So, how much less would I weigh on the top of the mountain? If I were on top of Mount Everest, I would lose about two-thirds of a pound of weight from what I weighed laying out on the beach. My clothes would still fit me just as well. I'd be the same size, I would just weigh less. Not only would I weigh less, but everything with me would weigh less. So, if I happen to bring some free weights or some dumbbells with me, and assuming I could cope with the freezing temperatures and the thin atmosphere, I would notice lift a slightly heavier weight. It would not be that I had gotten strong, it would be the the numbers labeling the weights were no longer accurate. That weight that was labeled 20 lbs down at sea level would actually only weigh 19.93 lbs on the peak.
*Assumptions used to make these calculations. The mass of the Earth is 5.9 x 10^24 kg, the radius of the earth is 6,371 km. The distance from the top of Everest to the center of the Earth is 6382.3 km and the distance from the top of Chimborazo to the center of the Earth is 6384.4 km. Also, I used 6.67 x 10^-11 as the gravitational constant. Also, in real life, the mass of the mountain likely effect the calculations. It would be interesting to know if anyone has brought a very accurate scale up Everest.