The purpose of the present study was to examine whether excessive CO2 output (V . co2excess) is dominantly attributable to hyperventilation during the period of recovery from repeated cycling sprints. A series of four 10-sec cycling sprints with 30-sec passive recovery periods was performed two times. The first series and second series of cycle sprints (SCS) were followed by 360-sec passive recovery periods (first recovery and second recovery). Increases in blood lactate (?La) were 11.17±2.57 mM from rest to 5.5 min during first recovery and 2.07±1.23 mM from the start of the second SCS to 5.5 min during second recovery. CO2 output (V . co2) was significantly higher than O2 uptake (V . o2) during both recovery periods. This difference was defined as V . co2excess. V . co2excess was significantly higher during first recovery than during second recovery. V . co2excess was added from rest to the end of first recovery and from the start of the second SCS to the end of second recovery (CO2excess). ?La was significantly related to CO2excess (r=0.845). However, ventilation during first recovery was the same as that during second recovery. End-tidal CO2 pressure (PETco2) significantly decreased from the resting level during the recovery periods, indicating hyperventilation. PETco2 during first recovery was significantly higher than that during second recovery. It is concluded that V . co2excess is not simply determined by ventilation during recovery from repeated cycle sprints.
To determine the relationship between hyperventilation and recovery of blood pH during recovery from a heavy exercise, short-term intense exercise (STIE) tests were performed after human subjects ingested 0.3 g · kg-1 body mass of either NaHCO3 (Alk) or CaCO3 (Pla). Ventilation (V . E) - CO2 output (V . co2) slopes during recovery following STIE were significantly lower in Alk than in Pla, indicating that hyperventilation is attenuated under the alkalotic condition. However, this reduction of the slope was the result of unchanged V . E and a small increase in V . co2. A significant correlation between V . E and blood pH was found during recovery in both conditions. While there was no difference between the V . E - pH slopes in the two conditions, V . E at the same pH was higher in Alk than in Pla. Furthermore, the values of pH during recovery in both conditions increased toward the preexercise levels of each condition. Thus, although V . E - V . co2 slope was decreased under the alkalotic condition, this could not be explained by the ventilatory depression attributed to increase in blood pH. We speculate that hyperventilation after the end of STIE is determined by the V . E - pH relationship that was set before STIE or the intensity of the exercise performed.
Inactive forearm muscle oxygenation has been reported to begin decreasing from the respiratory compensation point (RCP) during ramp leg cycling. From the RCP, hyperventilation occurs with a decrease in arterial CO2 pressure (PaCO2). The aim of this study was to determine which of these two factors, hyperventilation or decrease in PaCO2, is related to a decrease in inactive biceps brachii muscle oxygenation during leg cycling. Each subject (n = 7) performed a 6-min two-step leg cycling. The exercise intensity in the first step (3 min) was halfway between the ventilatory threshold and RCP (170±21 watts), while that in the second step (3 min) was halfway between the RCP and peak oxygen uptake (240±28 watts). The amount of hyperventilation and PaCO2 were calculated from gas parameters. The average cross correlation function in seven subjects between inactive muscle oxygenation and amount of hyperventilation showed a negative peak at the time shift of zero (r = -0.72, p<0.001), while that between inactive muscle oxygenation and calculated PaCO2 showed no peak near the time shift of zero. Thus, we concluded that decrease in oxygenation in inactive arm muscle is closely coupled with increase in the amount of hyperventilation.
- MeSH
- blízká infračervená spektroskopie metody využití MeSH
- ergometrie metody využití MeSH
- hyperventilace krev metabolismus MeSH
- kosterní svaly fyziologie metabolismus MeSH
- lidé MeSH
- oxid uhličitý krev škodlivé účinky MeSH
- paže fyziologie krevní zásobení MeSH
- spotřeba kyslíku fyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
Práca porovnáva parametre rovnováhy po rôznych formách silových cvičení a vôľovej hyperventilácii. Skupina študentov FTVŠ vykonala 20 drepov, výponov, tlakov za hlavou a bicepsových zdvihov s dodatočnou váhou 50 % 1 RM. Okrem toho, rovnaký čas ako trvalo zaťaženie testované osoby hyperventilovali. Výsledky ukázali, že k výraznejšiemu zvýšeniu rýchlosti pohybu ťažiska došlo po drepoch (16,4 ± 1,4 mm/s) ako po výponoch (15,2 ± 1,3 mm/s), vôľovej hyperventilácii (14,8 ± 1,2 mm/s), bicepsových zdvihoch (14,0 ± 1,1 mm/s) a tlakoch za hlavou (13,6 ± 0,8 mm/s). Podobný trend bol zaznamenaný aj v prípade ventilácie a pulzovej frekvencie. Navyše, významný vzťah sa ukázal medzi stupňom ventilácie a rýchlosťou pohybu ťažiska vo fáze zotavovania. Z toho vyplýva, že najmä zvýšená ventilácia je zodpovedná za výraznejšie narušenie stability postoja po silových cvičeniach vykonávaných svalovými skupinami dolných ako horných končatín.
- MeSH
- financování organizované MeSH
- hyperventilace metabolismus MeSH
- posturální rovnováha genetika MeSH
- Publikační typ
- srovnávací studie MeSH
