Red Spinach Extract Increases Ventilatory Threshold during Graded Exercise Testing

Angelique N Moore^{1

2}, Cody T Haun³, Wesley C Kephart⁴, Angelia M Holland⁵, Christopher B Mobley⁶, David D Pascoe⁷, Michael D Roberts^{8

9}, Jeffrey S Martin^{10

11}

Affiliations

¹ Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL 36832, USA. amoore@auburn.vcom.edu.
² School of Kinesiology, Auburn University, Auburn, AL 36849, USA. amoore@auburn.vcom.edu.
³ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. cth0023@auburn.edu.
⁴ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. wck0007@auburn.edu.
⁵ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. angholland@augusta.edu.
⁶ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. moblecb@auburn.edu.
⁷ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. pascodd@auburn.edu.
⁸ Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL 36832, USA. mdr0024@auburn.edu.
⁹ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. mdr0024@auburn.edu.
¹⁰ Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL 36832, USA. jmartin@auburn.vcom.edu.
¹¹ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. jmartin@auburn.vcom.edu.

PMID: 29910440
PMCID: PMC5969023
DOI: 10.3390/sports5040080

Red Spinach Extract Increases Ventilatory Threshold during Graded Exercise Testing

Angelique N Moore et al. Sports (Basel). 2017.

. 2017 Oct 16;5(4):80.

doi: 10.3390/sports5040080.

Authors

Angelique N Moore^{1

2}, Cody T Haun³, Wesley C Kephart⁴, Angelia M Holland⁵, Christopher B Mobley⁶, David D Pascoe⁷, Michael D Roberts^{8

9}, Jeffrey S Martin^{10

11}

Affiliations

¹ Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL 36832, USA. amoore@auburn.vcom.edu.
² School of Kinesiology, Auburn University, Auburn, AL 36849, USA. amoore@auburn.vcom.edu.
³ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. cth0023@auburn.edu.
⁴ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. wck0007@auburn.edu.
⁵ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. angholland@augusta.edu.
⁶ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. moblecb@auburn.edu.
⁷ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. pascodd@auburn.edu.
⁸ Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL 36832, USA. mdr0024@auburn.edu.
⁹ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. mdr0024@auburn.edu.
¹⁰ Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine-Auburn Campus, Auburn, AL 36832, USA. jmartin@auburn.vcom.edu.
¹¹ School of Kinesiology, Auburn University, Auburn, AL 36849, USA. jmartin@auburn.vcom.edu.

PMID: 29910440
PMCID: PMC5969023
DOI: 10.3390/sports5040080

Abstract

Background: We examined the acute effect of a red spinach extract (RSE) (1000 mg dose; ~90 mg nitrate (NO 3 - )) on performance markers during graded exercise testing (GXT). Methods: For this randomized, double-blind, placebo (PBO)-controlled, crossover study, 15 recreationally-active participants (aged 23.1 ± 3.3 years; BMI: 27.2 ± 3.7 kg/m²) reported >2 h post-prandial and performed GXT 65⁻75 min post-RSE or PBO ingestion. Blood samples were collected at baseline (BL), pre-GXT (65⁻75 min post-ingestion; PRE), and immediately post-GXT (POST). GXT commenced with continuous analysis of expired gases. Results: Plasma concentrations of NO 3 - increased PRE (+447 ± 294%; p < 0.001) and POST (+378 ± 179%; p < 0.001) GXT with RSE, but not with PBO (+3 ± 26%, -8 ± 24%, respectively; p > 0.05). No effect on circulating nitrite (NO 2 - ) was observed with RSE (+3.3 ± 7.5%, +7.7 ± 11.8% PRE and POST, respectively; p > 0.05) or PBO (-0.5 ± 7.9%, -0.2 ± 8.1% PRE and POST, respectively; p > 0.05). When compared to PBO, there was a moderate effect of RSE on plasma NO 2 - at PRE (g = 0.50 [-0.26, 1.24] and POST g = 0.71 [-0.05, 1.48]). During GXT, VO₂ at the ventilatory threshold was significantly higher with RSE compared to PBO (+6.1 ± 7.3%; p < 0.05), though time-to-exhaustion (-4.0 ± 7.7%; p > 0.05) and maximal aerobic power (i.e., VO₂ peak; -0.8 ± 5.6%; p > 0.05) were non-significantly lower with RSE. Conclusions: RSE as a nutritional supplement may elicit an ergogenic response by delaying the ventilatory threshold.

Keywords: Amaranthus dubius; anaerobic threshold; endurance exercise; nitrate; submaximal.

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Conflict of interest statement

DolCas Biotech LLC had a role in the design of the study, but had no role in the collection, analyses, or interpretation of data, in the writing of the manuscript, and in the decision to publish the results. The authors declare no conflict of interest.

Figures

**Figure 1**
Representative illustration of computer plots showing agreement between the (a) excess CO₂ (ExCO₂); (b) ventilatory equivalent (VEQ); and (c) modified v-slope methods for determination of the ventilatory threshold (VT) using expired gas data. Open circles indicate 20 s average expired gas data points and solid lines indicate regression lines fitted to the pre-VT and post-VT segments of the data set.

**Figure 2**
Plasma concentrations of (a) nitrate (NO $_{3}^{-}$ ) and (b) nitrite (NO $_{2}^{-}$ ) following ingestion of a red spinach extract (RSE; ●) and placebo (PBO; ○) at baseline (BL), 65–75 min following ingestion (PRE), and immediately following graded exercise testing (POST). Data are presented as mean absolute values in μM concentrations ± SD. When a significant time*treatment interaction was observed, post-hoc tests were performed using Student’s paired t-tests. * Significantly different from baseline within conditions (p < 0.01). † significantly different between conditions at the same time point (p < 0.01), respectively).

**Figure 3**
Graded exercise testing (GXT) performance outcomes following acute ingestion of a red spinach extract (RSE; ●) and placebo (PBO; ○). Condition means ± SD, as well as individual values, are presented for (a) time-to-exhaustion (in minutes), (b) relative VO₂ peak (in mL/kg/min), and (c) observed ventilatory threshold (in L O₂/min) during the Bruce protocol GXT. Student’s paired t-tests were performed to compare performance between conditions. * Significantly different between conditions (p < 0.05).

See this image and copyright information in PMC

References

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Red Spinach Extract Increases Ventilatory Threshold during Graded Exercise Testing

Affiliations

Red Spinach Extract Increases Ventilatory Threshold during Graded Exercise Testing

Authors

Affiliations

Abstract

Conflict of interest statement

Figures

References