Often in our busy lives, we can take for granted our health or indeed ignore minor ailments when we should perhaps treat them. Therefore it will come as no surprise that often certified divers don't think about their fitness or health before they dive or if they have had a period of time out of the water.
General health & fitness are particularly important when diving due to currents, hot or cold weather, the physiological changes our bodies experience under pressure and of course general swimming and endurance from a dive.
We often experience divers who hold an Advanced or Rescue diver certification who struggle to swim even 20m on the surface with their equipment or to swim through a mild current. The impact of lack of fitness could not only endanger your life but also that of your buddy or other divers by leading to panic or the inability to control or manage the situation you are in.
Anyone taking a course or beginner dive is requested to complete a medical questionnaire prior to any in water activity. The medical clearly states that if there are any YES answers, then a doctor's certificate must be obtained before the course/dive can commence. The questions cover a range of medical problems from frequent migraines to asthma to heart conditions. Only a dive doctor can review your medical history and advise whether any present problems are compatible with diving or whether indeed you are not able to dive because there is too high a risk.
So even as a certified diver, if your circumstances have changed or there has been an illness/surgery/medical problem, go and get yourself checked by a dive doctor to ensure you really are still fit to dive and that you are in the right shape to manage the conditions of the dive you are planning to attend.