The marathon is a physically demanding activity that induces muscle and cardiac damage. The exercise-induced muscle damage, or EIMD, releases components from the damaged muscles on the bloodstream, especially creatine kinase (CK) and myoglobin (MYO). The levels of these components can be used to determine the extent of EIMD. Similar analysis can be done for cardiac damage markers (NT-proBNP, TNI and TNT).
Training levels, genetics, age, exercise intensity and hydration can affect muscle damage. Additionally, it is well known the importance of nutrition on physical fitness and performance.
Could diet be used to reduce EIMD? A recent article has studied the effects of the last week diet on the EIMD induced by running a marathon. Lower levels of damage would imply delayed fatigue, faster recovery times, and consequently a better performance.
The study
Sixty-nine healthy male marathon runners, with more than 5 years of marathon experience and already registered for the Rock n´Roll Madrid Marathon participated in the study.
They were subjected to a medical screening before the study and recorded their food and drink intake during the last week before the race. They were told to avoid intense exercise and pain-relieve methodologies for the last three days. Within minutes of finishing the marathon a small blood sample was collected for analysis of damage markers. They also filled a questionnaire to rate the pain intensity on their legs.
The results
Pre-race
- Marathon runners ingested an average of 3000 kilocalories per day (carbohydrates 45.0 ± 4.9%, proteins 17.4 ± 2.6%, fat 3.3 ± 3.9%) during the week before the race.
- Consumed less than the recommended amount of carbohydrates, and more specifically cereals and potatoes, dairy products, vegetables, and legumes.
- On the contrary ate an excess of pastries, sweets and dried fruits.
Post-race
- Intake of meat was associated with higher levels of CK and MYO.
- Intake of fish could decrease CK, TNI, and TNT levels. It could be related with the anti-inflammatory properties of fatty acids present in fish oil.
- Olive oil was found to decrease post-race levels of TNI and TNT. Well known for improving biomarkers of cardiovascular disease, it also did so after the marathon, probably because its high content in polyphenols, with antioxidant and anti-inflammatory properties. We already focused one of our previous posts on this topic.
- Vegetables consumption is usually associated with a healthier diet. Carotenoids and
flavonoids, among other compounds have antioxidant effects, protective against
muscle and cardiac damage. Higher consumption was associated with lower EIMD levels.
Conclusions
During the previous week of a marathon you should try to:
- Eat LESS high-fat food, such as butter or fatty meats.
- Eat MORE fish, vegetables and olive oil.
Although the study had some limitations (small number of participants, no female runners, absence of elite athletes, Mediterranean Diet background…) the diet recommendations are easy to follow during the previous week of a marathon.
It would be easy to adjust your diet during the last days before your next marathon and see how your body responds. Then you could decide for yourself.
Thanks for reading.
Bibliography
Exercise-Induced Muscle Damage and Cardiac Stress During a Marathon Could be Associated with Dietary Intake During the Week Before the Race.
Mielgo-Ayuso J, Calleja-González J, Refoyo I, León-Guereño P, Cordova A, Del Coso J.
Nutrients. 2020 Jan 25;12(2). pii: E316. doi: 10.3390/nu12020316.
