How does 100-mile training affect the body?

By Henry Howard

As of this writing, I am exactly five months away from my goal race for 2025, the Burning River 100 in Ohio, my Western States qualifier the year. As part of my build toward the race, I got an InsiderTracker test in January and will get another closer to race day to gauge how the 100-mile training affected my health.

I did something similar last year as I was tested June 3, after my training for the Kettle Moraine 100 was completed and several days before that race. In 2023, I was tested in July, soon after my 100-mile training for Burning River took place.

Over the years, I have received regular InsideTracker tests so that I can keep an eye on how my training, recovery and nutrition are having an overall impact on my health. I trust them for their thorough analysis, easy-to-compare data and personalized recommendations, based on my age, fitness level, dietary preferences and more. I’ve learned a lot about my health over the years and regularly use the InsideTracker information and recommendations to improve my health.

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How does 100-mile training affect the body?

That’s the question I have set out to answer, using science. The first step was to see where my fitness was at the start of the build-up to the 100-mile race. As I finish my training, I’ll get a second InsideTracker test, then compare the data.

But for now, a look back on what the recent results mean.

Overall, recent data show an improvement in health, according to the biomarkers. A comparison over my previous tests within roughly 18 months:

Optimized: 39 (January 2025), 35 (September 2024 ), 36 (July 2024), 34 (December 2023), 34 (July 2023)

Needs improvement: 6 (January 2025) 9 (September 2024 ), 9 (July 2024), 8 (December 2023) 9 (July 2023)

At risk: 7 (January 2025), 8 (September 2024 ), 7 (July 2024), 10 (December 2023), 7 (July 2023)

One of the successes recently was my improvement in cortisol levels. Comparing my test from July 2023 to the recent one, my levels went from 26.2 to 20.1. That’s the lowest level in years and is in the normal range. What do I have to credit for this? An InsideTracker recommendation to increase my intake of ashwagandha to 600 mg daily. From InsideTracker: “A large body of research has found that ashwagandha effectively lowers cortisol levels by up to 27%! While the exact mechanism for ashwagandha's effects is unclear (like many adaptogens), some research suggests that ashwagandha directly inhibits the release of cortisol from the adrenal glands. Ashwagandha may also reduce the perception of stress, meaning that very stressful things don't seem as bad when taking ashwagandha.”

Another success was my HDL cholesterol, the good kind, which went from 78 to 91 to 87 to 72, which lands it in the highly optimized category. “An optimized HDL level is important for health as it helps to decrease the risk of poor heart health caused by elevated LDL cholesterol,” InsideTracker says. The LDL cholesterol, or bad kind, are also in the optimized zone. “Optimal levels of LDL are associated with increased energy, improved metabolism, and better heart health.”

Areas of improvement

Still there is work to be done. Among the areas I’ll monitor and work on:

• Iron: This biometric has been a roller coaster. The most recent test scored a 188 compared with the previous one of 107, which followed scores of 139, 216 and 169. The optimized zone is 75 to 115, and higher than 180 is at risk. The body stores excess iron in the liver, heart, and pancreas, and high levels of iron can damage these organs. High levels of iron can also cause your blood sugar to rise. As a plant-based athlete, it’s a good sign that my iron level is not low. However, I do need to watch when it spikes like it has twice in the past five tests.

• White blood cells: This level is consistently low, which is an indicator of inflammation. According to InsideTracker, “A low test may indicate that your body is working how it should in order to defend against invaders.” On the other hand, some people have naturally lower white blood cell counts. It’s worth monitoring going forward.

• Sodium levels. The new test put me at 130, a level that I have been at pretty consistently, which is in the at-risk category. The needs improvement threshold is 135 while the optimum levels are between 137 and 145. It’s a tricky balance because I don’t want to add salt to my diet. However, due to the consistency of the score, this could also be a result of my hydration the morning of a blood draw.

Conclusion

There has definitely been improvement, as shown by the recent test as compared to others from the previous 18 months. That’s reassuring, especially as I begin the challenging training for this summer.

I am thankful for good genes, the choices I’ve made to adapt a plant-based diet and the ability to run. And all of those elements allow me to live healthfully, at least according to InsideTracker. And, of course, I’m grateful for InsideTracker’s thorough analysis, personal recommendations and easy-to-use data.