Overheating problems on my turbo!

After having a go at a Maximal Aerobic Test earlier in the week I thought I would have a go at trying to find my threshold power by riding tts on my turbo

Originally I had planned to ride an hour tt on my turbo and gave this a go yesterday only to stop after less than 15 minutes feeling dizzy and overheated.

Not to be put off I realised the error I had made (i.e. leaving the windows closed) and decided to reschedule for this morning.

Set off with a steady pace for the hour with window open and fan on, but once again after about 20 minutes I started overheating.



However, again not to be put off I decided that a 20 minute test would have to suffice so after cooling off I went again this time pacing myself towards a 20 minute time trial by going off a little harder.



Think I either need to do more work on the turbo to acclimatize myself a bit better to exercising in the heat, or probably more likely limit myself to a 20 minute time trial and save the hour for doing outside on a good stretch of road in the good ole outdoors.