About This Project

Diving data indicates that closed circuit rebreather fatalities increase with age, specifically around 40 years of age. The current hypothesis is that the increase in deaths is related to the cardiac load of diving. However, the causes of such cardiac events remain unclear, in part because data is hard to collect and in part because the cardiac load of diving has not been adequately studied. This study will perform underwater cardiac testing using COTS wearables.

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What is the context of this research?

Diving presents unique physiological challenges that require a comprehensive understanding to ensure diver safety and optimize performance (Foster & Sheel, 2005; Mier & Kegeles, 2002; Matuszak & Cooper, 2019). Cardiac load has been particularly identified as a cause of accidents and death, notably by Divers Alert Network (DAN). (DAN Annual Fatalities Report, 2012-2015, 2018, 2020; Trout et al., 2016). However, real-time cardiac data remains elusive and has not been compiled, let alone studied. For instance, while it is known that humans experience a mammalian reflex underwater, it is unclear how this affects the heart. (Panneton, 2013; Vincenzi, 2019). Based on this, there is increasing interest in studying the cardiac responses of underwater diving.

What is the significance of this project?

To date, there are no civilian real-time recordings of cardiac response to elevated cardiac demands while diving on a rebreather. This project would shed light on heart rate underwater, notably, heart rate during exertion and maximum heart rate achieved while engaging in maximum physical demands. Of importance, it would start answering questions about whether the underwater environment makes it harder for the heart to adequately respond. This, in conjunction with known underwater fluid shift to center mass could yield a hypothesis as to the increase in cardiac events after a certain age. If the heart is overloaded by the fluid shift caused by immersion, and it is unable to achieve its baseline heart rate, it could be a cause of heart failure.

What are the goals of the project?

The goals of this project are to establish VO2 Max for the subjects, and subsequently ask them to conduct two dives. The first dive will be at 10m, which only doubles pressure. Each subject will be asked to swim 400m at a calm pace and then 400m at the hardest pace they can manage. Each 100m length will be measured in time and hart rate will be monitored the entire time. Subjects will then be asked to repeat the exercise at 30m.

The ultimate goal is to create a baseline of cardiac responses to depth and level of exertion.