Recovery Run After a 100km Ultra: Medicine or Poison? I Tested It Myself
Recovery Run After a 100km Ultra:
Medicine or Poison? I Tested It Myself
Two days after finishing a 100km ultra at Cheongnamdae, I laced up again.
Here's what happened — and what science says about it.
My Body Rejected the First 300 Meters
Two days after the Cheongnamdae 100km ultra, I put my running shoes back on.
Honestly, even walking wasn't comfortable. The moment my foot hit the ground, my palms went cold with sweat. My entire body was screaming at me.
"Not yet."
But then something strange happened.
Around the 300-meter mark, my body started to loosen up. By the time I hit 1km, I could actually run. I started at an 8:00/km pace, and before I knew it, I'd settled into 6:30/km. I ended up running about 5km total.
The real surprise came afterward. Walking felt noticeably easier than before the run.
That's when it hit me.
"So recovery runs really are a thing."
Why Does Running Help You Recover?
1. Increased Blood Circulation
After intense exercise, muscles accumulate metabolic waste, develop micro-tears, and experience inflammation. A very light jog increases blood flow to the muscles, delivering oxygen and nutrients more efficiently and speeding up the metabolic processes needed for repair.
[1] Tufano et al. (2012), Effect of Aerobic Recovery Intensity on Delayed-Onset Muscle Soreness.
2. Reduced Muscle Stiffness
That unusually stiff feeling the day after a long race? It's because your muscles are still locked in a state of tension. Light jogging restores range of motion and naturally releases the muscles that have been clenched tight.
[2] Dupuy et al. (2018), Post-exercise Recovery Techniques and Their Effects.
3. Nervous System Reset
After finishing an ultra, your body is essentially stuck in emergency mode. With the sympathetic nervous system in overdrive, light aerobic exercise helps activate the parasympathetic response, restoring balance to your autonomic nervous system. A recovery run is your body's way of hearing: "It's safe to return to normal now."
[3] Stanley et al. (2013), Cardiac Parasympathetic Reactivation Following Exercise.
Is Your Body Ready for a Recovery Run?
Good to Go
- You can walk without major pain
- Movement makes you feel looser, not worse
- No swelling or heat in your joints
- Tired overall, but stable condition
Rest Instead
- Limping-level pain
- Sharp, stabbing joint pain
- Swelling or heat
- Flu-like symptoms
- Extreme exhaustion
When in doubt, rest. Sometimes the best training is no training.
How to Do a Recovery Run Right
What a Recovery Run Really Means
I think the essence of a recovery run is starting slow and watching whether your body adapts. If it keeps hurting through the first kilometer, you should stop. If it gradually feels better, keep going — gently.
When I hit that 6:30/km pace, a thought crept in.
"Maybe I should push it a little?"Once my body loosened up, the temptation was real.
But I didn't. I wanted to recover properly so I could get back to running at full strength. That mattered more than one fast run.
Holding back that urge and staying slow —
maybe that's what a real recovery run is.
