Dive Log inc Sportdiving magazine

David Sawatzky, S.C., C.D., B.Med.Sc., M.D., M.Sc., is a diving medical specialist who was on contract at Defence Research and Development Toronto from 1998 to 2005. Previously he was the Canadian Forces Staff Officer in Hyperbaric Medicine at DCIEM (1986-1993) and later the Senior Medical Officer at Garrison Support Unit Toronto (1993-1998). He’s written a

diver warmer and the increased weight forces the diver to have larger muscles and stronger bones just to move their own weight around. In the water the diver does not have to support the extra weight. Women tend to have more fat on their legs than men resulting in more leg buoyancy, better trim, and more efficient finning. However, too much fat is a very bad thing in that it increases the cross-sectional area and drag while finning, makes getting into and out of the water much more difficult and dangerous. In addition, obesity is often associated with cardiovascular disease, endocrine disease (diabetes), orthopedic problems, lower levels of fitness, and increases the risk of hyperthermia. In warm waters, divers should be fit and lean. In cold waters, divers should be fit and a little extra insulation is not a bad thing. Does the decline in fitness and performance that comes with aging matter in diving? I think it does. In Australian commercial diving candidates, 20% fail to meet the medical standards in their 20s while 45% fail to meet the medical standards if they are older than 35. In recreational divers, two groups are over represented in fatality statistics. The new diver and the older diver. Historically, when divers tended to be fit and young, the most common cause of death in divers was arterial gas embolism (panic, hold breath and head for the surface). For the past couple of decades, when divers have been older and less fit, the most common cause of death in divers has been heart attacks. Diving is relatively hard work and has been compared to playing basketball. The ‘exercise’ of diving will often trigger a heart attack in a diver who is at risk of having one. If aging reduces performance in everyone, what can we do? We can’t stop aging. Actually we can but getting older is far better than the alternative (dying). Performance declines in everyone as they get older, but the ‘rate of decline’ can be fairly dramatically altered. We have to consider ‘chronological age’ and ‘physiological age’. Chronological age is simply the amount of time since you were born. Not much we can do about that! Physiological age is the performance age of our bodies and we can have a significant influence on that. Lifestyle choices have a huge effect. Smoking will add at least ten years to your physiological age. Obesity will accelerate wear and tear injuries and damage. A poor diet can result in raised blood pressure, elevated lipids (cholesterol) and other negative effects. Lack of proper sleep, excessive stress and anxiety, lack of ‘relaxation time’, and lack of a sense of ‘humour’ all cause us to ‘age’ faster. Exercise is critical. It dramatically slows down the rate of decline. You need to start when you are young and continue for the rest of your life. If you stop exercising for a few years, what you lose during those years can never be recovered. We all need to do 30 to 45 minutes of continuous aerobic training, every day. Aerobic training causes biochemical changes in our bodies that only last for 24 hours. Flexibility is also very important and stretching should be done at least once each day. Strength training is also important and is often targeted at recovering from a specific injury, preventing low back pain (stomach is critical) or acquiring a specific ability (to carry tanks, etc). I am back in clinical practice now, seeing patients all day. I have tried to ‘practice what I preach’ for most of my life and it is starting to show. I am fit enough to keep up with most people much younger than me, and I get told I ‘don’t look my age’ at least once a day. The effects of aging definitely can be “delayed” ☺ .

monthly column on diving medicine in Canada’s Diver Magazine since 1993, has been on the Board of Advisors for the International Association of Nitrox and Technical Divers (IANTD) since 2000, and is an active cave, trimix and closed circuit rebreather diver/instructor/instructor trainer. David’s first love is cave diving exploration and he’s been exploring and surveying underwater passages in Canada since 1985. David was responsible for the exploration and mapping of almost 11 kilometres of underwater passages in the Ottawa River Cave System. In 1995, he executed the first successful rescue of a missing trained cave diver. David received the Canadian Star of Courage for this rescue which took place in the chilly Canadian waters of Tobermory, Ontario.

www.divelog.net.au| ISSUE 379 | FEBRUARY 2020 | DIVE LOG Australasia inc. Sportdiving Magazine | 55

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