Posted on August 19, 2019 by Kate Halsall

Have you ever found yourself doing an exercise and then realise you’ve held your breath throughout? Why do we do it? Given that breathing is essential to our life, I find it strange that this is THE most common teaching point I give – don’t hold your breath during exercise. Honestly, I find I say “don’t forget to breathe” to a lot to my clients – especially when we box! Luckily I’ve never had anyone pass out on me yet! But surely a short hold of breath isn’t really bad for you? And what actually happens when you do hold your breath?

What Happens When You Hold Your Breath?

  • Carbon dioxide starts to accumulate in the body and cells.
  • Your breathing muscles like your diaphragm and intercostals start to get tight – if you hold your breath for a long time, they could go into spasm and start to feel like they are burning.
  • It will initially raise your blood pressure and then you’ll experience a drop in blood pressure.
  • Creates a higher acidity within the blood.
  • Blood is diverted to the brain to try and keep you alert.
  • It can create a lactic acid build up in the muscles.
  • Your face goes very pale.
  • You could pass out!

Is It All Bad Though?

There are a lot of websites out there that encourage you to not only slow down breathing, but also to hold your breath. There is research now that suggests carbon dioxide in the body can actually help with blood pressure, anti-inflammatory effects and relaxing the nervous system. Breathing and breath holding is widely used in yoga for the practice of pranayama.  It has also been shown that “breathing training” can strengthen the lungs and therefore increase their aerobic capacity. So no, it’s not all bad at all.


The difference here is that I’m referring to holding your breath whilst physically exercising eg high intensity exercise. Despite the picture on the blog, I’m not referring to swimming or diving here, as that’s a whole different kettle of fish. If you’re wanting to exert energy and keep going through your workout, then simply put, you need oxygen. And before you ask – and I know that you’re thinking it – how should you breathe during exercise? Take a look at this blog which will help you with that!