I’ve been training for over three decades. I know how to plan a training block. I know what intentional stress looks like in data, and I know what recovery is supposed to look like afterward.
In the spring of 2023 I was finishing a heavy training block (a deliberately high load to build fitness) and I had planned a summer of easier riding and genuine rest before returning to structured training in October. Textbook periodization. I’d done it dozens of times before.
The data from that block looked exactly like it was supposed to. You could see the hard work where I placed the system under stress and my HRV was orange and red. It was all on plan.
What happened next is where the story gets complicated.
The Recovery That Wasn’t
The summer of 2023 looked like recovery in my Garmin data. My HRV came back up and everything looked green. On paper, the plan was working.
But I was also dealing with a prolonged, stressful situation. It was something that I had no quick way out of and it went on for months. I won’t go into the specifics. What matters physiologically is that it was unresolvable on my timeline, and I was living inside it every day.
I didn’t connect that to my training recovery at the time. Why would I? I wasn’t training hard since I was resting. The two things felt separate.
They weren’t separate at all.
What Cortisol Actually Does
Cortisol is released in response to any stressor whether it be physical, psychological, or environmental. Your adrenal glands don’t distinguish between a hard interval session and an impossible situation. They respond to total threat load.
In the short term, cortisol is adaptive. It mobilizes energy, sharpens focus, and keeps you functional under pressure. Athletes work with acute cortisol all the time. It’s part of training.
The problem is chronic cortisol — when the stressor doesn’t resolve, the signal doesn’t clear, and cortisol stays elevated as a persistent background load. This is a different physiological state entirely.
Chronically elevated cortisol suppresses the deep slow-wave sleep where physical repair happens. It disrupts appetite signalling by blunting hunger cues and interfering with the hormonal feedback that tells you how much you need to eat. It also impairs the body’s ability to complete the recovery process even when you’re doing everything else right. And it shifts the body toward conservation mode by holding onto fat, breaking down muscle, and resisting adaptation.
For an athlete in a planned recovery period, this is catastrophic in the most invisible way possible. You’re resting and you think you’re recovering, but your system is spending every available resource managing a threat state. The recovery work is simply not getting done.
Menopause Made It Invisible
Postmenopause, the cortisol problem compounds. Estrogen plays a regulatory role in the HPA axis, which is the system that controls cortisol release. It modulates receptor sensitivity and helps the feedback loop that signals the adrenals to stand down after a stressor. I was on HRT (hormone replacement therapy), but my dose wasn’t high enough. But I didn’t know it at that time.
Without that buffer, the same stressor produces a larger cortisol response, and the recovery from that response takes longer. A situation that might have been physiologically manageable a decade earlier was hitting a system already running without its primary cortisol regulation.
Every symptom that emerged (fatigue, disrupted sleep, poor recovery, low energy) had an easy menopausal explanation. And my doctor assured me that’s all it was so I wasn’t looking for anything else. There was nothing signalling me to check whether my summer recovery actually happened.
Where RED-S Enters
RED-S (Relative Energy Deficiency in Sport) is fundamentally a problem of energy availability. The body isn’t getting enough fuel relative to its demands, and it begins to downregulate the metabolism to match.
Here’s what I didn’t catch: the demand side of that equation isn’t just training load. Chronic cortisol elevation is metabolically expensive. Managing a sustained threat state burns energy, and chronically elevated cortisol actively suppresses appetite signalling. At the precise moment your energy demands are highest, the hormonal cues telling you to eat more are being blunted.
I wasn’t tracking food (I eat intuitively when not actively training). I wasn’t tracking caloric expenditure. I was eating the way I’d always eaten, doing less training than usual, and assuming rest meant recovery. The same as I always did during a recovery block.
What was actually happening: my total energy demand had increased significantly due to cortisol load, my appetite signalling was suppressed, and the energy deficit was building invisibly through what should have been a recovery summer.
By the time my planned October training return came around, I wasn’t returning to training on a recovered system. I was loading a system that had spent months in deficit, had begun metabolic adaptation to protect itself, and had no reserve capacity left to absorb new training stress.
The planned training block in spring 2023 was normal stress. What followed was RED-S, and cortisol is what opened the door.
The Thing About Unresolvable Stress
There’s a particular kind of cortisol pattern that comes from situations you can’t fix on your own timeline. The kind where the threat is real, the exit isn’t available yet, and every day you’re managing it while also trying to live your life.
That pattern is especially damaging because the nervous system never gets the all-clear signal. The cortisol doesn’t spike and clear like it normally does. Instead, it lingers. You may hide it well and think you’re doing fine, but the data tells a different story.
I’m not sharing the details of my situation since that’s not the point. The point is the mechanism. Your situation will be different. Maybe it’s a relationship, a job, a family crisis, a health scare that took months to resolve. The cortisol response is the same regardless.
If you were going through something sustained and stressful during a period when your athletic performance or recovery seemed to fall apart, this is the missing piece of the explanation.
What I Wish I’d Known
I wish I’d known was how much the chronically elevated cortisol was actually affecting me. That you can be doing all the right training behaviours (sleeping enough, not overtraining, eating reasonably) and still not be recovering, because the recovery resources are being consumed by something else entirely. I knew I was stressed, but I also thought I was doing okay recovery-wise.
I wish I’d known that appetite suppression during stress isn’t just psychological. It’s hormonal. The body is actively interfering with its own ability to signal what it needs. I didn’t realize how little I was eating because I was on a recovery block and not tracking. And I wasn’t paying as much attention to what I was eating as i would’ve during an active training block.
And I wish I’d known that postmenopause, my tolerance for sustained cortisol load was meaningfully lower than it had been. This meant the same situation would have a larger physiological impact than it might have at 35.
My data was telling me something was wrong from August 2023 onwards, and I didn’t realize how dire it was at the time.
I do now and that’s what this whole series is about. I’m hoping that by sharing what happened to me will help someone else see the signs earlier than I did. I’ll share my Garmin data in the next post. It’s eye-opening. The things you see in hindsight…
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