Throughout my life, when people have suggested that I may be "burnt out" from a certain activity, I have shrugged it off. I have disregarded the comment because I've always been very driven and unless I was completely passed out and unable to move, I couldn't possibly imagine that expression could apply to me. "Burnout" conjured up images of somebody who couldn't get out of bed in the morning, was uninspired, rundown, unproductive and maybe even grumpy.

But the longer I've run my own business and the more I've worked directly with CEOs, I've come to realize, that driven executives who are heading toward burnout don't actually see it's happening, until it does. The good news is that burnout is treatable and when we tend to it in ourselves and our colleagues, everyone will be happier and more productive.

Based on my experience working with CEOs dealing with burnout, here are six warning signs...