This morning, immediately after excercising my Cavvie x springer (about 5 yrs old) he had a "funny" turn.  He shivered quite violently, and appeared very weak in his hind legs.  He didn't lose the use totally, but seemed very "rickety".  I wonder if I over excercised him (no more then usual) or if he could have had low blood sugar, as we always walk pre breakfast.  I would be grateful if any one out there has any ideas - thanks.  It wasn't a fit as such, and he's not done it before

I would have the vet check him out, listen to his heart and such.

Thanks Isabel, I will do, although he had an "mot" not long ago.  Better to be safe than sorry.

could be 'exercise induced collapse syndrome' common in lab ret and a few other breeds. Now more recognised by vets , worth mentioning it to him when you have a check up.
One of my dogs suffers from this only ever affected during the summer months when she gets hot, very scary to watch I have to make her lie in the shade stand her feet in cool water and drink slowly usually the eyes look a little glazed ,usually back to normal in 10-15 minutes and wanting to run   around again ,I have to be very aware of how much exercise she takes during the summer and try to keep her in the shade easier said than done.
My dog has had a complete check up bloods xrays scans the lot she came out of it very healthy.

Hope you get it sorted and it is nothing too worrying.

> could be 'exercise induced collapse syndrome' common in lab ret and a few other breeds

Our male Lab has this....

Hope you get it sorted and it's nothing too serious