When walking I have recurring pop-up thoughts. These come out of nowhere, and frequently appear unrelated to any current activity. They are like floating bottles with messages in them. They just happen to be floating on the surface of my thoughts.
Today, one set of these thoughts dealt with hypothermia. I experienced this at least three times while active in marine search and rescue. On one of these occasions I was in distress, in the water, and was unable to make a coherent call for help.
On another occasion, I made a series of poor decisions without being conscious of that fact. The third instance was during a shoreline search up a swollen river. Because of logs, a shallow bottom, and other obstacles, we ended up having to wade against the current and pull the work-boat behind us. This was mid-winter, the water was just above freezing; at a certain point, I could no longer feel my legs, or my feet. My fear was that I would lose my footing, be upended, be carried downriver by the rushing waters, and then become lost on the surface of the wine dark sea.
As I puzzled over these memories, I realized they were relevant to the events of the prior night when I attempted to speak and uttered nothing but babble. Hypothermia results from the attempt to conserve body core temperatures. The head, armpits, and groin, are the areas of maximum heat loss. When core temperature drops, the body reduces circulation to the extremities in an attempt to preserve bodily warmth. This has a direct effect on cognition.
The time I was in the water and unable to summon help bore a similarity to the babble response from the night before. Several hours had been spent deeply focused on task performance. When I finally got up, my body was extremely stiff and uncomfortable. Apart from a few momentary breaks, I had been seated for approximately five hours. Immediately before the conversation, I had eaten some of the catered food that was on offer. Digestion pulls blood to the stomach. A sedentary posture tends to reduce circulation. There is evidence that mTBI results in impairment to the extremely small blood vessels that feed glucose and oxygen to the brain.
In the period immediately after the accident, I became highly confused and disoriented when attempting to visit employer’s offices in areas of Kanata and Ottawa that I know quite well. I lack an exact memory of this confusion. I am also unable to make full recall of events from my SAR experience of 40 years ago.
Based on research performed at the University of Toronto, I suspect some part of my mTBI experience may be due to the impaired circulation of essential nutrients to areas of the brain mass. This thesis is supported by my positive response to walk therapy which has the effect of increasing oxygen perfusion of the brain.