The scientific concept of complexity is only a few decades old, but like many powerful ways of looking at the world it has spread rapidly throughout the public consciousness. Anyone who has watched even a couple of episodes of "The Big Bang Theory" would have heard multiple references to chaos theory, complex systems, and emergent phenomena. Remarkably, these very interesting topics from the fields of physics, mathematics, chemistry, and biology have special importance for human health and wellness.

Examples of complexity and chaos abound in the natural world. For example, weather systems are complex systems, which is why weather is notoriously difficult to predict even in the short-term. And long-range weather forecasts are not much better than guesswork, because the basic structure of a weather pattern can change in an instant. Study of avalanches has helped to advance chaos theory. And the flocking behavior of birds, especially the well-studied starlings, represents ever-shifting outcomes of a huge number of factors.

An emergent phenomenon is one that cannot be predicted from studying the various parts that make up the whole. Emergent phenomena include flocking behavior, in which large flocks create beautiful, always varying, dynamic patterns in flight; the architecture of beehives; and the World Wide Web. Even human consciousness may, from a certain perspective, be considered an emergent phenomenon.

From a health perspective, the relative wellness of any specific individual is an emergent phenomenon.1,2,3 For example, fighting off an infection is a dynamic process with many complex and chaotic interactions taking place before the final outcome is determined. We're not aware of these specific processes per se. We are aware of how things are going, that is, the sum total of the cellular and subcellular activities, based on how well or not well we feel.

Looking at one key area as an example of flocking behavior, are our white blood cells being effective in combating the infection? Is their behavior organized? Do they know where to go to battle the invading forces? Or is their behavior random and uncoordinated and are we not well and even sick as a result?

Long-lasting good health emerges from a variety of inputs, including nutritional balance, regular exercise, and sufficient rest. These activities are known as healthy behaviors or healthy lifestyle choices. As the interactions are complex, we can never predict a specific outcome. But we can base our choices on historical data and an analysis of facts. This information tells us that the outcomes we want - health and wellness - are likely to emerge from a set of healthy behaviors, i.e., healthy lifestyle choices taken consistently over the long-term.