It's not asked nearly as often as the which-comes-first question about the chicken or the egg. But it should be. After all, your answer to it affects your health.

"Which comes first, a healthy life or a healthy lifestyle?"Before you dismiss the question as a less-than-clever way to begin a health and fitness column, hear me out. Acquaintances often share with me a plan they have to improve their health.So I listen, nod a lot, wait 10 to 12 weeks, and then ask, "So how's that plan going?" Far more often than not, the acquaintance sheepishly admits that the plan is no longer going. It's gone.Long gone.Dead. Deceased. Done for. The admission is absolutely no surprise to me because in so many of cases, the plan was doomed from the start.That's because too many people have the wrong idea about what creates health. They expect a single positive change to somehow negate other ongoing unhealthy habits.It doesn't work like that. It works closer to the way you do when you construct a house.And you do so from the foundation up. But instead of using concrete and rebar, you build a foundation for the "health home" of your dreams by laying down a healthy lifestyle.If you're in the market for such supplies, consider this column your one-stop spot for shopping, a virtual Home Depot of health and fitness.One thing this savvy salesperson wants to show you is research about the unbelievable benefits from a single exercise session. But first, let me digress and explain why a competitor's perfectly good product isn't selling the way it should be.The U.S. government has been selling the benefits of performing 150 minutes of moderate-intensity aerobic activity each week since 2008, by stressing that it lowers the risk of premature death, coronary heart disease, stroke, high blood pressure, type 2 diabetes, and depression.Yet according to the Centers for Disease Control and Prevention, slightly more than half of adults have not bought in to this. Since nearly 60 percent of those who did make the purchase still neglect to lift weights twice a week, the CDC's current estimate is that nearly 80 percent of adults do not get the amount and type of exercise that promotes health.Why not? Why can't those who have been sedentary for a long time spend 15 fewer minutes with their smart phones and take a leisurely walk? And why can't those who have recently gotten away from working out, cut out an additional 15 minutes of television time and do the full 30-minute workouts that the government suggests?That's why I want to share some of the many benefits from a single exercise session. Maybe at least a few sedentary types will then realize what eventually amounts to about a four-hour-weekly time commitment is really a good use of time.Research done at the Center for Neural Science at New York University in New York City and published in the journal Brain Plasticity has determined that after a single 60-minute bout of exercise - just one! - you plan, focus, and multitask better; your mood improves; and you deal with stress more effectively. The conclusion was not reached by researchers pouring over thousands upon thousands of surveys or questionnaires, but rather by scientists interpreting brain images that revealed single bouts of exercise change the levels of neurochemicals in the body.For instance, the production of serotonin, a neurotransmitter that is a crucial to mood regulation, increases. Not only does this lessen the perception of pain and hunger, but it also mitigates feelings of anxiety and depression.Dopamine production also escalates with a single session of exercise, which has been shown to enhance all forms of learning. Another benefit to your body to producing plenty of dopamine is that a lack of it is believed to be a cause of Parkinson's disease.Additionally, a single exercise session also produces two other hard-to-spell neurochemicals - endogenous opioids and endocannabinoids, if you really want to know - which have been linked to the phenomenon known as "the runner's high," that feel-good feeling that often results during and after aerobic exercise.So if you buy what I'm selling, and start working out regularly, what happens long-term? According to a WebMD.com slide show, the following are the benefits beyond the ones previously mentioned.You'll have more overall energy, be more productive, and sleep better. You'll strengthen your muscles and bones, which may or may not be the reason that you'll feel more confident. Your chance of getting heart disease and many types of cancer will decrease, and so will the pain you feel if you already have arthritis.And you'll live longer.Recent research performed at Henry Ford Hospital in Detroit found that those subjects who increased their fitness level from "low" to "intermediate or high" over the course of one year were 40 percent less likely to die in the next nine years when compared to the subjects who started and stayed at a low fitness level.In short, the long-term benefits of consistent exercise have been so well documented that it's hard to find a fool to argue otherwise. Unfortunately, it's easy to find fools who still don't work out regularly.Don't be a fool. Exercise. It's a crucial component in constructing a healthy life.