How to breathe properly during hard cardio

As you work harder, your muscles burn more fuel and produce more carbon dioxide. Your body senses the rising carbon dioxide and responds by moving more air in and out of your lungs to blow it off and top up oxygen. That extra air is called your minute ventilation.

Here is the part most people get wrong. When effort climbs, your body increases air mostly by making each breath bigger first, then by breathing faster once the breaths cannot get much deeper. Shallow, rapid panting skips the efficient part. You end up mostly moving air in and out of the dead space in your airways rather than deep into the lungs where the exchange happens.

The diaphragm is the big dome-shaped muscle under your lungs and it does most of the work of a good breath. When you breathe well, your belly expands as the diaphragm drops and pulls air deep into the lungs. When you breathe poorly, you lift your chest and shoulders and only fill the top.

Deep breaths matter because doubling the size of a breath moves far more useful air than doubling the rate of shallow ones. A bigger breath reaches more of the lung, so more oxygen and carbon dioxide actually get exchanged. That is why a calm, deep pattern feels more sustainable than frantic panting at the same effort.

1. Feel it first at rest. Lie down, one hand on your chest and one on your belly. Breathe so the belly hand rises and the chest hand stays still. That is diaphragmatic breathing.
2. Take it to easy cardio. On a gentle walk or easy ride, practise letting your belly expand on the inhale. Keep your shoulders down and relaxed.
3. Carry it into harder work. As intensity rises, keep the breaths deep and full rather than letting them go shallow and high. This is the habit that pays off when it gets tough.

A rhythm gives your breathing structure so it does not spiral. Locking your breath to your steps or pedal strokes keeps it steady and gives your mind something to hold onto when the effort bites.

The exact count matters less than having one. Runners often like patterns that land the exhale on alternating feet so the same side is not always taking the impact at the bottom of the breath. Cyclists and rowers can tie the breath to the stroke. Pick something and let it become automatic.

This gets more debate than it deserves. For easy, low intensity cardio, nose breathing is pleasant and keeps you honest about pace, because if you cannot hold it you are probably going too hard for an easy day.

For genuinely hard efforts, your body needs to move too much air for the nose alone. Mouth breathing, or a mix of both, lets you shift enough volume. There is nothing wrong or weak about breathing through your mouth when you are working hard. It is simply the bigger pipe. Use the nose for easy work and open the mouth as the effort climbs.

That sharp pain under the ribs, usually on the right, is the classic exercise-related stitch. Its exact cause is still debated, but shallow, erratic breathing and eating a large meal too close to exercise both make it more likely.

• Slow down and deepen your breathing. Ease the pace and take a few slow, full breaths, pushing the belly out on the inhale and emptying fully on the exhale.
• Breathe out as the opposite foot lands. If your stitch is on the right, try timing your exhale to your left foot strike for a while.
• Do not eat a big meal right before. Leave a couple of hours after a large meal before hard cardio to lower the odds of a stitch.
• Press and exhale. Gently pressing the area while doing a long, slow exhale can settle it enough to keep going at an easier pace.