Originally Posted by Rick @ Reptilekeeper.co.uk

I've posted this for those who notice their beardie slowing down in the winter!
I don’t have any degrees or anything so this is all based on common sense, personal experience, & asking questions, so if anyone wants to query something please go ahead.
OK - a quick geography lesson – I’m using Central NSW for the figures which I’ve taken from our Bureau of Meteorology. So, mean max. temp in Feb is 30 ~ 33 deg whilst mean min temp is 18~21 deg ( around the recommended basic temps for our viv’s). In Aug the figures are, mean max 15 ~ 18 deg with a mean min of 3 ~ 6 deg.
As beardies don’t migrate and they obviously can’t get sufficient heat on a regular basis in the winter period then the alternative is to slow down the metabolism by one method or another. The safest way being to get in hole under a b l o o d y big rock and do nothing until something tells you it’s time to come out again – thus your basic brumation.
Now for the finer detail:-
No-one I know would try it on sub-adults (less than 12 months old) –they may slow down a bit over mid-winter but should still have temps & food maintained as they are still growing at an enormous rate.
Some adults don’t bother – they just keep on racing round all year, but others will show less interest in food & more in sleeping, so in mid-autumn start reducing temps over 4~6 weeks so that there is no heating on at all at the end of that period. Check that your bd had a good clear out of his bowel at the end of the 6 weeks as anything left in the gut can ferment/rot etc., turn off the last heating/lighting and a couple of days later put him in a cool place for the next 3 months. After around three months he will start to stir again, so reverse the process being ready for an eating binge. They don't lose weight (mine lost around 5grams only) but they wake up really hungry. I have a couple of large shoe boxes with a flap in the front floored with paper kitty litter pellets as insulation, these are put into a small tank in an unheated spare room. Water is provided as this is not full hibernation and occasionally on a good day one will get up for a short wander then back to bed DO NOT FEED AT THIS TIME as they will not be able to digest the food. Brumation assists with breeding but should not be used for this purpose only. It’s a natural thing and so, if/when your beardie shows signs of slowing down then follow the care sheet & let him/her have a rest.
It won't hurt if they don't brumate but it MAY shorten their life span if not offered the chance.
I think the bottom line is to do what your beardie wants. Ours actually start to slow down themselves, more sleeping, less interest in food! Once this happens then we bring the temps down over a month, reducing food & lighting. At the end of that time and after seeing that they don’t have a belly full of food we put them in a cool dark area until they show signs of waking again. If your guys show no sign of slowing down then there is no need to follow this regime.
There is no solid evidence that it does or doesn't shorten the lifespan but taken as part of the whole husbandry thing you could expect it to have some effect somewhere.
The trouble with beardies is that there does not appear to be any single really in-depth study available and to compound that, the UK ones have been bred from a limited number exported from Australia in the 60's & 70's (unless you’ve got smuggled stock !) so over the last 30~40 years it is quite possible that some traits have either been bred out or reinforced to some extent.
For those interested in a closer look at the type of land in which our beardies live, try this link. Remember that they live on the inland side of the dividing range (the big empty brown bit, left of the dark green on the east coast). This page includes some classic photos of open woodland, savannah etc.

www.wildernessaustralia.com.au/regions/ecology_map.htm

To check our climate conditions try the Bureau of Meteorology at
Climate information

Rick