Another breathability question

[Brett Peugh]

With it finally getting really cold around here for once I have stated to worry about breathability more. For an insulating layer I have the choice to either wear an R2 or a MicroPuff pullover which I will simplify down to a fleece or high loft insulation layer for this discussion. I know the high lofting insulation will also help stop the wind so that I don't need a shell for that. But it also would seem that it would act as a vapor barrier of sorts so that once the water vapor leaves my skin or baselayer it would have two go through both layers of nylon and the insulation before it gets out. This seems much harder than something like the fleece which is much more breathable. It would seem that it would be better to wear the fleece with a shell so that the moisture collects on the shell past the fleece rather than on the inside of the high lofting insulation. I was wondering what the data was to support this or not. Thanks

[Greg Mihalik]

Brett,
What level of exertion over what period of time? Much of what you are asking is highly dependent on individual physiology – sweat/hour of effort – in changing conditions. It comes down to your experience with your clothing systems.

Going uphill for 3 hours on skis at a barely-able-to- talk pace, at 10°F, and no sun, I can stay warm and dry with the equivalent of a long sleeved T-neck zip Capaline 2, a Houdini and a fleece hat. Oh yea – and food. I sweat, and I cook it off. I try to control things with the zips on the T-neck and the Houdini. When I turn around to return, it sometimes takes a Cocoon Hoody to keep me warm. You just have to get out there, do what you do, and learn – collect Your data for Your systems.

[Brett Peugh]

Thank you, but that is not what I was asking. My question was more to the point of how well water/vapor passes through a fleece versus a regular high lofting insulation.

[Denis Hazlewood]

If I'm going to be moving fast, and generating a lot of perspiration, I feel that fleece or pile jackets wick very well. I have a North Face wind blocker fleece jacket that wicks very well and I only need a shell if I stop walking. If it's colder my REI pile jacket offers more loft.

This is in northern California shoulder seasons. It's pretty dry and the evaporation rate is generally high.

[David Chenault]

Modern fleece (Patagonia R2 and R3, Mtn Hard. Monkeyman) breaths very well in cold weather. You're right on the money with it's advantages over things like Primaloft.

For example, my go-to lift riding system this year has been a capilene t-shirt, old R2 bodyrug pullover, and a hooded soft shell. It manages moisture well between freezing on the lift and sweating skiing trees.

[Roger Caffin]

Hi Brett

It may be that there is no simple answer to your question, for two reasons. The first is that there are so many different fleeces and versions of hi-loft insulation on the market that your question cannot be answered simply.

The second, which you should consider seriously, is that the question should not arise anyhow. You should not be wearing that much of either that you start to sweat. You should travel cool and non-sweaty – even at temperatures way sub-freezing.

Cheers

[Jon Rhoderick]

I have used both for moving. Often times I will start with my micropuff and R1 hoodie over a baselayer, just because I really haven't generated enough energy to stay warm, then i will quickly go down to the R1 and baselayer once I'm warmed up, but in reality having the fleece is much more important for moving and then having a layer that can cover everything for when you stop and the initial few minutes of warming up. If you can spare putting the moisture into synthetic or down by all means do so, cuz fleece is going to be warmer when its wet. I hope this answers your question somewhat.

[Brett Peugh]

I know if I start sweating to vent or cut down on the layers. But what about that sensile(sp?) perspiration that your body gives off?

[Inaki Diaz de Etura]

> It would seem that it would be better to wear the fleece with a shell so that the moisture collects on the shell past the fleece rather than on the inside of the high lofting insulation

that's exactly what I think. And no matter how well you manage your exertion level to avoid sweating there's gonna be sweat between pack and back. I try to avoid wearing any high loft insulation while moving and keep it for stops and camp. Fleece breathes well, is rugged (no problem to wear under the pack), comfortable to wear and manages perspiration so well. It's all the insulation I wear while moving. The problem with fleece is bulk and weight (in comparison to high loft garments) so the key is to carry just enough to keep you warm while moving but try to avoid carrying any inside the pack which is where the additional weight and bulk matter.

I usually carry two thin fleece items (100 polartec or similar) rather than one thick one in the winter so I can adjust. One is often in the pack but that's a small price to pay for the versatility. With a base layer and a shell over it all it's usually enough for anything I find in the winter while moving. I liked this system so much that I even re-introduced fleece in my three season list, a thin, snug, pullover style piece that weights like a typical base layer shirt and I can use over a base layer or as a base layer itself so I never have to use the high loft insulation while moving.

[Roger Caffin]

Hi Brett

> But what about that sensile(sp?) perspiration that your body gives off?
This may be more a problem of the pack design rather than the clothing design. My pack has a sprung mesh back which lets my body breathe through it. Silnylon frameless packs can be sweat-blankets.

Cheers

[Chad Miller]

Roger Caffin wrote:

"The second, which you should consider seriously, is that the question should not arise anyhow. You should not be wearing that much of either that you start to sweat. You should travel cool and non-sweaty – even at temperatures way sub-freezing."

I'm sorry Roger but this is completely untrue. No matter how cold it gets you will still sweat.

Take me for example, I sweat easily and often. On my last snowshoe day hike it was 6 degrees with high winds (wind-chill -17 degrees). I broke trail for nearly six miles through three feet of snow. I only wore a base layer silk weight long sleep merino wool top and a silk weight polypro long sleeve. When I removed my polypro outer layer I became very, very cold and had to don my polypro again.
Despite regulating my pace and venting my polypro outer layer I still sweated a great deal from my torso. So much so that by the end of my hike both my merino wool base layer and polypro top had completely sweated out.

Sometimes there is nothing you can do to keep from sweating regardless of how cold it is outside.

[Huzefa @ Blue Bolt Gear]

Chad >When I removed my polypro outer layer I became very, very cold and had to don my polypro again.

Were you wearing a windshirt?
If not, may be you got cold due to rapid evaporative cooling?

[Brad Groves]

Chad, not so much untrue, really… First, to stay on topic, the OP was asking about wearing a mid/heavy weight fleece or high-lofting insulation on the move–that is not something you should do, nor something that would provide optimal moisture management. In your own case, you were wearing two layers–perhaps a third in a windshirt–before you started sweating you should have stripped the extra layer. But that sounds nitpicky, and it does remove us from the OP question. I regularly cross-country ski in 10*F with a thin wool long sleeve zip T, starting with a windshirt until I warm up.

As to the breathability of fleece vs. high-loft synthetic, neither's optimal. A lighter weight down garment would be better. Failing that, the fleece will move moisture in such a way that you won't notice it as much (although if you were wearing a shell you'd find a bunch of excess moisture built up inside). Regarding insensible sweat, you have that all the time. Right now, sitting inside at a desk doing nothing. Are your clothes soaked? Cheers-

[Chad Miller]

My comments where to address that sometimes no matter how little clothing you wear you will still sweat regardless of the temperature.

As far as me wearing a wind shirt I have tried that and they make me sweat more due to the low breathability. To clarify I removed by outer polypro layer when I was in a sheltered area without wind. The air temp was simply too cold for me to be warring a single silk weight merino wool shirt that was completely saturated with sweat.

When it comes right down to it your layering system is relative when it comes to sweating. Some people can wear heavier garments without sweating while other will still sweat in the thinnest of layers regardless of temperatures.

[Roger Caffin]

> it was 6 degrees with high winds (wind-chill -17 degrees). I broke trail for nearly six
> miles through three feet of snow. I only wore a base layer silk weight long sleep merino
> wool top and a silk weight polypro long sleeve. When I removed my polypro outer layer
> I became very, very cold and had to don my polypro again.

I understand the problem, but I have to say that your choice of clothing is not one I would make. In windy conditions at those temperatures I would not even consider going without some sort of good windshirt. I would probably wear a light Malibu EPIC jacket and a polypro thermal top under it.

> Sometimes there is nothing you can do to keep from sweating regardless of how cold it is outside.
Ahhhh… I beg to disagree. Sweating is a physiological reaction to excess body temperature. Keep the temp down and the body does not need to sweat like that.

Yes, I do this in the snow, and no, I don't get sweated out.

Cheers

[Chad Miller]

Ah but Roger what I am saying is that simply some people sweat more and what works for you won't necessarily work for everyone. While you may not sweat very much when wearing light layers in cold temperatures you still sweat. The amount you sweat depend numerous factors: level of exertion, amount of muscle mass, and physical fitness.

Take these two examples where I wore what many here would deem very thin layers for the temperatures:

Snowshoeing in temperatures around 5-10 degrees without any wind. All I wore was my silk weight merino wool base layer and I still sweated out my top. I have tried this with silk weight polypro with the same results.

With temperatures around 5 degrees with a -15 degree wind chill I have snowshoed in a wind shirt (MontBell) and a silk weight base layer. Despite opening my wind shirt, removing my wind shirt before overheating, slowing my pace, and occasionally stopping to cool off I still wetted out both my base layer and wind shirt.

I both of the above cases I wore the lightest possible layer(s) and still sweated out my clothing. What would you recommend I wear to elevate this problem?

[Jim Colten]

Roger says: Ahhhh… I beg to disagree. Sweating is a physiological reaction to excess body temperature. Keep the temp down and the body does not need to sweat like that.

and Chad says: what works for you won't necessarily work for everyone

Could well be that you are both correct. Why is it that the strongest bicycle hill climbers are the small ones when power/weight ratio favors the big ones (at similar fitness levels)? It is because body temp is a limiting factor and the small ones can shed heat much much better.

Having snowshoed with Chad and having seen Roger's famous skiing avatar, I suspect that this could explain their differences.

So since Chad is already wearing relatively little insulation, perhaps his only option is to generate less heat by traveling slower … except I'm not sure he has any gears other than overdrive:-)

[Chad Miller]

I've tried shifting into a lower gear but my transmission is busted!

[Neil Bender]

For Chad's example I'd recommend switching the order of the tops: polypro with wool over that. The wool layer should take up the moisture that the polypro layer can't handle. When you stop, take the wet wool off and layer a windshirt over the damp poly base layer. What little moisture is in the poly layer can be dried off slowly under body heat under a wind layer. If that isn't enough, out comes a synthetic belay jacket with hood, right over the wind shirt/base layer.

I use this same order with socks and I usually only swap out the wool layer, the inner poly sock stays dry enough or dries quickly. The problem with this order of layering is the poly picks up stink faster, although Xstatic treated poly holds it down to a reasonable level.

Another thing that helps to keep cool and evaporate stinky sweat rather than trap it is matching pit zips in base layers, mid layer and wind layer. Exposing a small area of bare skin under arms to cool air really helps control temperature and one can manually 'bellow the layers to promote a draft. I've had to add these myself; with a one way zipper it's best for the zipper pull when closed to be at your fore-arm to prevent the pack strap from interfering with adjusting. Full open is wherever the pack strap stops the zipper pull.

For winter exertion I've gone so far as to make a wind shirt with a mesh back as I don't often remove my pack, and when I do the belay jacket isn't far behind. This doesn't completely prevent a wet back and it also makes the windshirt heavier than just using thin ripstop. But it helps. A winter only windshirt could have a roll up fabric back panel with zippers or velcro to make it useful as a stand alone garment without the pack, but again in winter rain repellancy isn't an issue, and without the pack if it is getting cold or windy the belay jacket is the ticket.

It's pretty easy to sew an open mesh panel to the inside back of an existing windshirt, zigzag top stitch for fray control, then carefully cut away the original windshirt just near the topstitching leaving a mesh panel. Or use an old shirt as a pattern and make one from scratch from 1.1 ounce ripstop, Thru-hiker's Momentum cloth, and athletic or poly mesh from outdoor Widerness fabrics.

[Roger Caffin]

> What would you recommend I wear to elevate this problem?
This sounds like a good excuse to investigate a whole range of clothing … :-)

Cheers

[John G]

If you sweat in a silkweight layer, and don't want to reduce your pace, just wear a windshirt without the silkweight layer. Then your baselayer stays dry in your pack, and you can dry your windshirt inside-out in a few minutes when you stop (and put on your belay jacket).

Sound's crazy, but works well. And the people who looked at you funny will understand when they are damp and trying to dry (ie: chilly) at the rest stops ;)

[Lynn Tramper]

I'm not sure I understand the question. Yeah, sweat happens, and the more you exert yourself, the higher the likelyhood you will sweat. But if you are sweating that much (at whatever exertion level), then why would you be wearing a high loft fleece or synthtic top? Are you saying that you sweat a lot but are still cold, therefore you need more insulation? It's a bit confusing, but ulitmately, Roger is right in that there is no correct answer to your question as there are so many types of fleece, synthetic insulation and shell materials. If you want to stop insensitive sweating (as opoosed to exertional), then a VBL nest to skin is your best bet. Other than that, all you can do is experiement. For instance, there was an article somewhere here on BPL that indicated the shell lining on MontBell garments (ballistic nylon) is less vapour permeable than some other fabrics.

[George Matthews]

The Theory Of Sweating In The Cold

Given a certain amount of exertion hiking, skiing, etc.

The colder it is outside, the less you sweat

The warmer you are, the more you sweat

Different fabrics vary in their breathability

The more breathable your fabrics, the less wet you get

Bottomline, if you are sweating yourself wet while out in the cold, then you are either wearing too much clothing or the wrong fabric.

Warning: this theory only applies to being outside in the cold and does not even suggest the possibility of indoor, clothing-less sweating exertion.

[Lynn Tramper]

>Bottomline, if you are sweating yourself wet while out in the cold, then you are either wearing too much clothing or the wrong fabric.

Or over-exerting yourself!

[Huzefa @ Blue Bolt Gear]

>Or over-exerting yourself!

There is nothing wrong about over-exerting yourself.

[Author]

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