Open Access Research article

Substantial and reversible brain gray matter reduction but no acute brain lesions in ultramarathon runners: experience from the TransEurope-FootRace Project

Wolfgang Freund1*, Sonja Faust1, Frank Birklein2, Christian Gaser3, Arthur P Wunderlich1, Marguerite Müller1, Christian Billich1, Markus S Juchems1, Bernd L Schmitz5, Georg Grön4 and Uwe H Schütz16

Author affiliations

1 Department of Diagnostic and Interventional Radiology, University Hospitals Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany

2 Department of Neurology, University Medical Centre Mainz, Langenbeckstraße 1/503, 55131 Mainz, Germany

3 Departments of Psychiatry and Neurology, Jena University Hospital, Jahnstraße 3, 07743 Jena, Germany

4 Section Neuropsychology and Functional Imaging, University Hospitals Ulm, Leimgrubenweg 12-14, 89073 Ulm, Germany

5 Section Neuroradiology, University Hospitals Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany

6 Outpatient Rehabilitation Centre at University Hospitals Ulm, Pfarrer-Weiß-Weg 10, 89077 Ulm, Germany

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Citation and License

BMC Medicine 2012, 10:170  doi:10.1186/1741-7015-10-170

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Published: 21 December 2012



During the extremely challenging 4,487 km ultramarathon TransEurope-FootRace 2009, runners showed considerable reduction of body weight. The effects of this endurance run on brain volume changes but also possible formation of brain edema or new lesions were explored by repeated magnetic resonance imaging (MRI) studies.


A total of 15 runners signed an informed consent to participate in this study of planned brain scans before, twice during, and about 8 months after the race. Because of dropouts, global gray matter volume analysis could only be performed in ten runners covering three timepoints, and in seven runners who also had a follow-up scan. Scanning was performed on three identical 1.5 T Siemens MAGNETOM Avanto scanners, two of them located at our university. The third MRI scanner with identical sequence parameters was a mobile MRI unit escorting the runners. Volumetric 3D datasets were acquired using a magnetization prepared rapid acquisition gradient echo (MPRAGE) sequence. Additionally, diffusion-weighted (DWI) and fluid attenuated inversion recovery (FLAIR) imaging was performed.


Average global gray matter volume as well as body weight significantly decreased by 6% during the race. After 8 months, gray matter volume returned to baseline as well as body weight. No new brain lesions were detected by DWI or FLAIR imaging.


Physiological brain volume reduction during aging is less than 0.2% per year. Therefore a volume reduction of about 6% during the 2 months of extreme running appears to be substantial. The reconstitution in global volume measures after 8 months shows the process to be reversible. As possible mechanisms we discuss loss of protein, hypercortisolism and hyponatremia to account for both substantiality and reversibility of gray matter volume reductions. Reversible brain volume reduction during an ultramarathon suggests that extreme running might serve as a model to investigate possible mechanisms of transient brain volume changes. However, despite massive metabolic load, we found no new lesions in trained athletes participating in a multistage ultramarathon.

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body weight; brain volume; catabolism; DWI; lesion; MRI; ultramarathon