Trying to Run Half Marathon: In Under 1:30

Hi, I am 18 years old and I've entered for my local half marathon, which is in 2 months. My goal is to bring my race time to below 1 hour 30 mins. At the moment, I have been training about 5 days a week, my average running length being around 3–4 miles, with 6–8 mile distances now and then. I can do 2 miles in 12 minutes, 3.1 miles in 21 minutes and 6 miles in 43 minutes. I feel that I should be able to run much faster than these times, as I also spend a lot of time cycling and doing other sports. Any advice you can give would be great, thanks. – Eliot

Hi Eliot,

Your times tell an interesting story — and honestly, quite an encouraging one once you know how to read it.

Here's what we'll cover:

1. What your pace data is actually telling you
2. Why sub-1:30 in two months is a stretch — and what is realistic
3. Building the aerobic base that closes the gap
4. Race strategy for your upcoming half marathon

1. What your pace data is actually telling you

Let me lay your times out so you can see exactly what I see.

Your 2-mile time of 12 minutes is 6:00 per mile — genuinely fast. Your 3.1-mile (5K) time of 21 minutes is 6:46 per mile. Your 6-mile time of 43 minutes is 7:10 per mile. Notice the trend: your pace slows as the distance stretches — 6:00 per mile at 2 miles, 6:46 at the 5K mark, 7:10 over 6 miles, a drop of roughly 24 seconds per mile between the 5K and 6-mile efforts alone. That is classic aerobic base deficit — your speed is real, but your aerobic engine is not yet big enough to sustain it.

Sub-1:30 for a half marathon requires holding 6:52 per mile for 13.1 miles. Your current 6-mile pace extrapolates to roughly 1:37 — so the gap is about seven minutes. That is not a fitness failure. It is simply the gap between a runner with good speed and a runner with good speed plus an aerobic base to match it.

Being 18 is a massive advantage here. Recovery is fast at your age, adaptation happens quickly, and the aerobic base you can build over the next 12 months will be extraordinary. The question is not whether you will get to sub-1:30. The question is how soon.

2. Why sub-1:30 in two months is a stretch — and what is realistic

I want to be straight with you rather than give you false hope. Closing a seven-minute half marathon gap in eight weeks requires both speed and endurance to improve simultaneously — and endurance adaptation simply takes longer than that. Your cycling and cross-sport background has given you a good cardiovascular base, but running-specific endurance at half marathon distance is a different thing entirely.

What is realistic in two months? With sensible training — which I will describe below — you could reasonably target 1:33 to 1:36. That is still a strong debut. At 18, with that 2-mile speed in your legs, you have everything you need to break 1:30 within the next year. Possibly sooner.

The mistake I see young runners make most often is piling on more hard sessions when their pace drops at longer distances. More intervals will not fix this. More easy running will. The aerobic base is what raises your pace at every distance — short and long — and the only way to build it is steady, progressive, mostly easy mileage. The trick is resisting the urge to run fast when you should be running easy.

For comprehensive guidance on what a proper training cycle looks like, the training for a half marathon page walks through structure and progression in detail.

3. Building the aerobic base that closes the gap

Here is what I would focus on over the next six weeks before your race — and beyond it into the following months.

Easy running should make up 80% of your weekly mileage. That means genuinely easy — a pace where you could hold a full conversation without any strain. For you right now that is probably around 8:00–8:30 per mile. I know that will feel frustratingly slow given your 2-mile speed. Do it anyway. This is where the aerobic base is built. Every easy kilometre you run is a brick in the engine that will eventually carry you to sub-1:30.

Build your long run progressively. You mention 6–8 miles now and then — let's make that structured. Over the next six weeks, build your long run from 7 miles to 10–11 miles, adding roughly a mile every 10–12 days. Run these entirely at easy pace. The goal is time on your feet, not speed.

Keep one weekly tempo session. A tempo run is comfortably hard — an effort you could sustain for roughly an hour if you had to. For you that is probably around 7:15–7:30 per mile currently. Start with 20 minutes at tempo effort, sandwiched between easy warm-up and cool-down running. This session teaches your body to clear lactate efficiently, which directly improves your pace at longer distances.

Do not add more hard sessions. I suspect you are already running hard on several days each week. That explains the pace drop-off at distance — you are accumulating fatigue rather than building base. Pull the easy days back to genuinely easy, keep one tempo session, build the long run, and watch your times come down over the coming months.

In the final two to three weeks before the race, you can add a couple of shorter race-pace efforts — a mile or two at 6:52 per mile to get a feel for the target rhythm. But do not overdo this close to the race; the key sessions are already done by then.

If you want to sharpen your speed for shorter distances alongside your half marathon build-up, the 10K running tips page covers tempo and threshold work that maps directly onto what you need here.

4. Race strategy for your upcoming half marathon

With two months to go and a realistic target of 1:33–1:36, here is how to run a smart race.

Start conservatively. I mean genuinely conservatively — 7:45 to 8:00 per mile for the first five miles. That will feel easy. It is supposed to feel easy. Half marathon races are routinely run by people who go out at sub-1:30 pace, feel wonderful through mile 6, and then disintegrate between miles 9 and 12. Do not be one of them.

Miles 1–5: warm-up. Settle in, find your rhythm, resist the pace of runners going past you. Miles 6–10: your main effort. Gradually pick up the pace if you feel strong. Miles 11–13.1: whatever you have left — and if you have paced properly, you will have a lot.

Use this race as a learning session. Notice where fatigue sets in, how your pacing held up, how your legs felt in the final miles. This information is gold for your next training block — and there will be a next block, because one race is not the story. At 18, you are just getting started.

Treat this half marathon as your baseline. Come back to it next year with six months of proper aerobic base behind you, and sub-1:30 will not be a stretch. It will be a formality.

You have genuine speed, Eliot. Now you just need to build the engine to hold it for 13.1 miles. That is entirely doable.

Kind regards,

Some Other Pages You May Like