I just turned 68. I also just shot one of the best groups of my life with an AR - off sand bags, but my unsupported shooting is suffering from what I'm reluctantly assuming is age related unsteadiness.
I DO drink coffee but don't think it's all that much. Went off it for 40 days a few months back and it made no difference I could discern. I take a small daily dose of Lorsartan (sp?) for blood pressure and a 40mg dose of Pravestatin for cholesterol.  Otherwise I'm in fairly good shape for an old fart. I walk, and work out on an elliptical machine to try and stay in shape. I'm not overweight.
Do any of you old dogs out there deal with the same problem and have any of you found a way to overcome or at least minimize it.  If I'm not shooting from a rest I prefer to shoot offhand and I would like to use the currently fashionable combat stance with my ar carbine as it seems to help a little.
Thanks guys/gals
Gettin old sucks!
Ron

I have a bunch of health challenges at 60 and take more than a few meds and have the shakes when standing still compounded with
some balance issues in general both from meds and neuropathy..just can't hold still.


I rely pretty much on snap shooting which I am still pretty good at. but focused precision rifle shooting days are over I stay in 4" at 100 yrd
and I am going to pray that's the worse it gets, that's a heart/head shot and will take down bambi or a bad guy out of the fight.


Pistol shooting I am still doing OK at 25' or less I am in the red..at 15' I'm right on zero..beyond that we're back to focused shooting again.


and yes Getting old sux..

Shaking worse at rest, or when doing activities?  Happen in your sleep?  Change in fine motor skills, like penmanship?

Not all tremors are benign.

The arrow only points in one direction.

At rest or after exertion seems to be about the same, increased heart rate notwithstanding. I sleep well. I'm going to try some strength training to see if that helps. All of a sudden things weigh more and that doesn't help much. Supposedly the older you get the more resistance training (to a point) helps you. we'll see I suppose.
The heaviest handgun I have is an 8.5 barreled S&W Performance Center .500.  I can still hold that steady enough to hit a gallon can at 80 - 100 yards most of the time. But I have shot big bore handguns since I was 12 years old. I can't do nearly as well with my much lighter Ruger Red Hawk .44.  
Similarly, I can hold my old M-70 .375 H&H much steadier than even my 20" mid weight barreled AR.  Obviously the weight is 'soaking' up some of the shakes.
I have all these big bores because we live in the heart of Brown Bear country and it's possible to run into one even in the village. Walking, fishing, wood cutting, berry picking and hunting all require going armed with something big enough to stop one.
I just got into ARs last year and love shooting them because they are so light and relatively cheap to shoot. On top of that I have been amazed that a semi-auto is capable of such good accuracy.
I just can't hold the darned thing steady - it is what made me aware of these shakes. Years ago I competed with flint lock rifles and most shooting was done off hand. I did very well and was steady as could be. Seems those days are waning but I sure want to find something that will put them off as long as possible.
Thanks for the feed back so far -

Look at some of the Hi-power competition mods, you can get a weight that fits in the back/stock that will make it heavier  and you can lean back in your stance, ARs don't kick.

Look at your grip and stance, get longer free floating handguards and grip forward (look at a 3-gun) shooter.  Makes a steadier platform vs holding at magwell or gripping plastic hand guards.