How long does it take to train for a 45-minute half marathon?

Most runners need 8–12 weeks of structured training, assuming a base fitness of running 25–30 kilometres per week comfortably. If you're starting from a lower fitness level, add 4–6 weeks of steady base-building first.

Can I run a 45-minute half marathon on four runs per week?

Yes, if those four runs include a long run, a tempo or threshold session, a speed session, and an easy run. You'll need 40–50 kilometres total per week; if you can't fit that in four runs, you're likely not yet ready for the 45-minute mark.

What's the difference between pace and effort in half marathon training?

Pace is speed (e.g. 3:26 per km); effort is how hard it feels. A 3:26 pace might feel easy for one runner and hard for another. Use both metrics: pace tells you if you're hitting your target, effort tells you if it's sustainable. If the pace feels unsustainable, your goal pace may need adjustment.

Training 13 Oct 2026 7 min

45 half

A 45-minute half marathon requires a 3:26 per kilometre pace—fast but achievable with structured training. This guide covers the pacing strategy, weekly mileage, and key workouts needed to break 45 minutes.

What pace do you need for a 45-minute half marathon?

A 45-minute half marathon is 21.1 kilometres in 45 minutes, which breaks down to 3:26 per kilometre or 5:34 per mile. This pace sits between a solid club runner and competitive standard, demanding consistent speed work and aerobic fitness.

Weekly training structure for sub-45

Most runners targeting 45 minutes train 40–50 kilometres per week, spread over four to five runs. Build this volume gradually over 8–12 weeks, then sharpen with shorter, faster work in the final three to four weeks before race day.

Easy base run: 45–60 minutes at conversational pace, twice weekly
Threshold or tempo run: 20–30 minutes at race pace or slightly faster, once weekly
Long run: 16–18 kilometres, one per week, at comfortable aerobic pace
Short speed session: 6–8 × 800 metres or 10 × 400 metres at 5K pace, once weekly
Recovery run: 30–40 minutes very easy, one or two per week

Key workouts to build speed

Speed work is non-negotiable for a 45-minute half. Focus on sustained efforts at or just faster than your goal race pace, plus some shorter intervals to boost neuromuscular power and VO₂ max.

Tempo runs: 3 × 8 minutes or 2 × 12 minutes at 3:20–3:24 per kilometre, with 2-minute recovery jogs
Cruise intervals: 3 × 10 minutes at goal race pace (3:26 per kilometre) with 90-second rests
Ladder repeats: 400m, 800m, 1200m, 800m, 400m at 5K pace, jog recovery between efforts
Long-run surges: steady 16–18 kilometres with three 2-minute pushes at 3:15 per kilometre in the middle third

Pacing strategy for race day

Start conservatively in the first two kilometres—aim for 3:30 per kilometre to settle into your rhythm and conserve energy. Move onto goal pace (3:26) from kilometres three to 16, then push slightly harder in the final five kilometres if you feel strong. Negative splits (running the second half faster than the first) reduce injury risk and psychological fatigue.

Nutrition and hydration

A 45-minute half demands steady fuel. Practise your race-day nutrition in training: take on 30–60 grams of carbohydrate per hour (via sports drink, gels, or energy food) and sip water or electrolyte fluid at every opportunity. Train your gut to handle your chosen fuelling strategy weeks in advance.

Common mistakes to avoid

Starting too fast: adrenaline makes the first kilometre feel easy; stick to your pacing plan
Skipping easy runs: building aerobic base reduces injury and improves race-day resilience
Neglecting strength work: core, glutes, and calf strength prevent breakdown in the final kilometres
Undertesting pace: know your threshold and 5K pace before race day; don't guess on the start line

Data-driven training and adaptive pacing

Modern running apps like RunV track your pace, heart rate, and effort across every session, revealing which workouts build speed most efficiently for your fitness profile. By logging your threshold pace, long-run pace, and 5K repeats, you gain real-time feedback on whether your current intensity is sustainable—or whether you need to adjust your target pace or training load. This personalised feedback loop removes guesswork and keeps you on the edge of improvement without overtraining.

FAQ

How long does it take to train for a 45-minute half marathon?: Most runners need 8–12 weeks of structured training, assuming a base fitness of running 25–30 kilometres per week comfortably. If you're starting from a lower fitness level, add 4–6 weeks of steady base-building first.
Can I run a 45-minute half marathon on four runs per week?: Yes, if those four runs include a long run, a tempo or threshold session, a speed session, and an easy run. You'll need 40–50 kilometres total per week; if you can't fit that in four runs, you're likely not yet ready for the 45-minute mark.
What's the difference between pace and effort in half marathon training?: Pace is speed (e.g. 3:26 per km); effort is how hard it feels. A 3:26 pace might feel easy for one runner and hard for another. Use both metrics: pace tells you if you're hitting your target, effort tells you if it's sustainable. If the pace feels unsustainable, your goal pace may need adjustment.

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