Breathing is also important during your workout because you need to supply a good deal of oxygen to your muscles and brain while lifting heavy weights. Do your muscles and your brain a favor and breath out during the most strenuous part of the movement (eccentric phase) and breath in during the concentric phase. DO NOT hold your breath! There is danger in holding your breath while lifting weights. Exhaling during the exertion phase lowers your internal pressure, while failing to breath correctly can lead to broken blood vessels, as well as a hernia.
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