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(The Gear Loop) - Although base layers are more often associated with extreme cold weather hiking or climbing, they can actually be a much more versatile item for any runner’s wardrobe.

Granted, some garments will naturally promote the trapping of heat to keep runner’s warm, which is great for the colder running months, but they are also traditionally designed to wick sweat away from the body quicker than a standard cotton T-shirt, while compression tops actually work to improve running posture, encouraging shoulders backward and opening up the chest for better oxygen intake.

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We’ve rounded up some of our favourite running base layers below, all hand-selected for their ability to either promote warmth or keep wearers cooler and protected from the sun's rays on a hot day. 

You’ll also find a selection of athletically-cut compression-style tops that we feel move with the body’s natural gait and can even help train runners to stride with more thought paid to correct posture and upper body positioning.

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Better still, all of the tops mentioned are extremely versatile and can either be worn alone on those more temperate days, or can be layered up with an additional waterproof or running-specific insulated jacket when winter really bites or the mornings start off frosty.

The best base layers for running

CEP SportsThe best base layers for running product photo 1

CEP Run Ultralight Long Sleeve

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For 

  • Lightweight and breathable
  • Soft seams for comfort
  • Reflective elements for safety

Against

  • Not the warmest
  • Only three colour choices

CEP specialises in compression gear, creating everything from socks to tights that grip the muscles to improve circulation, stabilise joints and beat fatigue by removing metabolic waste products faster.

However, the Run Ultralight doesn’t go too heavy on the company's compression tech and instead offers a featherweight base layer so runners can hit the open road feeling like they are wearing nothing at all.

But unlike a bare torso, the clever fabric promotes sweat wicking and is designed to be as breathable as possible. On a hot summer’s day, it provides long sleeve protection from UV rays and dissipates sweat faster, while on those colder days it can act as an additional warming layer.

There are also reflective elements, so the shirt catches headlights when out pounding the streets after dark.

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Madison Isoler Mesh Baselayer

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For

  • Excellent price
  • Great fit
  • Very comfortable

Against

  • Material isn’t the plushest 
  • Limited sizes and colours

As affordable technical base layers go, things don’t get much better than this offering from cycling specialists Madison. Although primarily dealing in the two-wheeled world, Madison’s lightweight top can be applied to any outdoor pursuit: from running to hiking.

The 3D back fit prevents the top from bunching up and promotes additional air flow to keep the wearer cool, while the circular knit construction means there’s nothing to rub against the skin and cause discomfort.

Admittedly, the open mesh fabric doesn’t feel as nice as, say, merino wool against the skin, and it looks a bit odd when worn without an additional layer, but you can’t argue with the air flow it promotes. If you’re one to overheat, this is a great and very affordable option.

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Rab Forge LS Tee

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For

  • Super soft merino wool
  • Great temperature regulation
  • Quick drying

Against

  • Relaxed fit won't be to all tastes
  • It’s pricey

Rab’s merino wool base layer screams quality from the moment you put it on. The fabric is soft against the skin, the flat-lock, low-bulk seams are barely noticeable and the top does a fantastic job of regulating body temperature.

That said, it’s not the most athletic cut on the list, which some might like, but we found it doesn’t quite promote the same kind of performance running as the more compression-orientated numbers we tried out.

As a layer for trail-running or speed-hiking, it’s excellent, with anti-odour properties meaning it can be worn fr multiple days on the trail and its rapid-drying nature ensuring it can be rinsed, hung up and worn again in no time at all.

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Under Armour Seamless Run Long Sleeve

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For

  • Stretch fabric greater movement
  • Smart graphics
  • Neat reflective elements

Against

  • Bulkier than other layers mentioned
  • Not the warmest

Sporting a slightly looser cut than some of Under Armour’s athletic compression tops and base layers, this running-specific soft shirt is great worn as a singly layer, or beneath an insulated jacket on those colder days.

The soft knit fabric packs plenty of ventilation panels, promoting sweat wicking and breathability, while the seam-free construction reduces any risk of chafing over longer distances.

Raglan sleeves also offer an extra bit of comfort and we like the subtle reflective detailing for added visibility.

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Icebreaker BodyfitZone Merino 260 Zone

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For

  • Very comfortable
  • Warm and sweat wicking
  • Great fit

Against

  • Too hot for summer runs
  • Dull colours and design

Designed for highly aerobic days in the mountain, or for those punishing runs in the chilly mornings, this snug-fitting merino wool option from thermal experts Icebreaker is a fantastically comfortable beast.

There are numerous breathable zones to prevent overheating in key areas, like the back and armpits, while flat lock seams help to prevent any rubbing or chafing when out on the trails.

Primarily for layering underneath other warmer garments, we actually found the Icebreaker to be plenty warm enough to be worn on its own, especially when tackling high intensity runs, while the thumb loops are a nice touch for keeping hands warm.

It’s a pricey option, but if you’re after extreme comfort and warmth, not much pips the current Icebreaker range, in our humble opinion.

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What to look for in a running base layer

Stay warm or keep cool?

A good base layer should help you do both, but it’s worth considering the climates you are going to be regularly running in. A heavier merino wool option is designed to keep runners warm and you’ll likely overheat on a bright summer’s day.

That said, well-designed, fast-wicking and breathable long sleeve base layers can be great at shielding delicate skin from harmful UV rays and generally keeping the torso cooler by drawing sweat away faster.

Athletic cut or loose fit?

Some like the posture improving qualities of really tight fitting compression layers, while others find it cloying and uncomfortable. Getting the right fit is going to be key if you want to remain comfortable over longer distances.

We’ve included a nice mix of both those athletically-cut tops and looser, more relaxed fit options. The final decision will be down to personal preference and how buff (or not) you like to look on a run.

Materials matter

We’ve said it before when talking about socks, but natural materials -such as merino wool - are fantastic at promoting increased breathability and comfort against the skin. These tend to be more expensive, but the quality really shows.

The lower the price, the more likely the top will be made from manmade fabrics, which can be a little uncomfortable and not as good at pulling sweat away from the skin. Look out for technical features, such as breathable panels, in those manmade shirts to ensure you stay cool on hot days and warm on cold days.

Writing by Leon Poultney.