Short answer: Yes! If I stop here, it would be a short article :)
Like most things in life it depends on factors. Hiking, especially peak bagging, is very tough on the body. Around Las Vegas, you are either scrambling to the peaks or doing fairly long hikes in Mt. Charleston to the peaks.
Red Rock hikes are especially tough on the upper body and knees. There's lots of climbing and maneuvering through tight spots that can be rough on shoulders. Descending steep standstone can be very tough on knees.
The hikes to the peaks in Mt. Charleston are on the long side, ranging from 8 to 16+ miles. The constant pounding puts a lot of stress on the lower back, ankles and feet. Some of these hikes can also be tough on the knees.
Most of these hikes range from four to eight hours! That's a long time to exercise. How many times do you workout four or more hours in the gym? And, unlike the gym, you can't choose to work certain muscles, giving other muscles a rest.
The above reasons are why I think you can hike too much. The name of the game is longevity. There's not much to admire about someone who stopped hiking in their forties, because they overdid it. The person to be admired is the person going strong in their seventies.
The million dollar question: How much is too much? That's impossible to say. What I can tell you is to listen to your body. If you are really hurting, then take some time off. The mountains are not going anywhere.
Branch Whitney is the author of Hiking Las Vegas and creator of the 52 Peak Club where members hike to the best 52 Peaks around Las Vegas, NV