Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists

David J. Muggeridge, Nicholas Sculthorpe, Fergal M. Grace, Gareth Willis, Laurence Thornhill, Richard B. Weller, Philip E. James, Chris Easton

Research output: Contribution to journalArticle

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Abstract

Dietary nitrate supplementation has been shown to increase nitric oxide (NO) metabolites, reduce blood pressure (BP) and enhance exercise performance. Acute exposure to ultraviolet (UV)-A light also increases NO bioavailability and reduces BP. We conducted a randomized, counterbalanced placebo-controlled trial to determine the effects of UV-A light alone and in combination with nitrate on the responses to sub-maximal steady-state exercise and time trial (TT) performance. Nine cyclists (VO2max 53.1 +/- 4.4 ml/kg/min) completed five performance trials comprising 10 min submaximal steady-state cycling followed by a 16.1 km TT. Following a familiarization the final four trials were preceded, in random order, by either (1) Nitrate gels (NIT) + UV-A, (2) Placebo (PLA) + UV-A, (3) NIT + Sham light (SHAM) and (4) PLA + SHAM (control). The NIT gels (2 x 60 ml gels, similar to 8.1 mmol nitrate) or a low-nitrate PLA were ingested 2.5 h prior to the trial. The light exposure consisted of 20 J/cm(2) whole body irradiation with either UV-A or SHAM light. Plasma nitrite was measured pre- and post-irradiation and VO2 was measured continuously during steady-state exercise. Plasma nitrite was higher for NIT + SHAM (geometric mean (95% CI), 332 (292 377) nM; P=0.029) and NIT + UV-A (456(312-666) nM; P=0.014) compared to PLA + SHAM (215 (167-277) nM). Differences between PLA + SHAM and PLA + UV-A (282 (248-356) nM) were small and nonsignificant. During steady-state exercise VO2 was reduced following NIT + UVA (P = 0.034) and tended to be lower in NIT + SHAM (P = 0.086) but not PLA + UV-A (P = 0.381) compared to PLA + SHAM. Performance in the TT was significantly faster following NIT + UV-A (mean +/- SD 1447 41 s P = 0.005; d = 0.47), but not PLA + UV-A (1450 40 s; d = 0.41) or NIT + SHAM (1455 +/- 47 s; d = 0.28) compared to PLA + SHAM (1469 +/- 52 s). These findings demonstrate that exposure to UV-A light alone does not alter the physiological responses to exercise or improve performance in a laboratory setting. A combination of UV-A and NIT, however, does improve cycling TT performance in this environment, which may be due to a larger increase in NO availability.
LanguageEnglish
Pages3-9
Number of pages7
JournalNitric Oxide: Biology and Chemistry
Volume48
Early online date5 Oct 2014
DOIs
Publication statusPublished - 1 Aug 2015

Fingerprint

Whole-Body Irradiation
Nitrates
Eating
Irradiation
Gels
Placebos
Ultraviolet Rays
Nitric Oxide
Blood pressure
Nitrites
Light
salicylhydroxamic acid
Blood Pressure
Plasmas
Metabolites
Dietary Supplements
Biological Availability

Keywords

  • nitric oxide
  • nitrite
  • exercise
  • nitrate supplementation
  • exercise performance

Cite this

Muggeridge, David J. ; Sculthorpe, Nicholas ; Grace, Fergal M. ; Willis, Gareth ; Thornhill, Laurence ; Weller, Richard B. ; James, Philip E. ; Easton, Chris. / Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists. In: Nitric Oxide: Biology and Chemistry . 2015 ; Vol. 48. pp. 3-9.
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Muggeridge, DJ, Sculthorpe, N, Grace, FM, Willis, G, Thornhill, L, Weller, RB, James, PE & Easton, C 2015, 'Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists' Nitric Oxide: Biology and Chemistry , vol. 48, pp. 3-9. https://doi.org/10.1016/j.niox.2014.09.158

Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists. / Muggeridge, David J.; Sculthorpe, Nicholas; Grace, Fergal M.; Willis, Gareth; Thornhill, Laurence; Weller, Richard B.; James, Philip E.; Easton, Chris.

In: Nitric Oxide: Biology and Chemistry , Vol. 48, 01.08.2015, p. 3-9.

Research output: Contribution to journalArticle

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T1 - Acute whole body UVA irradiation combined with nitrate ingestion enhances time trial performance in trained cyclists

AU - Muggeridge, David J.

AU - Sculthorpe, Nicholas

AU - Grace, Fergal M.

AU - Willis, Gareth

AU - Thornhill, Laurence

AU - Weller, Richard B.

AU - James, Philip E.

AU - Easton, Chris

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N2 - Dietary nitrate supplementation has been shown to increase nitric oxide (NO) metabolites, reduce blood pressure (BP) and enhance exercise performance. Acute exposure to ultraviolet (UV)-A light also increases NO bioavailability and reduces BP. We conducted a randomized, counterbalanced placebo-controlled trial to determine the effects of UV-A light alone and in combination with nitrate on the responses to sub-maximal steady-state exercise and time trial (TT) performance. Nine cyclists (VO2max 53.1 +/- 4.4 ml/kg/min) completed five performance trials comprising 10 min submaximal steady-state cycling followed by a 16.1 km TT. Following a familiarization the final four trials were preceded, in random order, by either (1) Nitrate gels (NIT) + UV-A, (2) Placebo (PLA) + UV-A, (3) NIT + Sham light (SHAM) and (4) PLA + SHAM (control). The NIT gels (2 x 60 ml gels, similar to 8.1 mmol nitrate) or a low-nitrate PLA were ingested 2.5 h prior to the trial. The light exposure consisted of 20 J/cm(2) whole body irradiation with either UV-A or SHAM light. Plasma nitrite was measured pre- and post-irradiation and VO2 was measured continuously during steady-state exercise. Plasma nitrite was higher for NIT + SHAM (geometric mean (95% CI), 332 (292 377) nM; P=0.029) and NIT + UV-A (456(312-666) nM; P=0.014) compared to PLA + SHAM (215 (167-277) nM). Differences between PLA + SHAM and PLA + UV-A (282 (248-356) nM) were small and nonsignificant. During steady-state exercise VO2 was reduced following NIT + UVA (P = 0.034) and tended to be lower in NIT + SHAM (P = 0.086) but not PLA + UV-A (P = 0.381) compared to PLA + SHAM. Performance in the TT was significantly faster following NIT + UV-A (mean +/- SD 1447 41 s P = 0.005; d = 0.47), but not PLA + UV-A (1450 40 s; d = 0.41) or NIT + SHAM (1455 +/- 47 s; d = 0.28) compared to PLA + SHAM (1469 +/- 52 s). These findings demonstrate that exposure to UV-A light alone does not alter the physiological responses to exercise or improve performance in a laboratory setting. A combination of UV-A and NIT, however, does improve cycling TT performance in this environment, which may be due to a larger increase in NO availability.

AB - Dietary nitrate supplementation has been shown to increase nitric oxide (NO) metabolites, reduce blood pressure (BP) and enhance exercise performance. Acute exposure to ultraviolet (UV)-A light also increases NO bioavailability and reduces BP. We conducted a randomized, counterbalanced placebo-controlled trial to determine the effects of UV-A light alone and in combination with nitrate on the responses to sub-maximal steady-state exercise and time trial (TT) performance. Nine cyclists (VO2max 53.1 +/- 4.4 ml/kg/min) completed five performance trials comprising 10 min submaximal steady-state cycling followed by a 16.1 km TT. Following a familiarization the final four trials were preceded, in random order, by either (1) Nitrate gels (NIT) + UV-A, (2) Placebo (PLA) + UV-A, (3) NIT + Sham light (SHAM) and (4) PLA + SHAM (control). The NIT gels (2 x 60 ml gels, similar to 8.1 mmol nitrate) or a low-nitrate PLA were ingested 2.5 h prior to the trial. The light exposure consisted of 20 J/cm(2) whole body irradiation with either UV-A or SHAM light. Plasma nitrite was measured pre- and post-irradiation and VO2 was measured continuously during steady-state exercise. Plasma nitrite was higher for NIT + SHAM (geometric mean (95% CI), 332 (292 377) nM; P=0.029) and NIT + UV-A (456(312-666) nM; P=0.014) compared to PLA + SHAM (215 (167-277) nM). Differences between PLA + SHAM and PLA + UV-A (282 (248-356) nM) were small and nonsignificant. During steady-state exercise VO2 was reduced following NIT + UVA (P = 0.034) and tended to be lower in NIT + SHAM (P = 0.086) but not PLA + UV-A (P = 0.381) compared to PLA + SHAM. Performance in the TT was significantly faster following NIT + UV-A (mean +/- SD 1447 41 s P = 0.005; d = 0.47), but not PLA + UV-A (1450 40 s; d = 0.41) or NIT + SHAM (1455 +/- 47 s; d = 0.28) compared to PLA + SHAM (1469 +/- 52 s). These findings demonstrate that exposure to UV-A light alone does not alter the physiological responses to exercise or improve performance in a laboratory setting. A combination of UV-A and NIT, however, does improve cycling TT performance in this environment, which may be due to a larger increase in NO availability.

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