How to Run a
Sub-4 Hour Marathon
Sub-4 is the most popular marathon goal for good reason. It's ambitious but achievable with the right training. Here's what you need to know.
What sub-4 looks like
A sub-4 hour marathon means averaging 5:41 min/km over 42.195 km. That's a VO2max of about 40. In terms of equivalent fitness, you should be able to run a 10K in around 53-54 minutes or a half marathon in about 2:02 before starting marathon training.
If those numbers feel close to where you are, a 16-week training plan can get you there. If you're further out, start with a half marathon plan and build up.
Sub-4 is not a sprint. It's a pacing exercise. You need to be fit enough that 5:41 min/km feels comfortable for a long time.
Be honest about the work
A marathon demands volume. You need to run consistently for 16 weeks. That means 4-5 days per week, building to 50-65 km per week at peak. Long runs will reach 30-35 km.
There's no shortcut. Plans that promise a marathon on 3 runs per week are setting you up for a very painful final 10 km. More volume (at easy pace) builds the aerobic base that carries you through the wall.
The good news: most of it is easy running. About 80% of your weekly distance should feel relaxed. If you enjoy easy running, marathon training is actually pleasant. The hard sessions are only once or twice a week.
The training phases
Weeks 1-4Foundation
Build your weekly volume to 40-45 km. Run 4-5 days per week, all easy. Introduce one tempo run of 15-20 minutes. Get comfortable on your feet for extended periods. Long run up to 18 km.
Weeks 5-10Build
Volume climbs to 50-60 km per week. Tempo runs extend to 30 minutes. Add one interval session. Long run reaches 28-30 km. Recovery weeks every third week with 30% volume reduction.
Weeks 11-14Specific
Marathon-pace work. Long runs with 8-10 km at goal pace (5:40 min/km). Tempo and intervals continue. Peak volume week. This is the hardest block.
Weeks 15-16Taper
Volume drops 40-60%. Keep two short quality sessions. Long run drops to 14-16 km. Sleep well. Eat well. Trust the training.
Sample week: Build phase (5 runs)
Snel generates all of this personalised to your current fitness and adjusts weekly.
| Day | Workout | Duration | Details |
|---|---|---|---|
| Monday | Rest | , | , |
| Tuesday | Easy run | 45 min | 6:30-7:00 min/km |
| Wednesday | Intervals | 55 min | 5 x 1km at 4:55 min/km, 2 min jog |
| Thursday | Easy run | 40 min | 6:30-7:00 min/km |
| Friday | Rest | , | , |
| Saturday | Tempo | 50 min | 30 min at 5:25 min/km |
| Sunday | Long run | 110 min | 24-26 km at easy pace |
The wall and how to avoid it
Training volume
Long runs teach your body to burn fat as fuel. The more long runs you've done, the further you can go before glycogen depletion hits.
Pacing
Starting too fast burns through glycogen faster. Running the first half at 5:45 min/km instead of 5:35 min/km can mean the difference between a strong finish and a death march.
Fuelling
Practice taking gels or energy drink during long runs. Your stomach needs training too. Race day is not the time to try something new.
Race day plan
| Section | Target pace | Notes |
|---|---|---|
| Km 1-10 | 5:42-5:45 | Hold back. It will feel too easy. That's correct. |
| Km 10-21 | 5:40-5:42 | Settle into rhythm. Eat at regular intervals. |
| Km 21-30 | 5:38-5:42 | Stay focused. Pacing discipline pays off here. |
| Km 30-42 | Whatever you have | If paced right, slight slowdown but stay under 5:45. |
Negative splits (second half faster than first) are the holy grail of marathon pacing.
Frequently asked questions
Can I run a sub-4 marathon as a first-timer?
Yes, but you need a strong base. If you can already run a half marathon in around 2:00, sub-4 is realistic with 16 weeks of proper training.
How many kilometres per week do I need?
Plan for 45-65 km per week at peak. Snel builds up gradually so you don't jump too fast.
What should my longest run be?
32-35 km, done 3-4 weeks before race day. Snel programmes this during the Specific phase.
How important is the long run?
It's the most important session in marathon training. It teaches your body to burn fat, strengthens your legs for extended running, and builds mental toughness. Don't skip it.
Should I run a half marathon before my marathon?
Strongly recommended. A half marathon 4-6 weeks before your marathon gives you a fitness check and race experience. Snel supports B-race scheduling.
What if I'm hitting 2:05 for a half marathon right now?
You're close but not quite there. A 2:05 half suggests a marathon around 4:20. Focus on building aerobic volume and threshold pace over 16 weeks. Sub-4 is within reach.
How does Snel adapt my marathon plan?
Snel monitors your RPE, pace trends, and training consistency. If you're handling the volume well, it progresses normally. If you're accumulating fatigue or missing sessions, it adjusts load and redistributes workouts.
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