Reassure me that this is wrong, please.

I was walking my dog with a couple of friends the other day, one has a 6 year old chocolate labrador and after a while she put her on lead, saying that she would be too tired to walk home if she carried on swimming (we were by the river).
I was pretty surprised by this as my lab is nearly 8 and is tireless, but she said that because her dog is a chocolate she is a 'throwback' (her words not mine) and they age faster. I have thoroughly researched my own breed and have read a good few books and sites about them and have come across nothing about this.
Can anyone shed any light on whether this is true or not?

I've never heard of such a thing......

Nor I. It could be a problem in certain lines.

poppycock and balderdash

is the dog overweight?

Nah, nothing to do with being a 'throwback'! What on earth?! My lab is 6 and imo has aged faster than some labs, for example my lab seems much older than my FIL's lab who is over a year older. He still is very energetic and would run and run but I have to take him home before he wants to go or he would run himself flat (and he has arthritis!).

Sounds like an excuse to me, would rather make something up then admit she doesnt want her dog to smell like dirty river water.

I`ve met a few Labrador owners who put their dogs on lead round water. You can`t help but wonder why they chose a Lab.

Rubbish. A lazy Lab, yes (proud owner of one of those!), but not a 'throwback' which ages faster.

I've never heard of any such thing before!

Obviously some dogs tire quicker than others, & obviously age plays a part in this; but being a "chocolate throwback" as the reason for tiring more quickly..... Where did that come from?!!

Funnily enough Barney's hydrotherapist has a theory about labrador colour & fondness for water ~ nothing scientific, just from her experiences. Apparently black labs love water & swimming & are completely fearless, diving into any ponds, rivers, streams, pools etc. Yellow labs also love getting wet & happily splash around in shallow water but only swim in deeper water if they have to. Choc labs either hate water or love like it like yellow labs.

No doubt everyone will have stories to completely destroy this theory.

You do have to wonder! Personally i love to see my dogs having a play in ther water. I know its cooling them down and means they enjoy there walk all the more, dogs arnt made to smell like roses anyway!