ANATOMY OF A DIVER
Obesity
Carrying a bit of lockdown flab ? Dr Ed Shattock of DDRC Healthcare sets out the safety concerns for overweight divers
OBESITY DESCRIBES EXCESS BODY FAT to the extent that it can have a negative impact on that person ’ s health . Current estimates suggest that one in four adults and one in five children in the UK are obese and this number is unfortunately increasing . Obesity is generally measured using Body Mass Index ( BMI ) which looks at weight in relation to height and can be broken down into several categories .
Healthy weight is considered 18.5-24.9 kg / m ² – you can check your own BMI using the NHS calculator ( www . nhs . uk / live-well / healthy-weight / bmi-calculator ). BMI is not a perfect measurement , for example it will over estimate body fat in more muscular and taller individuals , but is a useful “ rule of thumb ” for broad categorisation .
The UK Diving Medical Committee suggest that anyone with a BMI of greater than 30 kg / m ² should normally be excluded from diving . This often causes concern with divers during medicals who may not have been told previously that weight can be a problem for diving . So why is it important for a diver to be a healthy weight ?
Obesity and decompression illness ( DCI )
Nitrogen is at least five times more soluble in fat tissue than in muscle . Therefore , divers with a greater amount of body fat will be able to store an increased amount of nitrogen , potentially resulting in increased numbers of bubbles forming post-dive .
A study in 2017 looking at bubble grades after diving supported this idea by showing that divers with a higher BMI had more significant bubbles post-dive . However , translating this increased bubbling to an actual increased risk of DCI is not so clear cut and there are several studies with conflicting results . This is likely due to DCI being a relatively rare event , which makes large studies of the factors involved problematic .
We should also remember that dive tables , and the computers that are programmed using them , were created using young , fit divers . The greater the difference between the individual using the tables and the divers the tables were based on , the greater the risk that the table will not represent safe limits for that individual .
Obesity and fitness
Increasing obesity correlates well with decreasing aerobic fitness . Although diving is mostly a low intensity activity , the ability of a diver to respond to an emergency scenario is extremely important . A diver with poor fitness may struggle to rescue themselves if they get into trouble and will be less able to assist a buddy in a similar situation . Furthermore , divers with good fitness levels have been shown to have a lower risk of DCS and also use gas less quickly allowing them to dive for longer .
Obesity also comes with an increased risk of other underlying health issues such as diabetes or heart disease . These diseases come with an increased risk of death while underwater as well as increasing the risk of certain diving related problems . The main culprit here is Immersion Pulmonary Oedema ( IPO ) a life-threatening condition linked to high blood pressure , another common finding in obesity . IPO describes an increased amount of blood returning to the heart when submerged , as a result of compression of peripheral blood vessels by water pressure . This increased blood volume may overwhelm a poorly functioning heart , leading to fluid on the lungs and difficulty breathing . It is often described as feeling like you have run out of air .
Detail from a public information campaign showing ( l-r ), normal , overweight and obese physiques
Obesity and Covid-19
Another condition of concern with obesity is Covid-19 . We know that overweight or obese patients are more likely to suffer from severe Covid symptoms when compared to their healthy weight counterparts , so losing some weight may be more important now than ever . ‘ Long Covid ’ or persistent symptoms following resolution of Covid-19 infection , is also now being studied and although it seems to affect even those who were asymptomatic , it is likely that those who have had more serious Covid-19 are more likely to suffer from ongoing symptoms . One of the main concerns of this for divers will be persistent shortness of breath and underlying lung changes , which may lead to an increased risk of air trapping .
Obesity and fitness to dive
Overall , obesity increases your risk of other serious underlying health conditions , reduces your fitness level and may increase your risk of DCS . So , maintaining a healthy weight and good level of fitness are clearly an important part of diving safety . If a diver has any concerns about their weight and how it could impact their diving , they should discuss it with their local diving referee . �
This page is produced with DDRC Healthcare , specialists in diving and hyperbaric medicine
www . ddrc . org
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