Sugar increasing RPE during endurance ride?

This may have been posted somewhere else given the high number of sugar-related posts have in here, but I couldn’t find just what I was looking for, so here it is:

I went on an endurance ride today (a little over 2 hours) and felt good overall up to 90 minutes in. I had waited until then to fuel as I didn’t really feel the need and all metrics (including RPE) looked alright. I took what must have been 50 - 70g of sugar (75-100ml of maple syrup from a flask) chased with 2-3 mouthful of water and I almost immediately felt RPE go way up. There’s also a clear disconnect in my decoupling chart from that moment on.

Is this something anyone else experienced? Any idea what could be causing this?

Could have just been your gut deciding to fire up. That takes blood and energy as well. Generally you shouldn’t be waiting until you are hungry to start fueling though. Figure out how much you are going to take on during the ride and meter it out evenly the whole time.

Is this a “new” practice for you?

Meaning, have you previously used the same fuel, amount, timing, etc. or is this different in one or more ways from your prior use in a ride of this intensity and duration?

To Erick’s point, I’ll typically even intake out throughout the ride and get started with fuelling almost right away. As for content, I usually mix and match homemade bars (mostly maple syrup and oatmeal with PB and corn flour to hold it together) and pure maple syrup. So similar content, different intake timing. I also hadn’t done a pure Z2 ride in some time - there’s almost always some tempo/SS thrown in. I wasn’t expecting a boost whatsoever as it was all fine and I was nearly done anyway, but I certainly didn’t expect any negative impacts.

And you took this during 1h or you took this in one go? Because if taken in one go it is a huge amount of sugar into your guts that probably have fired up. On the other hand I have sometimes see my HR rising a little bit (5-6 bpm) during endurance rides after I have fueled with carbs - usually when I do not fuel for first 1h and then taken 20-30g carbs in one go. This never happens with solid food only with liquid carbs. And if carbs are taken systematically during the ride also everything happens without any HR rise.


Over the course of a few minutes, but still fairly quickly, yes. Thanks for sharing your experience!

I reckon I took too much too agressively and shook things off balance. I would have been better off making it home and have a regular meal there instead.

Rather sip some carbs and rinse with water over the course of longer time :slight_smile: your gut will be more pleased.

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For me chugging 100mls of pure maple syrup would be hard to do at any time.

I’ve been experimenting home make drink mix (mostly dextrose). Last Saturday I sipped 120g of sugar over 3 hours alternating with water. It worked well. I’m going to up it to maybe 180g for my next big ride. This was a 2200kj ride, so pretty intense.

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