I have been a regular at my local gym twice a week for several years. When I exercise in the gym on an elliptical trainer I always try to limit my max heart rate to 162bpm (200-my age). I also try to burn as many calories as possible within that limit.

I usually work out for 40 minutes. My heart rate slowly builds through that time and in the last 10 minutes I either have to slow down or my heart rate will go above 162. But recently I have noticed that taking deep breaths and holding those breaths for 3-5 seconds seems to force my heart rate down although I am still exercising at the same pace. Does anybody know what causes this effect? It only works for a short period of a minute or two before I get totally out of breath and have to revert to rapid breathing again.

  • 1
    Ignore 220-age. Also breathe as you need, not to artificially hit some mythical range.
    – JohnP
    Commented Oct 24, 2018 at 23:47
  • Fair comment, but the question remains
    – Slarty
    Commented Oct 25, 2018 at 1:09
  • @Slarty I would assume it is because you're not taking in as much oxygen and you've forced your body to slow down by taking deep breaths, controlling your body with air. Then you run out of breath because you've used up the lack of oxygen then start breathing heavily to regain the oxygen you're lacking
    – Twyxz
    Commented Oct 25, 2018 at 6:34
  • @Twyxz perhaps - I was wondering if there is some difference between oxygen absorbtion and C02 removal? Perhaps oxygen is more easily absorbed where as CO2 removal is hindered with inflated lungs? Not sure though...
    – Slarty
    Commented Oct 25, 2018 at 13:40

1 Answer 1


This has been popularized lately as "box breathing" which may help you in your research.

As to the actual mechanism, I haven't seen a lot of serious study. This paper seems to indicate it's related to cortisol, which might be a start.

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