Half Marathon Training 2025
Master 13.1 Miles with Science-Based Training
By Glen Meade
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January 20, 2025
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16 min read
The half marathon represents the perfect distance—challenging enough to demand respect, accessible enough for ambitious goals, and long enough to reward smart training. At 13.1 miles, it's where speed meets endurance, where tactical racing shines, and where personal bests feel achievable with the right preparation.
Having completed multiple Ironman 70.3 races and coached dozens of runners to half marathon success, I've learned that the 21K distance rewards those who balance aerobic development with targeted speed work. This guide provides everything you need to train smart, race tactically, and achieve your half marathon goals in 2025.
🎯 What You'll Achieve in 12 Weeks
- ✅ Complete your first half marathon with confidence
- ✅ Run negative splits using proven pacing strategies
- ✅ Develop the aerobic base for sustained 13.1-mile effort
- ✅ Master race-day fueling and hydration tactics
- ✅ Build speed with targeted tempo and interval training
- ✅ Prevent injury with smart progression and recovery
- ✅ Race tactically for optimal performance
- ✅ Set new personal records with confidence
📋 Complete Training Guide
Calculate Your Half Marathon Pace
Use our free calculator to determine your optimal half marathon race pace and training zones.
Try the Pace Calculator →🧠 Half Marathon Training Philosophy
⚡ The 80/20 Training Principle
Half marathon success follows the proven 80/20 rule: 80% of your training should be at an easy, conversational pace to build your aerobic base, while 20% consists of targeted speed work to develop lactate threshold and VO2 max power.
- • Builds mitochondrial density
- • Improves fat oxidation
- • Develops capillary networks
- • Allows high training volume
- • Raises lactate threshold
- • Improves running economy
- • Develops neuromuscular power
- • Practices race-specific pacing
🏃♂️ Aerobic Base Building
The foundation of half marathon success is a robust aerobic system. Easy miles at 65-75% max heart rate build the metabolic machinery needed for sustained effort.
- • Increased stroke volume
- • Enhanced oxygen delivery
- • Improved fat utilization
- • Greater mitochondrial capacity
⚡ Lactate Threshold Development
Tempo runs and threshold intervals improve your body's ability to clear lactate, allowing you to sustain faster paces for the 13.1-mile distance.
- • 15K-half marathon race pace
- • "Comfortably hard" effort
- • 85-90% max heart rate
- • 20-40 minute sustained efforts
🚀 Speed Development
Interval training at 5K-10K pace develops VO2 max and running economy, providing the speed reserve needed for strong finishing kicks.
- • 3-8 minute intervals
- • 90-95% max heart rate
- • Equal work-to-rest ratio
- • 5K-10K race pace efforts
📅 Complete 12-Week Half Marathon Plan
Phase 1: Base Building (Weeks 1-4)
Build your aerobic foundation with gradually increasing mileage. Focus on running all easy miles truly easy while establishing a consistent routine.
Week 1-2: Foundation
Week 3-4: Building
Phase 2: Build Phase (Weeks 5-8)
Introduce quality workouts while continuing to build mileage. Add tempo runs and interval training to develop lactate threshold and speed.
Week 5-6: Quality Introduction
Week 7-8: Peak Build
Phase 3: Peak & Taper (Weeks 9-12)
Peak fitness development followed by strategic taper. Practice race pace and prepare your body for optimal race day performance.
Week 9-10: Peak Training
Week 11-12: Taper & Race
🎯 Half Marathon Pace Strategies
📊 Optimal Pacing Strategy
Research shows the most effective half marathon pacing is slightly negative splits: run the first 10K conservatively, settle into goal pace for miles 7-10, then finish strong in the final 5K if you have energy remaining.
- • Miles 1-3: Goal pace + 10-15 seconds per mile
- • Miles 4-8: Settle into goal pace
- • Miles 9-11: Hold goal pace with focus
- • Miles 12-13.1: Gradually increase if feeling strong
🧮 Calculate Your Target Paces
Use our pace calculator to determine your optimal training and racing paces based on your current fitness level.
🥉 Sub-2:00 Half Marathon
🥈 Sub-1:45 Half Marathon
🥇 Sub-1:30 Half Marathon
💪 Essential Half Marathon Workouts
🏃♂️ Tempo Runs
The cornerstone of half marathon training. Tempo runs develop your lactate threshold—the pace you can sustain for roughly an hour of hard effort.
- • 20-minute tempo (after 2-mile warmup)
- • 3x8 minutes @ tempo pace (2-min recovery)
- • 30-40 minute sustained tempo
- • 2x15 minutes @ tempo (5-min recovery)
- • "Comfortably hard" effort level
- • 15K-half marathon race pace
- • 85-90% maximum heart rate
- • Controlled breathing pattern
⚡ Interval Training
Speed intervals develop VO2 max and running economy, providing the speed reserve needed for strong half marathon performance.
- • 6x800m @ 5K pace (400m recovery)
- • 5x1000m @ 10K pace (2-min recovery)
- • 4x1200m @ 10K pace (400m recovery)
- • 3x1600m @ 10K pace (3-min recovery)
- • Equal work-to-rest ratio
- • Focus on consistent splits
- • 90-95% maximum heart rate
- • Recovery should be active jogging
🎯 Race Pace Runs
Practice sustained efforts at goal half marathon pace to build confidence and teach your body the target rhythm.
- • Week 5: 3 miles @ HM pace
- • Week 7: 5 miles @ HM pace
- • Week 9: 6-7 miles @ HM pace
- • Week 11: 3x2 miles @ HM pace
- • Practice nutrition timing
- • Build pacing confidence
- • Develop race rhythm
- • Test gear and clothing
🏃♀️ Long Runs
Build the aerobic endurance needed to sustain race pace for 13.1 miles. Long runs are where you develop race-day confidence.
- • Weeks 1-4: 6-10 miles
- • Weeks 5-8: 10-14 miles
- • Weeks 9-10: 15-16 miles
- • Week 11: 10-12 miles (taper)
- • Progressive: Start easy, finish moderate
- • Split: Easy miles with HM pace segments
- • Simulator: Practice race day routine
- • Steady: Consistent moderate effort
🍌 Half Marathon Nutrition Strategy
⚡ Fueling Strategy Overview
The half marathon sits at the perfect distance where fueling becomes optional but beneficial. While your body can complete 13.1 miles on stored glycogen, strategic fueling can prevent late-race fade and improve performance.
- • Miles 1-6: Water only (if cool) or sports drink
- • Miles 7-9: 15-20g carbs if feeling energy dip
- • Miles 10-13.1: Focus on hydration and pushing pace
💧 Hydration Guidelines
- • Pre-race: 16-20oz fluid 2-3 hours before
- • Start line: 6-8oz 15-30 minutes before
- • During race: 3-6oz every 15-20 minutes
- • Total intake: 12-24oz for full race
- • Weather adjustment: Increase 25-50% in heat
🍯 Carb Fueling Options
- • Sports drinks: Gatorade, Powerade (easiest option)
- • Gels: GU, Hammer, Maurten (15-25g carbs)
- • Chews: Clif Bloks, Honey Stinger
- • Natural: Dates, banana pieces, honey
- • Timing: Mile 6-8 if planning to fuel
🥐 Pre-Race Meal Strategy
- • Moderate carb loading (not excessive)
- • Familiar foods only
- • Good hydration throughout day
- • 300-400 calories of carbs
- • Low fiber, moderate protein
- • Examples: Bagel with banana, oatmeal with honey
⚠️ Fueling Mistakes to Avoid
- • Over-fueling: More isn't always better for 13.1 miles
- • New products: Never try anything new on race day
- • Too much too late: Avoid heavy fueling after mile 9
- • Ignoring weather: Adjust strategy for temperature
- • Dehydration: Check urine color for hydration status
🏁 Race Day Execution
🎯 The Perfect Half Marathon Race Plan
Successful half marathon racing is about patience early, confidence in the middle, and strength at the finish. Here's your mile-by-mile execution strategy.
🚀 Start: Miles 1-3
- • Pace: Goal pace + 10-15 seconds/mile
- • Effort: Should feel easy and controlled
- • Position: Don't get caught up in the pack
- • Breathing: Relaxed, rhythmic pattern
- • Form: Stay relaxed, conserve energy
- • Fueling: Hydrate if warm, otherwise skip
💪 Build: Miles 4-8
- • Pace: Settle into goal pace
- • Effort: Comfortably hard, controlled
- • Focus: Find your rhythm and lock in
- • Mental: Stay present, positive self-talk
- • Fueling: Consider 15-20g carbs if needed
- • Check-in: How do legs and breathing feel?
🏆 Finish: Miles 9-13.1
- • Miles 9-11: Hold goal pace with focus
- • Mile 12: Time to assess - can you push?
- • Final 1.1: Give everything you have left
- • Mental: "I've trained for this moment"
- • Form: Stay tall, drive with arms
- • Kick: Sprint final 200m if possible
✅ Pre-Race Checklist
- □ Lay out all race gear
- □ Check weather forecast
- □ Eat familiar dinner
- □ Set multiple alarms
- □ Review race course map
- □ Visualize race execution
- □ Wake up 3-4 hours before start
- □ Eat pre-race meal
- □ Hydrate gradually
- □ Arrive 60-90 minutes early
- □ 15-minute dynamic warm-up
- □ Final bathroom visit
Related Articles
Marathon Training Guide 2025
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Running for Beginners Ultimate Guide
Build a strong running foundation for half marathon success
10K Training Guide 2025
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Zone 2 Training Complete Guide
Build aerobic endurance for stronger half marathon performance
❓ Half Marathon Training FAQ
How long does it take to train for a half marathon?
A 12-week training plan is ideal for most runners with a running base of 15-20 miles per week. Complete beginners should build a 4-6 week base phase first, running 3-4 times per week for 20-30 minutes.
More experienced runners targeting a PR can use focused 8-10 week plans that emphasize half marathon-specific workouts. The key is consistency and gradual mileage progression—rushing the timeline increases injury risk significantly.
What is a good half marathon time for beginners?
A good half marathon time for beginners is 2:00-2:30 (9:09-11:27 per mile). Sub-2:00 is an excellent first-timer goal if you have a solid running base and can consistently run 8-10 mile long runs.
Focus on finishing strong rather than chasing a specific time on your first attempt. Your primary goals should be completing the distance, practicing your pacing strategy, and learning race-day execution.
With consistent training, most beginners can improve 10-20% in their second half marathon as they develop better pacing discipline and aerobic fitness.
How many miles a week should I run for half marathon training?
Weekly mileage depends on your experience level and time goals:
25-35 miles per week, building from base of 20 miles to peak of 35 miles
35-45 miles per week, with quality workouts and longer long runs
45-55 miles per week, including multiple quality sessions
Include one rest day and one cross-training day per week. Build gradually from 60-70% of peak mileage to avoid overtraining.
Can I run a half marathon without training?
Short answer: No, you shouldn't. While it's physically possible to complete a half marathon without training, it's strongly not recommended.
- • Significantly increased injury risk (stress fractures, IT band syndrome, knee pain)
- • Extremely painful experience that can turn you off running
- • Weeks of recovery needed, potentially with lasting damage
- • High likelihood of not finishing or requiring medical attention
Minimum training requirements: If you can currently run 5-6 miles comfortably, you need at least 6-8 weeks of structured training. Complete beginners should allow 12-16 weeks minimum.
Respect the distance. A half marathon is 13.1 miles of sustained effort—train properly and you'll have a rewarding experience.
What should I eat the night before a half marathon?
Eat a moderate carb-focused dinner with familiar foods. Aim for 60-70% carbohydrates, keep fiber moderate, and avoid spicy, fatty, or unfamiliar foods.
- • Pasta with marinara sauce (not cream-based)
- • Rice with grilled chicken or fish
- • Baked potato with lean protein
- • Turkey sandwich on white bread
- • Chicken and rice bowl
- • High-fiber foods (beans, cruciferous vegetables)
- • Spicy or heavily seasoned dishes
- • Fatty, fried, or cream-based foods
- • Excessive alcohol
- • New or unfamiliar foods
Important: Stay well-hydrated throughout the day. Don't overeat—you're topping off glycogen stores, not carb-loading like for a marathon.
Eat dinner 3-4 hours before bedtime to allow proper digestion. Your pre-race meal should be larger than the night-before dinner.
How do I pace myself for a half marathon?
Use a negative split strategy for optimal performance. This means running the second half slightly faster than the first, which requires discipline early in the race.
Most runners who "blow up" do so by running the first 5K too fast. Start conservatively to preserve glycogen and prevent early burnout. Use a GPS watch and check splits every mile to stay disciplined. Remember: every second you bank early costs you 2-3 seconds late.
🏁 Your Half Marathon Success Journey
The half marathon is the perfect distance to challenge yourself, build fitness, and experience the thrill of distance running. With 12 weeks of smart, progressive training, you'll develop the aerobic base, speed, and confidence needed to achieve your goals.
Remember: the key to half marathon success lies in patience during the early miles, confidence in your training during the middle portion, and the courage to push when it counts in the final 5K. Trust your preparation, execute your race plan, and enjoy the incredible accomplishment of completing 13.1 miles.
Your half marathon PR is waiting—now go train smart and make it happen!
📚 Related Training Guides
10K Training Plan 2025
8-week program to master the 10K distance with pace strategies and speed development.
Marathon Training Guide 2025
Complete 16-week training plan for conquering the full 26.2-mile distance.
Running Pace Training Guide
Master different training paces for improved performance and race execution.