The tidal volume is...
the amount breathed in and out in normal breathing
the maximum amount that can be breathed out
the amount of air that cannot be breathed out
the maximum amount of air that can breathed in


During exercise both tidal volume and breathing rate increase.



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Heart Breathing Aerobic Fitness Benefits

breathing and exercise

Breathing refreshes the air in the alveoli so that the concentrations of oxygen and carbon dioxide within them remain constant. Changing the depth and rate of breathing achieves this. At rest we need to ventilate our lungs with about 6.0 dm3 of air per minute. About 0.35 dm3 of air enters the alveoli with each breath representing only about one seventh of the total volume of air in the alveoli. This means that large changes in the composition of alveolar air never occur. In any cases it is impossible to empty the lungs completely and even when the chest is compressed during forced exhalation about 1.0 dm3 of air still remains in the alveoli and the airways. This volume is the residual volume. A much larger volume (approximately 2.5 dm3) remains in the lungs after breathing out normally. When breathing deeply the lungs can increase in volume by as much as 3 dm3. As exercise becomes harder the depth of breathing increases and often the breathing rate does too. This gives us the ability to respond to changes in demand for gaseous exchange during exercise. The effect of exercise on breathing is measured by calculating the ventilation rate. This is the total volume of air moved into the lungs in one minute. Ventilation rate (expressed as dm3min-l) is calculated as:

Ventilation rate = tidal volume x breathing rate

A well-trained athlete can achieve adequate ventilation by increasing the tidal volume with only a small increase in the rate of breathing.


Heart Breathing Aerobic Fitness Benefits