Hi Raam,
Personally, I see Eustress as just a label for positive activities. My body has to do some work when I am running around playing with my children. My heart, my lungs experience stress but this is not negative tension just positive stress. It is just my body at work and it keeps me fit!

When I work with clients I am excited to work with them. Sure, sometimes there is stress of a timeline but that is not tension to me simply a timed outcome. It all depends in how I look at things as to whether it is stressful or not.
Thanks for asking for my thoughts.