Comment by bborud

Perhaps it works if you are not physically active. But it is quite the opposite of what people do in cold regions.

The inner layers are usually the most important ones. The inner layer needs to do two things: transport moisture away from the skin and maintain a continuous layer of air close to the skin for insulation. It also needs to reduce skin contact points if you perspirate a lot.

Wearing dense layers close to your body would interfere with moisture management and heat distribution.

If you look at how Norwegian soldiers have dressed for winter exercises over the last 100 or so years, the inner layers will usually be a string/mesh undergarment. This holds a continuous layer of still air against the skin while minimizing fabric contact points. The holes allow sweat vapor to escape to the next layer, which then handles the transport of moisture. The second layer is usually a somewhat dense weave, relatively thin wool layer. Synthetics lose their insulating ability when they get wet/moist. Followed by a looser knit, thicker wool sweater. With a wind- and water proof uniform jacket as the outermost layer. This essentially creates two layers of air separated by a moisture transport layer.

The mesh garments were traditionally made of cotton, which is usually not a material you want next to skin, but it works in mesh form. Non-mesh cotton garments are terrible next to your skin because they get wet and then lose their insulating properties and stick to skin drawing off heat. If you sweat and then keep still for a while you will get cold and it feels wet and miserable. Wool doesn't have this problem as it keeps insulating even when wet. (Roughly the same cotton mesh garment, from the same manufacturer, that I wore in the military, was also worn by Tenzing and Hillary during their ascent to Mt. Everest in 1953).

You can get pretty good mesh garments today made from wool that also cover your arms. This is kind of the secret trick to staying warm and dry in polar conditions.

The configuration I wear most days is just light, thin, loose merino wool inner layer, thin, dense wool second layer and then a hard-shell. I started wearing this because I commute to work on my bike all year round, and I needed something that manages moisture, keeps me warm and doesn't smell. When it gets colder I add a cotton shirt or a loose knit sweater.

If it gets really cold (below -25) I usually drop the third layer and wear a down jacket (the kind climbers use on expeditions), but this has no vents so it doesn't work if it is warmer than -25C -- it gets too hot. If it drops below -30C I add a wool sweater. (The down jacket is overkill for where I live, so I use it perhaps 2-3 times per year)