Recovery After a Marathon
Racing a marathon is HARD on the body and it takes time to recovery.
After the race, your immune system is stressed, inflammation is elevated, stress hormones are high, and there are significant signs of muscle breakdown. Your kidneys are under stress too. I’ve written a very similar blog here, but this piece is modified to include the longer recovery timeline of a marathon.
What's Actually Happening in Your Body
Before we get to the recovery recommendations, it helps to understand what’s happening in the body after racing a marathon. Several biomarkers have been studied in marathon runners at multiple time points after the race.
Muscle damage markers rise dramatically after a marathon. These markers don’t return to baseline until 144-192hrs, which is 6 and 8 days respectively. ¹
Cardiac stress markers peak within the first few hours post-race and normalize somewhere between 24 and 96 hours depending on the marker and the individual. The elevation is transient and is not considered permanent damage, but it does mean your heart needs time to recover. ¹ ²
Acute inflammatory markers are the slowest to resolve. Research shows they remain significantly elevated at 192 hours — that's 8 full days after the race. ¹
Kidney stress markers peak immediately post-race. Studies show that somewhere between 40–82% of marathon runners meet clinical criteria for acute kidney injury after finishing. ³ ⁴ These markers trend toward normal within the first 24 hours, but some remain elevated at that point. Full resolution likely occurs within a few days.
How to Approach Recovery:
First 3 Hours
Your body is in its peak stress state right now. Muscle breakdown is highest, kidney stress is peaking, cardiac markers are high, and stress hormones are elevated.
Hydrate right after the race. Kidney stress is significant after a marathon — and research shows it can occur even in runners who were adequately hydrated during the race. ³ Drink fluids in the past-race area after you finish.
Eat within 30–60 minutes. You need carbohydrates and protein right away — carbs to refuel, protein to start rebuilding muscle. ¹ Even if you're not hungry, eat something. Grab a banana, some bars, or whatever food they have in the post race area. It’s not always fun to eat right after a race, but try to get something down.
Hours 3–48
The acute peaks are beginning to settle, but recovery is sitll ongoing. Muscle damage markers are still elevated. ¹ Cardiac stress markers are elevated. Kidney markers are trending toward normal but may still be elevated at the 24-hour mark. ⁴
This is also when tendons are most actively repairing. Tendon collagen synthesis peaks around 24 hours after exercise and stays elevated for about 3 days. ⁵ Your tendons are doing important work at this time.
Sleep is important. This is when tissue repair increases. Try to prioritize it just like you did before the race. ¹
Move, but don't train. Easy walking, light stretching, and low-intensity yoga are all fine. Structured running is not. Your body needs real rest — cardiac and kidney stress markers support this. ¹ ³
Hold off on cold therapy for now. Inflammation is still present and actively driving repair during this window. Cold therapy can interfere with that process. Save it for days 2–7.
Days 2–7
Runners are often still pretty sore even 3-4 days after a marathon. This fits with the research, as muscle damage markers are still significantly elevated at 48 hours and don't fully normalize until day 6–8. ¹
Cardiac stress markers are resolving but may not be fully normal until around day 4. ¹ ² Inflammatory markers are still elevated and won't return to baseline until around day 8. ¹
Tendons lag even further behind — research shows that tendon collagen remodeling continues for days after a significant loading event. ⁵
How you feel is not always a reliable guide. How you feel is not always a reliable guide. Muscle and tendon recovery happen behind the scenes even if you are starting to feel better.¹ ⁵
Cold therapy is fine here. The inflammatory peak has passed, so ice baths or cold showers won't interfere with repair signaling at this point. They'll also help with the muscle soreness that almost every runner experiences after a race. ¹
Engage in easy movement only. Easy walking, light stretching, cross training, and low-intensity yoga are all good options. No running yet. ¹
If you have a tendon issue, be especially conservative. Racing loads tendons far beyond what normal training does. Too-fast return to speed work or high mileage is one of the most common triggers for a tendon flare-up after a race. ⁵
Days 7–14
This is when easy running can start again. The earliest I’d recommend is 7 days, but I usually try to persuade clients to do at least 10 days off. Muscle damage markers are just reaching baseline at 8 days, so I think it’s a good idea to wait until that point to start running again.
When getting back into running, we ease back in with shorter, easier runs only. A simple approach is the Reverse Taper — run the same runs as your taper week, but in reverse order.
If you have a tendon issue, check in before starting back. Even if you feel fine, the tendon may still be remodeling during this window. ⁵
Days 14+
Based on how long these stress markers take to resolve, many coaches — myself included — recommend keeping the first two weeks of running completely easy before reintroducing any structured training.
The biomarker research tells us when the body has largely recovered, but it doesn't tell us exactly when it's ready to respond positively to hard training again. Two weeks of easy running is a conservative buffer that respects the recovery timeline and reduces the risk of digging yourself into a hole early in your next training block.
After day 14, you can start building back toward your normal training. How to build safely back into training is a whole separate topic that requires it’s own dedicated post, but ease into it slowly.
Brief Summary
A marathon creates muscle, tendon, cardiac, and kidney stress that takes up to 8 days to fully resolve based on biomarker research
Eat and hydrate immediately after finishing
Engage in gentle movement for the first several days — no structured training
Even when you start feeling good, markers of physiologic stress are still present for up to 7–8 days
Ease into light, easy running after 7-14 days
Based on the recovery timeline, keep all running easy for the full two weeks
No hard training until at least day 14, and build gradually from there
References
¹ Bernat-Adell MD, Collado-Boira EJ, Moles-Julio P, et al. Recovery of Inflammation, Cardiac, and Muscle Damage Biomarkers After Running a Marathon. J Strength Cond Res. 2021;35(3):626–632. doi:10.1519/JSC.0000000000003167
² Scharhag J, George K, Shave R, Urhausen A, Kindermann W. Exercise-Associated Increases in Cardiac Biomarkers. Med Sci Sports Exerc. 2008;40(8):1408–1415. doi:10.1249/MSS.0b013e318172cf22
³ Mansour SG, Verma G, Pata RW, et al. Kidney Injury and Repair Biomarkers in Marathon Runners. *Am J Kidney Dis.*2017;70(2):252–261. doi:10.1053/j.ajkd.2017.01.045
⁴ Atkins WC, Butts CL, Kelly MR, et al. Acute Kidney Injury Biomarkers and Hydration Outcomes at the Boston Marathon. Front Physiol. 2022;12:813554. doi:10.3389/fphys.2021.813554
⁵ Magnusson SP, Langberg H, Kjaer M. The Pathogenesis of Tendinopathy: Balancing the Response to Loading. Nat Rev Rheumatol. 2010;6(5):262–268. doi:10.1038/nrrheum.2010.43
