Base layers. Everyone is talking about them. But is everyone wearing them? And if so, should you wear one?

In this article, I’ll dive into what a base layer is, when you might wear a base layer, and why you would wear a base layer.

What Is A Base Layer?

A base layer, by simple definition, is the first layer of clothing you wear against your skin before you put on any other layers. It is the “base” of your outfit.

Generally, when someone says “base layer,” they mean an undershirt. Other garments (underwear, tights, etc.) are rarely considered base layers, but sometimes certain compression shorts and/or long underwear fall into the base layer category.

For the sake of simplicity, in this article I’ll be talking about base layers for cyclists, which will be undershirts. Typically, a good base layer will be made of high-tech synthetic fabrics (or wool,) and it will wick sweat away from your body. Sometimes they are like loose fit t-shirts, some are tight, some are compression fit, some are thin, and some are thick.

I suggest either a tight fit or compression fit base layer. To do its job, a base layer should be snug against your skin. A loose fit base layer will just bunch up, rendering it uncomfortable and unable to function very well.

The thickness of the base layer will depend on when you wear it…

When Do I Wear A Base Layer?

When I think of layering, I think of wearing multiple layers in cold or changing weather conditions so that I can always stay comfortable. However, you can wear a base layer in just about any weather conditions year-round.

Cold days, hot days. Summer, winter. Training rides, races. Road, mountain. Whatever.

There are arguments for all those times to wear a base layer. Hence the next section, “why wear a base layer?”

Why Should I Wear A Base Layer?

That’s a good question. In this section, I’ll analyze all the reasons you might wear a base layer.

• Base layers keep you warm in cold weather.

This is the most popular reason right here. You can wear a base layer in cold weather to help keep you warm.

It does this in two ways. First, the base layer provides an extra layer of insulation. Second, it will wick sweat away from your skin, so you stay dry.

• Base layers keep you cool in hot weather.

On warmer days, you can wear a base layer to stay cooler. That’s the promise at least. Somehow the sweat evaporating off the base layer is supposed to cool your body. But really, sweat evaporating straight off your skin would keep you cooler.

I say this idea is pure marketing; companies are simply trying to sell more base layers!

I mean, some shirts are even marketed as promoting “air to skin contact.” What’s that mean? How can you get more air to skin contact than having the air hit your bare skin?!

• Pro riders wear base layers.

I remember seeing ads and/or editorials talking about pros wearing base layers. Usually this was tied into the “base layer keeps you cooler in the heat” reason mentioned above.

Then I’d watch some pro cycling on TV, like a mountain stage of the Tour de France on a hot day, and maybe a couple riders out of the bunch were wearing base layers. Most wore just a jersey and had it fully unzipped at that. That should tell you something.

And for the pros that were wearing base layers, it could have been for a different reason, like road rash prevention and/or compression fit benefits. Or perhaps they’re paid to wear them. They are sponsored after all!

• Compression gear increases performance.

A compression base layer is a different ball game. In this case, the base layer is worn for the benefits of compression clothing, regardless of the weather conditions.

Some research shows that compression garments (Under Armour, SteelStretch, etc.) can delay muscle fatigue and increase performance when worn during exercise. I do like the feel of some compression shirts, but since cycling is primarily a lower-body activity, I wouldn’t worry too much about these benefits.

• A dry base layer is more comfortable than a clammy cycling jersey.

I found this reason mentioned on another cycling website and found it so senseless that I couldn’t forget it.

The comparison is between a dry base layer and a wet, clammy cycling jersey. Obviously the dry layer would be more comfortable, but how is this situation realistic?

First of all, your cycling jersey should wick sweat away from your body. If it doesn’t, get a new jersey!

But let’s say you have a nice base layer under your jersey. The base layer will wick your sweat away from your body, but then it must transfer the sweat to your outer layer (your jersey) for evaporation.

Assuming your jersey gets sweaty and stays sweaty/clammy, the base layer can no longer transport your sweat to the already saturated jersey. So you now have a clammy base layer under a clammy cycling jersey! How is that more comfortable?!

• Base layers can save your skin from road rash.

This is the reason that convinced me to purchase an undershirt before I started racing.

The theory is that, if you fall off your bike and slide or roll, your jersey will catch the asphalt, but your undershirt will keep sliding within the jersey. And sliding on an undershirt feels marginally better than sliding on bare skin.

Obviously, this won’t save you from everything. It definitely won’t prevent broken bones. And if the crash is big enough and you slide far enough, any road surface is going to eat through a couple layers of spandex in no time. (That’s why motorcycle racers, longboarders, etc. wear leathers!)

Base Layers: My Recommendation!

While there are quite a few reasons being thrown around, there are just two main times when I’ll wear a base layer.

First, when it’s cold and I want to stay warm and dry.

Wearing a base layer in cold or wet weather has always helped me stay warm. I love my fleece and wool undershirts (very warm and cozy,) but I also like my SteelStretch Ice undershirt since it’s tight and thin (so it easily fits under anything.)

Second, when I am in situations that could lead to crashes.

The ‘why’ for me comes down to reducing friction in a crash. I’m not expecting miracles, but a slightly reduced risk of injury is worth wearing a base layer.

Since I wear an undershirt during races, I’ll also wear one during training. Which means I’m bound to wear undershirts on warm days. And yeah, they’re more comfortable than some of my cycling jerseys. But I’m not expecting them to keep me cooler!

I suggest you buy at least two base layers.

First, get a thin, short sleeve base layer with a tight fit. White is preferable. This is your summer undershirt, (but it can also be worn in cooler temperatures, because any little bit helps.) This is mainly to help prevent road rash and keep you comfortable under any not-so-comfortable jerseys.

Then, get a thicker, long sleeve base layer. I suggest merino wool, but there are some fleece undershirts that are nice, too. This should also be a tight fit. This will be your cold weather base layer, and it will increase your riding comfort much, much more than the summer undershirt!

If you buy more undershirts, I recommend stocking up ones designed for cooler weather.

But really, just go ride your bike!

During my baselayer addiction/buying phase last summer, I got this Terramar Microlight Sleeveless Base Layer from Nashbar. I’ve been faithfully using Terramar’s clothing (mostly base layers) for many years since I love their stuff.

This shirt did not disappoint! Even better, it was only $15. (Compare that to the Demarchi one I hated which cost $20.)

This shirt rules. It’s soft and comfy. It just seems right.

I got a size small, but it’s pretty big for a size small. It’s barely smaller than the size medium stuff I have from Terramar. If you’re a skinny cyclist normally wearing size small, you’d probably fit XS just fine, since it’s nice to have base layers be pretty tight.

But the key is the arm openings – there’s plenty of room there, with no seams cutting into my armpits.

At first, the shirt was a good size for use while running or exercising. This year, after packing on some upper body muscle, I found this size small to fit just right.

Aside from just being comfortable, the material has cool technical properties. First, it’s rated UPF 25+. This rating means it blocks 96% of the sun’s UV radiation. (UPF is basically like an SPF rating, but it applies to clothing instead of sunscreen.)

Also, it uses “ec2 Qwik-Dri” technology:

EC2 Qwik-Dri technology has the ability to actually lift moisture molecules away breaking them down for rapid evaporation. This patented process does not involve the use of add-on chemicals but is a permanent molecular change. Since the EC2 Qwik-Dri process alters the molecular signature of the yarn in our fabric, the moisture control is permanent. It won’t wash out or wear off.

I wore the shirt for quite a few bike rides and it always worked well. The longest time I wore this shirt was as a base layer for a five hour motorcycle skills training program in direct sun (90 degrees,) and it kept me dry and comfortable.

I find this shirt even better for running and other workouts. I wear it as my only upper-body layer.

My final verdict is…

This might not be my #1 favorite undershirt, but it’s still a great moisture wicking shirt that I love to wear often. It has good construction, good fit, a very soft feel, and it’s stylish.

I’d definitely buy it again.

Official website: www.TerramarSports.com

During the past year I’ve become more interested in having nice base layers beneath my jerseys, and when I saw the De Marchi Contour Light Sleeveless Baselayer for a mere $20, I had to grab it. I have some De Marchi bib shorts and really like them, so I figured I’d like this baselayer, too.

On the website, it appeared to be a thin, white base layer. I was hesitant to purchase it though, because the picture at Nashbar didn’t give me the best idea of the construction. Also, the shirt appeared to be kind of like a “see through” mesh, which didn’t really appeal to me. But somewhere I saw the retail price for this listed at $75, and it’s made in Italy, so it must be good…

Well, I pulled it out of the bag and didn’t care for it at all. The mesh was way more open than I expected – it’s more “open hole” than it is shirt. And the material was not soft at all, it was very stiff and rough and certainly not something I’d want against my skin.

But I put it on, hoping to be impressed. I wasn’t.

I got a size Small, which matched my chest measurement at the time. Sure enough, the shirt fit nicely across my chest. But the arm holes are tiny, and the seams cut into my armpits! Here’s the funny part – it’s baggy in the stomach area. It bunches up down there, but everywhere else, it’s tight.

Am I supposed to have toothpick arms and a beer belly or what?

This shirt is just plain screwed up. You can tell it’s sewn for an ergonomic fit, but it’s totally wrong! Plus, the fabric doesn’t stretch. So it will either hang loose or cut into your skin, depending on your body’s proportions.

So even on sale for $20, plus one of Nashbar’s 20% off coupons, this was a ripoff.

Another funny thing is on the tag, it says:

“We take our famous Contour line and reduce to the essentials. Carefully chosen lightweight fabrics, minimal stitching and accessories make the designed in Italy Contour Light line from De Marchi offer the maximum in performance comfort with the minimum in weight.”

It’s funny because I think they left the stitching but got rid of the actual shirt material!

Anyway, as much as I hated it, I decided to ride in it a few times to see if it was worthwhile…

I will admit that if the shirt actually fit my body, and didn’t feel like sandpaper, it would be pretty nice. The ventilation was great, that’s for sure. (Even though the minimalist design raises the question, “why not skip the undershirt completely?”)

My final verdict is…

This is the most disappointing purchase of mine in the last couple years. It’s not even close to being comfortable, and I don’t see how it would be beneficial to wear it, because there isn’t much to it. If it was going to wick sweat, it would actually need fabric against my skin.

It’s basically an expensive fishnet. Or at least it feels like one. I cannot think of one reason to buy this, so it’s impossible for me to recommend it for anyone.

Official website: www.DeMarchi.com

If you’re not familiar with the Under Armour clothing line, the real core of their offerings is the compression-fit clothing. This compression fit is supposed to maximize performance since it bolsters muscle support and accelerates moisture transfer.

The brand may resonate a bit more with football players, but that doesn’t mean cyclists can’t get in on the action. I was looking for a good base layer for running and biking, so I decided to get a short sleeve t-shirt from Under Armour’s Heat Gear lineup.

The shirt in question is from mid-2008, and it has the same compression fit as the original, but was “updated with a new ergonomic fit and Anti-Odor HeatGear® fabric.”

I was actually looking at Under Armour shirts for years, but they were so expensive ($35 for a t-shirt,) I never bought one. When I finally went to get one in the store, my size was out of stock!

So I go to UnderArmour.com to find more info, and you can shop online, so I just went into the catalog. There’s my shirt for $24.99 – good thing I found this!

Worried about shipping charges? Have no fear! If you check retailmenot.com, you can probably find a coupon for free shipping. And once you’re a customer, they’ll send you current coupon codes, so you never have to pay for shipping and handling!

Let’s look at the shirt now…

Price

As mentioned, these aren’t cheap. But at $25 at their website, it’s not outrageous – most other performance base layers are the same price or more.

For someone that works out in the gym a few times per week, an old cotton t-shirt would be fine. But when you spend hours each day out in the hot sun, a $25 performance shirt is a good value.

Comfort

My first impression was that this shirt was awesome and worth every penny. It was nice and tight, and the compression felt great on my muscles. Size small seemed just about right for me, although it does take some effort to slip it on. (I wear size small bike jerseys and they fit fine.)

I have one complaint though – the seams. They don’t bother me on the sides, but the seam that goes under my armpit digs in. It’s not too uncomfortable for short time periods, and it’s fine for cycling since your arms don’t move much, but I wouldn’t want to run in it. I bet it would chafe me pretty bad.

Actually, I went running in it once to see. That seam was awful! It cuts into my skin, then scrapes back and forth, leaving my armpits sore for days!

Doing it over again, I’d get a size Medium to see if that helped. (But a loose fit Under Armour shirt in size small fits me fine.)

Durability

I’ve used this shirt for about a year and used it mainly as a cycling undershirt, but I’ve also worn it for some workouts. It still looks good as new, with no snags or any serious damage. However, across the back ( the shoulder blade area that supports the bar when I do squats,) it’s getting fuzzy from the abrasion of weight bars.

So durability should be good when not exposed to rough surfaces. If you’re just wearing it and washing it, it seems to be durable enough for years of use.

Style/Fashion

This is one of those shirts that looks good if you are big with chiseled muscles. If you’re a cyclist like me, you probably don’t want to be seen in this without something over top of it!

(But you can see me wearing it while demonstrating exercises such as the bird dog.)

Performance

The only reason to spend money on one of these shirts is for performance, so it better deliver! It does.

It does a very good job keeping me cool and wicking sweat away. It’s great for hot weather, but I also found it to be the perfect shirt to wear while indoor training on a trainer or rollers. It’s possibly cooler than going shirtless.

Also, the shirt boasts a UPF 30+ rating (stands for Ultraviolet Protection Factor,) which means it blocks 97% of the sun’s UV radiation.

My final verdict is…

Under Armour makes a very cool product; I like the compression fit. However, make sure you get the right size. (In this case, the right size is the one that doesn’t chafe due to rough seams!)

After the problem with the seams I would recommend you look at Zensah and SteelStretch compression shirts instead. I haven’t tried a Zensah yet, but I think the SteelStretch shirt is 100 times better than an UnderArmour compression shirt!

However, since I bought this one, I’ll still be wearing it as a base layer for bike rides and races on hot days.

Official website: www.UnderArmour.com (HeatGear Full T, new)