Thermarest Prolite Apex Review

The Prolite Apex is an ultra-light sleeping pad that combines air channels with a self-inflating foam skeleton to create a warm, packable, and comfortable sleeping pad. This is my review:

The Prolite Apex is built around Thermarest’s StrataCore technology. This technology takes a foam center and sandwiches it between two layers of air channels, one on the top and one on the bottom. The foam center provides warmth and allows it to self inflate, while the air channels provide loft and extra cushioning. The sleeping pad is built from printed 50D polyester, has an R-value of 3.8 and the regular size (tested here) weighs 1 lb. 6 oz. It packs up to about 13″ x 7″ and retails for about $120 depending on the sizing.

What I liked

More than anything a sleeping pad needs to be comfortable, and comfortable this pad is. Sleeping on rather uneven ground with rocks, sticks and even lumpy soil underneath, I found myself completely unaware of the rugged earth below. Thanks to the two inch thick air channels the pad is able to absorb and counter rather large obtrusions, even smoothing out walnuts that happened to sneak into some leaves under my tent on one particular backpacking trip. I’ve found that the ribbed like structure provides cushioning and cradling at the peaks, while the foam core provides a nice amount of compression and weight distribution in the dips. This combination of padded highs and structural lows works out really well. Several mornings I woke up feeling more refreshed and less sore than I would have if I slept at home, which speaks volumes about it’s ability to distribute pressure and provide support. I generally find myself not tossing and turning nearly as much when using this particular pad, instead staying in one position longer, which results in better rest. I’ve tested it on stomach, back and side, and found it to work well in every position, especially the back and stomach.

Soft yet supportive structuring doesn’t mean much if you’re cold and can’t sleep anyway. Thankfully, that isn’t a problem here. The R-value of 3.8 (a measure of how well a material insulates) promises a warm experience down to about 15 degrees F, and that it delivers. While I haven’t tested below 15 degrees yet, I’m yet to feel any cold seep through the pad at anything above this level and I believe based on its performance so far it should suffice to about 10 degrees. It’s definitely a warm pad, but I never found it overly hot. It provides a rather excellent next to skin warmth, although Thermarest’s own Prolite seems to feel a little warmer, probably due to the small separation of body and the foam core due to the air channels.

Thermarest Apex Plus side image

Build quality on this pad is also exceptional. The 50D Polyester has held up great so far and feels fairly rugged in the hand. I’ve experienced no leaks or slow seeping of air even after having it inflated for months on end for testing. The seams are basically flawless and the material is extremely consistent, which speaks well for long term viability. Even the valve is sturdy with a solid feel and rugged seal baked in around it.

Inflating the pad is as simple as opening up the valve, rolling it out, and letting the foam core do most of the work. As the foam expands it will pull air into the pad, inflating it to a usable state without intervention. I do always add a couple of extra breaths to firm it up, but not having to manually inflate the entire pad with my lungs saves me a lot of time, work and exertion at camp, which I really appreciate. Deflating is also rather easy, even if the foam core does provide some mild resistance. I just open the valve, and start rolling the pad from one end to the other. Then, I use my body weight via my knees to squish out the last bit of air. I’ll often just fold the mat up from there and stuff it into the back panel of my pack, or even unroll it again, fold it long ways and roll it into a half sized roll for a smaller pack size. It’s a bit larger than a liter rolled up, but is still rather manageable in a pack as it’s foldable, rollable or even somewhat stuffable .

What I didn’t like

At 1 lb. 6 oz., the weight of the pad is what I would call sternly O.K.. It’s not exceptional, it’s not heavy, it’s right in the middle. It is light enough that it can be considered for long, multi-day backpacking trips but not light enough to really be called ultralight. I’m happy with the weight personally as it offers better comfort than anything I’ve tested that is lighter, but it is definitely heavier than most pads I’m testing these days. Comfort does require some sacrifices.

My only other ever so minor complaint about the pad is the same with every other self-inflating pad: Packing is a little slower and labor intensive when dealing with foam. The end packed result is a little larger than many other pads too. It’s not a big deal and has never bothered me personally, but it does require a little more work and thought to pack it into a smaller sized pack, especially as the foam does take up a little more space than pure air mats. It also does provides a little resistance as it wants to unfold unless kept under tension, especially if the valve is open (so keep it closed while being packed).


The Prolite Apex takes everything I like about my all time favorite sleeping pad, the Prolite Plus, and doubles down on the comfort elements. The tall air channels provide extra padding and creates a nice buffer from the earth, while the foam core still conforms to the shape of the sleeper while trapping precious body heat against the skin. It packs down fairly small and is realistically light enough for most backpackers, short of dedicated ultra-lighters. For those who prefer comfort over the absolute lightest pack weight, this is an exceptional choice and one of the most comfortable, and durable, I’ve ever tested.

Thermarest Apex Plus

Highly Recomended

For more information on the Thermarest Prolite Apex, check out our Amazon Affiliate Link here. This helps us out.

For information on our rating system and our testing procedures, check out our About us/ Contact us page.

I want to extend a huge thanks to Thermarest for providing this product for review. We couldn’t do it without their help.

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