You Asked For It: Question Authority

Nieman, David C. Dr.P.H., FACSM

ACSM'S Health & Fitness Journal:
doi: 10.1249/FIT.0b013e318198e467
DEPARTMENTS: You Asked For It: Question Authority
In Brief

Is there any evidence that being an ultramarathoner poses health risks?

Author Information

David C. Nieman, Dr.P.H., FACSM, is professor and director of the Human Performance Laboratory, Appalachian State University, in Boone, North Carolina; an active researcher; and author of several textbooks on health and fitness. Email your questions to

Article Outline


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Nearly a decade ago, I was contacted by Robert Lind, M.D., the medical director of the 100-mile Western States Endurance Run (WSER). During more than 30 years of service to the athletes competing in this grueling mountain race, he had noticed that more than an expected number of the older runners were being diagnosed with cancer. After discussing this issue with the WSER medical board, Dr. Lind invited my research team to conduct a series of studies for 5 years to investigate whether the physiological and immunologic demands of competing in the WSER was beyond the limits of what the human body could tolerate.

I will share with you some of the key findings from data we collected on 350 WSER athletes (1-3,5-9). As you probably know, the 100-mile WSER is a point-to-point trail run in the Sierra Nevada Mountains of northern California and is regarded as one of the most arduous organized running events in the United States. The race starts at Squaw Valley, California (6,200 ft altitude) and finishes at Auburn, California (1,200 ft). The trail race course ascends 2,500 ft to Emigrant Pass (8,800 ft, the highest point) within the first 4 miles and then passes through remote and rugged territory to Auburn. The total altitude gain and loss during the race is 18,000 ft and 22,000 ft, respectively. The race starts at 5 a.m., and runners have to reach the finish line within 30 hours to be eligible for an award. Up to half of the trail is traveled at night, and most runners take about 26 to 27 hours to finish the race. A staff of more than 1,300 volunteers supports the runners and works 26 aid stations, including 11 medical check points. Subjects qualify for the WSER (held in late June each year) by completing 100 miles in less than 24 hours, or a 100-km race in 12 to 13 hours, depending on age.

Here are three major findings from our studies:

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1. One in four WSER athletes developed upper respiratory tract infections (URTIs) during the 2-week period after the race, although it is held in the summer(8). The killing capacity of neutrophils (the most abundant white blood cell involved in an immune response) fell by 50% during the race, limiting the immune system's up-front ability to kill foreign pathogens (1). The best predictor of URTI after the WSER was a low-post race ability to secrete saliva immunoglobulin A (IgA), an antibody, which is another key immune component that is a frontline protector of the upper airways (8). Saliva IgA output levels fell by half during the race.

2. Immune inflammatory proteins called cytokines rose to very high levels during the WSER, and we linked this to muscle damage and inflammation, which was extensive (5-7). Despite a high level of training, WSER runners reported high levels of muscle soreness for several days after the race. Serum C-reactive protein, an inflammatory protein from the liver, climbed to 32 mg/L, one of the highest values ever reported after exercise. Plasma interleukin 6, an important immune messenger secreted by the muscle during physiological stress, increased 130-fold above prerace levels. Overall, the data paint a picture of unusually high and prolonged inflammation in athletes competing in the WSER.

3. To cope with the pain and inflammation, the most common medication used by WSER athletes was ibuprofen (2,3,9). We showed that ibuprofen users (70% of all WSER athletes), compared with nonusers, still experienced the same degree of muscle damage and soreness. Moreover, ibuprofen use caused a small leakage of colon bacteria into the circulation that promoted even more inflammation, with a side effect of mild kidney dysfunction. We were unable to measure any benefit of using ibuprofen by WSER athletes, only harm.

We concluded that, although the 100-mile WSER mountain race is reserved for the top echelon of ultramarathon athletes, they still experienced significant immune system stress, inflammation, and physiological trauma. The immune changes we measured in WSER ultramarathoners were comparable to those measured in marathon runners after running 42.2 km marathon races, but the long duration of the WSER means that the physiological and immune stress was sustained for 5 to 10 times longer (4). To reduce the pain of running 160 km in the Sierra Nevadas, most WSER athletes used ibuprofen. However, every indication is that ibuprofen amplifies inflammation and oxidative stress while providing no relief from exercise effort or muscle damage and soreness.

Some of WSER athletes have competed in more than 100 ultramarathon races, and although the long-term impact on health and disease remains to be determined, every indication is that the repeated physiological and immunologic insult is an unhealthy stressor. I have run 58 marathons and ultramarathons including the 72-mile race around Lake Tahoe in California. So I understand both the satisfaction of surmounting the combined challenge of training and competing in long-distance races and the pain and potential health sacrifice of pushing a good thing (i.e., exercise) too far.

In general, my recommendation is to build up health and fitness reserves by keeping exercise within recommended limits or 20 to 90 minutes per bout on most days. The occasional marathon race should pose few health risks (4). Yes, there is the thrill of success in competing in an ultramarathon, but the risks to long-term health may be similar to the mountain climber that scales one too many peaks.

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1. Henson DA, Nieman DC, Davis JM, et al. Post-160-km race illness rates and decreases in granulocyte oxidative burst activity and salivary IgA output are not countered by quercetin ingestion. Int J Sports Med. 2008;29:856-63.
2. McAnulty SR, McAnulty LS, Nieman DC, Morrow JD, Dumke CL, Henson DA. Effect of NSAID on muscle injury and oxidative stress. Int J Sports Med. 2007;28:909-15.
3. McAnulty SR, Owens JT, McAnulty LS, et al. Ibuprofen use during extreme exercise: effects on oxidative stress and PGE2. Med Sci Sports Exerc. 2007;39:1075-9.
4. Nieman DC. Marathon training and immune function. Sports Med. 2007;37:412-5.
5. Nieman DC, Dumke CL, Henson DA, McAnulty SR, Gross SJ, Lind RL. Muscle damage is linked to cytokine changes following a 160-km race. Brain Behav Immun. 2005;19:398-403.
6. Nieman DC, Dumke CL, Henson DA, et al. Immune and oxidative changes during and following the Western States Endurance Run. Int J Sports Med. 2003;24:541-7.
7. Nieman DC, Henson DA, Davis JM, et al. Quercetin ingestion does not alter cytokine changes in athletes competing in the Western States Endurance Run. J Interferon Cytokine Res. 2007;27:1003-12.
8. Nieman DC, Henson DA, Dumke DL, Lind RH, Shooter LR, Gross SJ. Relationship between salivary IgA secretion and upper respiratory tract infection following a 160-km race. J Sports Med Phys Fitness. 2006;46:158-62.
9. Nieman DC, Oley K, Henson DA, et al. Ibuprofen use, endotoxemia, inflammation, and plasma cytokines during ultramarathon competition. Brain Behav Immun. 2006;20:578-84.
© 2009 American College of Sports Medicine