Breathe

Strength training is one of the safest forms of physical activity a person can engage in.  Focus on breathing throughout the repetition and set to make your workout as safe as possible.  You want to avoid holding your breath while exerting, known as the Valsalva maneuver, as this may acutely spike your blood pressure (potentially to unsafe levels).  The Valsalva maneuver generally involves closing your lips, holding your breath as you lift, and then slowly exhaling upon completion of the rep.  This is NOT ideal breathing. 

How should you breathe?

Focus on taking multiple short breaths as you lift the weight (especially during pushing movements such as chest press, overhead press, or leg press).  This is especially important toward the end of the set when exertion levels are high. 

Take home message: When the set gets tough, take multiple short breaths as you lift the weight.