All of the speedskaters, with no exceptions, were wearing helmets. About half of them had wristguards on and a few had knee and elbow pads. Personally, I always wear a helmet and wristguards. Wrist injuries are by far the most common skating injury, while head injuries are by far the most serious. It doesn't take much getting used to so it's no big deal to wear. There are some specially designed speedskating helmets. Apparently a speedskating helmet has more padding in the back than a cycling helmet does since cyclists very rarely fall over backwards while this is not uncommon on skates. I think I'm going to get a high-tech one this year. The cycling helmet that I wear is ok, but a little heavy.
Some of the skaters were wearing skinsuits which are spandex-esque skin-clinging shorts and tops. I have heard that the shorts can save up to 30% of expended skating energy, by preventing non-productive large-muscle vibration, but I have no idea if this is a myth or not. Other skaters were more casual in T-shirts or sweatsuits.