Chasing 1:40 – A 12‑Week Half‑Marathon Training Journey

The Goal

Target: Half Marathon – 1 hour 40 minutes (average pace ≈ 7:38 per mile / 4:45 per km).

Hitting 1:40 means you need a blend of:

• Speed: Ability to hold sub‑8‑minute miles for the majority of the race.
• Endurance: Comfort running 10‑12 miles at a steady effort.
• Mindset: Confidence to push through the “wall” that typically appears around mile 10.

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Pre‑Requisites

Before diving in, make sure you can comfortably meet these baseline markers:

• Current half‑marathon PB: 1:45–1:50 (or a 10K in ≤ 50 min).
• Weekly mileage: 15–25 miles (24–40 km) consistently for the past 4 weeks.
• Injury‑free: No lingering aches that worsen with a moderate run.

If you’re a few minutes slower, consider adding a 2‑week base phase of easy mileage before starting.

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How the Plan Works

Workout	Purpose	Typical Pace / Effort
Easy Run	Builds aerobic base, promotes recovery.	60‑70 % max HR, ~1:30‑1:45 per mile slower than race pace.
Tempo Run	Improves lactate threshold – the pace you can hold for an hour.	85‑90 % max HR, ~7:50‑8:00 min/mile (just a bit slower than race pace).
Interval (Speed)	Boosts VO₂ max and running economy.	Hard effort, 90‑95 % max HR; 5K‑10K race‑pace or faster for short reps.
Long Run	Extends endurance, trains fuel usage.	Easy to moderate, 60‑75 % max HR; finish last 2‑3 mi at goal race pace.
Recovery / Cross‑Train	Allows adaptation while reducing impact stress.	Light activity (cycling, swimming, yoga) 30‑45 min.
Rest	Full day off to repair muscles and replenish glycogen.	—

Pace numbers are guidelines; use perceived effort or heart‑rate zones if you prefer.

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Weekly Plan (12 Weeks)

Week	Mon	Tue	Wed	Thu	Fri	Sat	Sun
1	Rest	Easy 4 mi (9:00)	Tempo 3 mi @7:55	Easy 4 mi	Rest or cross‑train	Long 7 mi (9:15)	Easy 3 mi
2	Rest	Easy 4 mi	Interval 5×400 m @5K pace, jog 400 m	Easy 4 mi	Rest or cross‑train	Long 8 mi (9:10)	Easy 3 mi
3	Rest	Easy 5 mi	Tempo 4 mi @7:50	Easy 5 mi	Rest or cross‑train	Long 9 mi (9:05)	Easy 3 mi
4	Rest	Easy 5 mi	Interval 4×800 m @5K‑10K pace, jog 400 m	Easy 5 mi	Rest or cross‑train	Long 10 mi (9:00)	Easy 4 mi
5	Rest	Easy 5 mi	Tempo 5 mi @7:45	Easy 5 mi	Rest or cross‑train	Long 11 mi (8:55)	Easy 4 mi
6	Rest	Easy 5 mi	Interval 6×400 m fast, jog 400 m	Easy 5 mi	Rest or cross‑train	Long 12 mi (8:50)	Easy 4 mi
7	Rest	Easy 6 mi	Tempo 5 mi @7:40	Easy 6 mi	Rest or cross‑train	Long 13 mi (8:45)	Easy 4 mi
8	Rest	Easy 6 mi	Interval 5×800 m fast, jog 400 m	Easy 6 mi	Rest or cross‑train	Long 14 mi (8:40)	Easy 4 mi
9	Rest	Easy 6 mi	Tempo 6 mi @7:38	Easy 6 mi	Rest or cross‑train	Long 12 mi (goal‑pace finish)	Easy 3 mi
10	Rest	Easy 5 mi	Interval 4×1200 m @10K pace, jog 400 m	Easy 5 mi	Rest or cross‑train	Long 10 mi (steady)	Easy 3 mi
11	Rest	Easy 5 mi	Tempo 5 mi @7:40	Easy 5 mi	Rest or cross‑train	Long 8 mi (last 2 mi @7:38)	Easy 3 mi
12 (Race Week)	Rest	Easy 4 mi	Rest	Easy 3 mi (optional strides)	Rest	Race Day – Half Marathon 1:40!	Rest

All distances are in miles; convert to kilometers by multiplying by 1.609 if needed.

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Detailed Workout Descriptions

Easy Run

1. Warm‑up 5‑10 min of light jogging.
2. Run at a conversational pace – you should be able to hold a full sentence.
3. Cool‑down 5 min easy jog + stretch.

Tempo Run

1. Warm‑up 10 min easy.
2. 20‑30 min at tempo pace (just a little slower than race pace). If you can’t maintain a steady watch, aim for a “comfortably hard” effort where speaking is limited to short phrases.
3. Cool‑down 10 min easy.

Interval (Speed) Session

1. Warm‑up 10‑15 min easy + 4‑5 strides.
2. Run the prescribed repeats at target interval pace (e.g., 5K race pace for 400 m). Keep effort consistent across reps.
3. Recovery jog or walk for the specified recovery time (usually equal to the work interval).
4. Cool‑down 10 min easy.

Long Run

1. Start at an easy aerobic pace.
2. Gradually increase to a steady effort after the first half.
3. In weeks 9–11, finish the last 2‑3 mi at goal race pace to practice “finishing strong.”
4. Finish with a gentle cooldown and thorough stretching.

Recovery / Cross‑Train

Choose low‑impact activities (swim, bike, elliptical, yoga) for 30‑45 min. Keep intensity light – think active recovery, not another hard workout.

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Notes & Tips

• Progression: Increase weekly mileage by no more than 10 % to avoid overuse injuries.
• Listen to Your Body: If you feel lingering soreness, swap a hard day for an easy run or rest.
• Fueling: Practice race‑day nutrition on long runs (gels, sports drinks, or real food). Aim for 30‑60 g carbs per hour.
• Hydration: Learn your sweat rate; drink enough to stay ~2 % body weight loss or less.
• Strength: Add 2 × week strength sessions (core, glutes, hamstrings) – 20‑30 min each.
• Pacing Tools: Use heart‑rate zones or perceived effort if you don’t have a GPS watch.
• Mental Rehearsal: Visualize the race, especially the tough mile 10‑11 stretch. Positive self‑talk can shave seconds off.

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FAQ

Q: I missed a key workout. What should I do? A: If you miss a tempo or interval, simply replace it with an easy run and keep the rest of the week intact. Avoid doing two hard sessions back‑to‑back.

Q: My paces feel too fast/slow after a few weeks. A: Re‑assess using a recent time trial (e.g., 5K). Adjust all training paces by the same percentage; the plan is flexible.

Q: Can I substitute a run with a bike workout? A: Yes, for a cross‑train day. Keep intensity low to moderate; do not replace a quality interval or tempo session.

Q: I’m prone to shin splints. How can I protect myself? A: Incorporate more soft‑surface runs, strengthen the lower leg, and ensure you’re not increasing mileage too quickly.

Q: What if race day is hotter than my training? A: Practice at least one long run in warmer conditions or simulate heat with extra layers; adjust fluid intake accordingly.

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Closing & Suggested Workout

The beauty of chasing a 1:40 half‑marathon is that every mile you log is a step toward a stronger, faster you. Consistency, smart progression, and a dash of patience will get you over the line. To kick things off, try the Week 1 Tempo Run:

• Warm‑up 10 min easy.
• Run 3 mi at 7:55 min/mile (just a shade slower than race pace).
• Cool‑down 10 min easy.

Feel the rhythm, note how your breathing settles, and know you’re already building the foundation for that 1:40 finish. Lace up, trust the process, and enjoy the journey.

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References

• 1/2 Marathon 12 Week Beginner | running Training Plan | TrainingPeaks (Blog)
• 1/2 Marathon 16 Week Beginner | running Training Plan | TrainingPeaks (Blog)