The association between contrast-enhanced ultrasound and near-infrared spectroscopy-derived measures of calf muscle microvascular responsiveness in older adults

Background and Aim Contrast-enhanced ultrasound (CEUS) measures of post-occlusion skeletal muscle microvascular responsiveness demonstrate the microvascular dysfunction associated with ageing and age-related disease. However, the accessibility of CEUS is limited by the need for intravenous administration of ultrasound contrast agents and sophisticated imaging analysis. Alternative methods are required for the broader assessment of microvascular dysfunction in research and clinical settings. Therefore, we aimed to evaluate the level of association and agreement between CEUS and near-infrared spectroscopy (NIRS)-derived measures of post-occlusion skeletal muscle microvascular responsiveness in older adults. Methods During supine rest, participants (n=15, 67±11 years) underwent 5 minutes of thigh cuff-occlusion (200 mmHg). Post-occlusion CEUS measures of calf muscle microvascular responsiveness were made, including time to 95% peak acoustic intensity (TTP95 AI) and the rate of rise (slope AI). Simultaneous measures, including time to 95% peak oxygenated haemoglobin (TTP95 O2Hb) and slope O2Hb, were made using continuous-wave NIRS in the same muscle region. Results There were strong correlations between TTP95 measures derived from CEUS and NIRS (r=0.834, p=<0.001) and the corresponding measures of slope (r=0.735, p=0.004). The limits of agreement demonstrated by Bland Altman plot analyses for CEUS and NIRS-derived measures of TTP95 (-9.67–1.98 s) and slope (-1.29–5.23%. s-1) were smaller than the minimum differences expected in people with microvascular dysfunction. Conclusions The strong correlations and level of agreement in the present study support the use of NIRS as a non-invasive, portable and cost-effective method for assessing post-occlusion skeletal muscle microvascular responsiveness in older adults

Yuri Kriel - PLoS article 1 data.xlsx

NIRS (1sec), HR(1sec), mechanical power (1 sec) and VO2 (5sec) data from 12 participants completing three protocols involving 1) HIIT with passive recovery periods separating exercise bouts (PASS) 2) HIIT with active recovery periods separating exercise bouts (ACT) 3) ACT with HIIT bouts replaced with passive periods. <br

Yuri Kriel - HIIT versus CMIE

Data for research article: HIIT vs CMI

Yuri Kriel - PLoS article: Mode

NIRS (1sec), HR(1sec), mechanical power (1 sec) and VO2 (5sec), RPE and PACES data from 12 participants completing a maximal incremental exercise test to volitional cessation (MAX) and two experimental protocols: 1) cycling HIIT (HIITCYC) 2) running HIIT (HIITRUN)<br

Recovery format: RPE, BP, PACES

Ratings of perceived exertion, blood pressure and enjoyment data from twelve sedentary men performing a session of HIIIT with passive (HIITPASS) or active (HIITACT) recovery periods and a session of light intensity interval exercise (REC)

Yuri Kriel - article data: Mode

Yuri Kriel - article data: Mod

The Effect of Active versus Passive Recovery Periods during High Intensity Intermittent Exercise on Local Tissue Oxygenation in 18 - 30 Year Old Sedentary Men.

PURPOSE:High intensity interval training (HIIT) has been proposed as a time-efficient format of exercise to reduce the chronic disease burden associated with sedentary behaviour. Changes in oxygen utilisation at the local tissue level during an acute session of HIIT could be the primary stimulus for the health benefits associated with this format of exercise. The recovery periods of HIIT effect the physiological responses that occur during the session. It was hypothesised that in sedentary individuals, local and systemic oxygen utilisation would be higher during HIIT interspersed with active recovery periods, when compared to passive recovery periods. METHODS:Twelve sedentary males (mean ± SD; age 23 ± 3 yr) completed three conditions on a cycle ergometer: 1) HIIT with passive recovery periods between four bouts (HIITPASS) 2) HIIT with active recovery periods between four bouts (HIITACT) 3) HIITACT with four HIIT bouts replaced with passive periods (REC). Deoxygenated haemoglobin (HHb) in the vastus lateralis (VL) and gastrocnemius (GN) muscles and the pre-frontal cortex (FH), oxygen consumption (VO2), power output and heart rate (HR) were measured continuously during the three conditions. RESULTS:There was a significant increase in HHb at VL during bouts 2 (p = 0.017), 3 (p = 0.035) and 4 (p = 0.035) in HIITACT, compared to HIITPASS. Mean power output was significantly lower in HIITACT, compared to HIITPASS (p < 0.001). There was a significant main effect for site in both HIITPASS (p = 0.029) and HIITACT (p = 0.005). There were no significant differences in VO2 and HR between HIITPASS and HIITACT. CONCLUSIONS:The increase in HHb at VL and the lower mean power output during HIITACT could indicate that a higher level of deoxygenation contributes to decreased mechanical power in sedentary participants. The significant differences in HHb between sites indicates the specificity of oxygen utilisation

The structure and timing of measurements of the three conditions.

<p>(A) HIITPASS. (B) HIITACT. (C) REC.</p

Relative change from baseline of deoxygenated haemoglobin (HHb) concentration during the four bouts of the three conditions.

<p>(A) FH. a = significantly different to HIITPASS, bout 1; b = significantly different to HIITACT, bout 1; c = significantly different to HIITPASS, bout 2; d = significantly different to HIITACT, bout 2; e = significantly different to HIITPASS, bout 3; f = significantly different to HIITACT, bout 3; g = significantly different to HIITPASS, bout 4; h = significantly different to HIITACT, bout 4. (B) GN. a = significantly different to HIITACT bout 1; b = significantly different to HIITPASS, bout 2; c = significantly different to HIITACT bout 2; d = significantly different to HIITPASS, bout 3; e = significantly different to HIITACT bout 3; f = significantly different to HIITPASS, bout 4; g = significantly different to HIITACT, bout 4. (C) VL. a = significantly different to HIITPASS, bout 1; b = significantly different to HIITACT, bout 1; c = significantly different to HIITPASS, bout 2; d = significantly different to HIITACT, bout 2; e = significantly different to HIITPASS, bout 3; f = significantly different to HIITACT, bout 3; g = significantly different to HIITPASS, bout 4; h = significantly different to HIITACT, bout 4. Data are mean ± SD. (p >0.05).</p

Participant characteristics.

<p>Participant characteristics.</p