Acute and delayed effects of marathon running on cardiac and skeletal muscle damage

Exercise drastically reduces the risk for future cardiovascular events.
However, it has been demonstrated that an acute bout of extreme exercise (i.e.
marathon) can harm cardiac and skeletal muscle tissue. This is indicated by
increased biomarker concentrations for cardiac (troponins) and skeletal muscle
tissue (creatinine kinase). An important limitation of previous studies is the
lack of sensitive and specific measurements to detect cardiac and skeletal
muscle damage. Novel MRI techniques have been developed to allow for more
precise characterization of cardiac and skeletal muscle damage and can
therefore more accurately depict muscle damage presence, type, location and
severity. The combination of imaging data with pre- to post-race changes in
ultra-sensitive biomarker assays and high-resolution ECG allow novel insight in
the potential detrimental effects of extreme exercise.

To assess the effects of marathon running on changes in cardiac and skeletal
muscle structure and function using state of the art MRI techniques,
ultra-sensitive biomarker assays and a high resolution 64-lead
electrocardiogram.

In this observational pilot study, participants will undergo MRI scans, ECG
recordings and blood draws during 5 subsequent study visits (screening, >1 week
pre-marathon, <6 hours post-marathon, 24-72 hours post-marathon, *2 weeks
post-marathon).

The results of this study contribute to the knowledge on the effect of extreme
exercise on the heart and skeletal muscle. The risks associated with this study
are extremely low. MRI has no associated health risks. MRI does not require
ionizing radiation. The MRI protocol does include the administration of a
gadolinium contrast bolus, but gadolinium contrast is well tolerated with only
very rare cases of gadolinium allergy reported in the literature. To exclude
the risk of contrast-induced nephrogenic systemic fibrosis, individuals with a
glomerular filtration rate < 30 ml/min will not be included. When patients wish
to stop the scanning procedure and get out of the scanner they can press an
*alert button*, which is standard procedure for every MRI. Patients are also
able to talk to the researchers in the control room at any time during the
experiment. The 64-lead ECG has no risks and subjects may only develop a skin
rash from the adhesive ECG pads. The blood draws have a small risk (<5%) of
causing a local haemorrhage, which is unpleasant but harmless. Patients receive
no direct benefits. There is a chance that we will detect coincidental findings
on the MRI-scans and these will be discussed with a cardiologist. If further
research is necessary than the cardiologist will provide a letter for the
general physician of the participant in which the findings are explained and a
referral to a specialist (cardiologist/radiologist) is requested to initiate
the appropriate care.