scholarly journals The time to peak blood bicarbonate (HCO3–), pH, and strong ion difference (SID) following sodium bicarbonate (NaHCO3) ingestion in highly trained adolescent swimmers

2021 ◽  
Author(s):  
Josh W Newbury ◽  
Matthew Cole ◽  
Adam L Kelly ◽  
Richard J Chessor ◽  
Andy Sparks ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Exercise Performance ◽  
Time Course ◽  
Optimal Timing ◽  
Strong Ion Difference ◽  
Time To Peak ◽  
Course Changes ◽  
Dosing Strategies ◽  
Two Measures ◽  
Peak Blood

Background: Contemporary research suggests that the optimal timing of sodium bicarbonate (NaHCO 3 ) should be based upon an individual time in which bicarbonate (HCO 3 – ) or pH peaks within the blood. However, the mechanisms surrounding acidosis on exercise performance are contested, therefore it is plausible that the ergogenic effects of NaHCO 3 are instead a result of an increased strong ion difference (SID) following ingestion. Since the post-ingestion time course of the SID is currently unknown, the purpose of this study was to investigate the pharmacokinetics of the SID in direct comparison to HCO 3 – and pH. Methods: Twelve highly trained, adolescent swimmers (age: 15.9 ± 1.0 yrs, body mass: 65.3 ± 9.6 kg) consumed their typical pre-competition nutrition before ingesting 0.3 g?kg BM -1 NaHCO 3 in gelatine capsules. Capillary blood samples were then taken during quiet, seated rest on nine occasions (0, 60, 75, 90, 105, 120, 135, 150, and 165 min post-ingestion) for the assessment of time course changes in HCO 3 – , pH, and the SID. Results: On a group mean level, no differences were found in the time in which each variable peaked within the blood (HCO 3 – = 130 ± 35 min, pH = 120 ± 38 min, SID = 96 ± 35 min; p = 0.06). A large effect size was calculated between the timing of peak HCO 3 – and the SID  ( g = 0.91), however, suggesting that a difference may occur between these two measures in practice. Conclusions: A time difference between peak HCO 3 – and the SID presents an interesting avenue for further research since an approach based upon individual increases in extracellular SID has yet to be investigated. Future studies should therefore compare these dosing strategies directly to elucidate whether either one is more ergogenic for exercise performance.

scholarly journals The time to peak blood bicarbonate (HCO3–), pH, and the strong ion difference (SID) following sodium bicarbonate (NaHCO3) ingestion in highly trained adolescent swimmers

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0248456
Author(s):  
Josh W. Newbury ◽  
Matthew Cole ◽  
Adam L. Kelly ◽  
Richard J. Chessor ◽  
S. Andy Sparks ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Time Course ◽  
Future Research ◽  
Strong Ion Difference ◽  
Acid Base Balance ◽  
Personal Time ◽  
Time To Peak ◽  
Course Changes ◽  
Base Balance ◽  
Peak Blood

The timing of sodium bicarbonate (NaHCO3) supplementation has been suggested to be most optimal when coincided with a personal time that bicarbonate (HCO3–) or pH peaks in the blood following ingestion. However, the ergogenic mechanisms supporting this ingestion strategy are strongly contested. It is therefore plausible that NaHCO3 may be ergogenic by causing beneficial shifts in the strong ion difference (SID), though the time course of this blood acid base balance variable is yet to be investigated. Twelve highly trained, adolescent swimmers (age: 15.9 ± 1.0 years, body mass: 65.3 ± 9.6 kg) consumed their typical pre-competition nutrition 1–3 hours before ingesting 0.3 g∙kg BM-1 NaHCO3 in gelatine capsules. Capillary blood samples were then taken during seated rest on nine occasions (0, 60, 75, 90, 105, 120, 135, 150, 165 min post-ingestion) to identify the time course changes in HCO3–, pH, and the SID. No significant differences were found in the time to peak of each blood measure (HCO3–: 130 ± 35 min, pH: 120 ± 38 min, SID: 98 ± 37 min; p = 0.08); however, a large effect size was calculated between time to peak HCO3– and the SID (g = 0.88). Considering that a difference between time to peak blood HCO3– and the SID was identified in adolescents, future research should compare the ergogenic effects of these two individualized NaHCO3 ingestion strategies compared to a traditional, standardized approach.

scholarly journals Dose-Response of Sodium Bicarbonate Ingestion Highlights Individuality in Time Course of Blood Analyte Responses

2016 ◽  
Vol 26 (5) ◽  
pp. 445-453 ◽  
Author(s):  
Rebecca Louise Jones ◽  
Trent Stellingwerff ◽  
Guilherme Giannini Artioli ◽  
Bryan Saunders ◽  
Simon Cooper ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Dose Response ◽  
Time Course ◽  
Base Excess ◽  
Interindividual Variability ◽  
Response Relationship ◽  
Dose Response Relationship ◽  
Time To Peak ◽  
Main Effect ◽  
Blood Analytes

To defend against hydrogen cation accumulation and muscle fatigue during exercise, sodium bicarbonate (NaHCO3) ingestion is commonplace. The individualized dose-response relationship between NaHCO3 ingestion and blood biochemistry is unclear. The present study investigated the bicarbonate, pH, base excess and sodium responses to NaHCO3 ingestion. Sixteen healthy males (23 ± 2 years; 78.6 ± 15.1 kg) attended three randomized order-balanced, nonblinded sessions, ingesting a single dose of either 0.1, 0.2 or 0.3 g·kg-1BM of NaHCO3 (Intralabs, UK). Fingertip capillary blood was obtained at baseline and every 10 min for 1 hr, then every 15 min for a further 2 hr. There was a significant main effect of both time and condition for all assessed blood analytes (p ≤ .001). Blood analyte responses were significantly lower following 0.1 g·kg-1BM compared with 0.2 g·kg-1BM; bicarbonate concentrations and base excess were highest following ingestion of 0.3 g·kg-1BM (p ≤ .01). Bicarbonate concentrations and pH significantly increased from baseline following all doses; the higher the dose the greater the increase. Large interindividual variability was shown in the magnitude of the increase in bicarbonate concentrations following each dose (+2.0–5; +5.1–8.1; and +6.0–12.3 mmol·L-1 for 0.1, 0.2 and 0.3 g·kg-1BM) and in the range of time to peak concentrations (30–150; 40–165; and 75–180 min for 0.1, 0.2 and 0.3 g·kg-1BM). The variability in bicarbonate responses was not affected by normalization to body mass. These results challenge current practices relating to NaHCO3 supplementation and clearly show the need for athletes to individualize their ingestion protocol and trial varying dosages before competition.

Time Course of Blood Bicarbonate and pH Three Hours After Sodium Bicarbonate Ingestion

2008 ◽  
Vol 3 (2) ◽  
pp. 240-242 ◽  
Author(s):  
Michael J. Price ◽  
Malkit Singh
Keyword(s):  
Sodium Bicarbonate ◽  
Time Course ◽  
Sodium Bicarbonate Solution ◽  
Bicarbonate Concentration ◽  
Blood Ph ◽  
Peak Blood

This study examined the increase in blood pH and bicarbonate concentration after ingestion of a standard sodium bicarbonate solution. Peak blood pH and bicarbonate concentration occurred between 60 and 90 minutes. Values decreased over the remainder of the ingestion period although still elevated above preingestion levels.

scholarly journals Sodium and calcium currents in dispersed mammalian septal neurons.

1991 ◽  
Vol 97 (2) ◽  
pp. 303-320 ◽  
Author(s):  
A Castellano ◽  
J López-Barneo
Keyword(s):  
Time Constant ◽  
Time Course ◽  
Calcium Currents ◽  
Closing Time ◽  
Patch Clamp Technique ◽  
Average Value ◽  
Time To Peak ◽  
Time Courses ◽  
Fast Activation ◽  
Septal Neurons

Voltage-gated Na+ and Ca2+ conductances of freshly dissociated septal neurons were studied in the whole-cell configuration of the patch-clamp technique. All cells exhibited a large Na+ current with characteristic fast activation and inactivation time courses. Half-time to peak current at -20 mV was 0.44 +/- 0.18 ms and maximal activation of Na+ conductance occurred at 0 mV or more positive membrane potentials. The average value was 91 +/- 32 nS (approximately 11 mS cm-2). At all membrane voltages inactivation was well fitted by a single exponential that had a time constant of 0.44 +/- 0.09 ms at 0 mV. Recovery from inactivation was complete in approximately 900 ms at -80 mV but in only 50 ms at -120 mV. The decay of Na+ tail currents had a single time constant that at -80 mV was faster than 100 microseconds. Depolarization of septal neurons also elicited a Ca2+ current that peaked in approximately 6-8 ms. Maximal peak Ca2+ current was obtained at 20 mV, and with 10 mM external Ca2+ the amplitude was 0.35 +/- 0.22 nA. During a maintained depolarization this current partially inactivated in the course of 200-300 ms. The Ca2+ current was due to the activity of two types of conductances with different deactivation kinetics. At -80 mV the closing time constants of slow (SD) and fast (FD) deactivating channels were, respectively, 1.99 +/- 0.2 and 0.11 +/- 0.03 ms (25 degrees C). The two kinds of channels also differed in their activation voltage, inactivation time course, slope of the conductance-voltage curve, and resistance to intracellular dialysis. The proportion of SD and FD channels varied from cell to cell, which may explain the differential electrophysiological responses of intracellularly recorded septal neurons.

Time course changes of vasopressin-induced enlargement of the rat intrastrial space and the effects of a vasopressin type 2 antagonist

2009 ◽  
Vol 129 (7) ◽  
pp. 709-715 ◽  
Author(s):  
Masahiko Nishimura ◽  
Akinobu Kakigi ◽  
Taizo Takeda ◽  
Teruhiko Okada ◽  
Katsumi Doi
Keyword(s):  
Time Course ◽  
Course Changes

Cerebral oxygenation changes in response to motor stimulation

1996 ◽  
Vol 81 (3) ◽  
pp. 1174-1183 ◽  
Author(s):  
H. Obrig ◽  
C. Hirth ◽  
J. G. Junge-Hulsing ◽  
C. Doge ◽  
T. Wolf ◽  
...  
Keyword(s):  
Time Course ◽  
Near Infrared ◽  
Cerebral Oxygenation ◽  
Motor Task ◽  
Hemoglobin Concentration ◽  
Hemodynamic Response ◽  
Blood Oxygenation ◽  
Initial Increase ◽  
Cerebral Hemodynamic ◽  
Course Changes

We studied cerebral hemodynamic response to a sequential motor task in 56 subjects to investigate the time course and distribution of blood oxygenation changes as monitored by near-infrared spectroscopy (NIRS). To address whether response is modulated by different performance velocities, a group of subjects (n = 12) was examined while performing the motor task at 1, 2, and 3 Hz. The results demonstrate that 1) the NIRS response reflects localized changes in cerebral hemodynamics, 2) the response, consisting of an increase in oxygenated hemoglobin concentration [oxy-Hb] and a decrease in deoxygenated hemoglobin concentration ([deoxy-Hb]), is lateralized and increases in amplitude with higher performance rates, and 3) changes in [oxy-Hb] and [deoxy-Hb] differ in time course. Changes in [oxy-Hb] are biphasic, with a fast initial increase and a pronounced poststimulus undershoot. The stimulus-associated decrease in [deoxy-Hb] is monophasic, and response latency is greater. We conclude that NIRS is able to detect even small changes in cerebral hemodynamic response to functional stimulation.

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