Increasing My Running Pace: Why the Long Run Is Your Fastest Route to a Faster 5k

I've run 8 5ks this year and lost 20 lbs. I'm still at a 13 min/mile pace in training (no walking) and about 12 min/mile in races (walking 2–3 minutes total). I run 4–5 days a week, doing 5–6 fast intervals on Tuesday/Thursday (2-mile runs) and hilly 3.25-mile runs Monday/Wednesday/Friday. I love it, but would like to see some improvement in speed. Am I being impatient?

– Margaret, Asheville NC

Answer by Dom: Margaret, you've done something genuinely impressive — 8 races and 20 lbs down in one year, with 4–5 days of structured running already in the mix. You're not being impatient at all; you're asking exactly the right question at exactly the right time.

1. Where you are now — and what a realistic next target looks like
2. Why extending the long run is the highest-leverage change you can make
3. How the long run actually improves your race pace (the mechanism, not just the advice)
4. A four-week building plan to get you there safely
5. What your existing speed intervals are doing — and when they'll start showing up in your times

Where You Are and Where You Can Realistically Go

At 13 min/mile in training and 12 min/mile racing with a couple of minutes of walking, your current 5k is probably landing around 38–40 minutes. A sensible near-term target is 35–37 minutes — running the full 3.1 miles without walking at around 11:15–12:00 per mile. That's a meaningful step forward, and it's achievable.

Here's the honest diagnosis: you're not slow, and you're not under-trained in terms of frequency. You're under-distanced. Your longest run is 3.25 miles — and a 5k is 3.1 miles. You're essentially racing at your training ceiling. When you're already near your maximum comfortable distance before the race even starts, holding a harder pace becomes very difficult. The effort budget runs out early.

Your speed intervals on Tuesday and Thursday are developing real leg speed. Your hilly MWF runs are building strength. Both of those things are working. The missing piece is a longer run that extends your aerobic ceiling — because right now, your ceiling and your race distance are almost the same thing.

Why the Long Run Changes Your Race Pace

Imagine you can comfortably run 5–6 miles. How does a 3.1-mile race feel by comparison? Considerably easier. You'd start it knowing you have plenty left — and that confidence alone changes how you run the first two miles.

But there's more than psychology going on. Longer easy runs build mitochondrial density in your muscles, improve fat-burning efficiency, and increase your cardiovascular stroke volume — meaning your heart pumps more blood per beat. All of these adaptations directly raise the pace you can sustain comfortably. Research on beginner runners consistently shows VO2max improvements of 15–25% in the first 8–12 weeks of building long-run mileage — that translates directly into running faster at the same perceived effort.

This is the principle behind base building: aerobic capacity is the ceiling on your race pace. Raise the ceiling, and everything below it improves. You can keep doing exactly what you're doing on your other days — the long run just needs to become longer.

Your Four-Week Building Plan

Keep your existing Tuesday/Thursday intervals and your hilly MWF runs exactly as they are. The change is simple: make one of your MWF runs your new long run, and extend it gradually each week. Run this long run at easy pace — 13 min/mile or even slower is absolutely fine. The goal is time on feet, not pace.

Week 1: Long run 4.0 miles (easy pace)
Week 2: Long run 4.5 miles
Week 3: Long run 5.0 miles
Week 4 (consolidation): Long run 4.5 miles — let the adaptation settle before pushing further

From week 5 onwards, continue building: 5.5 miles, then 6. See the increasing mileage safely page for the full guidance on this — the key rule is no more than a 10% increase in total weekly distance in any single week.

That 10% rule matters more than it might seem. Your muscles adapt to running relatively quickly. Your tendons and ligaments are slower — and they're what give way when you push too hard too fast. A small niggle caught early and rested for three or four days is nothing. The same niggle ignored for three weeks becomes a real problem.

Your Speed Intervals Are Working — They Just Need Backup

Your Tuesday and Thursday fast intervals are building neuromuscular speed — teaching your legs to turn over quickly and your body to handle harder effort. That's genuinely useful. But interval fitness without aerobic base underneath it is a bit like a powerful engine in a chassis that can't handle the road. The speed is there; the support structure isn't yet.

Once your long run reaches 5–6 miles, you'll likely find your existing interval sessions start producing more visible results. You'll recover between reps faster, you'll feel less wrecked after a hard session, and — crucially — you'll be able to hold a harder race pace for longer because the aerobic base is there to support it.

Don't drop the hills either. Asheville's terrain is a genuine training asset — hilly running builds the glutes, hamstrings, and calves in ways flat running doesn't, and it translates directly to stronger late-race form when everyone else is fading.

A concrete near-term goal: run your next 5k all the way through without any walking. Then aim for sub-37. Small, honest steps — but they add up fast.

Not impatient — you're doing this exactly right. Give the long run four to six weeks and I think you'll surprise yourself.

Kind regards,
Dom

Some Other Pages You May Like