Objective: Caffeine is one of the most popular sports nutrition supplements. Inspiratory muscle training(IMT) can improve lung function and increase respi更多ratory muscle strength, thereby weakening the metabolic reflex of respiratory muscles, promoting recovery from respiratory muscle fatigue. However, research on the effects of caffeine on IMT is limited. To investigate the acute effects of caffeine intervention in inspiratory muscle training on lung function and cardiovascular system in young men. Methods: In this study, 12 healthy male college students aged 18 to 25 years with no training history were selected for two tests at a sports college in Beijing. Subjects underwent medium-intHepatic fuel storageensity inspiratory muscle training(60% MIP) in both tests, and lung function parameters were measured before and after training, including: spirometryMRTX849细胞培养, one-second rate, maximum inspiratory pressure; cardiovascular system, including heart rate variability, blood pressure. The study was reviewed and approved by the Ethics Committee of the Capital Institute of Physical Education(approval number 2022A57). Results: There were no significant differences between the pre-training caffeine and placebo groups at baseline levels in terms of basal information, lung function and cardiovascular system(p>0.05). Compared to the placebo group, there were significant differences in heart rate variability, heart rate, systolic blood pressure and maximum inspiratory pressure in the caffeine group after the intervention(P<0.05), and no significant differences in spirometry, one second rate, diastolic blood pressure or blood flow irrigation values(P>0.05). Further studies are needed to confirm the effects and safety of caffeine on the acute effects of inspiratory muscle training. Conclusion: caffeine intervention enhances training status in inspiratory muscle training and has a positive acute effect on lung function and the cardiovascular system in healthy male university students.