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August 06, 2012

Avoiding the Post-Run Bonk

Written by Dena Evans
toxins-cause-exhaustionClyde Wilson was a naval service member who enjoyed weight training and working out, when his doctor on the USS Carl Vinson informed him he was on the verge of needing medication for high blood pressure and cholesterol.  After making a transformative change in his nutritional habits, he went on to study chemistry and cell biology at Stanford and now teaches there and the University of California San Francisco Medical School.  In addition, he runs The Center for Human Nutrition and Exercise Science in Palo Alto, California.


This month, we asked Dr. Clyde to weigh in about the lethargy many runners struggle through after a long run.

1.  When many runners finish a big long run, often they report feeling extremely lethargic and low energy for much of the rest of the day, even after eating.  From a nutrition perspective, what may be going on here?

 Athletes need to replace their carbohydrate losses from training at a rate that their muscles are willing to absorb those carbohydrates.  If you burn 1000 calories in a workout, roughly 800 calories of which are carbohydrate, and attempt to replace all of those carbohydrates at one sitting, the over-flow of calories into your bloodstream will send more than half of it to fat cells, where the carbohydrate will be converted into fat. 

Therefore, eating enough calories is not enough. 

The calories have to go into lean tissues to actually help you recover.  Not eating enough is another way to fall short.  So the athlete has to eat enough carbohydrate, but spaced out over time or eaten with vegetables so that the carbohydrate calories enter the body at a rate muscle is willing to absorb them.  Protein helps re-build lean tissue but is unrelated to the feelings of lethargy after hard training.

2.  What are some best bet tips on things runners can do after the run to avoid that day-long bonky feeling?


The best thing a runner can do to avoid the day-long bonky feeling is to eat 100-200 Cal of carbohydrate, mainly in the form of glucose, every 2-3 hours.  You could start with a recovery drink (first ingredient should be maltodextrin) right after training, and then granola, bread, yams, or similar foods an hour later and every 2-3 hours after that.

3.  What, if anything, can runners do during the run to help avoid these post-run problems as well?

During running, consume 50-250 calories of glucose per hour (depending on training intensity, how much lean mass you have, and how well you are hydrating).
Last modified on July 10, 2013
Dena Evans

Dena Evans

Dena Evans joined runcoach in July, 2008 and has a wide range of experience working with athletes of all stripes- from youth to veteran division competitors, novice to international caliber athletes.

From 1999-2005, she served on the Stanford Track & Field/ Cross Country staff. Dena earned NCAA Women’s Cross Country Coach of the Year honors in 2003 as Stanford won the NCAA Division I Championship. She was named Pac-10 Cross Country Coach of the Year in 2003-04, and West Regional Coach of the Year in 2004.

From 2006-08, she worked with the Bay Area Women’s Sports Initiative, helping to expand the after school fitness programs for elementary school aged girls to Mountain View, East Menlo Park, and Redwood City. She has also served both the Stanford Center on Ethics and the Stanford Center on the Legal Profession as a program coordinator.

Dena graduated from Stanford in 1996.

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