Stomach Shutdown

One of the common problems of triathletes in long-course races and runners in marathons is “stomach shutdown.” This commonly happens starting around half way into the bike leg or sometimes as the run starts in a triathlon. Marathoners may also experience it about half way into the race.

When the stomach shuts down the feeling athletes experience is that nothing they take in passes through the gut. It just sits there causing a bloated and sometimes nauseous feeling. The most common method for dealing with this is to slow down and quit taking in anything until the bloating and nausea subside. Vomiting sometimes helps. When the bloated feeling begins to let up athletes will usually try plain water to see how that is processed. If that works then they gradually increase the effort as more substantial food sources are reintroduced. But by this time race goals are usually too far gone and motivation begins to subside.

Why me?

So what is “stomach shutdown” and what causes it? Assuming the cause is not medical—such as irritable bowel syndrome or vagus nerve damage—the cause more than likely is related to a mismatch between effort and fuel volume or the variability of intensity throughout the early portion of the bike or run. Also generally involved in both of these possible reasons for stomach shutdown is taking in fluids based on some sort of contrived “hydration” schedule. Learning to drink when you are thirsty will resolve this and make such schedules pointless. (I have athletes treat fluids and calories as two separate items in the race, but that’s a whole other discussion I’ll do another day.)

Another common confounding element is the type of food consumed during the race. Fiber-rich foods are slow to digest. Some athletes even have trouble using protein in a sports drink since it slows digestion. As more stuff is put in your gut (water, sugar, protein, fat, electrolytes, fiber, vitamins, minerals, etc) your digestive system is challenged to process it. You will eventually reach the tipping point if you keep taking in what you are told is “necessary” by brand marketers or what seems to work for other athletes and the stomach will shutdown. For long endurance events, the only things that are truly necessary and have been shown to be effective are water and sugar.

Possible Solutions

The best way to deal with this problem is to prevent it. Prevention starts long before race day. In the last 12 weeks prior to the race you should have been doing some racelike workouts in which your planned race-day nutrition was tried. To be “racelike” the workout has to be about half the duration of the race and done at the planned race intensity. Race intensity is the key element here. Rehearsing a nutrition plan at less than race effort is of little value. Try your eating plan in a C-priority race, especially one that’s about half as long as the A-priority race. A racelike workout or actual race should give you a good indication of what may or may not work on the day of your A-priority race.

Even this doesn’t always prevent bloating, however, due to other factors such as a nervous stomach or even swallowing too much ocean water during the swim. So the solution is to use only what you need while staying on the conservative side. If in doubt, eat and drink somewhat less. Plan to take in the lower end of the amount of food you think will be needed—not the most amount. And don’t try anything on race day if you haven’t done it successfully many times before.

Pre-race nutrition can set you up for a stomach shutdown, also. Have breakfast no less than 2 hours prior to the race start. Three hours is better. Eat only what has worked in the past. This also should have been rehearsed at least twice in the last 12 weeks. In the last hour before the race take in nothing but water. Ten minutes before the start use a sports drink or gel with water that you carried to the start line.

Here’s the most important part: If you have a tendency for stomach shutdown start the race slower than you feel like you could go. Much slower. Hold back. Be patient. Do not start the race anaerobically or even close to it no matter how great you feel. I’ve seen athletes anaerobic in the second mile of the bike leg of an Ironman. And they still have 110 miles to go. I’ve heard marathoners gasping for air at the mile 1 marker. What are they thinking?

Let’s look at it this way: If you were walking a marathon very slowly you could eat a Big Mac, French fries, and a milkshake. No problems. But if you were running a one-mile race as fast as you could go it would difficult for your stomach to process a sip of water. So effort is closely tied to digestion. They must match. If you go faster than rehearsed in the early portion of the race but take in fuel and fluids at the rate that worked at a lower effort in training then you have set yourself up for a stomach shutdown. Fuel volume and effort must match.

In a related cause, the athlete may start at an appropriate effort but frequently throughout the race he or she surges as other athletes pass or hills are “attacked.” Success in long-distance events generally requires very little intensity variability. Using WKO+ software we can now measure variability when racing with a power meter or GPS device. What I look for is a variability index (VI) of less than 1.06. I once viewed a triathlete’s Ironman file and saw that he had a VI of 1.25. That’s what I would expect to see in a bicycle criterium with lots of surges out of corners. This not only causes the stomach to shut down, it also wastes energy. He DNF’ed.

Bottom Line

So if you are prone to stomach shutdown some possible solutions are:

• Determine a pacing plan for the race, rehearse it, and then follow it—especially at the start of the race.
• Match the pacing plan with a nutrition plan which you have also rehearsed at race effort.
• Have a pre-race meal several hours prior to the race and take in nothing but water in the last hour—until 10 minutes before the start. And do not over drink at this time. You aren’t a camel. Drink only to satisfy thirst (it works, regardless of what marketers have told you).
  
• Use only foods and drinks that you have rehearsed at a racelike effort for a long duration many times. These foods should be low in fiber, known to not significantly delay your digestion, and are proven to work for you even if you go slightly too fast at first—because, unfortunately, you are likely to do that even though you know it’s wrong.
• Do not surge in the race. Ride or run at steady effort with only gradual and slight increases for hills.

Comments

[Jesse]

Joe,

Thanks for your consistent willingness to share your experience. On a somewhat related topic, I live in the Washington DC area. I am 7.5 weeks from IM Wisconsin (First IM). As you may know from the weather reports all over the US lately, we have some serious heat in the area. Saturday I had a planned long ride of 5 hours. This is obviously a key workout. Presumably the Heat Index will be close to 110 with the humidity in the area. I have a strong feeling that working out at this temperature for that long of duration, no matter how slow I go, has a possibility of doing more damage than good. Knowing my goal at hand what would you recommend? I have the ability to train on my trainer; workout outside from 6am to 9am before the heat comes hard and then finish on my trainer, as well as wait into next week to do this ride (may need to take a day off of work to accomplish it). I know I need to get this workout done and next weekend I will be traveling so I cannot perform a long ride. I would appreciate your thoughts or one of your coach’s thoughts.

Regards,

Jesse

[Joe Friel]

Jesse - Riding in such heat will more than likely force you to go slower/lower power than otherwise. Indoor, so long as it's cooler, might be better. But realize that if it's how to same degree in WIS that day you may not be heat acclimated. Good luck.

[Enrique]

I think this is probably my biggest concern for my upcoming IM. I just never got a good result with my calories and hydration during my long workouts at race effort. Every adjustment I tried resulted in less than good results. So now I'm left to make one last adjustment before the race and hope for the best. Thanks for posting Joe. It's good info and I plan to follow the advice.

[Mike Scott]

Joe -
Lotoja is my A race every year. Gut trouble has been my top limiting factor, often forcing me to slow to zone two at around 150 miles. Though your advice seems to be aimed at Tri, it seems the logic should hold true for Lotoja and I am going to give it a shot this year. Lotoja has the bulk of it's 9800' of climbing in the first 100 miles, so I have worked pretty hard, pretty early. This may have been my mistake. I am also curious about temperature. It seems that my gut is less happy when it is hot. Any merit to that observation?
Thanks for all of your great advice. I love your "Cycling Past 50" book.
Mike

[Joe Friel]

Mike S--I think you're right on both possibilities--there must be a match between intensity and food volume, and heat could also be an issue. Most athletes take in too much carbs (and other stuff such as electrolytes, protein, etc) when racing, far more than is needed.

[Michelle Payne]

I'm not a triathlete, but long distance runner who is just starting back. I ran a marathon yesterday and was running great until km 25 where I experienced, I'm guessing, stomach shutdown - it felt like I had about a gallon of water sitting in my stomach and it wouldn't leave, which forced me into a horribly slow run walk until km 37! I have another marathon scheduled the 25th of May and want to avoid this, and am hoping you can offer some advice. During the marathon I carried a hand-held bottle with me. I drank about 1.5 (20 ounce) bottles up to km 25, with one endurolyte tablet. At 6km I took 2 honeystinger chews, at 12km I took 2 more and at 19km I took 2 more, after that I tried just sipping water for the rest of the marathon, but it didn't help my stomach. I think I drank too much, and had too many chews for the pace I was running. If I cut back though I'm worried about bonking from not enough carbs and also concerned about electrolytes - any help/advice/suggestions? In training I would usually run 30km at a slower pace with one bottle and about 6 chews.

[Joe Friel]

Michelle--Take in less of everything.You don't need a lot. How much you may need I can't say for sure. But you know now what too much is. It also depends on your chronic diet. If you are fat adapted (low carb, high fat diet and low RER) then you will need _very_ little carb. Perhaps 100 cal/hour - at the most. Drink only when thirsty. You don't need electrolytes at all.