In this publication, the researchers used doppler ultrasound to look for bubbles in commercial breath-hold (Ama) divers from Japan in response to reports of symptoms consistent with neurological decompression sickness (DCS). They were able to detect circulating bubbles. They concluded that “intravascular bubbles may be formed after repetitive breath-hold dives with short surface intervals or after a long breath-holding session in Ama divers. Symptoms consistent with neurological accidents in repetitive breath-hold diving may be caused in part by the intravascular presence of bubbles, indicating the need for safety procedures.”
Here is a review on diving medicine.
Here is a publication that concludes that high-fat diets increase the decompression stress on divers. This appears to contradict a few studies done on ketogenic diets in mice. It also disagrees with studies being conducted by a variety of navies. Normally, I just point out interesting studies and let you read them and draw your own opinion, but the science associated with this one forces me to make some comments. This recent study has a few design flaws:
- It relies on food surveys which are a problem with many nutritional studies (they are notorious for poor accuracy);
- While the researchers collected data on age, height and weight, these are not always a good indicators of physical fitness, so it is difficult to extract general poor health from diet in their conclusions
- They looked at circulating blood lipids, but contrary to popular media reports, the science connecting dietary fat to circulating blood lipids is very convoluted. It is not simply a matter of eating fat raises blood lipids and decreases health, otherwise you would not see so many people on low fat diets that still suffer from poor health.
- Lastly, even if there is a correlation, it is not the same as causation, so their study does not support that eating higher quantities of fat will increase your risk of decompression illness. This is not the same as the more abundant research that indicates that being overweight increases your risk of DCI, in that case their are mechanisms of cause.
Over on the PADI TecRec blog, they have a post on robotic diving and a project called CADDY. This is not your typical diving robot, this one is intended more as a “buddy” to human divers. Personally, I prefer a human buddy so I have someone to talk to about the dive afterwards, but I can see applications for this project. Here is a direct link to the CADDY project.
National Geographic has a great article here on cave divers in Mexico finding a skeleton that is 12,000 to 13,000 years old; the oldest complete skeleton of its kind. Archaeologist and anthropologists hope it will fill in some of the gaps in their knowledge between early Paleoamericans and later-day Native Americans.
Here is an awesome youtube video by Steve Martin on side mount penetration techniques.