I did not start running marathons because I was athletic. I started because I wanted to make a difference. My first three marathons were run for the Leukemia and Lymphoma Society's Team in Training — a cause that means the world to me — and somewhere along the way, across nine finish lines and thousands of miles, I discovered something that changed how I think about wellness entirely.
The training did not make me stronger. The recovery did.
That realization did not come easily. In my early races, I did what most runners do. I followed the training plans, logged the miles, fueled carefully on race day. I treated recovery as the passive thing that happened between workouts — rest days and maybe a foam roller if I remembered. And I kept wondering why my body was not responding the way I expected it to.
It took me years to understand that recovery is not what happens when you are not training. Recovery is the training. And at the center of all of it is something completely free that most athletes systematically undervalue: sleep.
What Happens to Your Body After a Long Run
After a hard training run — especially anything over 16 miles — your body is in a state of deliberate damage. Muscle fibers have been broken down. Glycogen stores are depleted. Inflammatory markers are elevated. Your immune system is suppressed. You have essentially sent your body a very loud signal that it needs to adapt.
What most people do not realize is that adaptation does not happen during the run. It happens afterward, primarily overnight, when your body gets to work repairing everything you broke down. Up to 75 percent of daily growth hormone is released during deep sleep — growth hormone that is essential for muscle repair, protein synthesis, and fat metabolism. Sleep deprivation can reduce that release by 70 percent, severely impairing your ability to recover from training regardless of everything else you do right.
In other words, you can eat perfectly, train smart, and take every supplement on the market — but if you are not sleeping well, you are leaving most of your adaptation on the table.
Sleep deprivation also suppresses immune function by up to 70 percent — which matters enormously during heavy training blocks when your body is already under stress. I cannot count the number of times I watched fellow runners get sick two weeks before a race. In almost every case, they had been skimping on sleep during peak training.
The Lesson I Learned the Hard Way
My third marathon — my third in a single year — was my worst. Not because I lacked fitness. I had trained hard and I knew the distance. What I had not done was recover properly between races. I had not slept enough, not given my body the time it needed to rebuild between the demands I was putting on it. By race day I was running on empty in ways I did not fully understand at the time.
I hit the wall hard. My glycogen replenishment had been compromised for weeks. Sleep deprivation impairs the body's ability to restore energy stores regardless of how well you eat — meaning you can fuel perfectly and still start a race depleted.
That race was the turning point. I started treating sleep the same way I treated my long runs — as a non-negotiable part of the training plan, not an afterthought. The six marathons that followed were completely different experiences.
What the Science Says About Runners and Sleep
Sleep is one of the most underrated forms of natural recovery for endurance athletes. And the research increasingly backs that up with hard numbers.
Studies consistently show that athletes who prioritize sleep see marked improvements in speed, reaction time, and endurance. Just a few nights of poor sleep can impair performance, increase perceived effort, and make recovery take significantly longer.
A 2025 study published in the Scandinavian Journal of Medicine and Science in Sports found that lower sleep quality and quantity were directly associated with an elevated risk of running-related injury — and that a short-term decline in sleep quality in the weeks before an injury was a consistent predictor of that injury occurring. In other words, how well you are sleeping is one of the most reliable signals your body gives you about whether you are heading toward breakdown.
Recovery sleep after a marathon is actually more important than sleep during training — aiming for nine or more hours for three to four days post-race while monitoring heart rate variability gives you the clearest picture of your recovery progress.
What I Actually Do — Nine Marathons In
Here is what a recovery-focused sleep routine looks like in practice, based on everything I have learned:
Temperature is everything. Your core body temperature needs to drop to initiate deep sleep. I finish evening training runs at least three hours before bed, take a warm shower to accelerate the cool-down process, and keep my bedroom cool. This is also one of the reasons I am such a strong believer in sauna use — the deep heat followed by cool-down is one of the most effective ways to prime your body for sleep.
Magnesium is non-negotiable. After years of trial and error with supplements, magnesium bisglycinate before bed is the one I come back to every time. It supports the neurotransmitters that calm the brain and helps regulate the nervous system after a day of physical stress. On heavy training days, it is the difference between lying awake replaying the workout and actually sleeping through the night.
Block everything out — literally. Light is melatonin's enemy. I use a proper blackout eye mask and have covered every light source in my bedroom. It sounds extreme until you actually try it and realize how much ambient light you were sleeping in.
Wind down with intention. For the hour before bed on hard training days, I keep everything calm — no screens, no stressful content, nothing that keeps my nervous system in activation mode. Sauna sessions earlier in the evening have become part of this ritual. Red light therapy in the evening has also been shown to support melatonin production rather than suppressing it the way blue light does.
Take post-race sleep seriously. Most runners celebrate the finish line and immediately start planning the next training cycle. The most important thing you can do in the days after a marathon is sleep more than you think you need to. Your body is not finished adapting — it is just getting started.
The Bottom Line
Across nine marathons and more training miles than I can count, the single biggest performance upgrade I have ever made was not a new training plan, a better nutrition strategy, or a more expensive piece of gear. It was deciding to treat sleep as seriously as I treated the long run.
Research consistently shows that optimal sleep can enhance athletic performance by 10 to 15 percent — and that inadequate sleep impairs performance more than any other recoverable factor. For recreational athletes and serious runners alike, that is not a marginal gain. That is the difference between hitting your goal and missing it.
You work too hard in training to leave your recovery to chance. Protect your sleep. Invest in your recovery. Your future race-day self will thank you.
— Tricia
Disclaimer: This article is for informational and educational purposes only and does not constitute medical advice. Always consult your physician before beginning any new wellness or training practice.