16. Mar, 2017

Aging and the diver

Two pioneers: Jacques Cousteau and Stan Waterman.


When we grow older our bodily as well as brain functions change. Let start with the brain.  The  brain  is a high speed machine consisting of  billions of nerve cells connected by short and long nerve fibers -the dendrites and axons- and synapses. The fibers exchange information between nerve cells and clusters of nerve cells ('hubs') using neurotransmitters, a chemical substance that transmits signals at the synapses.A crude analogy is the map of your country with highways, secondary roads connecting numerous small villages and bigger towns.With advancing  adult age our brain network looses not only nerve cells but also its connectivity: the number of functional connections between nerve cells diminishes, a.o. due to changes in the nerve fibers, synapses and neurotransmitters. This means that the transmission of information in the brain will gradually become slower and less accurate. Its like a network of cities and roads where blocking a highway or an exit will slow down the traffic flow and  thus make it longer to reach your  destination.

Our mental functions are not just ‘mind’ drifting in thin air, but a product of the brain which like other parts of our body  is not  spared from aging. Which implies that  advancing age is accompanied by a gradual decline of cognitive abilities such as memory, dividing your attention (‘doing two things at the same time’), your reaction speed and even your IQ.  But in most healthy individuals it is a slow process that often goes unnoticed and  without substantially  impairing the quality of life. Age-related changes in brain structure and function are also not uniform across all cognitive domains or across all older individuals. An important factor is a persons experience or expertise which may moderate the impact of age on occupationally relevant performance and skills such as driving a vehicle, making decisions, playing  music or chess etc. In addition brain plasticity often keeps an aging brain functioning smoothly as the result of practice and expertise. Practising old and learning new skills does not give you new nerve cells, but it helps in keeping existing connections in the brain active and from loosing their functionality. It is like physical fitness that benefits from repeated physical exercise.

What  about divers? For recreational scuba divers physical fitness is the major factor that determines if they can dive safely. Slowing of the brain and mental functions with advancing age may be a limiting factor for professional pilots, bus drivers and air traffic controllers, but not necessarily for recreational divers. Recreational diving and underwater photography are activities that do not require rapid decision making, but instead careful planning and slow movements under water. Getting geared up and checking the UW camera before a dive is a highly familiar process repeated over and over during diving trips. In addition, experienced older divers with often more than thousand logged dives are likely to avoid situations that create psychological stress. So its mainly physical fitness that counts for the elderly diver. Fitness as a consideration for scuba  diving  is the ‘readiness or ability, especially in cardiovascular, respiratory and musculoskeletal systems, to perform tasks requiring increased energy expenditure such as extrication in a diving emergency’. Weaker muscles or cardiopulminary deficiencies can be limiting factors. But the bottom line is that fit elderly divers do not run a greater risk to get involved in diving accidents than younger divers. They have learned  to recognise and avoid physically strenous conditions. And they  do not feel the need to compete with younger and physically stronger divers. This is even more true for underwater photographers who generally avoid strong currents, deep dives and will not hesitate to ask some assistance when climbing on the diving ladder with their heavy gear.

I like to end with this eloquent quote taken from  Bob Halstead*

''Being older and a bit decrepit may actually be a benefit. We perhaps cannot rely on strength and fitness to get us out of trouble – but over the years the ocean has taught us that, even if we are super strong and fit, it can always overwhelm humans. What we have learned is sea sense – an ability to read the real, rather than imagined, risks that a particular dive entails, and self-knowledge so that we can determine whether our skills are sufficient to overcome the risks''