Breathing

What It Is

How you breathe through a working set.

Why It Matters

Breathing technique is not one of the levers that decides what you get out of training, and the confident advice attached to it rests on a thin base. In healthy young women squatting at light and moderate loads, holding the breath through the lifting phase raised systolic blood pressure and the load on the heart against breathing through the same set, and made the effort feel harder. In untrained adults, a randomized trial traced the arterial stiffening that follows a moderate-load session to the breath-hold rather than to the lifting, since the same session performed with paced breathing produced none. Both are single sessions, and nothing here follows anyone long enough to show that those swings matter.

Holding your breath is not simply a mistake. Bracing against a held breath is how lifters stiffen the trunk, and the pressures it generates inside the abdomen are highest in exactly the lifts people brace hardest for. A brief hold appears to happen whether you intend it or not once an effort approaches maximal, and where the strain was measured at lighter loads the investigators read it as moderate but not dangerous, in the healthy young women they studied. The blanket prohibition came from exercise advice written for people with cardiovascular disease, so if that is you, or you are at risk of glaucoma, keep breathing through the set and treat it as a question for your doctor rather than a training one.

Which airway you use appears not to matter for lifting: breathing in and out through the nose, in through the nose and out through the mouth, or entirely through the mouth showed no difference in repetitions to failure, perceived effort or blood oxygen in either sex, with only a small heart-rate difference among the men. So use whichever airway moves air comfortably, and keep any hold to the repetition you are in rather than carrying it across the set. Then give your attention back to load, volume and progression, which are what actually change the result.

• MacDougall, J.D. et al. (1992). Factors affecting blood pressure during heavy weight lifting and static contractions. Journal of Applied Physiology. doi.org/10.1152/jappl.1992.73.4.1590
• Blazek, D. et al. (2019). Systematic review of intra-abdominal and intrathoracic pressures initiated by the Valsalva manoeuvre during high-intensity resistance exercises. Biology of Sport. doi.org/10.5114/biolsport.2019.88759
• Lörinczi, F. et al. (2024). Nose vs. mouth breathing- acute effect of different breathing regimens on muscular endurance. BMC Sports Science, Medicine and Rehabilitation. doi.org/10.1186/s13102-024-00840-6
• Hummelmann, S. et al. (2026). Breathing technique-dependent acute cardiopulmonary responses during squats in healthy females. Physiological Reports. doi.org/10.14814/phy2.70831
• Perry, B.G. et al. (2026). Resistance exercise with combined Valsalva manoeuvre acutely increases carotid-femoral pulse wave velocity in healthy untrained individuals. European Journal of Applied Physiology. doi.org/10.1007/s00421-026-06167-z