On freestyle, I generally try to breathe bi-laterally every 3 strokes, and begin my exhale as soon as my head enters the water.
However, sometimes when I am doing sprints or laps with little rest in between, I find myself holding my breath instead of beginning the exhale immediately. When I do this it feels that my body is able to get more oxygen.
Its seems like my body is craving oxygen, and beginning the exhale immediately gets rid of some of that precious oxygen before I have a chance to process it.
Of course, I realize that delaying the start of my exhale means that I will get able to get more fresh air on the next inhalation, unless I can manage to get rid of all my air very quickly (which seems impossible).
So is it best to just force myself to keep the same breathing pattern (every 3 strokes with exhale starting immediately), even when I am feeling tired or out of oxygen? Or are there times when it is safe, or even better, to hold my breath for at least a second before beginning the exhalation? Maybe at the end of a race (or timed lap)?
Lindsay's right -- the primary drive to breathe is hypercapnea (elevated CO2) -- there is a hypoxic (low O2) drive to breathe as well but it is secondary. This is why the average healthy person with no lung disease can not hold his or her breath until the oxygen saturation falls (I have tried many times).
The question about oxygen exchange during breath holding is complicated but I think a simple but reasonably accurate answer is that there is continued gas exchange between the alveoli and the pulmonary capillaries during a breath hold but that it becomes less efficient as the gradient between the alveolus and blood is reduced.
(Reference West JB: Essentials of Respiratory Physiology)
This doesn't answer the question about what helps you swim fastest, of course. I would not dream of giving advice on the most efficient way to breathe while sprinting.
Lindsay's right -- the primary drive to breathe is hypercapnea (elevated CO2) -- there is a hypoxic (low O2) drive to breathe as well but it is secondary. This is why the average healthy person with no lung disease can not hold his or her breath until the oxygen saturation falls (I have tried many times).
The question about oxygen exchange during breath holding is complicated but I think a simple but reasonably accurate answer is that there is continued gas exchange between the alveoli and the pulmonary capillaries during a breath hold but that it becomes less efficient as the gradient between the alveolus and blood is reduced.
(Reference West JB: Essentials of Respiratory Physiology)
This doesn't answer the question about what helps you swim fastest, of course. I would not dream of giving advice on the most efficient way to breathe while sprinting.
