A 47-year-old runner comes into my clinic because something has changed. Her pace is slipping. Recovery is taking longer than it used to. She's waking up at 3 a.m. for no obvious reason. Her periods have become unpredictable. She asks the question most women in her position ask: can we just test my hormones?

It's a completely reasonable question. But here's where it gets more complicated than it looks. Is this estrogen? Iron deficiency? Thyroid? Under-fueling? Perimenopause? Or more than one of those things happening at once? Simply ordering a large female hormone panel doesn't automatically give you the answer — and sometimes it adds confusion instead of clarity.

This is the fourth and final article in this series on female athlete hormonal health. We've covered recognition, mechanism, and practical intervention. This one is about testing — specifically, how to think about it strategically instead of simply ordering everything available.

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

The First Surprise: You May Not Need a Hormone Test to Diagnose Perimenopause

Let's start with the biggest misconception I encounter in practice. There is no single blood test that confirms perimenopause.

For most women over 45 presenting with typical symptoms and menstrual cycle changes, perimenopause is primarily a clinical diagnosis. That means age, menstrual history, how the cycle has changed, hot flashes, night sweats, sleep quality, mood, and the overall symptom pattern carry more diagnostic weight than any single hormone measurement.

Here's why. During perimenopause, ovarian function becomes increasingly variable. Estrogen doesn't decline in a straight line — it fluctuates considerably, sometimes spiking before it eventually trends down. FSH fluctuates too. That means measuring estradiol or FSH gives you a snapshot of a moving target on any given day. A single normal result doesn't rule perimenopause out. A single abnormal result doesn't confirm it.

Current clinical guidance from The Menopause Society — the leading North American medical organization dedicated to menopause and midlife women's health — recommends identifying perimenopause clinically in otherwise healthy women 45 and older with appropriate symptoms, rather than relying on hormone testing to make the diagnosis. In practice, that means I regularly see women who have spent real money chasing laboratory confirmation of something their history was already telling us clearly.

So Why Test Hormones at All?

Because there are situations where hormone testing genuinely helps — and the key is asking the right question before ordering anything. The framework I use is simple: will this result change what we actually do next? If yes, it's worth testing. If not, it's likely just adding noise to a picture that's already clear.

A few specifics worth knowing:

FSH can be useful in women between 40 and 45 when symptoms suggest early ovarian insufficiency — a different clinical question than straightforward perimenopause in a woman over 45.

Estradiol and progesterone have their place in specific clinical contexts, but progesterone in particular requires careful timing. It depends on ovulation, and a random measurement taken without knowing where a woman is in her cycle can give you very little usable information.

For Athletes, This Is Where Testing Gets More Interesting

Go back to our 47-year-old runner. Tired. Recovering poorly. Performance declining. Cycle irregular. It would be very easy to attribute all of that to perimenopause and stop looking. But what if she's also iron deficient? What if she has underlying thyroid dysfunction? What if she's chronically under-fueling relative to her training load? What if several of these things are happening at the same time, compounding each other?

This is exactly why, in athletic women, I'm thinking well beyond reproductive hormones from the start.

Iron Status

Iron status is often the first place I look, particularly in endurance athletes. Iron plays a critical role in oxygen transport, mitochondrial function, and energy metabolism — covered in more depth in the lab testing article. An athlete with depleted iron stores may experience fatigue, declining endurance, and poor recovery that looks identical to perimenopause on the surface.

Ferritin specifically needs to be ordered — it is not part of a standard iron panel — and the performance target for endurance athletes sits well above the reference range floor of roughly 12 to 15. I'm generally looking for ferritin above 50, not simply "within range."

Thyroid Function

Thyroid function is the next major overlap worth evaluating. Changes in energy, temperature tolerance, mood, body weight, menstrual patterns, and heart rate can all mirror perimenopausal symptoms almost exactly. TSH alongside Free T3 and Free T4 helps identify or rule out thyroid dysfunction as a contributing factor. The Endocrine Society specifically notes thyroid testing as part of evaluating conditions that can mimic menopause-related symptoms — this isn't a fringe consideration, it's a recognized part of a proper workup.

Low Energy Availability

Low energy availability deserves specific attention in athletic women, because it can affect reproductive function, recovery, and performance in ways that closely resemble perimenopause while having a completely different driver — and requiring a completely different intervention. This is the territory covered extensively in the RED-S series. Menstrual irregularity in a 40-something athlete could be coming from ovarian aging. It could be influenced by chronic under-fueling. It could be both simultaneously. That's exactly why the history matters just as much as the lab results — the two have to be read together, not in isolation.

Metabolic and Cardiovascular Health: The Bigger Picture

Being fit doesn't make an athlete immune to age-related changes in cardiovascular or metabolic risk. The perimenopausal transition is an opportunity to assess the broader health picture — blood pressure, lipids, glucose regulation, and bone health — alongside the hormonal picture. The Endocrine Society specifically recommends using this transition as a window to address cardiovascular risk and bone health, not just reproductive hormone status in isolation.

The goal isn't simply "tell me what my estrogen is." The goal is protecting performance and health through the next several decades. That's a meaningfully different question, and it requires a meaningfully different evaluation than a basic hormone panel can provide.

The Three-Layer Framework

Here's how I simplify this for athletic women experiencing changes in their 40s and 50s.

Layer One: Does the clinical picture fit the menopausal transition? Age, cycle changes, hot flashes, night sweats, sleep, mood. This history often tells us more than any single hormone measurement.

Layer Two: Is there another condition explaining or amplifying what's happening? Iron deficiency, thyroid dysfunction, low energy availability, sleep disorders. These need to be actively ruled out — not assumed away simply because the woman in front of me happens to be 45.

Layer Three: What do we need to know about longer-term health and performance? Bone health, cardiovascular risk, metabolic health, nutrition, recovery, and training load. That evaluation is frequently more actionable than a comprehensive hormone panel on its own.

Change the Question You're Asking

If you've been asking "what labs should I get for perimenopause," I'd encourage you to reframe the question entirely. Ask instead: what are we actually trying to explain?

Because perimenopause isn't a lab value. It's a physiological transition happening inside a much larger system — training stress, nutrition, iron status, thyroid function, sleep, bone health, cardiovascular health, and recovery capacity, all interacting at once.

Sometimes reproductive hormone testing is useful. Sometimes it's unnecessary. And sometimes the most important finding in the whole workup isn't a reproductive hormone at all. The goal was never to collect the biggest possible panel. It's to collect the right information to make a better decision — one that actually changes the plan.

Dr. Jason Barker is a naturopathic doctor with over 20 years of clinical experience working with endurance athletes, including female masters athletes navigating this exact transition. He is a two-time Ironman finisher and the founder of Natural Athlete Clinic. If you're an active woman navigating perimenopause and trying to understand why your training, recovery, sleep, or body feels different, visit naturalathleteclinic.com for individualized evaluation and testing options.