Alameda, CA, an island city on the edge of San Francisco Bay
Heat exhaustion, or something else?
Last week I visited Moab, Utah and rented a road bike for 2 days.
First day, 45 mile ride. Started early, nice pace out 22 1/2 miles, gradual uphill. Returning via the same route (gradual downhill) I completely lost energy, was stopping every mile or so to rest, finally made it back.
So was it heat? When I started, it wasn't super hot, but by 11:00 when I started the return trip, it was at least 95F, maybe 100F at noon. Or was it altitude? I had just arrived in Moab the day before from a coastal location, this ride was at 5500 feet average. Or fluids? I carried only 2 water bottles, drank 1 on the way out, had to ration the other on the way back because it wasn't enough. Or was it the rental bike? Good quality full carbon frame, but a seat that was uncomfortable after 20 miles.
Second day, 35 mile ride. Brought more than enough water. Lower elevation (4000 feet). Same bike with minor adjustments to seat. A little hotter. The same thing happened. Easy outbound, incredibly exhausted on return.
By comparison, now that I'm home (California), took a ride yesterday in 90+ heat on my own bike at sea level, 45 miles with lots of climbing. Hot and sweaty but nothing close to the complete loss of energy I experienced last week.
So I'm trying to figure just what happened in Moab in case I'm dumb enough to do this again in the summer? Was the extra hot temp (over 100) the issue? Or the altitude? Or both? I don't think it was fluids, because day 2 the same thing happened even though I had adequate fluids.
It must have been heat exhaustion since food is not an issue, you're going downhill, little or no wind, and you've got water. Heat exhaustion can be pretty sneaky and you may not realize it until too late.