Pursuit of Happiness Unhealthy?

Tom Rath, in his latest book Are You Fully Charged? The 3 Keys to Energizing Your Work and Life, discusses the difference between happiness and meaning.

Happiness, unlike meaning, is a more selfish and lonely activity: you are looking to take or get joy for yourself. Meaning, on the other hand, is about giving and/or improving things for someone else, which gives purpose to your activity and life.

Tom shares a study done by Barbara Fredrickson of University of North Carolina. Apparently people who pursue only happiness exhibit the same stress-related gene patterns as those who undergo repeated adversity. This gene pattern triggers an inflammatory response and eventually chronic inflammation, which has been linked to conditions such as cancer and heart disease.

So selfishly pursuing your own happiness and not looking to give back leads to chronic illness. 

Tom of course ties this back to work and life, since finding meaning is one of the three keys to a fully energized life. Employees who find meaning at work are not only more fully engaged but also less likely to leave, and the companies with such employees have higher profit margins. 

He also explains that those chasing happiness are less likely to find it than those chasing meaning. 

This is also why pursuing passion instead of meaning at work won't lead to the perfect career: passion in work, like happiness, is selfish, whereas starting the pursuit by finding the overlap of one's interest, strengths, and what others need is not.

Although I agree that meaning should be our goal, and it's become more important to me the older I get, I don't think all pursuit of happiness will lead to illness. I'm curious (and may look up) whether the experiment's participants had family and friends, or whether they were wealthy loners. I find it hard to believe that it's as black-and-white as this experiment makes it sound. 

I think the 80/20 rule should apply here too: if you spend 80% of your time on meaningful activities and work, it is perfectly okay—and healthy—to spend 20% of your time on your own happiness. I'd go so far as to argue that the 20% will actually help recharge you and make the 80% effort more effective.

What do you think? Is the pursuit of happiness unhealthy or does it just have to be balanced with meaning?