Race-day execution guide

Pacing Your Boston Qualifier Marathon or Sub-5 70.3

A race-week reference for age-group athletes who've done this before and are chasing a specific number: a Boston Qualifying time, or a sub-5:00 half-Ironman finish.

On this page

  1. Current Boston Qualifying standards
  2. Marathon BQ pacing: the three phases
  3. Marathon fueling
  4. 70.3 pacing by discipline
  5. 70.3 fueling

Current Boston Qualifying standards

These are the active B.A.A. qualifying times. Hitting your standard gets you a registration window, not a guaranteed entry — recent years have required beating the standard by an additional buffer to actually get in (4:34 in 2026, 6:51 in 2025). Plan to run faster than the number in this table, not to it.

Age groupMenWomen / non-binary
18–342:55:003:25:00
35–393:00:003:30:00
40–443:05:003:35:00
45–493:15:003:45:00
50–543:20:003:50:00
55–593:30:004:00:00
60–643:50:004:20:00
65–694:05:004:35:00
70–744:20:004:50:00
75–794:35:005:05:00
80+4:50:005:20:00

Source: B.A.A. qualifying standards. Standards are reviewed periodically — confirm your exact cutoff on baa.org before you commit to a goal race.

Marathon BQ pacing: the three phases

Every reliable fast marathon is run in negative or even splits — nobody runs a BQ off a positive split. The plan below assumes you already know your goal pace (your BQ standard, divided across 26.2 miles, minus whatever cushion you're targeting).

Miles 1–4

Run slower than you want to

Target 5 sec/mile slower than goal pace. This is the single most common place a BQ attempt dies — adrenaline and a fast field make goal pace feel easy in mile 2. It isn't. Fifteen seconds per mile too fast in the first 5K costs 10–15 minutes in the last 10K.

Miles 5–22

Settle into goal pace and hold it

Build to exact goal pace by mile 5 and hold it through mile 22. Take in fuel every 45–60 minutes starting early — don't wait until you feel like you need it. Check your split at the half: you want to be within 30 seconds of your target time at 13.1. If you're not, this is where you adjust, not at mile 20.

Miles 23–26.2

Take back the time you banked

Target 5 sec/mile faster than goal pace if you've got it. Break the last 5K into pieces — mile 24, mile 25, the final 1.2 — rather than thinking about the whole thing at once. This is where the conservative start pays for itself.

Marathon fueling

Fuel on a schedule, not on feel — by the time you feel like you need carbs, you're already behind. Start at 45–60 minute intervals from early in the race, and rehearse your exact fueling plan (brand, timing, water vs. sports drink) in training long runs before race day. Race day is not the day to try something new.

70.3 pacing by discipline

The 70.3 is won or lost on the bike. Go out too hard there and the run — the leg with the least room to hide pacing mistakes — falls apart. The effort targets below are for a sub-5:00 finish; use whichever metric you actually train with.

SegmentPower (% FTP)Heart rate (% threshold)RPE (1–10)
Swim——7–8 first 5 min, then settle to 6–7
Bike83–84%88–92%6
Run—90–92%5, easing to feel after halfway
Bike effort should be smooth and constant — no surges on hills or in headwind sections. Chasing speed instead of effort is how a good bike split turns into a run that falls apart at mile 8.

Effort targets adapted from published half-distance triathlon pacing guidance (MyProCoach). Your actual numbers depend on your tested FTP and threshold heart rate — these are relative targets, not absolute paces.

70.3 fueling

Aim for roughly 60g of carbohydrate per hour starting on the bike, from a mix of gels, chews, and sports drink — whatever you've already trained your gut to handle. Drink to thirst rather than forcing a fixed volume; a 2–4 lb bodyweight loss by the finish is normal and fine. Sodium rarely matters unless you're a known heavy/salty sweater or racing in serious heat — don't overthink it if you're not.

Fueling guidance adapted from TrainingPeaks.

Your paces change as your fitness does

These are starting targets. Nduro's AI coach recalculates your actual goal paces and effort zones off your real HRV, sleep, and training data — and adjusts your plan in the weeks before race day instead of leaving you to guess. Two-plus races in, chasing a BQ or a sub-5 70.3? That's exactly who it's built for.

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