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

Luke Liddle, Christopher Monaghan, Luke McIlvenna, Mia Burleigh, David 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[FIGURE DASH]5.2 ± 3.8 %, P<0.01; BR Δ[FIGURE DASH]4.0 ± 3.5%, P=0.02), sitting (CON Δ[FIGURE DASH]10.1 ± 3.7 %; BR Δ[FIGURE DASH]6.4 ± 3.6 %, both P<0.001) and following exercise (CON Δ[FIGURE DASH]18.1 ± 5 %; BR Δ[FIGURE DASH]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. © 2017 American College of Sports Medicine
Original languageEnglish
Pages (from-to)1002
Number of pages1
JournalMedicine & Science in Sports & Exercise
Volume49
Issue number5S
Publication statusPublished - 2017

Fingerprint

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

Cite this

@article{cfd0858c920b44a3acc62be27b29962e,
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[FIGURE DASH]5.2 ± 3.8 {\%}, P<0.01; BR Δ[FIGURE DASH]4.0 ± 3.5{\%}, P=0.02), sitting (CON Δ[FIGURE DASH]10.1 ± 3.7 {\%}; BR Δ[FIGURE DASH]6.4 ± 3.6 {\%}, both P<0.001) and following exercise (CON Δ[FIGURE DASH]18.1 ± 5 {\%}; BR Δ[FIGURE DASH]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. {\circledC} 2017 American College of Sports Medicine",
author = "Luke Liddle and Christopher Monaghan and Luke McIlvenna and Mia Burleigh and David Muggeridge and Chris Easton",
year = "2017",
language = "English",
volume = "49",
pages = "1002",
journal = "Medicine & Science in Sports & Exercise",
issn = "0195-9131",
publisher = "American College of Sports Medicine",
number = "5S",

}

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

In: Medicine & Science in Sports & Exercise, Vol. 49, No. 5S, 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, Christopher

AU - McIlvenna, Luke

AU - Burleigh, Mia

AU - Muggeridge, David

AU - Easton, Chris

PY - 2017

Y1 - 2017

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[FIGURE DASH]5.2 ± 3.8 %, P<0.01; BR Δ[FIGURE DASH]4.0 ± 3.5%, P=0.02), sitting (CON Δ[FIGURE DASH]10.1 ± 3.7 %; BR Δ[FIGURE DASH]6.4 ± 3.6 %, both P<0.001) and following exercise (CON Δ[FIGURE DASH]18.1 ± 5 %; BR Δ[FIGURE DASH]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. © 2017 American College of Sports Medicine

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[FIGURE DASH]5.2 ± 3.8 %, P<0.01; BR Δ[FIGURE DASH]4.0 ± 3.5%, P=0.02), sitting (CON Δ[FIGURE DASH]10.1 ± 3.7 %; BR Δ[FIGURE DASH]6.4 ± 3.6 %, both P<0.001) and following exercise (CON Δ[FIGURE DASH]18.1 ± 5 %; BR Δ[FIGURE DASH]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. © 2017 American College of Sports Medicine

M3 - Meeting Abstract

VL - 49

SP - 1002

JO - Medicine & Science in Sports & Exercise

JF - Medicine & Science in Sports & Exercise

SN - 0195-9131

IS - 5S

ER -