DESPITE HEAT EXCHANGER MASKS BEING COMMON IN OTHER SPORTS LIKE XC SKIING AND WINTER ULTRARUNNING, AND THE PRINICPLES OF THEM COMMONLY RECOGNIZED, DEDICATED MASKS FOR USE IN SERIOUS COLD HAVE ONLY CREPT INTO HIGH ALTITUDE CLIMBING IN THE LAST FIVE YEARS OR SO.
IN THIS CASE WE WILL DEFINE ‘EXTREME COLD’ AS ANYTHING BELOW MINUS 10c, GIVEN THE CONTEXT OF ALPINE CLIMBING WHERE THE EFFECTS OF WIND AND ALTITUDE ARE ALSO PRESENT. IN ITSELF, MINUS 10c IS NOT PARTICULARLY COLD, BUT IS CHOSEN AS THE THRESHOLD BELOW WHICH HUMIDITY IS SO LOW AS TO HAVE AN EFFECT. CORRELATE THIS WITH WINDCHILL AND THE EFFECTS ON THE BODY OF ALTITUDE OVER 5000m, AND BREATHING COLD AIR BECOMES A SIGNIFICANT IMPACT ON CLIMBING.
THE OFTEN-FORGOTTEN PATHWAY OF HEAT LOSS IS ADVECTION, WHICH IS EITHER THE REMOVAL OF A HEATED COMPONENT OR THE INTRODUCTION OF A COLD ONE, AND IN THE CASE OF RESPIRATION IT IS BOTH. NORMAL RESPIRATION SWAPS OUT ABOUT 500ml OF WARM AIR FOR COLD WITH EACH BREATH, BUT EXERTION AT ALTITUDE IS FAR HIGHER, PUSHING TO AROUND 100L OF AIR A MINUTE. AT THAT RATE THERE’S NO WAY THE AIR CAN BE WARMED MUCH INTERNALLY, MEANING COOLED AIR IS EXCHANGED OVER THE LUNGS LARGE SURFACE AREA (ABOUT THAT OF A TENNIS COURT), MAKING IT A MAJOR SOURCE OF HEAT LOSS AND THEREFORE DEMAND FOR KCALS TO BE CONSUMED. HIGH BREATHING RATES SUSTAINED OVER EVEN SHORT PERIODS INDUCE AN ASTHMA-LIKE EFFECT, INFLAMING THE AIRWAYS ON TOP OF THE LOSS OF FLUID AND CORE TEMPERATURE. IN A WAY IT IS POSSIBLE TO ATTRIBUTE SOME OF THE RECOVERY FROM TIME UP HIGH AS BEING PARALLEL TO THE RECOVERY OF AN ASTHMA BOUT AND ALL THAT GOES WITH IT.
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XC SKIIERS IN ALL THEIR WISDOM AND OLYMPIC-LEVEL BUDGETS HAVE WARMED THE AIR THEY BREATH FOR DECADES IN THE SEARCH FOR INCREMENTAL COMPETITIVE ADVANTAGES. IT’S ALSO WORTH NOTING THAT XC COMPETITION IS POSTPHONED AT -20c BEFORE ANY REFERENCE TO WIND OR ALTITUDE IS INCLUDED, SOMETHING WHICH IS CONSIDERED SIMPLY NORMAL ON MOST TRIPS TO HIGH ALTITUDE.
THERE’S A LOT OF RESEARCH OUT THERE, AND STUDIES LIKE THIS AND THIS INDICATE THAT HEAT EXCHANGER MASKS HAVE A REAL EFFECT ON PERFORMANCE, THOUGH IT DOESN’T TAKE MUCH EXPERIENCE TO FEEL FOR YOURSELF THAT BREATHING WARMED AIR IS BETTER. BEYOND THE MICROCELLULAR EFFECTS INSIDE THE BODY IT IS CLEAR TO ANYONE CLIMBING IN COLD AND EXPOSED TERRAIN THAT WARM AIR AND A PROTECTED NOSE AND MOUTH RELATE DIRECTLY TO SURVIVAL.
WE DON’T ADVOCATE A SPECIFIC BRAND OR MODEL BUT WE DO ADVOCATE EXPERIMENTATION AS THEY ARE QUITE INDIVIDUAL. MOST ARE FAIRLY CHEAP THOUGH IT CAN HINGE ON IS THEY COME INTEGRATED WITH BALACLAVAS etc. FWIW WE PREFER STANDALONE MODELS, MOSTLY BECAUSE WE HAVE NOT BEEN IMPRESSED WITH EITHER THE MATERIALS NOR DESIGNS OF INTEGRATED ONES.
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WHAT ARE THEY?
AT THEIR MOST BASIC, HEAT EXCHANGER MASKS CREATE A SPACE OF WARMED, MOISTENED AIR THAT YOU BREATH THROUGH. THEY MAKE LOOK LIKE COVID OR DUST MASKS BUT ONLY SUPERFICIALLY, HAVING NO PROPERTIES TO FILTER VIRUSES etc, INSTEAD HAVING DAMPENERS THAT ALLOW EASY VENTILATION INWARDS BUT THAT CONTAIN SOME EXPIRED AIR ON EXHALATION.
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WHAT IS AND WHAT ISN’T A HEAT EXCHANGER MASK?
EVEN THOUGH BUFFS AND BALACLAVAS CAN FUNCTION LIKE HEAT EXCHANGER MASKS TO A POINT, THEY DIFFER FROM THE REAL THING IN THAT THE MOISTURE THEY TRAP CAN FREEZE AND RENDER THE THING COUNTER-EFFECTIVE. REAL MASKS ARE MADE OF MATERIALS THAT DON’T SATURATE AND OFTEN HAVE VALVES, THAT AVOID TRAPPING TOO MUCH CONDENSATION THAT WHEN FROZEN COMPROMISE AIR INTAKE.
MASKS TOO ARE SPECIFICALLY SHAPED, TO CREATE A VOLUME OF WARMED AIR SPACE, BOTH TO HAVE AN OPTIMAL VOLUME TO BREATH THROUGH THAT’S NEITHER TOO WET NOR TOO COOL, BUT ALSO TO MAKE A GAP BETWEEN SKIN AND THE OUTSIDE ELEMENTS. THIS MEANS MATERIALS LIKE FOAM, NEOPRENE AND 3D MESH, THAT DON’T COLLAPSE WHEN SATURATED OR FREEZE AND DISTORT.
REAL HEAT EXCHANGER MASKS ARE SEMI-RIGID AND DARTH VADER-LIKE, AND CAN BE EITHER STAND ALONE OR INTEGRATED INTO NECK GAITERS AND BALACLAVAS. MASKS FOR CLIMBING COVER BOTH MOUTH AND NOSE.
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WHAT MAKES A GOOD ONE?
NOT ALL HEAT EXCHANGER MASKS ARE GOOD FOR CLIMBING, WITH THE PRIMARY PROBLEMS BEING THE EASE OF VENTILATION, FOGGING OF LENSES AND COMFORT TO LIVE WITH.
MASKS MADE FOR MOTORBIKING, MILITARY AND OUTDOOR WORK ARE EASY TO FIND IN WORKWEAR STORES BUT DON’T USUALLY HAVE THE PERMEABILITY FOR THE INCREASED VENTILATION OF CLIMBING. THE MOST COMMON ONES TO MEET SPEC COME FROM THE COMPETITIVE SKIING AND CYCLING WORLD, AND SOME CLIMBING BRANDS MAKE NEOPRENE MASKS OF VARYING EFFICACY BASED ON HOLES RATHER THAN MECHANISMS LIKE VALVES.
EVERY MODEL WILL SAY THEIR DESIGN AVOIDS FOGGING UP GOGGLES, BY SEALING OFF UPWARD EXPULSION, BUT NO MODEL TOTALLY DOES. FOR ALL THE DESIGN FEATURES MEANT TO RESOLVE THIS, IT SEEMS THE THING THAT WORKS BEST ARE DUMP-VALVES, THAT EVACUATE AIR RAPIDLY, MORE SO THAN IT CAN FORCE UPWARDS.
SOME MODELS ARE MORE COMFORTABLE THAN OTHERS, WITH PERSONAL CHOICE BEING THE MEASURE OF IT. STRAPS CAN BE PROBLEMATIC, THE WAY THE MATERIAL CONTACTS THE FACE IS HIGHLY INDIVIDUAL, AND SOME SHAPES FIT DIFFERENT NOSE STRUCTURES THAT MAY MEAN HAVING TO MODIFY OR FORM THE THING YOURSELF. LIKE ANYTHING STRAPPED TO YOUR HEAD FOR LONG PERIODS AT A TIME, ANY PROBLEM WILL SURFACE BUT MAY BE HARD TO ADDRESS UNDER THE CONDITIONS.
DIFFERENT DESIGNS BLOCK WIND DIFFERENTLY, WITH SOME BLOCKING IT COMPLETELY AND OTHERS USING THE PERMEABILITY OF THE MATERIALS AS PART OF THE MECHANISM. 3D MESH IS USED IN SOME FOR THE WAY IT STABILIZES AIR, AS WELL AS ALLOWING SOME CONDENSATION TO ESCAPE AND AVOID POOLING AND REFREEZING. NEOPRENE HAS A GOOD SEMI-PERMEABILITY THAT AVOIDS POOLING, BUT SOME MODELS WE’VE TRIED HAVE HOLES SLIGHTLY TOO LARGE TO BE WINDPROOF, WHICH COMPROMISES BREATHED AIR TEMPERATURE A DEGREE AND STILL ALLOWS THE SKIN TO CHILL.
SEVERAL TYPES HAVE VALVES WHICH WORK IN DIFFERENT WAYS, EITHER DAMPENING INTAKE SO IT MIXES WITH TRAPPED WARM AIR, OR SHIFTING BETWEEN INHALING THROUGH THE MASKS FABRIC AND EXHALING UNIMPEDED TO AVOID FOGGING UP GOGGLES.
A GOOD HEAT EXCHANGER MASK YOU CAN LIVE IN, MEANING THEY ARE EASY TO EAT AND DRINK WITH MINIMAL FIDDLING AND DON’T REQUIRE TOO MUCH ATTENTION. DROOL VALVES THAT FREEZE HAVE BEEN A COMMON PROBLEM, AS HAVE BREATHING VALVES THAT CLOG, AND SOME MODELS ARE GREAT FOR SHORT SKI EVENTS IN GOOD WEATHER BUT DON’T COVER ENOUGH SKIN SO REQUIRE INTEGRATING WITH OTHER THINGS LIKE BUFFS.
THE BEST HEAT EXCHANGER MASKS – LIKE ALL HIGH ALTITUDE GEAR – HAS THE FEWEST MOVING PARTS AND PERFORMS BEST UNDER THE HARDEST DEMANDS. WE THINK STANDALONE MASKS MADE OF 3D MESH ARE THE SIMPLEST AND MOST IDIOT-PROOF AS THEY CANNOT BE DAMAGED.
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WHEN TO USE THEM?
BECAUSE THEY HELP MAINTAIN BODY TEMPERATURE WHICH RELATES TO ENERGY CONSUMPTION, HEAT EXCHANGE MASKS ARE USEFUL LIKE ANY OTHER METHOD OF STAYING WARM. THINK OF THEM LIKE YOU DO EXTERNAL INSULATION AND ADJUST OVER THE COURSE OF A DAY AND ACTIVITY LEVELS. A GOOD MASK WILL BE EASY TO CARRY AND PUT ON, BEST KEPT SOMEWHERE WARM FOR IMMEDIATE USE, AND SHOULD BE A GO-TO ANYTIME YOU FEEL YOUR BODY TEMPERATURE AT RISK.
SLEEPING IN A MASK IS A GOOD IDEA AS IT NEGATES THE URGE TO BREATH INTO YOUR SLEEPING BAG, BUT WITHOUT AMBIENT WIND YOU WILL COLLECT A DEGREE OF MOISTURE SO THE SMART CLIMBER CARRIES TWO.
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OVERALL, HEAT EXCHANGER MASKS WORK, AND FILL A REAL ELEMENT IN THE HIGH ALTITUDE CLIMBERS NEED TO STAY WARM. EVEN CLIMBERS WHO MAY NOT HAVE FELT THE DEMAND PREVIOUSLY MAY WELL FIND THEY SIMPLY DIDN’T RECOGNIZE THE HOLE IN THEIR SYSTEM, AND IT IS SOMETHING THAT IS ADDRESSED RELATIVELY EASILY AND CHEAPLY. THERE IS A LOT OF SCOPE FOR IDEAS AND GARAGE EXPERIMENTATION, AND THINGS SHOULD BE TESTED AT LOWER ELEVATIONS BEFORE COMMITTING TO UP HIGH.
