Acute Effects of Inspiratory Muscle Warm-Up on Performance and Cardiorespiratory Parameters of Scuba Divers—A Preliminary Study

<b>Background/Objectives</b>: The inspiratory muscles play a fundamental role in cardiorespiratory performance, especially in water sports. The main objective of this study was to investigate the effects of an inspiratory muscle warm-up (IMW) protocol on the performance and respiratory parameters of scuba divers prior to performing two diving tests, one static and the other dynamic. <b>Methods</b>: Eight young, active divers (six men and two women; 26.63 ± 4.67 years of age) volunteered for the study. In two sessions, one using an IMW protocol and the other without IMW, participants performed two underwater tests with a gas tank: a static immersion at the bottom of the pool for 5 min and a dynamic test consisting of swimming underwater for 12 min at 1 m/s. Some cardiorespiratory parameters such as gas expenditure, oxygen saturation (SO₂), heart rate (HR), spirometry, and rating of perceived exertion (RPE) were measured before and after each of the tests. <b>Results</b>: Significant differences were observed in gas expenditure using IMW in both static and dynamic testing (<i>p</i> < 0.05) and in RPE in dynamic testing (<i>p</i> < 0.05). HR values were significantly higher in the pre-dynamic test with IMW and the post-static test with IMW. Finally, with the use of IMW, spirometry values were significantly higher (<i>p</i> < 0.05) in static tests after immersion, whereas in the dynamic test, they were significantly higher before the immersion (<i>p</i> < 0.05). <b>Conclusions</b>: Based on the results of this study, the use of the IMW prior to a dive would be recommended for better overall physical performance, oxygen expenditure, improved pulmonary function, and lower perceived exertion.