As you shop, do bicep curls. Lift the packages or handbag several times with each arm while perusing the shelves for the right brand to buy.
Holding on to a banister for balance, place the ball of one foot on the edge of a step and raise the other foot slightly so it's off the step. Press your heel Downwood and upward several times, then repeat with your other leg.
Do tricep dips off your chair at work for a 30-second exercise break.