Hi Catstar, I always lurk, but had to respond. I think Dr Greene is generic advice ONLY and it is worth researching further. Nursery staff are used to children's ways, and in mentioning DD's behaviour it might not be usual, hence them bringing it to your attention.
While I appreciate children do hold their breath, there may be another explanation. Taipo I wonder if your DS was experiencing syncope and/or a reflex anoxic seizures.
See: www.stars.org.uk/
GPs will describe Temper Tantrums (kaos73 - your GP is an ignoramus), and others describe babies and small children as holding their breath deliberately. Oh yeah? Try it. Babies are not mini-David Blaines (davidblaine.com/news/?p=53)!!!
Triggers can be emotional stimulii, frustration, shocks and suprises and pain.
Dangers of falling from faints, or the location (top of stairs is a good one, or getting into the swimming pool). SO understanding the triggers is really important. Informing carers/teachers/nursery staff likelwise.
First aid is blowing into mouth (rather than just face), reassurance and reorientation when child comes around, and dealing with bumps and cuts if you don't catch 'em
Best one yet for our DD (now 5; growing out of it slowly) was an ignorant twat clattering her with a trolley in Ikea, just as she bit into a hot dog. Cue syncope and RAS, choking on hotdog, blue child, not independently starting to breath again, heimlich, vomit, mouth-to-mouth, tears and chaos. Slack jawed, knuckle dragging, trolley pusher stares on, not a word of sorry or real concern. FUCKWIT. All delightfully public; all done in 45 seconds, and another education moment for all - and purleeze do not call an amublance (again)! Just get me a new hotdog and some polish for my shoes.
DD is growing out of it, has learned consciously to breath, triggering breathing again and stopping syncope, or she will try to get to us prior to collapse. Episodes are a lot less frequent now as she is more worldly wise, frustrated at the world (as a toddler I am sure that was a lot of it) and perhaps more risk averse too (fewer bumps and scrapes).
As a parent you end up wonderfully blase that your child has crumpled to the floor, blue and apparently not breathing .
Scares the hell out of nursery staff and teachers in the first place. It is a shocking thing to see, but provided there are no consequences to the syncope (faint) and subsequent fall, it soon becomes matter of fact.
Sorry it is long, but lots of experience. I could go on and on. Would recommend the charity, who will arrange a visit to school or nursery if you really need it, They have been terrific.