Postural induced changes in plasma volume inversely influences plasma nitrite concentration in humans

Luke Liddle, Chris Monaghan, Luke C McIlvenna, Mia C. Burleigh, David J. Muggeridge, Chris Easton

Research output: Contribution to journalMeeting abstract

Abstract

Moving from a supine to a standing position typically reduces plasma volume (PV) and while this increases the concentration of some molecules in the blood, the effect on plasma nitrate [NO3-] and nitrite [NO2-] has not been reported. PURPOSE: To determine the change (Δ) in PV, [NO3-] and [NO2-] while lying supine, sitting, standing, and following short-duration exercise. METHODS: Fourteen participants (9 male, age 27 ± 4 yr, body mass 71 ± 11 kg) completed two trials. The first was conducted with no dietary intervention (control; CON) and the second was preceded by ingestion of 3 x 70 ml of NO3--rich beetroot juice the day before and 2 x 70 ml two hours before the trial (BR; total of ~31 mmol NO3-). Both trials comprised 30 min lying supine followed by 2 min of standing, 2 min of sitting, and then 5 min of cycling at 60% of the age-predicted maximal heart rate. Repeated blood samples were collected to allow measurements of haemoglobin and haematocrit in whole blood and plasma [NO3-] and [NO2-] by chemiluminescence. The ΔPV was calculated using the Dill and Costill formula. RESULTS: Following the supine phase, PV increased from baseline in both trials (CON Δ12.6 ± 10.3 %; BR Δ12.5 ± 7 %, both P<0.01) and then decreased upon standing (CON Δ‒5.2 ± 3.8 %, P<0.01; BR Δ‒4.0 ± 3.5%, P=0.02), sitting (CON Δ‒10.1 ± 3.7 %; BR Δ‒6.4 ± 3.6 %, both P<0.001) and following exercise (CON Δ‒18.1 ± 5 %; BR Δ‒15.5 ± 3.4 %, both P<0.001). Plasma [NO2-] levels at baseline were 120 ± 49 nM and 357 ± 129 nM in CON and BR, respectively. Plasma [NO2-] decreased from baseline after lying supine in both trials (CON 77 ± 30 nM; BR 231 ± 92 nM, both P<0.05) before increasing during standing (CON 109 ± 42 nM; BR 297 ± 105 nM, both P<0.001) and sitting (CON 131 ± 43 nM; BR 385 ± 125 nM, both P<0.002). Plasma [NO2-] remained elevated following exercise in the CON trial (125 ± 61 nM, P<0.05) but was not different to the 30 min supine value in the BR trial. There were no statistical differences in [NO3-] between measurement points in either condition (all P>0.05). CONCLUSIONS: Plasma [NO2-] changes in the opposite direction to PV during changes in posture, both in the presence and absence of prior dietary NO3- supplementation. Given that [NO2-] offers the best approximation of nitric oxide bioavailability, researchers must be cognisant of these outcomes when designing and interpreting dietary NO3- research.

Fingerprint

Plasma Volume
Nitrites
Posture
Anethum graveolens
Dietary Supplements
Luminescence
Hematocrit
Nitrates
Biological Availability
Nitric Oxide
Hemoglobins
Eating
Heart Rate
Research Personnel
Research

Keywords

  • supine
  • standing
  • plasma volume
  • nitrate
  • nitrite
  • bioavailability

Cite this

Liddle, Luke ; Monaghan, Chris ; McIlvenna, Luke C ; Burleigh, Mia C. ; Muggeridge, David J. ; Easton, Chris . / Postural induced changes in plasma volume inversely influences plasma nitrite concentration in humans. In: Medicine and Science in Sports and Exercise. 2017 ; pp. 1002.
@article{05d66ad1c02b4cdca379325bc1e34ac2,
title = "Postural induced changes in plasma volume inversely influences plasma nitrite concentration in humans",
abstract = "Moving from a supine to a standing position typically reduces plasma volume (PV) and while this increases the concentration of some molecules in the blood, the effect on plasma nitrate [NO3-] and nitrite [NO2-] has not been reported. PURPOSE: To determine the change (Δ) in PV, [NO3-] and [NO2-] while lying supine, sitting, standing, and following short-duration exercise. METHODS: Fourteen participants (9 male, age 27 ± 4 yr, body mass 71 ± 11 kg) completed two trials. The first was conducted with no dietary intervention (control; CON) and the second was preceded by ingestion of 3 x 70 ml of NO3--rich beetroot juice the day before and 2 x 70 ml two hours before the trial (BR; total of ~31 mmol NO3-). Both trials comprised 30 min lying supine followed by 2 min of standing, 2 min of sitting, and then 5 min of cycling at 60{\%} of the age-predicted maximal heart rate. Repeated blood samples were collected to allow measurements of haemoglobin and haematocrit in whole blood and plasma [NO3-] and [NO2-] by chemiluminescence. The ΔPV was calculated using the Dill and Costill formula. RESULTS: Following the supine phase, PV increased from baseline in both trials (CON Δ12.6 ± 10.3 {\%}; BR Δ12.5 ± 7 {\%}, both P<0.01) and then decreased upon standing (CON Δ‒5.2 ± 3.8 {\%}, P<0.01; BR Δ‒4.0 ± 3.5{\%}, P=0.02), sitting (CON Δ‒10.1 ± 3.7 {\%}; BR Δ‒6.4 ± 3.6 {\%}, both P<0.001) and following exercise (CON Δ‒18.1 ± 5 {\%}; BR Δ‒15.5 ± 3.4 {\%}, both P<0.001). Plasma [NO2-] levels at baseline were 120 ± 49 nM and 357 ± 129 nM in CON and BR, respectively. Plasma [NO2-] decreased from baseline after lying supine in both trials (CON 77 ± 30 nM; BR 231 ± 92 nM, both P<0.05) before increasing during standing (CON 109 ± 42 nM; BR 297 ± 105 nM, both P<0.001) and sitting (CON 131 ± 43 nM; BR 385 ± 125 nM, both P<0.002). Plasma [NO2-] remained elevated following exercise in the CON trial (125 ± 61 nM, P<0.05) but was not different to the 30 min supine value in the BR trial. There were no statistical differences in [NO3-] between measurement points in either condition (all P>0.05). CONCLUSIONS: Plasma [NO2-] changes in the opposite direction to PV during changes in posture, both in the presence and absence of prior dietary NO3- supplementation. Given that [NO2-] offers the best approximation of nitric oxide bioavailability, researchers must be cognisant of these outcomes when designing and interpreting dietary NO3- research.",
keywords = "supine, standing, plasma volume, nitrate, nitrite, bioavailability",
author = "Luke Liddle and Chris Monaghan and McIlvenna, {Luke C} and Burleigh, {Mia C.} and Muggeridge, {David J.} and Chris Easton",
year = "2017",
month = "5",
day = "1",
doi = "10.1249/01.mss.0000519747.12877.f8",
language = "English",
pages = "1002",
journal = "Medicine and Science in Sports and Exercise",
issn = "0195-9131",

}

Postural induced changes in plasma volume inversely influences plasma nitrite concentration in humans. / Liddle, Luke; Monaghan, Chris; McIlvenna, Luke C; Burleigh, Mia C.; Muggeridge, David J.; Easton, Chris .

In: Medicine and Science in Sports and Exercise, 01.05.2017, p. 1002.

Research output: Contribution to journalMeeting abstract

TY - JOUR

T1 - Postural induced changes in plasma volume inversely influences plasma nitrite concentration in humans

AU - Liddle, Luke

AU - Monaghan, Chris

AU - McIlvenna, Luke C

AU - Burleigh, Mia C.

AU - Muggeridge, David J.

AU - Easton, Chris

PY - 2017/5/1

Y1 - 2017/5/1

N2 - Moving from a supine to a standing position typically reduces plasma volume (PV) and while this increases the concentration of some molecules in the blood, the effect on plasma nitrate [NO3-] and nitrite [NO2-] has not been reported. PURPOSE: To determine the change (Δ) in PV, [NO3-] and [NO2-] while lying supine, sitting, standing, and following short-duration exercise. METHODS: Fourteen participants (9 male, age 27 ± 4 yr, body mass 71 ± 11 kg) completed two trials. The first was conducted with no dietary intervention (control; CON) and the second was preceded by ingestion of 3 x 70 ml of NO3--rich beetroot juice the day before and 2 x 70 ml two hours before the trial (BR; total of ~31 mmol NO3-). Both trials comprised 30 min lying supine followed by 2 min of standing, 2 min of sitting, and then 5 min of cycling at 60% of the age-predicted maximal heart rate. Repeated blood samples were collected to allow measurements of haemoglobin and haematocrit in whole blood and plasma [NO3-] and [NO2-] by chemiluminescence. The ΔPV was calculated using the Dill and Costill formula. RESULTS: Following the supine phase, PV increased from baseline in both trials (CON Δ12.6 ± 10.3 %; BR Δ12.5 ± 7 %, both P<0.01) and then decreased upon standing (CON Δ‒5.2 ± 3.8 %, P<0.01; BR Δ‒4.0 ± 3.5%, P=0.02), sitting (CON Δ‒10.1 ± 3.7 %; BR Δ‒6.4 ± 3.6 %, both P<0.001) and following exercise (CON Δ‒18.1 ± 5 %; BR Δ‒15.5 ± 3.4 %, both P<0.001). Plasma [NO2-] levels at baseline were 120 ± 49 nM and 357 ± 129 nM in CON and BR, respectively. Plasma [NO2-] decreased from baseline after lying supine in both trials (CON 77 ± 30 nM; BR 231 ± 92 nM, both P<0.05) before increasing during standing (CON 109 ± 42 nM; BR 297 ± 105 nM, both P<0.001) and sitting (CON 131 ± 43 nM; BR 385 ± 125 nM, both P<0.002). Plasma [NO2-] remained elevated following exercise in the CON trial (125 ± 61 nM, P<0.05) but was not different to the 30 min supine value in the BR trial. There were no statistical differences in [NO3-] between measurement points in either condition (all P>0.05). CONCLUSIONS: Plasma [NO2-] changes in the opposite direction to PV during changes in posture, both in the presence and absence of prior dietary NO3- supplementation. Given that [NO2-] offers the best approximation of nitric oxide bioavailability, researchers must be cognisant of these outcomes when designing and interpreting dietary NO3- research.

AB - Moving from a supine to a standing position typically reduces plasma volume (PV) and while this increases the concentration of some molecules in the blood, the effect on plasma nitrate [NO3-] and nitrite [NO2-] has not been reported. PURPOSE: To determine the change (Δ) in PV, [NO3-] and [NO2-] while lying supine, sitting, standing, and following short-duration exercise. METHODS: Fourteen participants (9 male, age 27 ± 4 yr, body mass 71 ± 11 kg) completed two trials. The first was conducted with no dietary intervention (control; CON) and the second was preceded by ingestion of 3 x 70 ml of NO3--rich beetroot juice the day before and 2 x 70 ml two hours before the trial (BR; total of ~31 mmol NO3-). Both trials comprised 30 min lying supine followed by 2 min of standing, 2 min of sitting, and then 5 min of cycling at 60% of the age-predicted maximal heart rate. Repeated blood samples were collected to allow measurements of haemoglobin and haematocrit in whole blood and plasma [NO3-] and [NO2-] by chemiluminescence. The ΔPV was calculated using the Dill and Costill formula. RESULTS: Following the supine phase, PV increased from baseline in both trials (CON Δ12.6 ± 10.3 %; BR Δ12.5 ± 7 %, both P<0.01) and then decreased upon standing (CON Δ‒5.2 ± 3.8 %, P<0.01; BR Δ‒4.0 ± 3.5%, P=0.02), sitting (CON Δ‒10.1 ± 3.7 %; BR Δ‒6.4 ± 3.6 %, both P<0.001) and following exercise (CON Δ‒18.1 ± 5 %; BR Δ‒15.5 ± 3.4 %, both P<0.001). Plasma [NO2-] levels at baseline were 120 ± 49 nM and 357 ± 129 nM in CON and BR, respectively. Plasma [NO2-] decreased from baseline after lying supine in both trials (CON 77 ± 30 nM; BR 231 ± 92 nM, both P<0.05) before increasing during standing (CON 109 ± 42 nM; BR 297 ± 105 nM, both P<0.001) and sitting (CON 131 ± 43 nM; BR 385 ± 125 nM, both P<0.002). Plasma [NO2-] remained elevated following exercise in the CON trial (125 ± 61 nM, P<0.05) but was not different to the 30 min supine value in the BR trial. There were no statistical differences in [NO3-] between measurement points in either condition (all P>0.05). CONCLUSIONS: Plasma [NO2-] changes in the opposite direction to PV during changes in posture, both in the presence and absence of prior dietary NO3- supplementation. Given that [NO2-] offers the best approximation of nitric oxide bioavailability, researchers must be cognisant of these outcomes when designing and interpreting dietary NO3- research.

KW - supine

KW - standing

KW - plasma volume

KW - nitrate

KW - nitrite

KW - bioavailability

UR - http://www.acsmannualmeeting.org/

U2 - 10.1249/01.mss.0000519747.12877.f8

DO - 10.1249/01.mss.0000519747.12877.f8

M3 - Meeting abstract

SP - 1002

JO - Medicine and Science in Sports and Exercise

T2 - Medicine and Science in Sports and Exercise

JF - Medicine and Science in Sports and Exercise

SN - 0195-9131

ER -