CGM losing data during exercise

My daughter is on the Dexcom G5 and has just started running high school cross country. She carries her phone on her for CGM readout. At just about every practice, her phone loses data from her transmitter. It seems particular to this heavy exercise. Has anyone else experienced this? Is it due to heat? Any solutions out there?
Thanks.

Has she tried also running with the receiver instead? While my phone works fine most of the time, I have found that it does not have as strong of a connection to the transmitter as the actual Dexcom receiver. There are times that my phone will lose signal and no longer get data, but the Dexcom receiver is still working just fine. Might be something to try.

My dexcom receiver also maintains better connections than my phone when swimming or running.

Thanks to you both for your reply. We will give the receiver a try during running workouts.