At first glance of the question, Can you wear two base layers? You immediately think yes you can but why would you want to? Most outdoors people are well versed in the principles of the layering system – base layer, insulating mid layer, protective outer layer – so why would you ignore this and just wear two base layers. The problem is that in certain situations this layering system can be impractical.
BASE LAYERS FOR AEROBIC EXERCISE
If you are going to take part in a high intensity aerobic exercise in winter such as rowing, it is unfeasible to wear lots of different clothing layers. For a start you are going to get warm very quickly as well as producing a lot of perspiration. You are also going to need full range of movement which will be hampered with a traditional layering system. Plus there is also the problem of storing all these different clothes when removed.
What a lot of professional rowing teams practice in winter is wearing two thermal base layers at the start of a days training programme. Without being restrictive, these thermal layers will keep you warm whilst also managing perspiration more efficiently. Once the warm up is complete, one of the base layers is removed and easily stored in the bottom of the boat. At the cool down, the discarded base layer can be worn again to reduce rapid cooling.
Even in the coolness of early summer mornings a two layer base layer system is often used. Next to the skin will be worn a summer base layer to manage perspiration, with a thermal base layer as a second layer to provide extra warmth during the warm up.
BASE LAYERS FOR SPRING AND AUTUMN WEATHER
Out of the winter season, the need for a full thermal layering system is usually unnecessary. With the temperatures very rarely reaching freezing, you should be able to get away with just wearing your base layer. However, some early mornings and evenings may see temperatures drop low enough to require wearing extra layers for a boost in warmth. You could pack a thermal mid layer on the off chance, but it is a lot of unnecessary weight to carry.
Instead, ensure you are carrying a second base layer – you should be carrying a spare set anyway if you are heading away from civilisation. They can easily be worn over your first base layer and are light enough to be stored in a small rucksack.
BASE LAYERS FOR EXTREME COLD ENVIRONMENTS
When it comes to very cold weather, such as found in the polar regions or the Himalayas, mountaineers and explorers will often wear more than one base layer as part of their layering system. The main reason for this is you can trap more air between thin layers than wearing bulky insulating layers. And trapping air is essential if you want to keep warm because air is the insulator, not the fabric. It is not uncommon for mountaineers to wear two or even three base layers beneath their insulating mid layer.
SO CAN YOU WEAR TWO BASE LAYERS?
Instead of being a bit of a wacky question there are certain situations where wearing two base layers can actually be desirable. It is a lightweight alternative to heavier insulating mid layers and also offers greater flexibility in less demanding weather conditions. So the question shouldn’t be can you wear two base layers? but have you tried wearing two base layers?