Ultralight Water Treatment Options for Backpacking

I find that on long desert treks, I experience noticeable heat adaptation (less sweating) after 5 to 7 days.

There are a couple parts to heat adaptation in a dry climate and less sweating isn’t one of them. Heat adaptation in a dry climate means your body sweats more and sooner in response to an increase in core temperature.

There are multiple sources, but from this one (https://www.sciencedirect.com/science/article/pii/B9780444640741000318):

A critical physiologic change that occurs during heat acclimation is the “training” of sweat glands to produce a greater amount of sweat. This leads to a progressive increase in whole-body sweat rate for a given work intensity or core temperature

If someone says they sweat less after 5-7 days in the desert and they consider this as being “heat adapted”, then I think they are sweating less because they have become progressively dehydrated during the trip and have total lower water volume. From the same paper as above:

As water availability in the body decreases, so does the ability to sweat and increase skin blood flow during heat stress (Horstman and Horvath, 1972). Dehydration increases the core temperature at which the onset threshold for skin vasodilation occurs and decreases sweat rate for a given body core temperature

Increased sweating is a heat acclimation (HA) response (and a good one at that), but it doesn’t get after the core physiological process by which HA occurs. The real benefit of HA is that you become physiological more capable as you adapt to heat. So, for a given amount of effort, your heart rate stays low, your skin capillaries promote better blood flow, thermoregulatory processes aren’t stressed, and thus, you sweat less for a given amount of effort on i.e., day 7 vs. day 1.

Increased sweating comes into play as an HA mechanism when you’re exertion level is high enough (think, closer to your AeT) to stress thermoregulation in order to maintain core temp.

At lower heart rates, HA results in a few really important changes that can actually reduce the need to sweat: more efficient cellular fluid balance, higher plasma volume, and more water retention.

Check out some of the work by Julien Periard and colleagues, they’ve built a pretty good picture of HA across the spectrum of athletic performance.

Getting this back to water treatment options, I ordered the tiny Ultralight model Ryan recommended and then returned it when I realized it only treats in 1L increments. I’d prefer the ability to treat in .5L quantities so I ordered the Ultra instead. Doing so also gives me the option to treat in a Smartwater or similar bottle without carrying a scoop or pot (one more thing to keep track of).

The Ultra is rated for 50L (Ultralight is rated for 20L) and weighs about 2.5 ounces more. This weight is offset by the need to carry extra recharge capacity that I’d need if I was using the Ultralight in the manner I’d prefer on a trip of more than a couple nights and it doesn’t require a scoop.

YMMV

I haven’t played with dirty water or using the sawyer over extensive periods but in my set up with a sawyer squeeze I can filter a liter of water in 1min all for 5.4oz in a gravity set up. so that means i can just stand there for 1 min and gravity feed 1L for 1min.

haven’t seen the quickdraw yet and looking forward to that article.

i’m going to give the tabs a ago again but last time i used them i didn’t have a good experience with them

Looking through the comments I feel compelled to react to two sentiments about SteriPens in regard to

1. Customer Service
2. Ease of use with water bottles

1) I’m using SteriPens for 12 years and had recently a malfunction with my roughly 10 year old SteriPen Freedom. I contacted Kathadyn via their Online Form and received an email reply in less than 2 hours with a clarifying question. Less then 20 minutes after my reply I received an email informing me that they are sending me a replacement unit for free. Since my SteriPen Freedom is discontinued Kathadyn sent me a SteriPen UltraLight which has the same form factor, but treats 1 liter instead of 0.5 liter. In my book that is excellent customer service – not only did Kathadyn respond very fast, but they are also standing 100% behind their (acquired) product even though it was roughly 10 years old in my case.

2) Using a SteriPen with the water bottle that I carry in my shoulder pouch is extremely easy as it fits perfectly on the bottle. All I have to do is set my SteriPen Freedom on the 0.5l bottle for 45 seconds or the SteriPen Ultralight on a 1l bottle for 90 seconds. The photo shows three bottle sizes that I use (16 oz Apple Juice, 20 oz Gatorade, 32 oz Snapple) with SteriPens resting on them. Once I put the SteriPen on the bottle, I take care of other things during the time the water is treated – like taking electrolytes out of my backpack.

I’m aware that newer Gatorade bottles have a smaller opening. Our bottles are 10 years old, fit perfectly, have lasted over several thousand miles of backpacking and are still going strong.

In another thread I mention getting a dud Steripen Ultralight; one email with one follow up phone call, remedied that. My new one has worked flawlessly (as does my 7-8 year old Adventurer!)

Well . . . How do they handle viruses?
BeFree: No
Quickdraw: No
Squeeze: No
UV (Steripen): Yes, to EPA specs

COVID is a virus.

Hum . . .
Cheers

Grayl and 1st need yes, those are the only 2 filters i known of that do viruses but at a weight penalty of roughly 150z…..don’t forget about chemical options as well that take care of viruses.

Covid is very unlikely in water, you have a greater chance of a dead decaying animal upstream then covid

Covid is very unlikely in water
Certainly, but there are MANY other viruses on this planet which can be in water and which can affect us. Dangerous things, viruses.

Cheers

Yup and many more that we don’t know of possibly frozen deep below or else where

…

almost forgot about P&G water purifier or just found out about purinize which both take care of viruses. both light weight

Do they meet the full EPA regulations? URL?

The P&G stuff used to be called PUR. Their web site claims it handles viruses as well as bacteria.

The purinizer stuff may handle bacteria, but it does not handle viruses. It may ‘clean up’ water, but it does not ‘purify’ it.

Cheers

Purinize did not do very well in their own testing:

https://www.purinize.com/pages/product-testing

97% isn’t great, but p&g is 99.999%

Forgot to there is also chlor-floc

Purinize didn’t look bad for most of everything they tested.  Crypto was 97% and so far only lab results that showed blue green algae as not detectable.  I can personally live with 97% especially where I go and more importantly I’m surrounded by lakes with blue green algae.

I just put the Steri Pen into the top of my Gatorade bottle, turn it on and slowly rotate it until finished. Never invert bottle.

Steripen ultralight
Ryan says twice plus in videos, “Water only needs to be exposed to this lamp for about 60 seconds to be purified.” The lamp runs for 90 seconds for treatment. Does Ryan remove the lamp at 60 seconds? What are his sources for the 60 seconds treatment regimen?

  .5 L light is on for 48- 60 sec/ or 1 L for 90 sec

Agree with J-L on this one. The only thing reduced (relating to sweat) in heat acclimatization is sweat sodium concentration. There is also a shift in the onset threshold for sweating, which occurs earlier and at a lower core temperature. Julien Periard in this paper states the same thing, as does the Wilderness Medical Society and the gold standard Guyton Textbook of Medical Physiology.

https://www.autonomicneuroscience.com/article/S1566-0702(16)30007-8/fulltext

https://www.wemjournal.org/article/S1080-6032(18)30199-6/fulltext

It’s never good when an article wants to change definitions of insensible water loss to now include active sweating.

Guyton textbook of medical physiology (2021) states, “Some water losses cannot be precisely regulated. For example, humans experience continuous water loss by evaporation from the respiratory tract and diffusion through the skin, which together account for about 700 ml/day of water loss under normal conditions. This loss is termed insensible water loss because we are not consciously aware of it, even though it occurs continually in all living people.

Insensible water loss through the skin occurs independently of sweating and is present even in people who are born without sweat glands; the average water loss by diffusion through the skin is about 300 to 400 ml/day.”

Here is a good article (leading to 3 more good articles) on heat adaptation.

https://www.outsideonline.com/health/training-performance/how-to-heat-proof-your-training

I didn’t realize that now heat acclimatization (heat adaptation in outdoor environment) is not exactly the same as heat acclimation (heat adaptation in artificial environment).

A heat adapted person will show a lower heart rate (HR), internal body temperature, skin temperature (Tsk), and sweat electrolyte concentration, and increased plasma volume and sweat rate (SR). If you perceive a decreased sweat rate, then you are losing heat adaptation. The increased sweat rate may last up to a month, but other parameters may last longer.