Mizuno’s Breath Thermo Base Layers lets your Sweat work for You

I am pretty sure we have finally crossed over into full on winter weather – which means that it’s time to pull out the baselayers. We were recently sent a few items from Mizuno’s Thermo Line – the Thermo Running Half-Zip and Thermo Running Long-Sleeve. For those familiar with Mizuno apparel, you know they make some good quality pieces that stand up to the wear and tear of us runners. As we run, we sweat, and generate a fair amount of heat, but that heat dissipates quickly on colder days. Mizuno’s Breath Thermo line of running gear is designed to “generate heat as you sweat”. With such a claim, we were excited to test these two tops.

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The two tops are the Half-Zip and the Long Sleeve. Both tops look good and fit very well (size Medium/ 5’-9” male). The first thing you will notice is the density of the fabric, which is to say it is not a thin layer. My initial concern was breathability but that went away quickly once I got outside. The tops breathe well while keeping me warm, but not so warm I ever felt the need to take the top off (41 degrees/foggy).

Both tops feature thumb holes along with sleeves that are long enough to ensure your knuckles are covered when using them. The half zip features a nice neck line that provides additional skin coverage from the long sleeve model. Both are available in 3 colors; Olympian Blue (tested), Black, and Ensign Blue.

In each case I ran in these as a top layer, but either one could be a base layer with a coat. It is noteworthy to point out that the long sleeve is more snug from the chest down, where the half-zip is slightly more loose near the bottom.

Bobi Jo:



The half-zip is really more of a quarter-zip, but is the standard top with a zippered collar for a more casual look and ventilation function. Though both tops are long-sleeve, the one named that looks and feels more like a base layer. Both styles come in 3 colors: clover (a maroon red-ish color), peacoat (purple), or a classic black.


The half-zip provides a bit more room throughout the ribs and mid-section, allowing an additional base layer to be worn underneath for particularly chilly adventures. The long-sleeve version fits a bit more snug. Both styles are a thicker material, which is something to keep in mind if adding an additional outer layer.


The sleeves feel like an adequate length (especially for those of us who like additional length to cover the hands) and have a thumb hole for dexterity.

My only complaint about these tops is that the reflective strip along the upper arm reduces the stretchiness of the fabric in that localized spot, so it feels a bit tighter across the bicep.


Not only are both of these tops great for running, but I am looking forward to using them on ski and snowshoeing adventures for the upcoming snowy season. The BREATH THERMO® technology, exclusive to Mizuno, uses escaping body vapor to generate heat. Each also has 360 degree reflectivity as a safety feature in winter darkness, and flatlock seams to reduce rubbing and chafing.


Mizuno Running Tops $85 - $95



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Thank you to Mizuno for providing us with samples. Please read our transparency page for info on how we do our reviews.

About Author

We started the Run Oregon blog in February 2007, because felt like running in Oregon and SW Washington deserved more positive coverage. We also wanted to level the playing field so that small, non-profit races could compete with big events; and to support local race organizers.

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