Career perspective: Alf O. Brubakk-looking back to see ahead.

The following describes my professional life up till today, but it also describes what I think lies ahead. I have led an interesting professional life and been lucky enough to be at the centre of some of the important development in modern medicine and diving, namely ultrasound in cardiology and the mechanisms of decompression. I therefore should be able to see some of the most challenging and exciting problems ahead. Ultrasound in cardiology has developed from simply listening to the Doppler signal to determine the velocity of blood flow to the complicated description of images presented today. Diving, in addition to being an important commercial and environmental activity, exposes the individual to intermittent hyperoxia and pressure reductions. These challenges evoke the production of radical oxygen species (ROS) and microparticles (MP) that also are central to many pathophysiologic mechanisms that are involved in a number of severe human diseases. Thus, diving can be regarded as an important model of disease and allows us to study their effects on healthy young individuals. The future thus points towards an integration of environmental physiology with detailed physiological and pathophysiological mechanisms and makes diving physiology a potentially very important field of study.