I've been struggling recently with health issues, and from past experience suspected my iron levels were down again. I self-tested, and this was confirmed.
About four weeks ago I had my bloods tested and my GP put me on folic acid supplements. These had no effect, so I bought some 210mg ferrous sulphate (iron) tabs which I've been on for the last week. I can already see the difference.
I've done 4 x 5kms this week, in 31:42, 37:30, 32:11 and 31:31. The difference is in the breathing. Iron carries Oxygen around the body, and without it, you can feel lethargic and out of breath.
My aims now are to get back to 30 minute 5ks, and extend to possibly a 10km in the next few weeks. Then hopefully a 16k around Derwentwater when I go on holiday to Keswick in July.