N2 Trail Hiking
Route-Tested Since 2017
The Bonk-Risk Index™
A field-tested rubric built from 1,400+ miles of in-person route work, 312 products run through the Sierra Nevada gear lab, and 2,140 trail reports since 2017. Read the methodology, study the worked examples, and download the PDF — no medical claims, no mysticism, just the math we use ourselves.
Read the methodology
The scale, at a glance
Methodology
The index is not a vibe check. It is a weighted sum of seven input variables, each scored on its own scale and then folded into a single number. We publish every variable, every weight, and every source so you can argue with us — and you should.
Expenditure estimates start from the N2 route team's own HR/pace/power logs — 1,400+ trail miles per year across the same corridors we score. We do not run a clinical lab; we cross-check published exercise-physiology sources (Jeukendrup, Burke, ACSM Position Stands) and our own Sierra Nevada gear-lab food-matrix testing. Anything above Class 3 terrain, anything in active wildfire closure, or anything medical is explicitly out of scope.
The weighting is re-fit every January against the prior season's bonk-event log: every time a route tester bonked, we retroactively scored their pre-trip plan and re-ran a regression to update the coefficients. The current v6.2 weights reflect 312 gear-lab products and 847 scored plans.
A score of 67/100 (the JMT northbound, Day 4 example above) means the plan is publishable with a caveat — carbohydrate delivery is borderline on the Forester Pass climb, and the logistics subscore is dragged down by a long water carry. A 75+ plan is one we would hand to a friend without flinching. A sub-40 plan is one we would refuse to publish.
Worked examples from the 2024 field log
Each card below is a plan the route team actually executed in 2024 — the score, the two biggest risk drivers, and what we changed before publishing the next iteration. Verify trail conditions with the local land manager before you use any of these on actual trail.
Carbohydrate delivery plateaued at 58 g/hr on the climb — too low for the grade. Logistics subscore dragged by a 14-mile water carry across the dry bench. We re-cut the plan to a 4:1 maltodextrin-fructose blend and added a cached bottle at 10,800 ft. Re-score: 74/100.
Top risk drivers: CHO delivery, logistics.
The plan scored well on calories and electrolyte coverage but failed the palatability fatigue index by day 3 — three straight days of the same savory wrap matrix. Two testers reported voluntary intake dropping 31% by day 4.
Top risk drivers: palatability fatigue, gut tolerance.
Short enough that logistics nearly maxed the score. We tested a 90 g/hr CHO gel protocol starting at 12,500 ft; no tester bonked, but two reported GI discomfort in the last 800 ft — the altitude-gut variable still wants work.
Top risk drivers: gut tolerance at altitude, CHO delivery.
A clean small-plan score. The only deductions came from a lighter-than-ideal protein bolus on day 2 and a resupply that forced a 3.2-day food carry. Easy to fix on the next iteration — drop a 25 g protein shake at the cache and re-test.
Top risk drivers: protein adequacy, logistics.
FAQ
The weighting coefficients are re-fit every January against the prior season's bonk-event log. The current version is v6.2 (published Q1 2025). We publish a short changelog every quarter — even when the only change is a single coefficient drifting two points.
Baked in. Altitude is not a free-standing variable — it modulates carbohydrate delivery (the "gut tolerance at altitude" variable) and caloric match (resting metabolic rate climbs roughly 10–17% above 8,000 ft). Putting altitude in as its own column would double-count the same physiology and inflate the score.
Yes. N2 Pro members (6,400 paying readers as of Q4 2024) can submit up to four plans per year for a full scoring pass plus a written review from the route team. Free readers can submit a plan and we'll return the top two risk drivers within two weeks — no full re-score, but a useful sanity check. Email [email protected] with the subject line "BRI score request".
Three big things. One: medical-grade nutrition. We are a media outlet, not a clinic — anything involving diagnosed conditions, electrolyte prescriptions, or clinical refeeding is out of scope. Two: mountaineering above Class 3 terrain. We focus on Class 1–3 hiking. Three: real-time trail conditions. The score assumes the route is open; always verify with the local land manager before you go.
The Bonk-Risk Index is an editorial scoring system published by N2 Trail Hiking, LLC. It is built from public exercise-physiology sources, our own Sierra Nevada gear-lab testing, and 1,400+ miles of annual route work. It is not medical advice, is not FDA-evaluated, and is not a substitute for consultation with a registered dietitian or your physician — especially at altitude, on multi-day trips, or if you have a diagnosed condition.
The index also does not replace current trail information. Conditions, closures, and wildfire restrictions change daily. Always verify with the local land manager — U.S. Forest Service, National Park Service, or BLM — before you step on the trail.
— The N2 route team, Bend, Oregon. 11 Wilderness First Responder certifications between us, none of them a substitute for your own preparation.
Want the full plan in your pack, not just the rubric?
Get the Free 47-Page Trail PlannerIncludes the Bonk-Risk Index worksheet, the 847-plan dataset summary, and printable CalTopo overlays for the JMT, PCT, AT, and 12 Colorado 14ers.