Running is clearly not your problem. You should probably consider
spending more time biking and swimming. Try having some days where
you swim 1 hour, then immediately bike for 2 hours. Or, you can do
what I do -- commute 25 miles by bike to the pool, swim at least an
hour, then ride back home. I don't know what the difference between
your triathlon run split and stand-alone 10k split is, but if it is
large (> 1 min/mile), that suggests you're not spending enough time
biking and/or swimming.
BillX said:I'm doing triathlons this year where the ending run is 10K. Today's
race destroyed me with high humidity, temperature around 90, and no
shade or clouds. Are there dietary and training changes I can make to
adapt myself to these conditions? I'm almost 50 but still in good
enough shape to break 40 minutes on a 10K when it's cold outside
however as the temperature climbs above 60 my run falls apart.