what does it mean?

So I am a little freaked. I have a 17% lack in lung capacity. I have no idea what the implications of that are.

Diminished Capacity

No sooner had I written my previous post than I put my back out again, but in a different spot. I was sitting eating, a bit stressed out, and my back started to cramp. 1 hour later I was doubled over and could hardly move. I managed to make it to the car and the drive home was full of cussing at every gear change.
The chiropractor came the next day and snapped me a few times, so I could eventually straighten up.
We went camping finally after the little one had been running a huge fever. The fever broke she visited the doc who gave us the go ahead. I spent my time throwing boy in the air instead of doing any meaningful workout. My back was feeling better.
This week I cycled to and from work and while I was faster than last time the climb home killed me. I had been feeling pretty low on energy since we came from camping. I couldn't figure out why the fatigue. I finally left monaco at 8pm in the evening getting home about 940pm shattered.
I left Monaco late as I had to visit my allergolog. He has told me now I have a diminished lung capacity. This explains a lot, an awful lot. Possibly the fatigue too. I am waiting today to find out how dimished. I am still tired. The new inhaler takes a bit of getting used to.
Oh and here is the bike route Go tap the elevation button when it loads it looks like fun