"And what about health? Is it a source of well-being? Once again, it certainly is. As most of us have experienced for ourselves, when we are in constant pain or discomfort, maintaining a positive attitude can be very difficult. So, looking after our physical health is crucial. We must eat well, sleep well, and take some exercise... This much is obvious. If, however, we consider health to be an entirely physical matter, and concern ourselves only with the state of our body while neglecting mental and emotional factors, then we are mistaken. For there is no necessary or direct link between enjoying good physical health and being happy. After all, isn't it possible for someone with a healthy, strong body to be unhappy? In fact it is quite common. And isn't it equally possible for someone in poor, even very poor health nonetheless to be happy? I am sure it is. Does the physical frailty of, say, very old people necessarily entail unhappiness? Certainly not! So, although physical health certainly contributes to human happiness, it is not its ultimate source. Instead, the real source of happiness once again involves our state of mind, outlook, and motivation, and our level of warmhearted ness towards others."

From Beyond Religion by His Holiness the Dalai Lama.