Hi, Patrick. I'm a regular platelet donor. In fact the whole reason I got interested in the first place is that I'd get to keep my red blood cells (well, most of them, they take a couple of lab tubes but it's pretty small).

As someone posted above, the anticoagulant can make you feel tingly, dizzy, and nauseous. (If you've ever done a super hard workout and noticed that your nose and ears tingle from the adrenaline, it's a lot like that.) If you get nauseous, make sure to ask for some Tums. They should have them just for this reason.

The other thing is that you may get cold. The anticoagulant has to be kept cold and although they try to warm up the return blood before pumping it back to you, it's still a few degrees lower than body temp. They'll probably offer you a blanket. Another thing I recommend is to take a zippered sweat shirt or cardigan sweater and wear it backwards so you can keep your other arm and torso warm.

As far as riding after donating, they'll tell you no strenuous exercise, hot tubs, or hot baths for 72 hours, same as for whole blood. But in my experience, you'll be up to snuff within 24 hours. Typically, I give a single platelet and plasma on Friday mornings before work and I'm feeling up to going on a 50 mile shop ride Saturday morning. The day of, however, I take it really easy. Make sure to eat all the cookies they offer and drink, drink, drink.

Of course, your mileage may vary. The first donation, take it really easy the day of, and don't plan a long ride for a couple of days after. See how it goes.

And thanks for donating.