Note the reading:
屏 here is bǐng (third tone, 'to suppress / restrain'), NOT píng ('screen'). The very common four-character expression
屏气凝神 (bǐngqì níngshén, 'hold breath, focus mind') describes intense concentration or anticipation. For everyday 'hold breath' (e.g. when swimming),
憋气 (biēqì) is more colloquial.
