> Dealing with stress over time can break down the body’s ability to deal with short bursts of stressful situations, he says.

For what I could get from the article, under (mild) stress your thinking becomes sharper, but as it lasts longer, it breaks you down and you can't handle stressful spikes.

So, perhaps, not being stressed all day long is the key? I mean, just surf the stressful spikes, don't have a light stress constantly, because you won't be able to deal with those hard moments of stress (and yes, they will come someday and all you've gained from the light-stress-boost will be thrown away because you'll burn out).