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Mizuno Breath Thermo Review: Turning Sweat into Warmth!

Mizuno Breath Thermo logo

The Mizuno Breath Thermo Collection operates off of their patented Body Warming Technology. The fabric operates not only on its thickness, but is designed to "activate" once it contacts sweat and uses it to warm your body. As they say, "You work for your sweat. Now let your sweat work for you." Our team tested out various parts of the Breath Thermo line to offer their thoughts on the technology for your winter runs.


Ryan testing the Breath Thermo vest, wind gloves, tights, and Neck Gaiter
GENERAL IMPRESSIONS: I have been wearing Mizuno Breath Thermo clothing for the past 2 winters and it has become my go to choice for cold weather activities. I wear the clothing not only for running but also for winter fat biking. As there is a bit more wind flow during biking activities, I often wear a thin windproof jacket over the top of the breath thermal material. As the Breath Thermal material performs best with perspiration, I try to keep the breath thermal material close to the skin and layer over it.

Breath Thermo Vest: A (The Breath Thermo vest is designed to keep you warm when the temps dip down. The breath thermo technology works by turning your perspiration into heat keeping the body warm. The vest works well for colder temperatures in the spring and early winter when the temps dip down to the low 20s deg F and upper teens. When running in single digit temps I typically switch to the Mizuno Breath Thermo Jacket. There were a couple runs last winter when the temperature dipped to -10 deg F and the Jacket kept me warm only using a thin base layer underneath. The durability of the vest and jacket is also very good. I have washed them both many times and they continue to look new. The vest and Jacket have been a staple in my winter running collection and are the o outerwear pieces that I continue to grab during winter runs.)

Breath Thermo Tights: B+ (The Breath Thermo Tights fit slightly looser than your typically running tights but that didn't affect performance. They are best suited for temperatures above 15 deg F when worn alone. In colder temps, I typically wear the tights as a base layer and wear a thicker jogger over the top. The Breath Thermo material is comfortable and feels soft against the skin. For those individuals working out in the darkness, the tights have small reflective decal over the sides making them more visible at night.)

Breath Thermo Wind Gloves: B- (The wind gloves are a mid weight glove with a thin layer of added wind protection on the dorsal side of the hand. The material used for the wind protection is not as warm or as comfortable as fleece. The wind gloves perform best in temperatures above 30 deg F while running in windy conditions. It was challenging to find a time when the wind gloves were a better option compared to the breath thermo fleece gloves which were more comfortable. My recommendation would be to increase the thickness of the breath Thermo material and keep the layer of wind proof material over the fleece. This would allow the gloves to be used in colder weather but add a layer of protection against the wind.)

Breath Thermo Neck Gaiter: A- (I found the Breath Thermo neck gaiter much more useful than I thought I would. I chose to wear it when I needed an extra layer of protection but felt like the Balaclava was too much. The top of the gaiter has an elastic rim that allows it to be pulled up and over the nose and mouth when needed. The material is easy to breathe through and is unnoticeable when breathing heavily. This is a piece that I will continue to reach for throughout the winter.)Breath Thermo Balaclava: A (When the temperature dips down into single and negative digits I bring out the Breath Thermo Balaclava. The Balaclava provides warmth over the top of the head as well as the neck. It can be worn alone or as a base later as it sits very close to the skin. On very cold days, I wear a hat over the top of the balaclava comfortably for extra warmth. The material around the mouth is slightly thinner and allows some air to pass though making it easier to breath. I have found that other balaclavas I have used restrict too much air and make it more challenging to breathe. This was not an issue when using the breath thermo material. The Balaclava stays well formed to the face and head and it is easy to pull down over the face if you become too warm.)

FAVORITE PIECE: Breathe Thermo Jacket and Vest. The Breath Thermo vest and Jacket are my two favorite pieces while the Balaclava comes in at a close second. Both the jacket and the vest are comfortable, warm, and durable and have become my go to outer layer as the temperature declines. Their durability is fantastic as they have each been washed many times and continue to display no signs of wear. The jacket and vest both fit slightly long and loose but it does not affect running motion and I actually prefer that as it is easier to layer depending on the weather.

Mizuno Breath Thermo on runner
Megan testing the Breath Thermo tights, vest, head band, and gloves.
GENERAL IMPRESSIONS: The Breath Thermo line has become the one of the first things I reach for when getting ready to run on cold, winter days. The vest, tights, and headband have become staples in my winter running wardrobe providing a lightweight, durable, and breathable option. The unique breath thermo thermal technology holds true to its goal of generating and keeping in body heat.

Breath Thermo Vest: A (The Breath Thermo Vest is a lightweight, breathable top-layer that is great in cold weather conditions ranging from late fall (~45deg) into winter temps (<35deg) With a thick base layer, this vest is the perfect addition to keep a warm core temp in the temperatures down to 10-15deg. Zipped all the way up, the collar extends up right below the chin, keeping your neck warm. The hand pockets and chest zipper pocket provide a lot of storage options for keys, gloves, gels, etc. )

Breath Thermo Tights: B+ (The tights use Breath Thermo thermal fabric technology which uses body vapor to generate heat. These tights perform best in colder conditions (<25 deg and even down into the single digit temps) due to the fabric’s technology. The material is slightly thicker, however it maintains comfort and mobility making these a good option for cold-weather workouts. The side pockets have depth and are convenient for storage; however, because they aren’t sewn down into the fabric, they occasionally have to be flattened out to avoid irritation/rubbing on the leg. They are slightly longer in terms of fit - I would go with a size smaller than normal with these in the future.)

Breath Thermo Headband: A- (The Breath Thermo headband uses the same thermal technology to use escaping body vapor to generate heat. The headband is an excellent option to use as an ear warmer in any cold-weather conditions (I wore it down to 15deg, so far). The fabric is thin as well, which makes it possible to be used as a base underneath a hat or underneath a headlamp (for all the early morning/late night runners out there).)

Breath Thermo Wind Guard Gloves: B- (The Wind Guard gloves fit true to size, are lightweight, and are snug around the wrist which assists in keeping body heat in. These gloves are good in mild winter conditions (25-35deg) and as a lightweight option for longer runs and/or workouts. The gloves lost points as they didn’t prove to keep my hands warm in temps of 25 degrees or below (most winter days in the Northeast). With any wind involved, my hands got cold pretty quickly. I recommend trying these with a base glove layer underneath to keep the hands warm.)

Breath Thermo Socks: A- (Excellent option for colder runs to keep the feet and ankles warm. The socks also utilize breath thermo thermal technology using body vapor to generate and keep heat in. Many cold-weather socks tend to come with increased thickness of the fabric affecting shoe fit; however, the Breath Thermo socks are able to do the job without adding thickness. They fit true to size with slightly extra padding around the heel and forefoot. Extending ~3” above the ankle, they are perfect to fit underneath a base layer, preventing escape of heat.)

FAVORITE PIECE: Breath Thermo Vest. The Breath Thermo Vest is my favorite piece of this line. It is a versatile top layer effective in temperatures ranging from ~45 degrees (paired with a thin base layer) down to <15 degrees (paired with a thicker base layer and/or additional long sleeve). It maintains core body temperature while also being lightweight, breathable, and durable. When fully zipped, the collar extends high enough to keep your neck warm. This piece will continue to be a staple in my winter running wardrobe for all types of runs.

Andrea testing the Breath Thermo tights, jacket, wind gloves, and head band.
GENERAL IMPRESSIONS:  I really enjoyed testing the Breath Thermo line. The clothing actually does what Mizuno claims it to do, which is to turn your sweat into heat and keep you warm in cold weather. I also find it to be very breathable, which is not the case for a lot of winter running clothing. There is nothing worse than being out on a longer run and getting cold because your sweat is weighing down your base layer. I am really impressed with how warm the fleece gloves are, considering how thin the material is. These items are now a big part of my favorite winter clothing, which is greatly needed in the unpredictable CT winters.

Breath Thermo Jacket: A
This jacket has become my favorite cold (<25F) weather running jacket. It is extremely warm, lightweight, and vents extremely well. I wore this jacket for some threshold intervals in 20F temps and definitely found the sweet spot of not being cold or sweaty. The pockets are well placed and I particularly like that it includes a front chest pocket. I like that the wrist cuffs are fitted, which allows me to wrap my watch around them instead of having to roll up the sleeve to see the watch.

Breath Thermo Tight: A- The tights are very warm and are best for below freezing temperatures. The side zippered pocket is perfect for a key or gel and more easily accessible than a rear waistband pocket. They fit slightly loose, but not to the point that they affect performance. My one dislike about these tights is that the waist is very high. I have a long torso and the waistband extends above my belly button. Some people prefer very high waisted tights, but I would prefer these tights to sit a little lower.

Breath Thermo Wind Gloves: A- The wind gloves are lighter weight gloves that I found worked best in 35-45F temperatures. I was most aware of the Breath Thermo technology in the gloves that I tested. When I started my runs, my hands were cold, but as the run went on I definitely could feel the gloves trapping my body heat and warming up my hands. These gloves also do not get as sweaty as other gloves because they seem to vent better than most.

Breath Thermo Fleece Gloves: A These gloves surprised me with how well they perform. They are very lightweight and soft, which made me think that they would not be very warm. They far exceeded my expectations and I have really enjoyed wearing them for runs between 30-40F and particularly interval workouts. They keep my hands warm without getting sweaty. The wrist cuff fits securely and comfortably. I would definitely choose these for a race in colder temperatures due to their warmth and breathability.

Breath Thermo Headband: A-
The Breath Thermo material really shines in this piece. It is thin, lightweight, and versatile in temperatures from the 30s down to the teens. Headbands tend to get sweaty and feel cold on longer runs, but I did not experience this with this headband. It is also not as wide as most running headbands, which I found to be quite comfortable.

FAVORITE PIECE: Breath Thermo Jacket. The jacket is my favorite piece because of its versatility, breathability, and lightweight material. Jackets for temperatures below freezing are often bulky and do not breathe well. This jacket outperforms every other winter jacket I own. I also appreciate the smaller details - the chest pocket and fitted cuffs add to its performance and convenience during workouts and longer runs. I love the electric blue color, which improves visibility, but is not the typical neon yellow hi-viz option. This is now my go-to cold weather jacket for easy runs, long runs, and intervals.

Nathan testing the balaclava and beanie.
GENERAL IMPRESSIONS: Mizuno did a great job assembling gear for the colder temperatures, and the Breath Thermo technology did very well. A direction I'd love to see Mizuno go would be to add additional visibility components, especially since days are shorter in the winter. There is some reflective components to all the gear, but expanding this would really improve the line.

Breath Thermo Long Sleeve: B+ (If I could go back, I would order a small. The top fits a bit loose throughout the chest and torso and the length went below the glutes completely (very long). Since I see this functioning as a base layer and only layering on top of the shirt (not underneath), I would want to size down to get it to be a bit more snug, particularly since there is good stretch to the material. Speaking of stretch, the feel of this shirt is overall quite comfortable. It isn't the softest shirt you will put on as you can feel the Breath Thermo stitching when putting it on, but it does not scratch or itch when running. Finally, the underarm is constructed with a softer material, which avoids irritation in more sensitive areas.

A thicker base layer like this is best (in my opinion) when it can keep the torso warm. The Mizuno Base Layer Long Sleeve does a great job at this task, and it really is because of the action of the Body Warming Technology. What this means is that until you start sweating, it'll feel like any other base layer you've used. However, the way it utilizes your sweat to warm is effective, and I found myself sweating more once things got going because I really would warm up. This leads to one piece to be aware of. Because it uses your sweat to warm you, I did find the shirt would be a bit more wet by the end of the run (and therefore my skin as well). This did not cause any problems with rubbing or irritation, but is something to know going in to using this base layer.)

Breath Thermo Vest: A- (The FZ Vest fit me very well. It is also on the slightly loose end, but this works well as it works best over a base layer underneath. The width of the shoulders will cover the entire length of the shoulder to keep things warm, and the length sits a few inches below the waist line, keeping it from letting any cold air in from below pretty well. The vest is also comfortable and flexible, with a softer material underneath and a wind resistant material that allows movement with ease.

This vest does its job overall, which is to keep the core of the body nice and warm. The wind resistant exterior and Breath Thermo internal construction provide protection from the cold and still allows the material to heat your body using your sweat. One area for improvement would be to synch up the lower part of vest or have some sort of drawstring to allow people to close up the opening under the vest depending on body type. The other thing to note is that once you layer too much underneath, you will no longer get the effects of the Breath Thermo technology, but just the effects of the thickness of the vest and wind resistant outer construction. That said, the beauty of the Breath Thermo technology is that you can get the same warmth with less combining the Breath Thermo Base Layer and this Vest was the perfect combination for me, even in the low teens (deg F). The FZ Vest also has pockets that function well for carrying gloves or a hat when things warm up throughout the run.

If you live in a more mild climate and haven't tried a vest vs. jacket, I really think this is a great vest to check out. For people who live in places like me (Stevens Point, WI), you'd likely need to get a running coat of some kind in addition to this vest to make it through the whole winter, so you'd have to weigh your value of having a vest for some more mild days and a coat for the more extreme days. )

Breath Thermo Half Zip: B (There’s no mystery to me after two years of testing and wearing Breath Thermo gear that this stuff really does well in colder weather. I’ve used the Long Sleeve for over a year and it functions really well for anything in the 20 deg F and below as a very warm base layer. The Half Zip takes the base layer function and dials it up a notch, and I’ve done runs in the upper teens with only this and another long sleeve underneath. The problems I’ve had with the Half Zip, which I haven’t with other Breath Thermo shirts or gear, is that I’ve gotten “lines” forming after only 1-2 washes where I followed cleaning instructions. Although it has not worsened with subsequent cleaning, that is something I think should be improved upon. Also, the stitch across the chest was slightly abrasive when wearing a thin layer underneath. Fit is much improved over last year’s Long Sleeve which was very long, and I would say fits true to size and slightly on the looser end, which is useful for layering.)

Breath Thermo Wind Gloves: C- (The best part of the Breath Thermo line is the accessories like hats, gloves, etc. My favorite pair of running gloves is the Breath Thermo Fleece gloves. I use them for all my gold weather running from -20 deg F – as a base under my windproof mittens – up to the 20-30 deg F runs. They are comfortable and once the Breath Thermo technology activates with sweat, they are warm yet breathable enough to not make your hands a sweaty mess. The Wind Gloves were a miss for me. Despite the windproof nature, they do not allot for any additional warmth independent of another glove layer compared to the Fleece. They are thin and form fitting to the hand, and the windproof material is less comfortable than the fleece and given the form fitting nature you cannot layer anything underneath. In other words, I found the functionality to be the same as the Fleece gloves, just less comfortable. I’d love to see the Wind Gloves be bolstered up a bit so that the temperature range they work best in is differentiated more from the other glove options.

Breath Thermo Balaclava: A- (My typical winter running includes a beanie hat, with another layer if really cold, and a buff that I use for face coverage when it gets really cold. The Breath Thermo Balaclava is great for many reasons. First, it covers both of those bases as it gives a thin “beanie” coverage over the head and ears and a face covering. The face covering is more breathable than the other material, but given that the fibers activate on moisture, it heats up quickly. The thinner face coverage also stays shaped really well and doesn’t get sucked into your mouth when breathing heavily, which is an issue I have with buffs from time to time. It’s also easy to layer more hats on top of the Balaclava when it gets colder. It also functions well if you pull down the face covering and only use the head covering or pull down the head covering portion and only use the face covering. It stays in place well any way you set it up. Additionally, it covers the neck and keeps that warm as well. Only place to improve is the comfort of the seam between the head and face covering. If that could be thinned slightly, it would be that much more comfortable.)

Breath Thermo Socks: A (I think that these socks have the highest value for me. There are lots of tricks out there for keeping feet warm in the winter (like using some duct tape to block wind from getting through the upper), but these socks kept my feet toasty in any shoe that I wore without modification.)

FAVORITE PIECE: Breath Thermo Balaclava. The Balaclava is a versatile, well fitting, head, face, and neck warmer that allows for layering over the top when it’s really cold and easy adjustments during the run if things warm up and you need some of that cool winter air on your face or head. It functions as the perfect base layer and does the job of three different pieces of running accessories on colder days (beanie, buff, neck gaiter). It has been a surprising mainstay in my winter running gear

David in the Breath Thermo Jacket and wind gloves
GENERAL IMPRESSIONS: Overall I enjoyed the Breath Thermo collection of apparel. The largest takeaway from the larger garments like tights and jackets is that these pieces don’t mess around when it comes to temperature. They are certainly designed for colder conditions. Where I live we get cold mornings but usually not too windy and not something I want to keep on for full sessions so the collection works great for warm ups.

Breath Thermo Jacket: B+/A- (The jacket fits true to size, though I went a size down to SM. Outside of having the armpits fitting a little tighter all of the dimensions are on point. The jacket does a great job of keeping me warm both statically and dynamically. The jacket really comes alive with movement and will keep most warm even in pretty harsh conditions. It is a great balance of lightweight, wind resistance, and warmth.)

Breath Thermo Tights: A- (Overall the tights work really well for their intended purpose. The tights are a little more loose fitting than some other tights I have had in the past, but still hold on the contours of the leg well enough. There is some excess space through the knee and calf areas and so this works really well for warmups but I am not sure I would like it on for full workouts. The Breath Thermo technology works great for keeping the legs warm though.)

Breath Thermo Wind Gloves: B (The wind gloves execute their job really well in that they do indeed block wind. When running over the Ben Franklin bridge with a sharp wind across the river my hands were totally fine. They kept the hand warm and don’t seem to overheat too quickly which is nice. The palmar aspect of the gloves are comfortable but do seem to be a little inconsistent with the rest of the glove. I would like it to maybe have a tad more thickness or texture for grabbing things since I find I wear these much more in adverse weather conditions rather than just cold conditions. Note: I have not taken these under 30 degrees yet, but over 30 it seems to work well.)

Breath Thermo Knit Gloves: B (The knit gloves are definitely cozy. I find myself wearing these the most. The material is a performance like knit that is soft and almost mitten like but still is breathable enough for running efforts. These certainly are not the most weather resistant and I wear them more just for cold mornings or being cozy around the home on cold days. There’s a lot of versatility here. My main recommendation is the dimensions of the glove. The finger length seems to run short while the wrist portion runs long, requiring me to roll it a tad so it doesn’t push into watch buttons.)

FAVORITE PIECE: Breath Thermo Tights.
 My favorite piece would have to be the tights. These have a large comfort factor for me and keep my legs very warm even when its at its coldest here in Santa Barbara (yes it can still get cold here). If I wear them for the whole effort it is usually an easy day on a cold morning but I normally lean on them for warming up for track sessions or workouts.


GENERAL IMPRESSIONS. The Breath Thermo line features genuinely fantastic technology, perhaps some of the best Mizuno has to offer. The warming technology works incredibly well and will absolutely keep runners warm in any climate. The line itself is best for those who live in particularly cold regions that will get a lot of use out of hte items. For those who live in warmer climates, one or two pieces, however, will go a long way towards covering any winter runs you may have a few times a year which means great value long-term.

Breath Thermo Half Zip: A-
(The half zip has one main function: keep you feeling super warm in freezing temperatures. I felt this performed incredibly well at the job in sub-freezing temperatures. The technology absolutely works, almost too well. This is something I highly recommend for people living in temps well below freezing where the value really shines. If you live in a warmer climate, however, and are looking for something to cover cold mornings and those rare days below freezing, this is a good do-it-all that will cover a lot of your winter runs. Half size down recommended for snug fit, otherwise true to size for relaxed fit.)

Breath Thermo Vest: B+/A- (The vest does an incredible job at keeping your core warm. The vest does run a half size large and I would recommend a size down (and for Mizuno to make an extra small). I found the vest best in a very specific temperature range of 35-45 degrees, with long runs in the 45 degree weather to be fairly warm by the end of the run. Anyone who gets warm easily will be able to take this sub-freezing into the mid-20s and likely still be fairly comfortable.)

Breath Thermo Beanie: B- (There’s a big pro and big con. The pro is the beanie is incredibly toasty and features comfortable material. The con is that it fits VERY snug. I personally like a looser fitting piece of headwear and found this to be too tight on my head, which is average sized)

Breath Thermo Knit Gloves: A- (These gloves are absolutely perfect for winter runs. They warm up nicely, have a nice fit and on hand keeps you feeling relatively nimble. Despite how relatively thin they are, I found them to be quite warm and very good at keeping the hands toasty. Due to the technology, they can run quite warm mid-run, but I have no problem taking them off and folding them away into my belt or pocket)

FAVORITE PIECE: Breath Thermo Half-Zip. I thought I would be using the vest the most, but I found myself picking up the half zip for cold mornings time and time again. The material is soft and comfortable and I enjoyed the thumb holes for days where I didn't feel like running with gloves. The technology keeps you warm and comfortable, and I was able to pair it with my lightweight Mizuno Alpha Eco gear to get a good balance of layering and keeping my body temperature at good level through my daily mileage.

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