She explained it simply. The way only a nurse who's seen a thousand exhausted moms would explain it.
Stress drains a specific mineral out of you. The mineral is magnesium.
When you're under stress — and motherhood after 40 is one long stress — your body releases cortisol. That's the stress hormone. And cortisol tells your kidneys to flush magnesium out of your body.
She said magnesium is the mineral your body uses to turn cortisol off again. To shift you out of fight-or-flight. To bring you back down.
So stress drains magnesium. Low magnesium means your body can't shut cortisol off. Cortisol stays high. Which drains more magnesium.
She said, "It's a loop. And once you're in it, no amount of resting will get you out. Because the thing that breaks the loop is the mineral that's gone."
That hit me hard. Because that was exactly the pattern. The weekend I'd taken away in January didn't fix it. The week of vacation I'd taken in June didn't fix it. I'd come home from both more wrecked than when I'd left.
She said, "Your doctor probably didn't test for this. Most don't. The blood test isn't reliable for magnesium because your body keeps blood levels stable by pulling magnesium out of your tissues. By the time the blood test shows low, you've been depleted for years."
She said magnesium isn't just for sleep. It's what your nervous system uses to feel things normally. To laugh. To get excited about something. To care.
"When magnesium runs low, the volume on your emotions gets turned down. You're not depressed. You're flat. You go through the motions but nothing reaches you. That's what's happening to you. And no doctor is going to tell you because they don't know what to look for."
She said, "You don't have to do less. You have to put back what your body's been losing every single day."
She gave me two magnesium gummies out of a bottle she'd brought with her. She said she takes them every night herself. She said to make sure it was a form my body could actually absorb because most of the cheap ones go straight through you.
I took them that night. About 30 minutes before bed.
Went to sleep.