What is obesity?
Obesity is now very common a recent report by the World Health Organisation (WHO) showed that over 64% of UK Adults were obese or overweight. This is being reflected in the diving population. Being overweight or obese can have adverse effects in divers as it can impact on a person’s general physical fitness and diver safety in the event of a rescue.
You are classed as overweight if you have a Body Mass Index (BMI) of over 25 and obese if your BMI is over 30. Although your BMI is not the only thing to take into consideration. Cardiovascular fitness is also extremely important. If you are obese or overweight a diving doctor will likely ask you about your levels of physical activity or ask you to complete an exercise test.
What’s the problem with obesity and diving?
When you are obese you have an increased fat content of the body. Nitrogen (or other inert gases) slowly build up in fat cells and take a long time to dissipate. This means obese people will have a bigger inert gas load over a dive than somebody with a body weight in the healthy range. This means that obese people are more likely to develop DCS. In addition dive computers are programmed with dive tables based on studies done on people with a weight in the healthy range. As they are not adjusted based on body fat content this increases the risk of DCS in obese divers.
Lastly, it is well established that obesity increases the incidence of many other medical conditions such as diabetes, heart attack, high blood pressure, lung disease, gastro-oesophageal reflux and stroke. These conditions can cause further complications when diving which, in the worst cases, can cause death when SCUBA diving.
Can I dive if I am obese?
If you are overweight or obese it is strongly recommended that you see a diving doctor before undertaking any diving activity. It is likely that you will be required to have a face to face medical where many factors other than your weight (such as cardiovascular fitness) will be considered. A BMI of more than 39.9 will exclude diving although regard should be given to the distribution of the weight and muscle mass.
Your diving doctor can then advise you on steps to improve your fitness to dive if required or may restrict the type of diving you can do in order to keep you safe.