Oh so that's why my "I'd rather be cross country skiing" thoughts haven't been working.
The study allowed each participant to choose a motivational statement that spoke to them. So maybe you could go with, "Sweating this much is making me so fit for XC ski season!" Or "Sure glad I decided to do climate change research. KaCHING!!" ;)
Or "pretty soon there will be only one slice left."
Or "only one buttertart" - although that didn't work for Harps.