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Suunto D4i User Guide

  • Apnea timer

Apnea timer

You can use the apnea timer for interval training when freediving. You can adjust the following settings:

  • Vent.: ventilation time; this is the starting duration of the time your breathing time. The time is increased by the increment time for each interval.
  • Incr: increment time; this is added to the ventilation time for each interval. For example, if your ventilation time is 1:00 minute and your increment time is 0:30 seconds, the first interval ventilation is 1:00, the second is 1:30, the third is 2:00, and so on.
  • Repeats: number of intervals

To adjust apnea timer settings:

  1. While in time mode, keep UP pressed to enter the apnea timer view.

apnea timer view Dseries

  1. Keep DOWN pressed to enter apnea timer settings.
  2. Adjust the ventilation time with UP or DOWN and confirm with SELECT.
  3. Adjust the increment time with UP or DOWN and confirm with SELECT.
  4. Adjust the number of intervals with UP or DOWN and confirm with SELECT.

To use the apnea timer:

  1. Press SELECT to start the first interval. The timer counts down the ventilation time. The countdown continues up to -0:30 seconds beyond the defined ventilation time.
  2. Press SELECT to start the apnea cycle. You can start this at any time during the ventilation countdown. The apnea time is not defined in the watch. It is as long or short as you choose.
  3. Press SELECT again to start the next ventilation cycle.
  4. Repeat until the end of the defined number of intervals.
  5. Press MODE to exit the apnea timer.

You can reset the apnea timer by keeping SELECT pressed.

The apnea timer supports up to 20 intervals, but this is dependent on the ventilation and increment times. The last ventilation cycle cannot be shorter than 0:05 seconds or longer than 20:00 minutes.

WARNING:

Anyone who engages in any form of breath hold diving is in danger of shallow-water blackout (SWB), the sudden loss of consciousness caused by oxygen starvation.