Heat & Aging, Nitrates & Birth Risk, Stress & Diabetes

Good morning, it’s officially summer 😎 But heads up: the heat might literally be killing us, at least according to some fresh research. Plus, those tense conversations at work? They could be nearly doubling your diabetes risk. Here's what you need to know this week.

New research says heat is bad for you?

Not quite. In a recent members-only AMA, Dr. Rhonda Patrick unpacked a 2025 study showing that older adults living in areas with frequent high-heat days were aging epigenetically up to 14 months faster than peers in cooler climates. Some took that to mean heat is harmful, period, and were worried about saunas. But Patrick was quick to clarify: this study looked at chronic, passive heat exposure, not the short, deliberate bursts you get from something like sauna use. In fact, she’s published research herself on ‘sauna bathing’, showing it mimics moderate exercise and can support healthy aging.

Our take: I agree with Patrick. This study wasn’t about saunas, it was about chronic, environmental heat stress. Different beast altogether. - Tash J (Newsletter Nerd, Superpower)

Common agricultural runoff causes preterm births.

Even tiny amounts of nitrate in your water (just 1% of the EPA standard) could raise risks of preterm births and low birthweights, according to new research (PDF of the study here). The researchers argue that EPA standards, unchanged since 1992, urgently need revising to protect pregnant women and infants.

Our take: The study linking nitrate in drinking water to preterm birth is thought-provoking, but we should be careful not to overinterpret it. The researchers didn’t measure how much nitrate individual women actually consumed - they used average levels from public water systems in each county. They also didn’t fully account for other factors that can affect pregnancy outcomes, like air pollution, pesticides, infections, or overall maternal health. Interestingly, the strongest effects showed up at low nitrate levels, not the highest ones. That’s unusual, and it might mean the relationship isn’t straightforward - perhaps there’s a threshold or non-linear effect that we don’t fully understand yet.

The biological explanation is still a bit uncertain. While there are theories - like nitrate causing low oxygen in the blood or triggering harmful chemical reactions - the study didn’t include any direct evidence from the body to support those ideas. Also, the size of the effect was small: just a 0.33% increase in risk for low birth weight. But when exposure is widespread, even small risks can add up across a large population.

Bottom line: this study raises important questions and highlights a possible concern, especially since nitrate levels considered “safe” may still carry some risk. But we’ll need more detailed research - with better individual data and biological testing - before we can draw strong conclusions or change public health guidelines. - Julija Rabcuka, (Clinical Strategy, Superpower, BA (Oxon), MSc, PhD (ABD), University of Oxford)

Is your job making you diabetic?

Jobs heavy on emotions (think teachers, nurses, social workers) might boost your risk of type 2 diabetes, says a new study of over 200,000 people. Having emotionally tough conversations? 20-24% higher diabetes risk. Confrontational roles? 15-20% increase. And if you have an unsupportive workplace? That risk jumps to 47%. The culprit might be stress: it jacks up your cortisol, messes with insulin, and throws your metabolism out of whack.

Our take: Stress significantly impacts metabolic health and can even trigger Type 2 diabetes, we know this. But what was particularly interesting from this study is workers who regularly have to hide their true emotions (“masking”) are especially prone to burnout and compassion fatigue. Moral of the story: keep it real, friends! - Tash J (Newsletter Nerd, Superpower)

Superpowered by you: Achilles health for runners.

Weeks before his first Half Iron-man, Jeff (48, Laguna Beach) wrecked his Achilles playing basketball. Not ideal. His race suffered, obviously. But afterwards, he started warming up with eccentric calf raises (raising up, then lowering heels below a step).

Turns out, weighted eccentric calf raises can get runners with chronic Achilles issues back to pain-free running in just 12 weeks. And even unweighted, they're stupidly easy and still effective. So add them in before your next jog.

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That’s all for this week 🫡

P.S If you’re in the Bay Area on Sunday July 13, come join us for a run around around the Marina District (especially if you’re a new mom, I’ll be there with my running pram at the ready!) 👟

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