Decompression Illness

Can drinking wine provide benefits for divers?

Historically, alcohol was used to treat bends in Greek sponge divers. In the late 1980s attempts to verify the possible beneficial effects of ethanol on prevention of DCS led to prevailing opinions that there was no proven benefit and that divers should not drink and dive. On the other hand, the assumption that wine drinking has beneficial effects on general health is still propagated.

wine_shutterstock_85339912The so called “French paradox” fueled a search for possible healthful components in wine that, as some researchers posted, protect French people from heart disease despite their fat rich diet and high blood cholesterol levels. Tannins and phenolics, a large group of substances that together make up to 0.1% of wine mass and determine the color and the taste of wine, were identified as beneficial substances. The most intriguing and studied phenolic is resveratrol which is now also sold as a dietary supplement.

Studies of resveratrol in vitro (on cellular cultures or in various models of biochemical systems) have shown anti-oxidant and other effects that with basic biological processes may provide protection against aging, various diseases and death. Further animal studies appeared to confirm beneficial effects. Some of the suspected mechanisms involving resveratrol included functions of endothelial cells (inner lining of blood vessels) and platelets which are also affected in diving. If resveratrol could prevent endothelial cell dysfunction and platelet aggregation, it may help to avoid decompression sickness. Recent resveratrol studies claimed several additional health benefits that could be appealing to divers.

The first claim is that resveratrol has beneficial effects on
skeletal and cardiac muscle functions similar to what is seen with endurance exercise training.1  Wouldn’t it be nice to work on your fitness by relaxing and sipping wine after a long workday rather than going to the gym and sweating?

The second claim is that resveratrol improves brain perfusion and provides neuroprotection2, both of which may be helpful in reducing risk of decompression sickness. Why not drink wine before or after diving?

Unfortunately, there is only one problem with all these studies; the amount of resveratrolDelicious  portion of  fresh salmon fillet  with aromatic herbs, used is equivalent to drinking 50 to 3000 liters of wine per day. It is far more than is needed to get drunk. It’s enough to dive in. Thus, drinking red wine does not seem to be a practical prophylaxis of decompression sickness.

But don’t despair. Even French Paradox is not due to wine drinking as was believed forty years ago. Most population studies indicate that health and longevity may be associated with overall diet. The benefits of French diets appear to come from plenty of fresh vegetables, moderate caloric intake and physical activity rather than just from wine. The French diet has a lot in common with the so called Mediterranean Diet which is widely considered most favorable. In fact, in 2010 it was acknowledged by UNESCO as an Intangible Cultural Heritage of Humanity. (http://www.unesco.org/culture/ich/en/RL/mediterranean-diet-00884)

This story illustrates a common wisdom that there is no one single dietary supplement that could provide what mortals want. To stay healthy and fit for diving, adopt a healthy diet3 and, if you drink wine, limit yourself to one glass with your meal. More importantly, do not drink before the dive.

For quick orientation about healthy meal check MyPlate

http://health.gov/dietaryguidelines/2015/guidelines/chapter-3/strategies-for-action/#callout-myplate

 

References

  1. Dolinsky VW, Kelvin E. Jones EJ, Robinder S. Sidhu SS, Mark Haykowsky M, Michael P. Czubryt MP, Tessa Gordon T, and Jason Dyck   Improvements in skeletal muscle strength and cardiac function induced by resveratrol during exercise training contribute to enhanced exercise performance in rats. J Physiol 590.11 (2012) pp 2783–2799
  2. Otto MA. Resveratrol improves cerebral perfusion in type 2 diabetes. Clinical Endocrinology News Digital Network. January 17, 2016 http://www.clinicalendocrinologynews.com/specialty-focus/diabetes/single-article-page/wdc-resveratrol-improves-cerebral-perfusion-in-type-2-diabetes/1fe1ba3439a5ae9dc24b003d21793512.html
  3. US Department of Health and Human Services and US Department of Agriculture 2005 – 2020 Dietary Guidelines for Americans. 8th December 2015. Available at health.gov/dietaryguidelines/2015/guidelines/.

Validation of Tasmania’s Aquaculture Industry “Yo-Yo” Diving Schedules

Validation of Tasmania photo (3)

Office of Naval Research 2014

While vacationing in Croatia, I heard a story about a diver who fits the description of people I sometimes call “robo-divers.” The story’s hero is a famous Croatian sponge diver, with whom I share an acquaintance. My friend, who is one of his teammates, described this robo-diver’s practice, which is similar to previously described empirical dive practices of other local sponge divers: Reportedly, he does four descents per day to extreme depths, after each of which he ascends very slowly without decompression stops. After the last dive of the day, he quickly takes his boat to shallow waters (within approximately 10 minutes) and descends for about two hours of decompression, split between stops at nine, six and three meters (30, 20 and 10 feet).

I don’t know about his decompression sickness history, but I do know that he is 64 years old now, and the fact that he has survived this long following those types of dive practices make me think of him more as a robot than as a man of flesh and bone. At very least, it is unlikely that this diver has a PFO.

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Using the Selfie as a Telemedical Tool

isolated hand holding smartphone or phone
Last April, a Canadian woman named Stacey Yepes experienced stroke symptoms, but by the time she made it to the hospital her symptoms were gone. Because her physicians could not find any signs of stroke, they believed that she was displaying symptoms of stress and released her home. A few days later, she had a similar attack and used her phone to tape herself during an episode in which she suffered from facial drooping and slurred speech. The video helped her doctors diagnose her with TIA (transient ischemic attack).

In many cases of diseases with transitory symptoms, physicians are unable to diagnose patients and opportunities for early treatments are missed. In the case of TIA, it is especially important to establish an early diagnosis and provide treatment to prevent the progression of symptoms and permanent loss of brain tissue. TIA can lead to blood clotting in the brain, but early administration of thrombolytic medication can prevent clotting and brain damage. Because of the transitory nature of TIA symptoms, some hospitals offer stroke telemedical consultations to enhance diagnosis of and establish early eligibility for thrombolytic medication. By using video connections, they establish a correct diagnosis in 96% of cases, as compared with only 83% of cases in which symptoms are only reported by phone.

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Microparticles and Decompression Stress: Connecting the Dots

blood sample

During the ONR-NAVSEA Progress Review Meeting that took place in Durham from July 15-17 this summer, Stephen Thom summarized the current status of his research on circulating microparticles (MPs), which are small fragments shed by various cells that have been exposed to stress. These MPs can be found in subjects with inflammation or injury and in divers after diving.

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High-Fat Diet and Risk of Decompression Illness

dietObesity has been long considered a risk factor for decompression sickness (DCS). It has been based on findings in animal studies and epidemiological data in military diving. There was no data to confirm the same effects of obesity on incidence of DCS in recreational diving; however, there were some studies indicating a positive correlation between body mass index (BMI) and likelihood of venous gas emboli (circulating gas bubbles) after dive.

In a recent paper, Kaczerska D, et al. The influence of high-fat diets on the occurrence of decompression stress after air dives. UHM 2013;40(6):487-497, intended to test possible effects of high fat intake on risk of DCS.

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