I generally enjoy running trail ultras, if enjoy is the right word. But I have found a considerable trend in as much as my body overheats when the temperature is "hot". And I'm coping less and less as the years go by.
Last winter I very comfortably ran a 48mile race, which was -3c. No issues. Last weekend I started a race that was 21c and I could not cope and had to withdraw after 12miles. The same event 2 years earlier at 27c I tried to carry on and that was a mistake.
When the ambient temp is above X degC, after a period of Y time I get goose bumps. At that point in time my heart rate shoots up skywards, normally rises by about 40bpm. Ie walking gently is mid 160's and a slow jog of 12min/mile is mid 180's. I am in no way out of breath but sustaining that elevated HR is only possible for a small period of time. If I ignore that sign and carry on, about 30minutes later I feel sick, my tummy bulging and sloshing with fluids, another hour or so later and I'm heaving.
I sweat like crazy, never seen anyone sweat as much as I do. All of my clothes are completely soaked through, wringing wet, socks, shorts tee the lot within 30minutes of running if the ambient is above 5c. Even the winter -3c race I was sweating like a pig, my gloves were soaked through from the inside. I drink/sip as much as I can when I run and before the run. Typically over an autumnal 50km I'll drink about 8litres.
I cross train on a turbo trainer (exercise bike) in my shed with the door closed and the fan off - in summer around 32c. My training runs are at the hottest points in the day. I try to acclimatise but I don't seem to reap much benefit from it. For the race just gone, I put in the most training that I ever have done but that simply did not compensate for the overheating.
My 5k and 10k PB's have both been set sub zero ambient, and my marathon was set at 2c - I suspect I would be quicker sub zero but never run one that cold.
What can I do? Any suggestions? I'm getting worse and worse as the years go on. Now I can barely cope in double digits.....