Lily Body Battery stuck at 5

I have just had a long discussion with Garmin On Line Help  with regard to my body battery stuck on 5 and my stress level constantly high even when asleep! They replied that because I have a fast heart rate averaging 80 bpm that the watch recognises this as highly stressful and will therefore not recharge my body battery.  Seems absolutely ridiculous and must be the same for so many users ?!   Garmin Help  will not escalate my query and said ‘this is by design and not a software issue’.  I would like to know if anyone has found  a solution.