Photo by Tristan Gevaux on Unsplash
How often can you do long runs? Once per week. Two times per week if you’re very experienced and know your limits. Anything more is asking for injury.
The confusion comes from misunderstanding what a “long run” actually is. It’s not just “running far”—it’s a specific training stimulus that creates massive physiological stress. Your body needs time to adapt.
What a Long Run Does Physiologically
A long run:
1. Depletes muscle glycogen — uses up stored carbohydrates in your muscles
2. Breaks down muscle tissue — accumulated impacts create micro-damage
3. Stresses your aerobic system — taxes your heart and lungs
4. Requires immune response — inflammation and repair processes
Recovery from a long run doesn’t happen in 24 hours. It happens over 3–5 days. If you do another long run before recovery is complete, you accumulate fatigue, increase injury risk, and actually get slower.
The Standard Protocol: Once Per Week
Do one long run per week, on the same day each week (usually Sunday or Saturday). Here’s why:
- Predictable adaptation — your body knows what’s coming and prepares
- Clear recovery window — 6 days until the next long run is enough for most runners
- Sustainable across 16 weeks — one per week for 16 weeks is manageable; twice per week will break you down
For a typical weekly schedule:
| Day | Workout |
|---|---|
| Monday | Easy run (6–8 km) |
| Tuesday | Easy run or rest |
| Wednesday | Tempo/speed work (8–10 km total) |
| Thursday | Easy run or rest |
| Friday | Easy run (6–8 km) |
| Saturday | Rest or very easy 5K |
| Sunday | Long run (16–26 km depending on week) |
This gives you the long run on Sunday, then 6 full days of recovery before the next Sunday. Perfect.
The Problem: Back-to-Back Long Runs
Some runners think they’ll adapt faster by doing two long runs per week (say, Saturday and Sunday). This is a mistake.
Why it fails:
– First long run depletes glycogen
– Second long run (24 hours later) finds you still glycogen-depleted
– You’re running the second long run on a weakened system
– Recovery compounds: you need more time to recover from both
– Injury risk multiplies
Experienced ultramarathoners sometimes do two long runs per week, but they:
1. Have 8–10 years of training base
2. Know their body’s signals intimately
3. Do one shorter (18–20 km) and one longer (24–28 km), not two maximal efforts
4. Space them with a hard workout in between for variation
5. Still get injured sometimes
Unless you’re in this category, stick to one long run per week.
How Much Recovery Between Long Run and Next Hard Effort?
If you do a long run on Sunday, when can you do your next hard workout (tempo, intervals)?
Wait at least 3 full days. So long run Sunday = earliest hard workout Thursday.
Progression that works:
– Sunday: long run
– Monday: easy (6–8 km, very easy pace)
– Tuesday: easy or rest
– Wednesday: easy
– Thursday: hard workout (tempo, intervals) — at this point, you’ve had 4 full days of recovery
– Friday: easy
This gives you a full recovery week with one hard long run and one hard speed session, separated by 4 days.
Long Run Frequency Across Training Phases
Base Building (Weeks 1–4): 1 long run per week, 16–18 km
– Low intensity, focus on time on feet
Build Phase (Weeks 5–8): 1 long run per week, 18–22 km
– Slightly harder effort, maintain aerobic capacity
Race Prep (Weeks 9–12): 1 long run per week, 22–26 km
– Some long runs include race-pace sections
Taper (Weeks 13–15): 1 long run per week, 18–20 km
– Reduced volume, same rhythm
Race Week: 1 final long run, 12–14 km, very easy, 10–14 days before race
Consistent once-per-week works across all phases.
The Cumulative Fatigue Problem
Marathon training is inherently fatiguing. Doing too many hard efforts (long runs + tempo runs + intervals) in a single week compounds fatigue.
Here’s a bad week:
– Sunday: 24 km long run (hard)
– Tuesday: 6 × 1 km intervals (hard)
– Thursday: 10 min tempo (medium-hard)
That’s a lot of stress in 5 days. Your body can’t recover. By Sunday, you’re tired, slow, and injury-prone.
Here’s a better week:
– Sunday: 24 km long run (moderate effort)
– Monday: 6 km easy
– Tuesday: rest or 5 km very easy
– Wednesday: 8 × 400m intervals (hard, but short duration)
– Thursday: 6 km easy
– Friday: rest
– Saturday: 6 km easy
One major stress stimulus per week (the long run), one secondary stimulus (intervals), rest and easy running filling the rest.
Signs You’re Doing Too Much Too Soon
- Resting HR elevated by 5+ bpm — your parasympathetic nervous system is stressed
- Sleep disrupted — racing thoughts, waking during night
- Morning motivation absent — you dread the training schedule
- Pace slower than expected — you’re running out of glycogen or neuromuscular reserve
- Lingering muscle soreness past Wednesday — still not recovered from Sunday’s run
- Elevated injury niggles — knee, shin, hip bothering you more than usual
If you see these signs, you’re accumulating too much fatigue. Reduce volume or space your hard runs further apart.
The Long Run and Your Marathon Goal
Your longest training long run should be 32–35 km (20–22 miles). You don’t need to run the full 42.2 km in training.
Why? Because:
– Additional distance beyond 35 km doesn’t add aerobic benefit
– It adds injury risk and extended recovery time
– The mental confidence from a 35 km run (you know you can run far) transfers to marathon day
– Race day adrenaline and nutrition help you go the final 7 km
Most marathon training plans peak at 32 km long runs with 6–8 days of recovery, then taper down to 18–20 km in the final 3 weeks.
Practical Scheduling Example (16-Week Plan)
| Week | Long Run (km) | Day | Next Hard Effort |
|---|---|---|---|
| 1 | 16 | Sun | Wed (easy, no hard effort yet) |
| 4 | 18 | Sun | Wed (tempo run) |
| 7 | 22 | Sun | Thurs (intervals) |
| 10 | 26 | Sun | Thurs (race pace run) |
| 13 (taper) | 18 | Sun | Thurs (easy, reduced volume) |
| 14 (taper) | 16 | Sun | Rest week |
| 15 (race week) | 12 (very easy) | Thurs | Race on Sunday (if race is Sunday) |
Notice: long run always on Sunday, hard efforts always 3+ days away, taper reduces both long run volume and hard effort.
The Honest Takeaway
Long run frequency is simple: once per week, same day each week, 6 days until the next one.
- One long run per week is standard — twice per week is for experienced runners only.
- Space long runs and hard efforts 3+ days apart — your recovery needs time.
- Peak at 32–35 km — you don’t need to run the full marathon distance.
- Watch for fatigue signs — if you’re wrecked beyond Wednesday, you’re doing too much.
- Consistent scheduling is more important than volume — 16 km every Sunday beats 14 km, 20 km, 12 km, 22 km randomly.
The runners who finish marathons strong aren’t the ones who did the most miles. They’re the ones who managed fatigue, recovered well, and trusted that consistency beats volume. Nail your long run rhythm and everything else follows.
Sources:
– Journal of Sports Medicine: Overtraining Syndrome and Recovery
– European Journal of Applied Physiology: Long Run Training Effects
Next read: Build long run endurance with our complete 16-week marathon training schedule.