Kids outside to play if they are sick??

Just curious - mine had fevers overnight, horrible coughs, J was throwing up this morning but once around 11 hit they were asking to go outside and were generally fine other than the coughing so I have rugged them up and let them play for a bit before they have a rest. Funny how they self regulate - normally would run around like mad and ride their bikes and trampoline etc. but they are playing quietly in their tree house and in the mud pit making cakes instead of bike riding which would make them cough.

So do you let yours out when sick?