One of the most interesting areas of sedentary behavior research is brain activity and movement. Dr Catherine Kotz has been investigating the activity of a neuro-chemical called Orexin and its effect on sedentary behavior. Orexin causes us to wake up. It could be a key element in getting people to move more. In some animal studies it has been found that without Orexin they are always falling asleep.
In one of her landmark studies she injected Orexin in half of her rodents while the other half received just a water injection. The results of this study showed that those rats that were injected with Orexin moved considerably more than than those injected with the water. This confirmed Dr Koyz theory that there are specific neuro-chemicals that can control our activity patterns.
To investigate this further Dr Colleen Novak studied the brain networks and chemicals that are responsible for sitting in a chair or moving about. Dr Novak’s study involved mating multi-generational obese rats with obese rats and lean rats with lean rats. Dr Novak discovered that the obese rats did not have the ability to initiate movement.
Irrespective of the types and amount of neuro-chemicals, these animals did not have the wiring in the brain to respond to the injected chemicals and so remained sedentary. Alternatively when the brain of the lean rats was injected their movement was almost uncontrollable. The lean rats were bred to move while the obese rats were bred to sit.
The question was “What makes the lean rats active and the obese rats sedentary? To answer this question Dr Novak compared rats that had been bred for marathon running and rats that had been bred for sedentary sitting.
She discovered that the muscles of marathon running rats were different to the muscles of the sedentary rats. There was a direct relationship between the muscles of the marathon rats and the signalling to the brain to keep moving. The sedentary sitters did not respond the same way. Their muscles were trained to be sedentary and as such the signal to move was stopped.
Obese clients tend to be less sensitive and unresponsive to moving signals from either the muscles or the brain. Their muscles are trained to sit as the marathon rats were trained to run. Whereas clients who are movers are sensitive to moving neuro-chemicals and have a strong feedback loop from the muscles to the brain which encourages movement. It could be that the movers’ brains are hard wired to move.
While we are the product of our DNA, the environment that we exist in still influences us. DNA provides the structure of our being but if the structure is either enhanced or destroyed then there are consequences. More recently we have been told to keep our brain active throughout our lifetime to maintain its optimal function. The term used for the changes in the brain is neuro-plasticity, which allows the brain to change with its environment.
As with other organs of the body if we do not stimulate our brain it will eventually turn off and become as dormant as the lifestyle it leads. If we choose to sit all day and watch television then our brain will adapt to the specific type of environment. Those people leading sedentary lives have a brain that will form a sedentary structure due to its interaction with their environment. A sedentary brain will ultimately lead to a sedentary lifestyle and vice versa.
Just as a muscle adapts with movement so will the brain. Obese clients are faced with a double-edged sword. They have a brain that is not responsive to the neuro-chemicals for movement and have muscles that are trained to sit and not sending feedback signals back to the brain to get them moving.
As the need to move is taken from us our brains will form to create a more sedentary lifestyle and as “sitters” become the majority, the environment further evolves to meet their sedentary lifestyle by introducing more labor saving devices, more cars and less walking, more office sitting rather than standing and more screen based entertainment during leisure time.
Dr Paul Batman