April 24, 2025 | Issue #151

Hey... is it time to move away from the tropics?

In this week's newsletter:🌡️ More Reasons to Plunge💅 Fingernail Clock

Hot = Bad, Cold = Good?

Temperature shapes our health in profound ways, influencing everything from our biology to our longevity.Two recent studies - one from Nature Aging and another from USC - reveal how cold and hot environments impact aging and offer insights into habits that can extend your lifespan.Let’s unpack the science and figure out practical ways to use temperature to your advantage...Cold Environments: A Lifespan BoosterResearch in Nature Aging shows that lowering core body temperature is a powerful driver of longevity across species, from invertebrates to mammals. Here’s what the study found:

• Lifespan Extension: Lower core body temperature increases lifespan, with studies in mice showing a 20% life extension when core temperature drops by less than 1°F. This effect is also seen in calorie restriction, a known anti-aging intervention, partly due to reduced Tb.

• Mechanisms: Cold promotes longevity through nutrient-sensing pathways, improved proteostasis (protein maintenance), and altered thermodynamics of proteins and nucleic acids, affecting ion channels and RNA stability. It’s not just about slower metabolism or fewer reactive oxygen species, as previously thought.

• Invertebrate Insights: In worms, cold activates specific genetic pathways that enhance longevity, suggesting targeted molecular benefits.

Takeaway: Cooler temperatures can slow aging processes, supporting cellular health and resilience.

Hot Environments: An Aging Accelerator

A USC study reveals that living in areas with more extreme heat days accelerates biological aging. Key findings include:

• Epigenetic Aging: Exposure to high heat (e.g., days above 90°F) speeds up epigenetic clocks, markers of biological age, leading to faster aging at the cellular level.

• Health Risks: Older adults are especially vulnerable due to reduced thermoregulation, increasing risks of heat-related illnesses like heat stroke. 

Takeaway: Chronic heat exposure accelerates aging and poses significant risks, especially for older adults.

2 Practical Habits to Extend Your Lifespan

1. Incorporate Cold Exposure with Cold Showers or Plunges

   1. How: Start with 30–60 seconds of cold water at the end of your shower (around 50–60°F), gradually increasing to 2–3 minutes. Alternatively, try a cold plunge if accessible.

   2. Why: Cold exposure may boost endorphins, reduce inflammation, and enhance sleep quality by activating the parasympathetic nervous system. It mimics the longevity benefits seen in studies of lowered core body temperature.

   3. Tip: Do this 2–3 times weekly, but avoid if you have heart conditions without medical clearance. Warm up gradually afterward to prevent circulation issues.

2. Optimize Your Sleep Environment for Coolness

   1. How: Keep your bedroom at 60–67°F, use breathable bedding, and consider a cooling mattress pad. A pre-sleep cold shower can further lower core body temperature.

   2. Why: Lower nighttime core body temperature enhances slow-wave sleep, crucial for repair and hormone regulation, aligning with longevity benefits of cold.

   3. Tip: If heat is unavoidable, use a fan or open windows to improve airflow, reducing heat stress during sleep.

Temperature is a powerful lever for health, and small, intentional habits can yield big rewards. We've talked about this extensively here at Spannr... especially when it comes to contrast therapy.  If you haven't jumped on the sauna-cold-plunge train yet, find out why it might be a good idea... See ya,

CodyFounder, Spannr

Schedule your free longevity telehealth appointment today.

• Top longevity doctor reveals sign in your fingernail that could tell you how long you'll live (Daily Mail)

• Why Do Millennials Appear To Be Aging Slower? Here's The Answer. (HuffPost)

• People with this blood group age more slowly, according to new research (Earth)

• High Heat Where We Live Accelerates Aging, USC Study Finds (Forbes)

• Promoting health and survival through lowered body temperature (Nature)

• The truth about alcohol and your brain: Scientists put a number on the years heavy drinking takes off your life (Fortune)

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