Power Faded on a 45 min Max Effort. Could it have been Nutrition?

I went for a PR on a local 8 mile climb. Time was 43:44. Good news is I knocked 4 min off my PR. Bad news is my power dropped further than expected in the second half.

My goal was to sit around 280w for the entire climb. First 10 min was a bit hot at 292. Second 10 was better at 281. Third and fourth dropped to about 270. In a race scenario I’ve held 280 for 40 min. But this time I had some real power fade and I had to dig far deeper to maintain 270 than I had in a previous effort.

There was 35 mile (1:55) group ride with two stops before the climb. During that time I avg Z1 for most of it (140w) with some sections in Z2 and a short burst at Z4. In time and before the climb I consumed 110g of carbs 150mg of caffeine and 1.2 liters of water. Weather was chilly at 50-58f.

During the climb I’m embarrassed to say I drank almost no water and had zero carbs. With my HR at 173 I just couldn’t drink/eat a gel. Do you think that not eating/drinking could have had an impact on the second half. I did have a SIS gel minutes before starting the climb.

FTP on TR is 268. Outdoors it’s 290.

There’s really no need to eat during a 40 minute effort so I don’t think your lack of fueling during the climb made any difference. I’d look more closely to your previous day’s and pre-ride nutrition. If you start the ride with half empty glycogen stores then, well, you have already used half of your fuel at the mile 0.

That being said, I think most likely you simply just went out too hard and faded. Perhaps your fitness isn’t at 290w, especially if your all-out race effort is 280w for 40 minutes. This would indicate an ftp of around 270w range which seems to be in line with this recent effort.


The only reason I said that was because I held 300 on a 20 min effort recently which reset my ftp to 290 and a month ago I held 283w for 39 min. But I hear you on the nutrition the day before and possibly going out to hard in the first 10. Thanks for the advice. :slight_smile:

I’m with Vpe, it is likely pacing.

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Just to make sure I am understanding, you road for 2 hours before this effort? Did you have any fuel during this part of the ride, or only the 110g of carbs? If that is all you had during your ride, I would say fueling may have impacted this effort.

Yes I had the 110g total of carbs plus breakfast. I was riding in Z1 for those 2 hours averaging 135w.

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That is not good advice, especially given the details @AussieRider gave us. He rode 2 hours to get to the climb and consumed only 55 g/h. That’s very little and quite far from the recommended 80–120 g/h.

I think you didn’t fuel properly. Doing an effort very close to FTP after 2 hours or riding — even at a mellow pace — is very hard. And you basically depleted a significant part of your glycogen stores to get to the bottom of the climb.

For many riders, it takes about 3ish hours to deplete a significant share of your endogenous glycogen stores — which is right around the time you reported your power loss. Have a look at this graph:

(I don’t want to exaggerate the importance of a single graph from a single study, but this is just illustrative of the larger point.)

So I’d work on upping my carb intake during — especially when you know in advance that you want to crush a climb in the middle of your ride at FTP. Plus, I assume you had to ride another 35 miles home. You don’t want to limp home, that feels horrible. (Ask me how I know :grin:)

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Totally. And my plan was exactly that. I loaded up expecting to do 90g per hour until the base but ended up drinking one less water bottle because it was cold. Incredible to think I had a firm plan and blew it. Thanks for slapping me in the face with some much needed wisdom. And yes, it was an 85 mile round trip. I felt fine but smashed a lot of carbs once I reached the top and carried on at 90g per hour.

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I know the feeling. I drink a lot less in the winter than in summer. (Japanese summers are very humid, and I sweat a lot.) Keeping an eye on your nutrition is doubly important. Perhaps you can munch on some gummi bears, gels or other more solid foods next time.

If it makes you feel any better: I basically tried the same, although my climb was longer (1:10–1:30 depending on the pace). I had to ride about 50 km to get to the base of the climb (similar to you), but there were some small climbs between me and that big climb. I do few rides of that length due to having young kids, so I am not as used to pacing such long rides.

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I’m not sure if you read that correctly. I noted that fueling during a 40min all-out effort is not going to make a significant difference. Especially when AussieRider mentioned that he ate a gel just before the start of the climb. It takes about 15 minutes for your body to digest and absorb the gel so that was pretty much ideal.

During extremely hard, short’ish efforts your blood circulation in your digestive system is drastically reduced in order to provide more blood towards the working muscles and cooling (skin) which are higher on your brain’s priority list to keep you alive. Therefore, eating during a hard effort will have a high likelihood to cause some stomach issues which will slow you down way more than the potential benefit of extra x grams of carbs.

And yes, fueling before the hard effort is important just like I noted. AussieRider mentioned he had fueled during the 2 hours leading into the climb so I didn’t want to nitpick on that. Not everyone is used to eating 100g of carbs per hour and advising someone to eat that much before an all-out effort is a bad advise. This, again, could lead to serious stomach issues and way, way slower time.

I read that correctly, and I disagree: the 2-hour ride prior to the threshold/sweet spot effort matters, because that will have significantly depleted your glycogen stores. Have a look at the graph I posted.

If @AussieRider drove to the bottom of the climb by car, then you would have an argument, physiologically, he could have done the climb then without running out. Although I would still recommend to fuel such a hard effort as at the very least it lowers RPE and helps with recovery. However, this was not the case.

I don’t think this is the established opinion, and it does not jive with my experience. Usually the recommendation is to go with liquid carbs. On longer rides that might be hard, because you run out of bottles and need to refill.

I have done such hard efforts in the past (e. g. a hill climb TT with 21 km and 1,200 m of climbing if memory serves), and I easily took in 1 bottle. Yes, you can easily take in carbs without feeling nauseous, and if you struggle, then this is definitely something you should train.

On very long rides stomach issues can be a thing, because you will have to introduce solid foods alongside liquid carbs. But that’s another topic.

Why not? He was very detailed, and it is clear that he fueled inadequately. Based on the number, my experience and that of others, it makes perfect sense to me that he couldn’t sustain performance towards the end and that this happened near the 3-hour mark.

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I think we are on a completely different page here. The 2 hour ride leading into the climb does matter and I don’t disagree there. But the 40min effort itself, I’m on a total disagreement: no matter what AussieRider had fueled during the climb would’ve changed the outcome. He went into the climb slightly too hot and faded - a simple pacing mistake. A gel or a drink during the 20min mark wouldn’t have made him last 'til the end magically.

I don’t think this is borne out by what we know about exercise physiology. And @AussieRider should have fueled properly on his ride to the climb, not just the climb.

Who recommended one gel or taking a drink after 20 minutes? E. g. one SIS gel has 22 g carbs, which is 1/4–1/6 of the recommended amount (80–120 g/h). You should fuel constantly and not just pace your effort, but also pace your nutrition. You shouldn’t just fuel when you feel your power fading, then it is usually already too late. IMHO he should have taking in 80–120 g/h from kilometer 0.

Could his pacing have exacerbated this? Perhaps. (It depends a little on the climb, too.) On the other hand, @AussieRider could have paced the climb properly — had he fueled properly. And he knows from experience he can hold 280 W for the duration of the climb. Given the circumstances, the lack of fuel seems to be the much more significant factor. The tell tale signs and the timing he described jive with my experience, too.

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agree with everyone saying pacing, and honestly it’s just 10w, could just be that day! You’re not ALWAYS going to hit every number. Don’t overthink it, ONWARDS