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Effects of Controlled Frequency Breathing During Exercise on Blood Gases and Acid-Base Balance R. L. Sharp, D. J. Williams, L. Bevan Exercise Physiology Laboratory, Department of Physical Education, Iowa State University
Introduction R. L. Sharp, D. J. Williams, L. Bevan, Effects
of Controlled Frequency Breathing During Exercise on Blood Gases and Acid-Base Balance. mt J Sports Med, Vol 12,No I,pp62—65, 1991. Accepted: May 7, 1990
A popular mode of competitive swimming training uses controlled frequency breathing (CFB) and has been referred to as "hypoxic training" (2). In this type of training, the swimmer breathes once every second to fifth arm cycle during freestyle swimming in an attempt to reduce the oxygen content of the arterial blood. Originally this was hypothesized to simulate the effects of altitude training (2), which has been shown to increase the oxygen carrying capacity of blood (7, 8),
The purpose of this study was to determine the effect of a reduced ventilatory frequency (Vt) on blood gases and acid-base changes during three intensities of cyc-
capillary density in peripheral tissues (16), and muscle myoglobin content (12). Whether these adaptations take place as a consequence of CFB is unknown and likely depends foremost
ling exercise. VO2max and lactate threshold workload
on whether or not hypoxemia and/or tissue hypoxia are
(LaT) of six subjects were assessed on a Monark ergometer.
achieved. Several authors have suggested CFB training may not reduce the Pa02 enough to be considered hypoxemic and that CFB training may in fact be "hypercapnic" training (4, 6). One study (9) examined the effect of CFB during exercise on blood PCO2, but sampled blood from a forearm vein, and no attempt was made to arterialize this blood. Although the re-
Experimental rides were performed 1) with no restriction on Vf (NB) and 2) with a prescribed Vf of 10/mm (CFB). Each exercise period consisted of 8 mm at 10% of VO2max below the LaT (WI), followed immediately by 8 mm at LaT (Wil), followed immediately by 8 mm at 10% of \02max above LaT (WIT!). Blood was taken from a heated fingertip at the end of each load and analyzed for lactate concentration, pH, P02, and PCO2. Respiratory exchange was monitored continuously using open circuit indirect calorimetry. Minute ventilation (VE) was significantly reduced by CFB at all three workloads. The reduced YE resulted in lower (p < 0.05) blood P02 at each workload (p
Effects of Controlled Frequency Breathing During Exercise on Blood Gases and Acid-Base Balance R. L. Sharp, D. J. Williams, L. Bevan Exercise Physiology Laboratory, Department of Physical Education, Iowa State University
Introduction R. L. Sharp, D. J. Williams, L. Bevan, Effects
of Controlled Frequency Breathing During Exercise on Blood Gases and Acid-Base Balance. mt J Sports Med, Vol 12,No I,pp62—65, 1991. Accepted: May 7, 1990
A popular mode of competitive swimming training uses controlled frequency breathing (CFB) and has been referred to as "hypoxic training" (2). In this type of training, the swimmer breathes once every second to fifth arm cycle during freestyle swimming in an attempt to reduce the oxygen content of the arterial blood. Originally this was hypothesized to simulate the effects of altitude training (2), which has been shown to increase the oxygen carrying capacity of blood (7, 8),
The purpose of this study was to determine the effect of a reduced ventilatory frequency (Vt) on blood gases and acid-base changes during three intensities of cyc-
capillary density in peripheral tissues (16), and muscle myoglobin content (12). Whether these adaptations take place as a consequence of CFB is unknown and likely depends foremost
ling exercise. VO2max and lactate threshold workload
on whether or not hypoxemia and/or tissue hypoxia are
(LaT) of six subjects were assessed on a Monark ergometer.
achieved. Several authors have suggested CFB training may not reduce the Pa02 enough to be considered hypoxemic and that CFB training may in fact be "hypercapnic" training (4, 6). One study (9) examined the effect of CFB during exercise on blood PCO2, but sampled blood from a forearm vein, and no attempt was made to arterialize this blood. Although the re-
Experimental rides were performed 1) with no restriction on Vf (NB) and 2) with a prescribed Vf of 10/mm (CFB). Each exercise period consisted of 8 mm at 10% of VO2max below the LaT (WI), followed immediately by 8 mm at LaT (Wil), followed immediately by 8 mm at 10% of \02max above LaT (WIT!). Blood was taken from a heated fingertip at the end of each load and analyzed for lactate concentration, pH, P02, and PCO2. Respiratory exchange was monitored continuously using open circuit indirect calorimetry. Minute ventilation (VE) was significantly reduced by CFB at all three workloads. The reduced YE resulted in lower (p < 0.05) blood P02 at each workload (p
