ZHVelo

So these last few weeks I have noticed that doing intervals (longer ones, 20-40 minutes) that after about 15 minutes my stomach starts to hurt, as if I am hungry. This appears regardless of how I have eaten beforehand (so maybe 1-1.5 hours lunch before, or after work so lunch several hours before and just a snack). One time it seemed to go well was when I went after work (so lunch was hours before) and I finished a dessert we had, which was very fatty and sugary (though not all that much was left).

I usually rarely get an upset stomach, but it must have something to do with what I eat, and when, and then doing efforts that are close to threshold and obviously going above it every so often as you try to maintain a certain level with changing terrain. I do not have this issue on long rides in Z2-Z3.

Any ideas? Maybe to do with my glycogen storage and actually going too hard? But I have gone at these wattages, even higher (though just for 10-15 minutes) without issues in the past.

Edit: Could it be the heat? It is a lot hotter here recently than before. E.g. today was meant to be a 60 minute FTP test that I cut short after 30. The average temp was 26 with a max of 31 (well Strava says 26, Wahoo said average 27 and max 31). Last time I did a 60 minute FTP test the temperature was 19 degrees (according to Strava, didn't have the Wahoo back then). My average HR last time was 164, this time 170 (which is borderline VO2 max HR zone if I have my HR zones correct, which they should be or at least very close). Would be a bit of a shame, because 27 is not even that hot and yet it seems to affect me so much So because of the heat, my power is actually way too hard for me, which means I am using up all glycogen, and once that is done my stomach starts to hurt and I can't keep up the power anymore, is that it?

If so, any advice about what one could do (about dealing with heat)?

Iride01 

If you are going too hard, then carbs are the only thing that are going to replete your glycogen stores fast enough to keep you going hard.

As for stomach, many times high fat foods, particularly greasy fried chicken, make my stomach feel blah and overall my performance riding suffers for 45 minutes to an hour afterward. I don't particularly worry about time between meal and riding but more often than not, I begin a ride on an otherwise empty stomach with the exception of water or other snacks like a candy bar, dried fruits or plain junk food in small quantity. I've never felt hungry on a ride, even after four and five hours. But a small box of raisins or a candy bar is a treat after mile 45 - 50 (72km - 80km).

As we get older, we become less invincible to things we did in our youth. However if this is something new, then you probably should consult with your doctor about it.

ZHVelo

I edited my original post, about heat. So because of the heat, I am actually going too hard, depleting my glycogen, and that makes my stomach upset? Because what, the body demands for carbs from the stomach or something?

Yea, I can go long without eating on rides too if I don't go too hard.

Iride01 

78.8°F to 87.8°F to us over here. I don't generally see heat related issues till the temps get over 35°C (95°F). And I do still ride in actual temps over 38°C. Thankfully those have stayed away from my state this year, but a couple states west, it's been HOT.

But higher temps are what I'm used too. As a kid I was always outside and active in the hottest days of summer. If these temperatures are something you are not used to, then yes that might be a reason. How about elevation? Are you riding at higher elevations than you used to ride?

Even if you can find enough reasons why it might be normal and you just need to get used to the new norm, I'd still recommend talking to your doctor about it or another health professional with some sort of sports experience. That certainly isn't me.

ZHVelo

Yes, agreed, it isn't 'hot' by most measures, however, my body does not like heat, I sweat easily and a lot as well and I grew up in Northern Europe that has a cooler climate.

What is the "your doctor". I do not have "a doctor". Does everyone in America have "a doctor"? Well those that can afford insurance I guess. Funnily enough, I could have one and it would be cheaper for me, but in my insurance model I have 'free choice', so I can go to any I want. But I am never sick, so I don't have a doctor. I guess you mean GP like in the UK?

Iride01 

Well the thing you keep wanting to know seems to be "is this normal" and "why".

I don't have stomach issues when I ride other than sometimes heavy fat meals make me feel blah and I don't want to go hard. Not that my stomach bothers me.

So to me, stomach issues are not a normal thing. I'd want to make certain none of the more serious medical conditions that it might be are ruled out before just assuming it is the new normal.

Carbonfiberboy 

Going by HR, I'm not sure that those zones are an accurate reflection of muscular effort, which is where the action is. HR is heart effort. In the heat you're pumping blood to the surface, lots of capillaries, etc. I doubt that effects glycogen use. That's a big reason that power has supplanted HR for measuring effort.

For long hard efforts, I like to have a full bottle of sports drink - i.e. water, maltodextrin, and electrolytes. I use HEED because it doesn't rot my teeth. (and it works OK and isn't sweet)

pdlamb

I think Lon Haldeman was the one who said, "Hot is 10 degrees warmer than what you're used to." (That would be about 5.5 of your Celsius degrees.) Add on to that "hot weather" that you're pushing about as hard as you can, and you have a wide range of problems possible. Adequate hydration? You may need to drink more. You drank something? There's no blood left to get it out of your digestive system.

From warm weather climes, the accepted wisdom is that you're going to lose speed in hot weather, so ride early, before it warms up too much, or late, after it cools down.

ZHVelo

So yes, compared to my last effort, it was definitely more than 5.5C warmer. No, I think I was not super well hydrated, plenty for a normal office day, but maybe not enough for a hard effort in quite hot weather.

And yes, on Thursday I intend to try a PR on a local climb. I will wait til evening for that, and drink more so I can directly compare that effort to today.

Iride01 

Hydration prior to a ride is not nearly as important as hydration during a ride.

pdlamb

Eh, I think I've got to disagree. First, O.P. is doing rather short (40-90 minute?) rides. I'd expect a 5 pound sweat loss in that time (2.2 kg), which is enough to make a person thirsty, but isn't going to adversely impact health or limit performance.

Second, he's not adapted to the temperatures he's riding in.

Third, we're talking about maximal effort.

Put 2 & 3 together: half of his blood volume is going to muscles (maximal effort) and the other half is going to skin to dump heat (limited heat adaptation). There's not a third half of his blood volume available to service his stomach and gut, so anything he drinks shortly before or during the ride is going to sit there and cause stomach pain.

Iride01 

You might expect five pounds of sweat loss in that time, but I don't. I have just ridden over a dozen times through some 95°F (35°C) days and I only loose less than 1 lbs (.45 kg). These are on 30 and 40 mile rides (48 to 64 km). I sweat profusely too. I drink up to 66 fl oz (1.95 litres) during those rides. While they aren't max effort rides, they are very high effort.

I can only offer anecdotally that I don't find that how well I hydrate prior to a short or long ride has any effect on my riding. Provided I hydrate adequately during the ride. My only caveat might be that if you start out dehydrated, then you got issues already prior to the ride.

ZHVelo

Well, considering the pains start after ca. 15 minutes and it was not quite that hot, I don't think in my case it was that. I am more convinced that it does correlate with the heat though, but that I am just going too hard, depleting glycogen after those 15 minutes. I will maybe try marginally less hard and eat some sugar beforehand, and going later in the evening.

Iride01 

Sugar isn't the best carbohydrate for fueling your bike ride. It will give you something more than you might have had if you don't have carbs.

But why is all your talking about hydration and now carbs always before and after? What do you fuel and hydrate yourself with while actively riding?

I just got back from todays ride of 43 mile (69 km) ride and drank 72 fl oz ( 2.1 litres) during the ride. All in 2hr 41 minutes. There was about 480 Calories (kj) or roughly 135 grams of maltodextrin in my bottles. Temps were cooler today, just 87°F (31°C). I rode at a pretty decent effort and consider my rate of hydration during the ride pretty good as I weighed only 1 pound (.45 kg) less than when I started. If I had the time and another bottle I would have rode further.

Also, I don't drink cold stuff when I ride. I use un-insulated bottles with no ice. The temp is pretty much whatever the air temperatures are for my ride. I suppose in my case if I were to drink ice cold water while riding, I might have a stomach ache. But I never have so I don't know. Ice cold beverages of any kind have never been my thing when working or exercising hard.

I have read that those of use that do high effort exercises do tend to have indigestion and/or reflux. Don't know where I read that of if it was even a credible source. If you are getting older, you might consider gall stones. Though I wouldn't think you'd confuse them with stomach. Usually that is a pain between your chest and right shoulder blade.

I had them once. Stubbornly I waited them out until they passed and the next morning there were some greenish yellow blobs of fat in my stool.

ZHVelo

Because this occurs after only ca. 15 minutes in the interval (which is 10-15 minutes after easy warm-up, I never do intense warm-up, at most gradual build up to high Zone 2). Nothing I do eat, or don't eat, or do or not drink at that stage should matter. And hasn't mattered before. FWIW I do drink during that interval, at least since it's gotten hotter.

On longer rides I do eat and drink, I have no stomach issues there. I did notice the heat there, too, but no stomach issues whatsoever.

Iride01 

As others have said, it could be you operating in hotter temps than you are used too. However I'm assuming that the temps gradually warmed up and you have been previously riding as those temps warmed up. So I'd think you are used to them and that is not the issue either.

You don't think it might have been a brief bit of indigestion? My cautioning you to see a health care professional is more that friends I've had that thought they were having a hear attack or other cardiac issue were not having one. It was something else. However my friends that thought it was something else.... like indigestion, were having a heart attack or some other cardiac issue.