2007, Piran, Slovenia

Diving Physiology
recorded (MIE Medical Research Ltd, UK). These dives were repeated on a separate
day.
For the dives in the immersion tank the subjects finned at a depth of one metre on a
specifically designed finning ergometer (Figure 1). The subjects undertook an
incremental test to volitional exhaustion to determine peak oxygen uptake (VO2)
whilst finning. On the second occasion and following completion of all the dives in
the lake the subjects completed two 10 minute dives (separated by a short rest period)
finning on the ergometer. The subjects finned at loads to elicit the same heart rate that
would be attained during finning in the lake at 0.7 and 1.1 kts. As the dives in the lake
were not completed at exactly 0.7 and 1.1 kts the heart rates at these speeds were
calculated from the actual velocity and heart rate from both dives in the lake for each
subject (assuming a linear relationship between velocity and heart rate). During the
pool dives, exhaled gas expelled from the diving regulator was continuously collected
using a Perspex hood under the water and analysed on the surface using a flow turbine
(KL Engineering, USA), mixing box and oxygen and carbon dioxide analyser
(PowerLab, ADInstruments, NSW, Australia). The system was calibrated using
known volumes of calibration gas bubbled into the water (at different rates 20, 40, 60
and 80 L.min -1 ) in the same position in the water as gas was exhausted from subjects’
SABA. Heart rate was recorded (MIE Medical Research Ltd, UK).
Expired air
bubbles
Figure 1. A photograph of the diver ergometer
Resistance is increased
by adding weights
Maximal oxygen uptake (VO2max) was measured during running on a treadmill,
using an incremental protocol to volitional exhaustion. Expired air was collected and
analysed using a flow turbine (KL Engineering, USA), mixing box and oxygen and
carbon dioxide analyser (PowerLab, ADInstruments, UK). Subjective assessment of
how closely finning on the ergometer corresponded with finning in open water was
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