Get Ahead of Aging, by Rebuilding Your Sleep First.

Sleep and the gut.Two areas of longevity science I keep coming back to — both in my own work and in my own health. I think the gut-sleep connection is one of the more underappreciated intersections in health, and it’s something I’ve wanted to explore in a focused conversation for a while.Today I get to do that — through a written Q&A with Scott C. Anderson.Scott is a science journalist and co-author of The Psychobiotic Revolution: Mood, Food, and the New Science of the Gut-Brain Connection — a National Geographic bestseller he wrote alongside John F. Cryan and Ted Dinan, the researchers who coined the term psychobiotics. He also writes on Substack about the gut-brain connection.I asked Scott six questions about the gut-brain axis, cortisol, probiotics, and what the research says about improving sleep through the microbiome.Here’s what he had to say:

If We Rely on “Normal” Lab Ranges, We’ll Miss the First Signs of Decline.

Waking to urinate once or twice overnight sits within the range of normal kidney physiology — kidneys have their own circadian rhythm, and their activity reduces during sleep, but they don’t stop. The challenge is when waking to urinate becomes a disruption in itself: the peeing happens, and then sleep doesn’t return. That’s a different kind of problem than urination frequency alone. There are multiple explanations for this pattern, and they don’t all lead to the same place. Some are best ruled out with a physician — there are medical causes that are important to consider. Others trace back to sleep itself. And the details — when it happens, how consistently — tend to matter in distinguishing between them. Here are 3 reasons you might be waking up to pee at night, how to distinguish between them, and what to do so you can stay asleep through the night:

Physiological studies show that total daily GH output begins to fall in our 30s largely because the bursts of GH released become smaller.In longevity circles, that observation is often interpreted in a linear way: GH decreases with age, so perhaps the solution is to increase GH again.Yet major endocrine reviews and guideline statements have not endorsed raising GH as an anti-aging approach in otherwise healthy adults. Trials in older adults without GH deficiency have produced modest improvements in body composition but also higher rates of adverse effects, and there is no GH-raising therapy approved specifically for anti-aging.The reason is that GH is not a single dial that can be turned up.GH output emerges from a regulatory network in the brain involving multiple interacting inputs:growth hormone–releasing hormone (GHRH), which stimulates GH releasesomatostatin, which suppresses GH releaseghrelin, which amplifies GH releaseThese inputs interact continuously with sleep depth, metabolic state, and reproductive hormones such as testosterone and estrogen.So when GH changes across the lifespan, the more complete explanation lies in the upstream regulators.In this article we will look at:what growth hormone–releasing hormone (GHRH) is and how it stimulates GH productionthe lesser-known role of GHRH as a sleep-promoting neuropeptide tied to deep sleepwhat tends to change after midlife in the sleep–GHRH–GH axiswhether aging itself is the primary driver of those changes — or whether age is partly a proxy for modifiable factorsLet’s get started.

“I haven’t changed anything” same schedule, same bedroom, same everything. So why is my sleep worse?”I hear some version of this often. Someone in their 40s or 50s whose sleep has gradually gotten worse, and who can’t point to a single thing that’s changed. No new stressors. No obvious cause. Just lighter sleep, more wakeups, less of that deep, restful feeling they used to take for granted.The easy explanation is age.And it’s true that sleep architecture does change over time. But in many of the individuals I work with, age is less of a direct cause and more of a context—one that makes certain disruptions hit harder than they used to. The same factors that barely registered in their 30s are now showing up as 3 a.m. wakeups and mornings where they feel like they never really slept.What’s behind those disruptions tends to surprise people.They’re not the ones most sleep advice focuses on. And they’re not things you’d necessarily notice from the outside.I walk through 3 of the more common—and less talked-about—reasons adults in midlife start losing sleep continuity here (& how you can start to address them):

A deep-dive on how dietary cholesterol might or might not affect your LDL-CCholesterol is one of the body’s most tightly regulated and energetically expensive molecules; however, it is still widely portrayed as something to restrict or minimize.Every nucleated cell can synthesize it, and several organs use substantial metabolic resources for its local production. In some tissues, most notably the brain, dietary cholesterol does not materially influence cholesterol content under normal physiological conditions because lipoprotein-bound cholesterol does not cross the intact blood–brain barrier.This raises a central biological question: if cholesterol can simply be obtained from food, why did evolution invest in such an elaborate and tightly regulated system to manufacture it internally?The answer lies in the indispensable structural, metabolic, and signalling roles of cholesterol and the biological necessity of local, on-demand synthesis.Cholesterol is not only useful but also essential for multicellular life.