Too much caffeine on a Granfondo - my experience so you don't do what I did

Hey everyone,

I just thought I would share my experience consuming way too much caffeine on a Granfondo I did yesterday (160Km). For context, I’m usually pretty caffeine tolerant as I’m an avid coffee drinker, so I got a little over zealous in estimating how much caffeine I could tolerate. I had three cups of coffee after breakfast and before my ride (probably made too strong), and then on the ride I had three bottles with gatorade mix and 400mg caffeine added (2x200mg pills) and seven Clif Double Espresso gels (100mg each) every half hour or so during the ride. Conservatively, I ingested 2400mg of caffeine from waking up to the end of the ride (about 6 and a half hours) . It’s amazing how stupid this seem in hindsight and I admit I didn’t actually add it all up beforehand. I also didn’t have any other food on the ride beyond a Clif bar right before the ride started (followed immediately by my first bottle).

My disclaimer - this is just an my personal anedote and I can’t be completely certain it was the caffeine. It’s just my hypothesis.

Here’s what happened to my performance:
-Overall my performance suffered as I finished 15 minutes slower than the same ride last year.
-I felt fine for the about the first hour of the race and maintained contact with the lead group for about 90Km (I got dropped on a mild surge that normally should not have been a problem). At this point, I inexplicably just started to come apart and my RPE went way up.
-Big muscle cramps set in way earlier than expected (cramping is common on this ride, even among strong riders), and I had been extra diligent about hydration leading up to the Granfondo. Admittedly the evidence of excess caffeine leading to muscle cramps during intense exercise isn’t great, bu there is enough for me to suspect a connection.
-I felt awful for the last 60-70Km of the 160Km and couldn’t put out much power.
-Generally a poor power performance as my NP was 277 for 4:26 (for comparison I did an NP of 304 for 4:10 two weeks before). My NPP was 288 last year on this ride for a time of around 4:11.
-My stomach was upset for a solid 24 hours or so afterwards.
-Took me forever to get to sleep last night.

So yeah, it wasn’t good. Don’t do what I did! Could have there been other factors in my poor performance? Absolutely. This is my caffeine hypothesis and I don’t wish to replicate the experience in order to confirm the results.

Disappointing to perform worse on a Grandfondo than the previous year, especially when my power has been demonstrably better this season. Oh well, live and learn!

More actual food and less caffeine next time! A few Clif bars and a few gels for the last half of the ride have worked well for me in the past (plus the Gatorade in my bottles), so I think I will return to that nutrition/hydration approach!


Wow!! Reminds me of a story a coworker told me about his first Triathlon experience. He didn’t know the gels they were giving out were caffeinated and basically had a similar experience to you after consuming over 10 gels during the event!

I usually keep caffeine down to about 200mg a race day.


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I know this isn’t what you meant, but I like to imagine that every half hour you were consuming 7 gels.

I’m very caffeine sensitive (200mg on race day gets me totally amped and focused, many days I go without and otherwise I usually max around 50mg), so the amount you took in overall just astronomical to me.

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Not gonna lie, my eyes widened when I read this bit.


Haha, it does read that way, doesn’t it? Whoops!

Yeah, that much caffeine would have put me into some sort of acute caffeine toxicity syndrome.

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Yeah, that’s an appropriate response. I sort of just shook my head at myself once I did the arithmetic afterwards.

I was listening to an interview with Gerraint Thomas on another cycling podcast recently, who said he was abstaining from caffeine in his TdF prep, to maximize the (perceived) impact of taking it during the race.

Personally I have stopped having a coffee before a long weekend ride, but for the more practical purpose of not having to stop and pee 30 minutes into the ride. Cafe stops during the ride of course are fair game.

It’s what, about 100 mg per cup of coffee?

24 cups of coffee is insane. I think I worked up to that when I was doing scrounge-what-sleep-you-can research for a week at a lab and I felt like death.

I had a very similar experience recently. After listening to the tr podcast on caffeine I took a lot more caffeine ( two coffees and 300 mg of tablets) than I normally would on a 200 k race and I fell apart at about 140 k I - no power, cramps etc. I never suffer cramps so this was very unusual. The same race a year earlier I had no such issues and was faster despite this year having 30 w higher ftp. Looking back I drank plenty but didn’t eat any real food just a couple gels. Maybe the caffeine is an appetite suppressant also? I’m doing the haute route double Pyrenees /Alps in a few weeks and I’ll be either avoiding caffeine altogether or at least minimising it

If you look at the papers that study caffeine as an ergogenic aid that is about the range of mg/hour for a cyclist of course for shorter durations generally. I drink a lot of coffee and probably avg 800-1000mg/day just in every day life


Good to know that someone else had pretty much the same experience! It lends some credence to my hypothesis (N = 2).

The funny thing when looking into this, there really isn’t all that much information on the effects of excessive caffeine during this kind of exercise. The negative effects of caffeine tend to be listed independent of exercise.

Caffeine is definitely an appetite suppressant, as most stimulants are. I would definitely be inclined to say that the lack of nutrition was the cause of the blow up and not the caffeine.

Hey John I notice this was 18 days ago, have you got to sleep yet?



I’m surprised you did 160km on just breakfast and a clif bar, I’d be so hungry without solid food (I noticed you had energy drinks and gels).

Would more solids have blunted the caffeine response in your digestion?

Not as much as John’s eyes widened.

I agree

On this occasion I think the big caffeine doses caused me to ignore the need to eat and drink as I normally would- I rode past all the drink and food stations and then suddenly collapsed having had no intake apart from 2x600 ml water and two or three gels in 4 hrs of hard race-pace riding ( including 2000m of climbing) on a pretty hot day ( 30 Celsius)

Lesson learned!

Hahaha! Yes, I have managed a bit of sleep since.

For further context, I did a ride on my own a couple of days ago. It was almost 3 and a half hours and 110Km. I had a really good day and managed 316 NP for the ride (compared to 287 NP over approximately the same amount of time in the Fondo from a few weeks ago; 277 NP for the entire ride).

Just had my regular bowl of cereal and a couple cups of coffee before the ride; then one Clif bar, two bottles with Gatorade, and two Clif Double Espress gels on the ride. I’m going to guess a total of about 500mg of caffeine that morning.

Still not definitive proof, but further evidence that the excess caffeine was the source of my problems on the Fondo a few weeks ago.