Hi Eve,
I agree with all the other comments...but if you know in advance that you will have extra physical activities, you can shorten the time interval between two doses of Mestinon. You said you were on a 4 hour 60 mg schedule, you can switch to every 3 hours or even 2.5 hours. In your case, I would have taken 60 mg every 3 hours the first 2 days and 60 mg every 2.5 hrs the last days if necessary.
Do it by steps and when the physical activities are over, revert progressively to your original scheme.
I hope a good rest will make you feel fine!
Maurice.