Sugoi, a Vancouver-based apparel company, calls its pricey new Majik shell “an elite waterproof jacket that offers amazing breathability.” But after testing this aerobic-sports jacket for a month, I call that an exaggeration that verges on fib.

To the point: No other comparable jacket I have tested keeps so much moisture inside, collecting droplets of sweat along its smooth inner fabric to actually pool in the sleeves after 20 minutes on a run.

Indeed, at home after a 45-minute run in cool weather I could literally pour accumulated moisture out of the sleeve, my sweat pooling in the drooping fabric under my forearms. It sloshed there with each stride and movement of my arm, and when I pointed a hand toward the ground droplets trickled out and splashed on the sidewalk.

In the chest pocket, a hand-size compartment with a waterproof zipper, moisture accumulated enough to soak a stashed fleece hat.

New this fall, the Majik (www.sugoi.com) comes in a men’s and women’s model and costs $170. It is marketed as the result of Sugoi’s “quest for truly waterproof laminate protection for aerobic activities.”

The conundrum of creating a waterproof shell that breathes enough for aerobic activity is one of the great unsolved mysteries of the outdoors world. Say you want to run in the rain or sleet. You need a waterproof shell to keep you dry. But your body pumps out sweat, creating its own weather system inside the shell fabric.

No fabric technology I know of — not Gore-Tex, not eVent, and especially not the polyurethane-based Sugoi fabric — can wick sweat or transfer moisture fast enough to compete with a body in aerobic motion. Get your heart rate above 140 beats-per-minute and stride like that for a mile or more through the rain or sleet. You’re going to be wet — from the inside with sweat or from the outside via the elements above.

The solution lies in regulating body temperature. This is possible in the winter, when cold temps combined with the right type of ventilating outerwear can acquiesce a tenuous equilibrium between the body overheating and the skin or your core getting too cold.

In rain and sleet I have found it’s almost impossible to stay dry. This isn’t a concern for a nightly training run. You can come home and shower or change. But on long outdoors endurance events that mix aerobic output into a wilderness survival scenario — adventure racing, as one example — too much sweat can soak a body to the edge of hypothermia.

For now, when I race or do a long training run, I’ve surrendered to staying wet. I try and keep warm when I stop, but usually if the weather is bad you just cannot stop for long before the cold starts to creep.

Jackets like the Majik serve as a layer of protection from wind and water. You can hunker down and stay warm if you’re at least somewhat dry inside. The Majik and its ilk also work fine for biking, where wind cools you, or during moderate aerobic output like hiking or jogging.

But for running, I found the high-priced Majik to be far from mystical. Hocus pocus, maybe. But not magic.

—Stephen Regenold writes the weekly Gear Junkie Scoop for Outsidemag.com and TheGearJunkie.com.