I went on a 5 hour ride yesterday and had some kind of exhaustion crash. It was in the high 70's so not too hot, but fairly warm for where I live. I drank about 5 bottles worth of gatorade over that 5 hours and had a couple clif bars and a couple cliff shots. I thought i was doing pretty well nutritionally, but about 65 miles in to a planned 90 mile ride i started losing my ability to think clearly and started losing my ability to keep my speed up. I was riding with a friend and we usually have our heart rates within about 5 BPM of one another but in the ending bit of the ride My heart rate would be around 155 while his was in the low 130's (155 is zone 4 for me). Any ideas about how to change my nutrition?

There are many more around here who know more than me, but I'll get the ball rolling:

- Start hydrating well several days prior to big rides, especially if it's going to be warm.
- Switch up the gatorade, try Cytomax or HEED or something else like that.
- You might try those electrolyte pills
- Train more in the heat.

Sounds like you were dehydrated. Exactly HOW MUCH Gatorade were you drinking per hour? You'll typicaly need 500-750ml of water PER hour.

And it really doesn't sound like a bonk since you made it to the end at a decent clip. If you had really bonked, you'd be crawling along at 8-9mph; not in pain, but without any energy at all. You'd also be scanning the ground for scraps of carbs to eat. So while the Gatorade itself doesn't provide adequate energy, the Cliff bars & shots supplementing it should've been fine.

Could also be your aerobic conditiong. Doing 5-hour rides at a decent clip is tough work. You might want to do 1-2 days tempo work on 1.5-hour rides.

Could also be your aerobic conditiong. Doing 5-hour rides at a decent clip is tough work. You might want to do 1-2 days tempo work on 1.5-hour rides.

Yeah, I ramped up too fast myself and had the same effects. It takes a lot of riding to do the distance rides without the effects. Also it takes time to know your body's needs when you put that kind of stress on it. Wait till it gets really hot and humid. It will really tax your system.

You'd also be scanning the ground for scraps of carbs to eat.

A few years back on a long ride that I really shouldn't have attempted, I got so knackered that I practically fell over sideways into a bush. Turned out it was a blackberry bush, so I just lay there stuffing as many (rather manky) berries into my face as I could for five minutes, before getting up and continuing.

Ok I’ll put my two cents worth in. It doesn’t sound like you were dehydrated, usually with dehydration your pulse rate goes down. It sounds more like you were overheated, the pulse rate went up trying to cool you down. How much training in the heat had you done before you did this ride? I have found, from living in Bakersfield, Ca, that it take me about three weeks of training in the heat before I’m fully acclimated to the heat. The sweat glands have tiny muscles around them and if they aren’t use to working that hard and long they tire and quit squeezing to pump sweat out to help cool you. Therefore the body increases the HR trying to get more blood to flow pass the surface trying to cool it self.