So on Monday I gave blood. However I did not ask or even think about whether it would affect my training. I knew I would have to take things easy for a little bit and as Tuesday was always going to be a rest day I thought this would be enough. Yesterday I went to the gym as normal and oh my, was it hard! I felt I was being flogged and afterwards I just felt very, very weary.
In my time honoured tradition of doing research after the event I have now found some information. From the blog Fitness & Health with Dr Gabe Mirkin I found that:
Following a donation of one pint, blood volume is reduced by around ten percent and returns to normal in 48 hours. So, for two days after donating, you should drink lots of fluids and probably exercise at a reduced intensity or not at all. Donating blood markedly reduces competitive performance for three to four weeks as it takes that long for blood haemoglobin levels to return to normal.
Also there was a thread on the Cycling Weekly message board which contained this information form their fitness consultant Hannah Reynolds
"We asked the Blood Donor agency for their answer for that particular feature. They recommended not training for the day you gave blood and to stick to very light training for another week. It will take several weeks to re-build your blood levels. While it won't affect your training too much in the off-season, as long as you follow guidelines and take care of your diet, it is best avoided during race season."
So it looks like I will taking it easy for the next few days.