The problem when it comes to reviewing baselayers, however, is that it's always going to be sujective and extremely dpendent on the metabolism of the individual carrying out the review. A baselayer that's comfortable for someone who "runs cold" or who spends extended periods static will lose much of it's appeal to a user who "runs hot" or expects the same breathability when active as when inactive. Over the last decade the technology used in base layers has progressed from being a means of water vapour/heat transpotation to an important asset in reducing muscle fatigue. 

What the manufacturers say:

Give your body what it needs to work harder and recover faster with this ultra technical running top featuring compression technology. Utilizing compression technology to reduce muscle vibration by up to 42%, the Muscle Force Running Warm top works harder to reduce muscle fatigue and increase recovery times. Designed to feel snug and supportive but never constrictive, this runner's top features seamless integrated functional zones that deliver body-mapped thermoregulation and freedom of movement right where you need it. Meanwhile, Odlo's permanent anti-bacterial Effect technology helps to keep you smelling as fresh as you feel. Perfect for pre-event training and post-recovery, this long sleeve crew neck is ideal for stepping up your performance while winding down muscle fatigue.

Features:

• 42% Reduction In Muscle Vibration for Less Impact and Quicker Recovery
• Seamless Integrated Functional Zones for Thermoregulation and Freedom of Movement
• Permanent anti-Bac

Odlo SUW Top on test:

The first thing you notice with the Odlo SUW Top is the fit. There's no getting away from it, the 14% Elastene content means a close fit. Put it on without additional layers and the world's going to see how ripped, or not, your torso is. Far from being all show, however, the close fit is all part of the compression system that apparently reduces muscle fatigue and helps recovery.

Compression technology, of course, is nothing new but rather than producing a single line in a packed catalogue  Odlo are specialists in base layers and "active" underwear. Where some compression baselayers can feel restrictive rather than supportive the most noticeable feature of the SUW Top is that it's close without being noticeably tight - or least it is once you get used to it. Although the top is extensively body-mapped, with different zones offering different breathability and wickability, the whole garment stretches in all directions. What this means is you can distribute the compression more equally rather than having tight spots where the material bunches up.

With the stretch fit you get a very high degree of flexibility, which is complimented by a true "flat seam" design. With no rub points from the stiching and the elasticity of the yarn the result is a baselayer than creates its own micro-climate, securely sealed at the extremities. 

For the first few uses you will feel the compression, particularly across the chest, but it's never oppressive and after around 20 minutes use you stop noticing it. Partially because of this the SUW Top is one of those products that you really need to assess over a prolonged period. Your body, and mind, will need a bit of time to adjust to the way the product works. It's designed to keep you warm as well as forming a vital part of your layering and primarily aimed at winter use. It's also designed for active use, specifically running. What it's not designed for is fine tuning your body temperature on a warm summer day. 

As is common these days the SUW Top uses anti-bacterial technology to reduce odours and you can expect to get 2 or 3 days use out of it before any odours start getting retained. It's not merino standard but like all such products there's a balance to be struck. Merino may wick faster and smell better for longer but synthetics dry faster and are far more durable. 

For many people a baselayer is at best just a baselayer and often an afterthought. To those in the know, however, the baselayer is probably the most important single part of your outdoor wardrobe after a well fitting pair of shoes. You wouldn't pick a single shell or boots to cover all 4 seasons and the same applies to baselayers. The Odlo SUW Top will keep you warm on those early morning winter runs but by early May it'll be back in your wardrobe for a few months. It does what it's designed to do and does it very well. With the durability of the fabrics and yarns the £70 isn't as expensive as it may initially seem as you can expect several years of winter use from it - and it's still cheaper than merino. 

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