title: Reliability of laser Doppler, near-infrared spectroscopy and Doppler ultrasound for peripheral blood flow measurements during and after exercise in the heat.
abstract: This study examined the test-retest reliability of near-infrared spectroscopy (NIRS), laser Doppler flowmetry (LDF) and Doppler ultrasound to assess exercise-induced haemodynamics. Nine men completed two identical trials consisting of 25-min submaximal cycling at first ventilatory threshold followed by repeated 30-s bouts of high-intensity (90% of peak power) cycling in 32.8 ± 0.4°C and 32 ± 5% relative humidity (RH). NIRS (tissue oxygenation index [TOI] and total haemoglobin [tHb]) and LDF (perfusion units [PU]) signals were monitored continuously during exercise, and leg blood flow was assessed by Doppler ultrasound at baseline and after exercise. Cutaneous vascular conductance (CVC; PU/mean arterial pressure (MAP)) was expressed as the percentage change from baseline (%CVCBL). Coefficients of variation (CVs) as indicators of absolute reliability were 18.7-28.4%, 20.2-33.1%, 42.5-59.8%, 7.8-12.4% and 22.2-30.3% for PU, CVC, %CVCBL, TOI and tHb, respectively. CVs for these variables improved as exercise continued beyond 10 min. CVs for baseline and post-exercise leg blood flow were 17.8% and 10.5%, respectively. CVs for PU, tHb (r2= 0.062) and TOI (r2= 0.002) were not correlated (P > 0.05). Most variables demonstrated CVs lower than the expected changes (35%) induced by training or heat stress; however, minimum of 10 min exercise is recommended for more reliable measurements.
authors.affiliation: a Centre for Exercise and Sports Science Research, School of Medical and Health Sciences , Edith Cowan University , Joondalup , Australia.
authors.forename: Hui C
authors.initials: HC
authors.lastname: Choo
authors.affiliation: a Centre for Exercise and Sports Science Research, School of Medical and Health Sciences , Edith Cowan University , Joondalup , Australia.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nosaka
authors.affiliation: b School of Psychology and Exercise Science , Murdoch University , Murdoch , Australia.
authors.forename: Jeremiah J
authors.initials: JJ
authors.lastname: Peiffer
authors.affiliation: a Centre for Exercise and Sports Science Research, School of Medical and Health Sciences , Edith Cowan University , Joondalup , Australia.|c Sports Physiology Department , Singapore Sports Institute , Singapore , Singapore.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Ihsan
authors.affiliation: a Centre for Exercise and Sports Science Research, School of Medical and Health Sciences , Edith Cowan University , Joondalup , Australia.
authors.forename: Chow C
authors.initials: CC
authors.lastname: Yeo
authors.affiliation: a Centre for Exercise and Sports Science Research, School of Medical and Health Sciences , Edith Cowan University , Joondalup , Australia.
authors.forename: Chris R
authors.initials: CR
authors.lastname: Abbiss
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006439:Hemodynamics; D006452:Hemoglobinometry; D006358:Hot Temperature; D006801:Humans; D017078:Laser-Doppler Flowmetry; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D018482:Muscle, Skeletal / Q000098:blood supply* / Q000000981:diagnostic imaging; D010101:Oxygen Consumption; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D012867:Skin / Q000098:blood supply* / Q000000981:diagnostic imaging; D019265:Spectroscopy, Near-Infrared; D018608:Ultrasonography, Doppler
keywords: Coefficient of variation; cutaneous vascular conductance; muscle oxygenation; reproducibility