Best Way to Train to Reduce 1.5 Mile Time by 1 Minute

I want to be a PTI in the army. I'm in the army already but to do this I need to run a mile and a half in under 9:30. I can do it in about 10:30.

What's the best training to do so I can get my time under 9:30 and how far should I run every day to be able to do this? Also, will changing my diet to become more healthy help me in getting this time and run fast?

Thanks

– Jenny, UK

Answer by Dom:
Hi Jenny, good on you for going after the PTI role — and you've asked exactly the right questions. You haven't told me how often you currently train or how long you've been running, so I'll need to stay somewhat general, but I'll give you as much specific guidance as I can. A one-minute improvement on 1.5 miles is achievable. It takes consistent training over several months, not weeks. I'd break my answer down like this:

1. Higher mileage — the foundation you can't skip
2. Speed variety — three types of session that will actually make you faster
3. Diet — the honest version

Higher Mileage: Build the Foundation First

Let me tell you the mistake I see most often with people preparing for the 1.5-mile test. They run three or four times a week, all at about the same pace, and wonder why they're not getting faster. The answer is almost always that they're not running enough total mileage, and most of what they do run is too hard.

The first step is to add one more running day. If you're currently running three times a week, make it four. If it's four, consider five. Most of that running should be easy — a pace where you could hold a conversation comfortably. I'd recommend reading the Building Your Base page to understand why easy running builds the aerobic engine that underpins everything else.

Your long run — once a week — should gradually extend. Work up to 5–6 miles at easy pace. It sounds counterintuitive to run 6 miles to prepare for a 1.5-mile test, but it works. The endurance you build on long easy runs translates directly into being able to sustain your race pace without fading. Build your mileage gradually — don't jump more than 10% per week. See the Increasing Mileage Safely page for practical guidelines on doing this without getting injured.

For reference: to run 1.5 miles in 9:30, you need to hold 6:20 per mile — that's 3:56 per kilometre. Your current pace of 10:30 is about 7:00 per mile. You need to find 40 seconds per mile. That doesn't happen through willpower on test day; it happens through months of progressive training.

Speed Variety: Three Sessions That Will Make You Faster

Once you have a solid base — which means being able to run 4–5 miles comfortably — it's time to add faster running. Each type of speed work stresses a different energy system, and you need all three in your programme.

Interval running is the most direct preparation. One session per week: 6 × 400m, each at around 1:33–1:35. That's roughly 3:53–3:58 per kilometre — right around your goal race pace — with 90 seconds of easy jogging between each repetition. This trains your legs and lungs to hold goal pace comfortably under repeated effort, so race pace starts to feel manageable rather than punishing. Check out the Interval Running page for more detail on how to structure these sessions.

Tempo running is equally important. Once a week, after a warm-up, run for 20 minutes at a comfortably hard effort — faster than easy but not gasping. This should feel like a 7 out of 10 effort. It trains your lactate threshold, which directly improves the pace you can sustain over 1.5 miles. See the Tempo Running page for a fuller explanation.

Goal-pace running is what ties it together. Once a fortnight, include goal-pace intervals in a session — for example, 2 × 0.75 miles at exactly 4:45 each (your 9:30 goal pace), with 2 minutes rest between. This teaches your body what race pace feels like when you're tired, not when you're fresh. Monthly, do a full 1.5-mile time trial to check your progress. If you can include some strides at the end of easy runs — 4 × 20 seconds of fast, relaxed running — those help too. The mix of all these — long easy runs, intervals, tempo, goal-pace work — is what will get you to 9:30.

Diet: The Honest Version

Yes, Jenny — diet will help. But not through anything complicated. Here is what actually matters.

If you are carrying extra weight, losing even 2–3 kilograms will make a noticeable difference to your 1.5-mile time. Running carries your bodyweight over every metre of the course. Less weight means less effort for the same pace. That's physics. See the Runner's Diet page for more on eating well as a runner.

Even if weight is not a factor, the quality of what you eat affects your training. Cut out alcohol completely during your preparation — it disrupts sleep, hampers recovery, and adds empty calories. Cut out junk food and processed snacks. Eat proper meals with enough protein (chicken, fish, eggs, pulses) to support the muscle recovery your body needs when you're running four or five days a week.

That's genuinely it. You don't need a complicated plan — you need consistency. Eat well, sleep well, train hard, and trust the process. With the right mix of mileage, speed work, and sensible eating, sub-9:30 is well within your reach.

Good luck with the PTI ambition, Jenny — it's a role worth working hard for.
Kind regards,
Dominique

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