Breathing Exercise 101: What Really Happens When You Finally Slow Down

Here's the bit that explains pretty much every benefit you've read about. Your breathing is the one part of your autonomic nervous system you can grab the steering wheel of. Heart rate, digestion and sweating all run on autopilot, but breathing you can override on purpose.

When you slow it right down, you nudge your body towards the parasympathetic side, the "rest and digest" setting, as opposed to the sympathetic fight-or-flight one. To calm yourself physically, slowing down your breathing is an easy technique. The more slow and rhythmic your breathing becomes, your heartbeat slows down and you become relaxed mentally not only during the exercise but even for a few minutes after that.

Cortisol is where I'd gently pump the brakes. One review suggests that sessions of 10 to 15 minutes bring measurable drops in cortisol and anxiety, while anything under five minutes gives patchy results. So a single dramatic gulp of air in a toilet cubicle won't rewrite your hormones. It might still help you feel steadier, but I'd rather be honest than sell you a miracle.

Dr. Sid Warrier, a neurologist and popular YouTube science communicator in his YouTube video said,, "Breathing exercise helps switch your autonomic system from a hyper sympathetic state to a calmer parasympathetic state."

This is the main reason most people land on this topic, so let's keep it separate from the lung stuff, because they're really two different jobs.

For stress, slow breathing works by telling your nervous system the danger has passed. Your brain reads your breath as a signal, so when it's slow and steady, it takes the hint. Some studies find real benefits for how anxious people feel, though it's not a clean picture. In one review, a 12-week slow breathing practice reduced psychological anxiety scores but didn't change the physiological stress measure. I find that quite reassuring, actually. It suggests that feeling calmer is worth having in its own right, even if the numbers on a heart monitor don't budge.

One caveat from me, as someone who's been there. Breathing exercises for anxiety are a tool, not a treatment. If anxiety is running your life, please talk to your GP. And some people find breath holds make them feel more panicky, which brings me neatly to the techniques.

Here are three I'd actually recommend, with the steps. Sit or lie somewhere comfortable first, and don't worry about getting it perfect.

Diaphragmatic (belly) breathing. The easiest one and the best place to start.

1. Put one hand on your chest and one on your belly.
2. Breathe in slowly through your nose for about four seconds. Your belly hand should rise while your chest hand stays fairly still.
3. Breathe out gently through pursed lips for six seconds or so.
4. Keep going for five minutes, or ten if you can.

Box breathing. It's popular with people who like a bit of structure, and I know a few who swear by it before presentations.

1. Breathe in through your nose for four counts.
2. Hold for four.
3. Breathe out for four.
4. Hold for four, then repeat for a few minutes.

It does seem to ease self-reported anxiety and help focus, although its effects on heart rate variability are less consistent than plain slow breathing without holds. If the holds make you tense, skip them.

4-7-8 breathing. This is the one for bedtime.

1. Breathe in quietly through your nose for four.
2. Hold for seven.
3. Breathe out through your mouth, making a soft whooshing sound, for eight.
4. Repeat up to four times to begin with.

The long hold can feel uncomfortable if you're prone to panic, so start small, and if you feel lightheaded, stop and breathe normally. That's not a failure, it's just your body being honest.

An exercise for breathing will not make you have magical larger lungs. The only thing that this exercise can help achieve is improving the efficiency of the lungs you already have by training the diaphragm, which is basically the muscle doing all the work, as well as stopping the reliance on shallow breaths from the chest. Belly breathing and pursed-lip breathing (breathing out slowly through the narrowed lips) are the techniques mostly used in people who have breathing problems such as COPD and asthma. This is the important point. If you are having difficulty breathing, wheezing or you have a chronic condition of the lungs, get an examination done and follow proper advice, rather than copying anything from the internet.

In all seriousness, link it to some other habit you have. Do the five minutes after brushing your teeth, while the kettle boils, or after you've parked the car before going inside to work. Consistency will beat intensity every single time. And go for the slow, relaxed breath, rather than the big gasp, since the latter may result in you feeling dizzy.

Breathing techniques may not be a miracle cure, but they're one of those things that is always available to you. Five minutes after you've brushed your teeth or when the kettle's boiling will not necessarily solve all your problems. They can help relieve some tension after a difficult day, which can be beneficial for you. Try belly breathing, don't worry if you can't hold it, and consult your GP regarding any troubles with your breath or anxiety.