Oil pressure

My oil pressure gauge usually reads 40, which is right in the middle, drove my trailblazer on a 45 minute drive and I noticed my oil pressure went up to 60. I've been watching it ever since and every time I step on the gas my oil pressure goes up and I let off the gas it drops back down to where it should be. I just did an oil change last weekend and used the recommended filter and oil. Other than the gauge fluctuating significantly it's running like normal, no service lights, no leaks, and no funny smells. What is going on?