All Posts by Date or last 15, 30, 90 or 180 days.
also by Lloyd: MacPerformanceGuide.com and WindInMyFace.com
Thank you for purchasing through links and ads on this site.
OWC / MacSales.com...
diglloyd B&H Deal Finder...
Buy other stuff at Amazon.com...
877-865-7002
Today’s Deal Zone Items... Handpicked deals...
$700 $500
SAVE $200

$4499 $2999
SAVE $1500

$60 $20
SAVE $40

$1699 $1199
SAVE $500

$950 $700
SAVE $250

$1597 $997
SAVE $600

$1499 $1259
SAVE $240

$400 $360
SAVE $40

$372 $247
SAVE $125

$9999 $2999
SAVE $7000

$4500 $3500
SAVE $1000

$1000 $500
SAVE $500

$1398 $898
SAVE $500

$829 $799
SAVE $30

$935 $549
SAVE $386

$309 $259
SAVE $49

$1300 $900
SAVE $400

$450 $280
SAVE $170

$1499 $1249
SAVE $250

$700 $600
SAVE $100

$2000 $1270
SAVE $730

$1499 $779
SAVE $720

$450 $120
SAVE $330

$250 $230
SAVE $20

$3998 $3498
SAVE $500

$150 $80
SAVE $70

$369 $175
SAVE $194

$1699 $1199
SAVE $500

$649 $449
SAVE $200

$1498 $998
SAVE $500

$999 $949
SAVE $50

$1099 $999
SAVE $100

$400 $320
SAVE $80

$2399 $2199
SAVE $200

$7697 $4997
SAVE $2700

Upgrade the memory of your 2019 iMac up to 128GB
OWC Envoy Pro EX SSD
Blazingly fast Thunderbolt 3 SSD!

Up to 4TB capacity, USB-C compatible.

USB-C model also available


Great for travel or for desktop!

Observations on High Altitude Adaptation (Fluid Loss / Gain and Hematocrit vs Hypoxia)

Over the past several years, I have kept detailed records on morning body weight as well as notes on my reactions and adaptation to altitude, and have arrived at some remarkably consistent findings (e.g., no exceptions, ever).

When I travel to high altitude (10,000' - 12,000'), the following occur:

  • The first 8-30 hours, I urinate like crazy, so much so that the first night I am up 5 or 6 times to empty my bladder. This always happens and I always lose 2-3 pounds of body weight, yet I am not dehydrated (clear urine, ample fluid intake).
  • At 24-36 hours, a marked improvement in aerobic ability occurs at high altitude.
  • At 36+ hours, the fluid-shedding behavior ceases and things return to normal. But if body weight was 172 prior, it is now 169.5 (or so): a loss of 2-3 pounds.
  • At 7-9 days, another bounce in aerobic capacity (this one has to do with maturation of additional red blood cells).

These things ALWAYS happen when I go to altitude, meaning every one of the ten or so trips I’ve made to altitude in the past 2.5 years. No exceptions.

What does this mean for a high-altitude race like the Everest Challenge? At the very least, arriving the day before is a very bad idea, two days being an absolute minimum, and camping at least at 9,000' to adapt. Nine days is ideal, which is why I make it a point to schedule a photography trip prior to EC.

What might be going on

My understanding is that somewhere in the first 24 hours of going from sea level to 11,000' elevation, the body dumps its “standby” reserves of spare red blood cells in the spleen into the bloodstream as an adaptive measure. In short, natural blood doping by using altitude!

The proof is in the performance 24-36 hours later: hugely better. And the initial “brain fade at 13,000'” disappears. Ergo, an increase in hematocrit. Also, my power meter is totally objective. And I pay close attention to how I’m performing on the bike, from long attention and practice of self-awareness. The effects are consistent and dramatic, every time.

Back to the fluid observation: my guess is that in order to “make room” for those red blood cells, the body needs to shed fluid for whatever new plasma balance is appropriate.

Since I adapt very quickly to altitude (a fact known from long experience), my guess is that my body is pretty darn good at dumping a large number of fresh red blood cells into the bloodstream, raising the hematocrit and dramatically increasing my aerobic ability at altitude. And that to do so, it has to shed fluid, a lot of it.

The graph below shows two marked dips just prior to the 2011 and 2012 Everest Challenge events: both show a sudden loss of body weight of 2-3 pounds corresponding to the pre-race acclimatization: this is not reduced eating or a sudden starvation diet: it is fluid loss plain and simple, observed and measured.

Note that after the Everest Challenge I return home to near sea level, and body weight bounces right back up. And my shoes become too tight! The body is now adjusting by adding all that fluid right back in. Happens every time, like clockwork.

Steady caloric deficit vs body weight
OWC Accelsior 4M2 PCIe SSD
6000 MB/sec!
Mac or PC.


Ideal for Lightroom, Photoshop, video.
Capacity up to 16TB!
OWC Mercury Elite Pro Dock

Up to 32TB Capacity!


Dual-drive solution from 4TB to 32TB, hardware RAID, USB ports, DisplayPort, gigabit ethernet, SD card reader.

Huge capacity in travel-friendly form-factor.
OWC Thunderblade Thunderbolt 3 SSD

Blazing fast, up to 16TB.

YEE HAH!



√ No more slow and noisy hard drives!

Zeiss Batis for Sony
View all handpicked deals...

Apple 15.4" MacBook Pro with Touch Bar (Mid 2018, Space Gray)
$4499 $2999
SAVE $1500

diglloyd.com | Terms of Use | PRIVACY POLICY
Contact | About Lloyd Chambers | Consulting | Photo Tours
Mailing Lists | RSS Feeds | Twitter
Copyright © 2020 diglloyd Inc, all rights reserved.
Display info: __RETINA_INFO_STATUS__