Should I Wear a Base Layer When Cycling in Summer

HTP Fresco Sleeveless Base Layer

Whether to wear a base layer on a hot day is a contentious topic and is a long-running debate on pretty much every cycling forum on the internet. Some say a summer base layer is a fantastic piece of kit that every cyclist should own; while others find no positive benefits. Here at HTP we highly recommend them and not because we want you to buy one, but because they do actually work. Our reasoning includes:

  • Sweating only cools you down when you’re naked.
  • Sunburn is not fun.
  • Nobody wants chaffed nipples.

Science and Nudity

Sweating is your body’s way of cooling you down, but it only works if the water can evaporate from the skin. This requires the skin to be exposed to the open air. In most cases, cycling jerseys will trap a certain amount of water, which gets trapped against the skin; even the most expensive jerseys. This stops the water from evaporating and prevents the body’s temperature regulation system from working. Despite all of the technology that has gone into jersey development over recent years, the weight of material required to make the garment durable and hold it’s shape means that the fabric will hold a water. So unless you’re riding topless, the sweating process is not going to keep you cool when you’re riding.

Cold When You’re Drinking Your Coffee

How many times have you been on a ride on a hot day and, when you stop at a coffee shop for a break, felt cold after 15 minutes? Because your body is not producing as much heat, when at rest, and your damp jersey has trapped cooling moisture against your skin. This is a great example of moisture not being able to evaporate and preventing your body’s heat regulation system from doing it’s job. A lightweight, mesh, base layer will draw the moisture away from the skin (known as wicking), and form a barrier that holds the damp jersey away from the skin.

UV Protection and Modesty

One argument against the humble base layer is that we can simply unzip our jersey to increase airflow. This is a valid point, but also has it’s downsides.

The first being that you need to zip your jersey back up on long descents. We are then back in the situation, as at the coffee shop, where your damp jersey is clinging to your skin. Except here the fast moving air will cause you to be cold before you get to the bottom of the descent.

Secondly, women, and quite a lot of men for that matter, may well feel uncomfortable riding with their jersey unzipped. A thin base layer will go a long way to providing some privacy, while allowing airflow to the skin.

An often overlooked problem with riding with an unzipped jersey, which we all do to try to keep cool, is skin damage from the sun. The exposed skin might feel cool from the airflow, but you are now at risk of sunburn. A mesh base layer will allow airflow to the skin, while you’re jersey is open, but will also add some UV protection to prevent skin damage.

Chaffed Nipples is No Joke - Ouch

While we’re on the subject of skin damage, another side-effect of having damp clothing is that wet fabric causes chaffing. Having damp straps on your bib-shorts rubbing on your shoulders, or  worse - your nipples can be extremely uncomfortable. This is exacerbated by riding with your jersey unzipped and the wind ruffling your clothing. Wearing a base layer under your bibs will add a protective layer to prevent skin damage and discomfort, particularly if you are riding on subsequent days.

Not Just Another Layer to Keep You Warm

So there you have it. Base layers are not just about keeping you warm on cold days, they are about temperature regulation and keeping you comfortable on the bike. There are caveats though, of course. Always make sure that your base layer is tight fitting. It needs to in contact with the skin to work properly. Also, ensure you are wearing the correct base layer for the season. A lightweight, mesh base layer is not going to help keep you warm on a winter ride and a heavier winter base layer will cause you to overheat in the height of summer. If you have the right product, a base layer will be a great addition to your outfit.

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