Some additional information to help people provide advice:

-What have you tried? (liquid volume and kcal/hr)?

-What has been your experience with hydration/nutrition in training?

-...especially, your experience with race-level fueling in training.

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ECMGN Therapy Silicon Valley:
Depression, Neurocognitive problems, Dementias (Testing and Evaluation), Trauma and PTSD, Traumatic Brain Injury (TBI)

If stomach does not shut down at same wattage in training 90 percent sure you are over swimming. If wattage is higher in racing than training then you are overbiking.

You probably never have stomach shutdown at lunch time or breakfast time on a normal day while doing zero exercise.

It is almost always intensity related.

Do you swallow water while swimming? This used to happen to me in my first few tris, and it was because I was swallowing enough lake or ocean water. I’m better about not doing that and haven’t had an issue in years.

Also, try an isotonic drink mix like Skratch. Mix regular strength. Works great at all intensities for me.

Agree with the others that it's likely intensity related. Either in the swim or the bike. Does this happen on standard training rides at your target race wattage/HR?

I would also say to experiment a bit in training with plain water + gels (or some other nutrition) if you can't do a sport drink/liquid nutrition. Other idea is to add some salt (like Base) - that has helped me when my stomach shuts down on the run.

Hope you figure it out!

Exactly!!

Have you been on long bike rides with gels and your stomach has survived?

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https://www.strava.com/...tes/zachary_mckinney

In my experience this is more HR related. You need to get your HR down to a level you can process the calories.

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http://www.sfuelsgolonger.com

I would add that you want to do lots of swim-bikes in training. Not may people do that. Bike over for your swim, hammer the swim until you are about to drop dead, quickly change, and get on the bike and do a full on 10km TT right after the swim trying to drink a solution of highly concentrated gatorade. If you feel like puking that and you will, concetrate the solution a bit more and get used to TTing taking in that fluid at 100% FTP and not puking it. It can be done, but it can't just be a race day gig.

Most of what the majority of triathletes do on race day, is the first time they do it all year. String it all together in pieces in training and find out.

I used to run camps where I would make people run 2 hrs on Friday night ending late in the day, and then start at 6am Saturday morning with a 90 min swim followed by a 180km ride. Almost everyone would have stomach issues that day. They would be doing longer than an IM swim, off no sleep, all fatigued in a group of hammerheads.

Finally, you can't be stopping on IM training rides because your heart rate will drop and you'll be able to digest your food. You need to keep the heart rate high, while taking in calories with no rest just like on race day.

Sounds like great advise. What I'd love to see is a ST approved protocol for figuring out your nutrition strategy. I'll book mark this and come back to it.

I've always assumed the best approach was a bike/run test because it's at some point during the run my problems show up. So great to hear about other ideas.

Never said to stop on the bike to get HR down, you train enough on the swim/bike/run to ride in the correct HR zone where you can process calories. IMO, Riding an Ironman with a high HR is a recipe for disaster.

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http://www.sfuelsgolonger.com

One thing people never consider is clothing. Are you wearing 1 or 2 piece? I hear of this often yet some don't realize with a 2 piece and a tight drawstring, you have basically but a tourniquet on your digestive system. When one goes aero, the gut expands (look at even tour riders and top triathletes when in aero) and having constriction in not a good plan, thus I always suggest a one piece kit. I'm just tossing this out as we have little info, but I have had quite good luck suggesting this to others. Simple fix if you keep exertion and similar nutrition under control.

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Kiwami Racing Team

I don't think you understood what I was saying. If you stop during a long ride, your heart rate will drop. This will allow you to digest calories more easily and give you a false sense of security. I can stop during a training ride, and get a massive coke, pizza and ice cream in a 10 minute break and absorb that since my heart rate will drop way down (depending on how cool it is, my heart rate may go down to 60ish). If I keep riding it will be 120-140. That 10 minute break when my heart does not deliver as much oxygen to muscles, allows for the digestion to really kick in. But we don't get to do that in a race. Slowman wrote many years ago, about backing way off, or even stopping on the bike to let your calories digest if you start burping. 5 min break to absorb those calories may end up saving 45 min on the marathon. If not you may puke those calories out or you may empty them at the porta potty at the run, not helping your race fueling.

dev is right here, plus do you take pain killer on race day? They can be very hard on your GI and shut you down quicker then without.

You also need hydration to digest and carry fuel within the body as well so.... check that too.

KEEP IT SIMPLE.

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Technique will always last longer then energy production. Improve biomechanics, improve performance.
http://Www.anthonytoth.ca, triathletetoth@twitter

I had the same issue. Would have inability to take anything at around 3 hours into HIM and 4 hours into IM races. Then I'd have to fight to get enough nutrition and fluids to make it to the run. Once on the run I'd be okay and could eat. Interesting thing was I was always in my aerobic zone. Saw a sports nutritionist who figured out that my adding an extra half scoop of infinit to get more calories (I thought 280 cals per hour was too little and wanted 350) was increasing the % of carbs to fluids above 6-8% that is apparently ideal. So I'd have 82 gms of carbs in a 2 oz (720 cc) bottle = 82/720= 11.3%. I went back to 2 scoops (66 gm) = 66/720= 9.1%. Even though it wasn't <8% it has helped tremendously. I haven't had any issues in the past few months. Something to try out