K A Wickham1, S W Steele1, S S Cheung2. 1. Environmental Ergonomics Lab, Brock University, St. Catharines, ON, Canada. 2. Environmental Ergonomics Lab, Brock University, St. Catharines, ON, Canada. stephen.cheung@brocku.ca.
Abstract
PURPOSE:Cold-induced vasodilation (CIVD) is a paradoxical rise in blood flow to the digits that occur during prolonged cold exposure. CIVD is thought to occur through active vasodilation and/or sympathetic withdrawal, where nitric oxide (NO) may play a key role in mediating these mechanisms. Beetroot juice (BRJ) is high in dietary nitrate (NO3-) which undergoes sequential reduction to nitrite (NO2-) and subsequently NO. Using a double-blind, randomized, crossover design, we examined the effect of acute BRJ supplementation on the CIVD response in 10 healthy males. METHODS:Participants had a resting blood pressure measurement taken prior to ingesting 140 mL of nitrate-rich BRJ (13 mmol NO3-) or aNO3--free placebo (PLA). After 2 h, participants immersed their hand in neutral water (~ 35 °C) for 10 min of baseline before cold water immersion (~ 8 °C) for 30 min. Laser-Doppler fluxmetry and skin temperature were measured continuously on the digits. RESULTS: Compared to PLA (100 ± 3 mmHg), acute BRJ supplementation significantly reduced mean arterial pressure at -30 min (96 ± 2 mmHg; p = 0.007) and 0 min (94 ± 2 mmHg; p = 0.008). Acute BRJ supplementation had no effect on Laser-Doppler fluxmetry during CIVD (expressed as cutaneous vascular conductance) measured as area under the curve (BRJ: 843 ± 148 PU mmHg-1 s; PLA: 1086 ± 333 PU mmHg-1 s), amplitude (BRJ: 0.60 ± 0.12 PU mmHg-1; PLA: 0.69 ± 0.14 PU mmHg-1), and duration (BRJ: 895 ±60 s; PLA: 894 ± 46 s). CONCLUSION:Acute BRJ supplementation does not augment the CIVD response in healthy males.
RCT Entities:
PURPOSE: Cold-induced vasodilation (CIVD) is a paradoxical rise in blood flow to the digits that occur during prolonged cold exposure. CIVD is thought to occur through active vasodilation and/or sympathetic withdrawal, where nitric oxide (NO) may play a key role in mediating these mechanisms. Beetroot juice (BRJ) is high in dietary nitrate (NO3-) which undergoes sequential reduction to nitrite (NO2-) and subsequently NO. Using a double-blind, randomized, crossover design, we examined the effect of acute BRJ supplementation on the CIVD response in 10 healthy males. METHODS:Participants had a resting blood pressure measurement taken prior to ingesting 140 mL of nitrate-rich BRJ (13 mmol NO3-) or a NO3--free placebo (PLA). After 2 h, participants immersed their hand in neutral water (~ 35 °C) for 10 min of baseline before cold water immersion (~ 8 °C) for 30 min. Laser-Doppler fluxmetry and skin temperature were measured continuously on the digits. RESULTS: Compared to PLA (100 ± 3 mmHg), acute BRJ supplementation significantly reduced mean arterial pressure at -30 min (96 ± 2 mmHg; p = 0.007) and 0 min (94 ± 2 mmHg; p = 0.008). Acute BRJ supplementation had no effect on Laser-Doppler fluxmetry during CIVD (expressed as cutaneous vascular conductance) measured as area under the curve (BRJ: 843 ± 148 PU mmHg-1 s; PLA: 1086 ± 333 PU mmHg-1 s), amplitude (BRJ: 0.60 ± 0.12 PU mmHg-1; PLA: 0.69 ± 0.14 PU mmHg-1), and duration (BRJ: 895 ± 60 s; PLA: 894 ± 46 s). CONCLUSION: Acute BRJ supplementation does not augment the CIVD response in healthy males.
Authors: M Hashimoto; M Akishita; M Eto; M Ishikawa; K Kozaki; K Toba; Y Sagara; Y Taketani; H Orimo; Y Ouchi Journal: Circulation Date: 1995-12-15 Impact factor: 29.690
Authors: Ditte A Hobbs; Marie G Goulding; Annie Nguyen; Thomas Malaver; Claire F Walker; Trevor W George; Lisa Methven; Julie A Lovegrove Journal: J Nutr Date: 2013-07-24 Impact factor: 4.798