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Table 1 In-water heart rate and ventilatory variables at the end of the four dive sessions

From: The Key Roles of Negative Pressure Breathing and Exercise in the Development of Interstitial Pulmonary Edema in Professional Male SCUBA Divers

 

Static

Fin exercise

PPB (A)

NPB (B)

PPB (C)

NPB (D)

Heart rate (bpm)

58.9 ± 4.9

50.1 ± 4.7

111.6 ± 5.6a

109.8 ± 45.5a

Tidal volume (L)

1.3 ± 0.1

1.3 ± 0.2

3.5 ± 0.2a

3.5 ± 0.2a

Minute ventilation (L min−1)

8.2 ± 2.2

8.2 ± 2.7

41.3 ± 9.7a

40.3 ± 9.6a

Breathing frequency (min−1)

6.4 ± 1.4

6.3 ± 1.3

11.8 ± 2.1a

11.5 ± 2.2a

Peak inspiratory pressure (mbar)

14.9 ± 1.8

− 25.4 ± 1.7b

12.7 ± 1.6

− 27.6 ± 1.58b

Peak expiratory pressure (mbar)

22.8 ± 1.2

− 18.6 ± 1.5b

25.2 ± 1.1

− 15.3 ± 1.9b

Static lung load (mbar)

18.8 ± 1.5

− 21.9 ± 1.3b

18.9 ± 1.3

− 21.4 ± 1.1b

WOB insp. (J)

− 1.9 ± 0.3

3.2 ± 0.7b

− 4.4 ± 0.8

9.5 ± 0.9ab

WOB/Vt insp. (J L−1)

− 1.5 ± 0.2

2.5 ± 0.2b

− 1.3 ± 0.2

2.8 ± 0.2b

cWOB insp. (J)

− 376 ± 140

+636 ± 244b

− 1615 ± 560a

+ 3345 ± 868ab

Ultrasound lung comet

0

0

4.2 ± 2.3a

15.1 ± 15.3ab

  1. Two-way analysis of variance (ANOVA) with repeated-measures and the post hoc Holm–Sidak test were used to compare values in the four conditions for each variable.
  2. Abbreviations: Static dive session simply floating without physical activity, Fin exercise dive with continuous fin swimming, PPB positive pressure breathing condition caused by positive transpulmonary hydrostatic difference or positive static lung load, NPB negative pressure breathing condition caused by negative transpulmonary hydrostatic difference or negative static lung load, SLL static lung load, WOB insp. breathing work for one tidal inspiration, WOB/Vt insp. one-cycle inspiratory work of breathing per volume unit, cWOB work of breathing cumulated over the 30-min session
  3. aExercise different from static dive
  4. bStatic-NPB different from static-PPB, or exercise-NPB different from exercise-PPB