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Does Bryan Johnson Cold Plunge?

ByBryan JohnsonBlueprintRecoveryLongevity

Hi friend,

Bryan Johnson doesn't cold plunge. But he is technically in a state of mild hypothermia most of the time.

Since starting Blueprint, Bryan's body temperature has dropped ~4°F to 95.1°F, with morning temperature as low as 93.4°F.

In context, it takes swimming a mile in icy water to achieve an equivalent temperature reduction.

Following Blueprint has him metabolically cold plunging 24/7.

In this email:

  • why Bryan doesn't cold plunge
  • why his body is getting cooler
  • protocols that lower his body temperature

Why Bryan doesn't cold plunge

Bryan has tried cold plunging, but it's not part of his normal routine.

If you cold plunge and enjoy it, then you do you. There are many paths to optimal health.

There is some early and inconclusive evidence that cold plunging has potential health benefits. But there currently isn't enough evidence in cold plunging as a longevity therapy for Bryan to add it to his routine.

But… other protocols are cooling his body. Most people sit around 98.7°F. Bryan runs significantly cooler, between 93–95°F.

Why Bryan's body is getting cooler

Bryan maintains a 10% caloric deficit and exercises rigorously for 1 hour almost every day. When people hear this, they assume a deficit means losing weight.

Instead his body is metabolically adjusting to this lower caloric intake while activity levels remain high, lowering the metabolic burden.

Research in both animals and humans suggests that a lower body temperature and a lower metabolic load (the amount of work your body needs to do to survive) may contribute to increased longevity.

Protocols that may be responsible for the lower body temperature

What Bryan does:

  • 10% calorie restriction, 2,250 calories (the main one)
  • 6 hours of vigorous exercise a week
  • Low-inflammation, high-fiber diet of vegetables, legumes, extra virgin olive oil, berries, nuts, and seeds
  • Daily supplementation via Blueprint stack
  • 6-hour eating window
  • Final meal at noon
  • 7–9 hours of sleep
  • Temperature-controlled mattress (70°F / 21°C)
  • Stress management: breathing exercises, meditation, time with friends and family

All of these stacked together lower his body's metabolic burden.

Sometimes the most important thing for your health is what you don't do. Bryan doesn't do/consume:

  • alcohol
  • stimulants
  • smoking or vaping
  • processed junk food
  • white/brown sugar

Bryan doesn't cold plunge… but there are many different paths to health. What's important is measuring and using data as a guide to your decision making.

Here is Bryan's free daily protocol with the latest learnings.

──

Be well, Blueprint

Originally published in Bryan Johnson's Blueprint newsletter (March 11, 2026). This content is for informational purposes only and is not medical advice. Consult your healthcare provider before starting any new wellness protocol.