What should we do today for our 45th birthday?

Bryan Johnson
3 min readAug 22, 2022

45 years have passed since I exited my mother’s womb. During the past 18 months, I’ve endeavored to measure — and then biologically age match — my every organ and biological process. One can be chronologically aged 45, but have a heart that is biologically representative of a 32 year old, or 71. I’ve completed hundreds of measurements now. It’s allowed my body parts and processes to get to know one another in unique ways. Upon waking this morning, this conversation happened:

Narrator: It’s our 45th birthday! What should we do today?

Heart Rate Variability (HRV) 54, age 40: Let’s go race the mountain trail again!

Lungs FEV1 age 22, FVC age 26, PEFR age 33, A lines age 33, DLCOc age 39, KCOc age 54, B lines age 70+: That’s a great idea. I’m in. Hey Max Heart Rate 183 age 37 can you step up your game today? We nearly had the boys (Narrator: sons aged 19 and 17) beat until you tapped out the last 500 meters.

VO2Max 53.6 mL/(kg·min), age 18: We did 3.27 miles in 33 min, climbing 1,000 ft. You averaged 159 bpm. A cool 170 bpm average would have done it. I have the capacity.

Diaphragm 155/117 cmH2O inspiratory/expiratory, age 20: Me too

MaxHR: I hear you…I’m working on it. I’ve improved 8% over the past year and am stalled as we try to figure out how to improve other parts of the heart.

Gray hair, age 60: you guys are always so extra. How about sailing? A brisk sea breeze always refreshes.

NAD 51.2 μM, age 16: Gray hair, honestly, get it together and rejuvenate yourself. You’re making us all look bad.

Gray hair: NAD, you pompous two sided di-nucleotide. You take a pill and then get all full of yourself. My situation is much more complex.

NAD: Gray hair, be like Epigenetics age 42.5 who succeeded at 5.1 yrs of age reversal in 7 months last year. Turning back the clock back .73 years, each month!

Gums, age 35: I also want to remind everyone that it was split-personality-HRV that ruined me by forcing me to grind my teeth for 15 years, putting us on a path for our teeth to fall out and give us periodontitis. Even still, I figured out how to reverse our age by 5 years.

HRV: you all have no idea how easy your life is compared to mine. I’ve got my control-freak Sympathetic Nervous System (SNS) obsessively worried about all things. Then my Parasympathetic Nervous System (PNS) constantly serving up hashtag platitudes #everythingisgonnabefine.

Inflammation age 10: HRV, you’re definitely 58% better than last year when your SNS was yapping 24/7. It’s been great spending more time with your PNS. By the way, from here on out, please refer to me as they.

VO2Max: Inflammation, that last bit…what are you even talking about?

HRV: Honestly, if someone compares my SNS to my PNS one more time, I’m going to light this place up!

Left ear, age 64: what did HRV say?

Right ear, age 43: don’t worry about it, I’ll fill you in if you’re needed for something.

Cholesterol HDL 63, LDL 52, Total 128 (ideal [1]): I kinda just wanna do the catwalk because I’m so perfect and photogenic.

Liver enzymes ALT 21, AST 24 (ideal [1]): ditto Cholesterol. I’ll join you.

Balance, one foot, eyes closed 110 seconds, age 18: my cat-like abilities are ready for action!

Lactic Acid: hey everyone, I’m ready to be deployed at a moment’s notice. A reminder, I had nothing to do last time we raced the trail. It was satisfying to see the boys limp around the house for days, complaining they could barely walk when we didn’t feel a thing.

Post trail run


[1] does not change reliably with age. Am in an optimal clinical outcomes range with lowest risk of all cause mortality and heart disease.