testosterone, impairs thyroid conversion, and elevates SHBG. Getting the cortisol picture right is foundational to reading everything else correctly.

But the pattern of cortisol across the day matters as much as — often more than — the absolute level. A single cortisol blood draw gives you one data point at one moment in time. It cannot tell you whether cortisol is chronically elevated throughout the day, whether it's lost its normal morning peak, or whether it's inverted — elevated at night when it should be low. Each of those patterns has different downstream implications and requires a different intervention.

What to order: A multi-point salivary cortisol test — four samples collected across the day (morning, midday, late afternoon, evening) — that maps the full diurnal curve. This tells you whether the HPA axis is in an appropriate stress-response state, chronically overactivated and stuck elevated, or exhausted and flattened from prolonged overtraining.

For masters athletes, this is frequently the most revealing piece of the full panel — because a dysregulated cortisol pattern often explains multiple other findings that look disconnected in isolation: poor sleep, suppressed testosterone, impaired T3 conversion, elevated SHBG. When cortisol is the upstream driver, addressing it moves multiple downstream markers simultaneously.

3. DHEA-S: The Most Consistently Overlooked Marker in Athlete Hormone Testing

DHEA is produced by the adrenal glands and serves as a precursor to both testosterone and estrogen. Beyond its precursor role, it has independent anabolic effects on tissue repair, immune function, and energy metabolism. And it's the adrenal hormone that declines most rapidly and consistently with age — more so than cortisol, and in many cases more dramatically than testosterone over the same time period.

DHEA-S (the sulfated storage form) is the measurement used in blood testing, and it's absent from most standard hormone panels. That's a significant gap for masters athletes, for two reasons.

First, DHEA-S reflects overall adrenal anabolic capacity. Low DHEA-S alongside low testosterone suggests the adrenal system is producing less of the anabolic hormones across the board — a broader pattern than a single-hormone deficit.

Second, and more clinically useful: the ratio of cortisol to DHEA is one of the most informative values in athlete hormone testing. A high cortisol-to-DHEA ratio reflects a system allocating adrenal output heavily toward stress response at the expense of anabolic function. That ratio often tells a more complete story than either marker alone — and it's the thing that makes sense of the clinical picture in athletes who are simultaneously exhausted and unable to adapt to training.

In the context of prolonged overtraining, DHEA-S declines as the HPA axis becomes increasingly dysregulated — it's essentially a marker of how long and how severely the stress response has been dominating adrenal output. Low DHEA-S alongside flattened cortisol and suppressed testosterone gives you a clear picture of adrenal exhaustion at a systems level.

What to order: DHEA-S (serum). Always alongside cortisol and testosterone — the pattern across all three is what's diagnostically useful.

4. Estrogen: Relevant for Both Men and Women, Differently

In Women Over 40

Estrogen is often the default focus of perimenopausal hormone conversations — and it's genuinely important, affecting bone density, cardiovascular function, muscle recovery, and sleep quality. But for active women navigating this transition, the relationship between hormones matters more than any individual value.

Progesterone deserves particular attention, because it's typically the first hormone to decline significantly in perimenopause — often years before estrogen drops meaningfully. Progesterone has direct effects on sleep quality, anxiety, and nervous system regulation, all of which directly impact recovery and training tolerance. A perimenopausal athlete dealing with disrupted sleep, elevated anxiety, and declining training tolerance may be experiencing progesterone insufficiency as much as or more than estrogen decline — and if progesterone isn't on the panel, that driver goes unidentified.

What to order for women: Estradiol, progesterone, total testosterone, free testosterone, and SHBG — as a complete picture evaluated together. The relative balance tells you more than any single number.

In Men Over 40

Estradiol is relevant in men because testosterone naturally converts to estradiol through aromatase — the enzyme found primarily in adipose tissue. In men with higher body fat, or in men using testosterone support without monitoring conversion, estradiol can become elevated relative to testosterone. Elevated estradiol in men is associated with body composition changes that resist training, reduced libido, mood changes, and impaired recovery.

This gets missed routinely because estrogen testing in men is widely assumed unnecessary. For masters male athletes noticing body composition changes despite consistent training, or dealing with symptoms that don't fully fit the low-testosterone picture alone, estradiol is worth including.

What to order for men: Estradiol (sensitive assay), alongside total testosterone, free testosterone, and SHBG.

5. Thyroid: TSH Alone Is Not a Thyroid Panel

TSH is a pituitary signal telling the thyroid to produce more hormone. It reflects the brain's assessment of thyroid output, not the actual output. Free T4 is the primary hormone the thyroid produces — but largely inactive in this form. Free T3 is the active form that binds to cellular receptors and drives metabolic effects. The conversion from T4 to T3 happens in peripheral tissues and is directly impaired by chronically elevated cortisol.

The result: an overtrained masters athlete can have completely normal TSH and normal Free T4, and still have insufficient Free T3 at the tissue level. The thyroid is functioning. The conversion step isn't — because cortisol is impairing it. You only see this if Free T3 is specifically measured.

For masters athletes experiencing fatigue, cold intolerance, slow metabolism, body composition that isn't responding to training, or cognitive sluggishness alongside the other symptoms in this picture — impaired T3 conversion is frequently contributing, and it's the piece most often missed because it requires specifically requesting Free T3.

What to order: TSH, Free T4, and Free T3 — all three. Not TSH alone. Adding thyroid antibodies (anti-TPO and anti-thyroglobulin) is worth considering to rule out autoimmune thyroid disease, which can produce fluctuating symptoms that compound the overall picture.

Reading the Pattern, Not the Numbers

When you look at these markers together, specific patterns emerge that tell you far more than isolated values. The pattern is where the clinical information actually lives.

Low free testosterone + high SHBG + normal total testosterone — a bioavailability problem, often age-related. The intervention targets SHBG specifically rather than testosterone production.

Low testosterone + elevated cortisol across the diurnal curve — stress-driven GnRH suppression. The intervention is managing the cortisol load, not treating testosterone directly. Treating the downstream number without addressing the upstream driver produces temporary results at best.

Low testosterone + low DHEA-S + flattened cortisol — adrenal exhaustion from prolonged overtraining. This pattern indicates the problem has been running long enough for HPA axis output to become depleted. The intervention requires aggressive recovery support and often DHEA repletion.

Normal TSH + normal Free T4 + low Free T3 + elevated cortisol — cortisol-driven impairment of peripheral T4-to-T3 conversion. Addressing the cortisol pattern typically improves T3 conversion without directly treating the thyroid.

In perimenopausal women: declining progesterone + low testosterone + dysregulated cortisol — a compounding effect on sleep, recovery, mood, and training tolerance that frequently gets attributed entirely to estrogen decline when progesterone and testosterone are equally or more relevant contributors.

These patterns move you from collecting numbers to understanding mechanism — and from mechanism to interventions that address the actual driver rather than chasing downstream values.

When to Test

If you're experiencing any combination of the following — and you've genuinely addressed training load, nutrition, and sleep as best you reasonably can — testing is the logical next step:

• Declining performance despite consistent, structured training
• Recovery that keeps getting worse rather than stabilizing
• Persistent fatigue that doesn't improve with rest
• Body composition shifting despite training and dietary consistency
• Motivation and drive that have flattened in a way that feels qualitatively different from normal tiredness

The goal is never just to find what's low. It's to understand why it's low — which part of the system is the upstream driver — and intervene there. When you fix the driver, downstream markers frequently improve without directly treating them.

The Complete Testing Panel

Testosterone: Total testosterone, free testosterone, SHBG — always all three, never total alone.

Cortisol rhythm: Multi-point salivary cortisol with four samples — morning, midday, late afternoon, evening.

DHEA-S: Serum, evaluated alongside cortisol for the cortisol-to-DHEA ratio.

Estrogen: Estradiol and progesterone in women as part of the complete perimenopausal picture; estradiol in men where aromatase conversion is relevant.

Thyroid: TSH, Free T4, and Free T3 — all three specifically requested.

Supporting markers: Ferritin (iron deficiency is common in endurance athletes and compounds fatigue independently of everything above); gut permeability markers (zonulin, LPS-binding protein) where persistent systemic inflammation or GI symptoms suggest a gut component to the picture.

Read them as a system. The pattern is the diagnosis.

Dr. Jason Barker is a naturopathic doctor with over 20 years of clinical experience working with endurance athletes. He is a two-time Ironman finisher and the founder of Natural Athlete Clinic. For individualized hormone testing interpreted through a performance lens for masters athletes, visit naturalathleteclinic.com.