Introduction
Cardiovascular Stress Response to Exercise
Measurements of the Cardiovascular Stress Response in Pediatric Population Studies
Exercise Methods for Detailed Cardiovascular Stress Response Assessment in Pediatric Research
Methods | Advantages | Disadvantages | |
---|---|---|---|
Treadmill exercise | An MRI compatible treadmill is placed in the MRI room. After the exercise, the subject has to take place in the MRI scanner as quick as possible | – Exercise can be performed to maximum exertion [64] – Motion artifacts are less compared to dynamic exercise in a MRI device | – The time period between peak stress and image acquisition may allow the subject’s cardiovascular system to recover [52] – Ultra-fast scanning is required to limit the breath holding time. A long breath hold is not feasible after intensive exercise – The device has to be placed inside the MRI room to reduce the time delay |
Bicycle exercise | An MRI compatible bicycle ergometer can be placed at the food end of the MRI table. Just before scanning, the exercise can be performed to high exertion. Then, the subject has to stop the exercise before the scan has started | – Exercise inside the MRI device is possible | – Ultra-fast scanning is required to limit the breath holding time. A long breath hold is not feasible after intensive exercise – Scanning while exercising is not possible without any motion artifacts – A fully circular movement of the legs is not feasible due to the limited space in the MRI |
Handgrip exercise | Immediately after the start of the exercise, the scan can be started. The exercise is performed during the scan protocol up to 8 min [52] | – Real-time scanning while exercising is possible without any motion artifacts [35] – Breath holds are feasible – Simple to implement and least expensive method – Good reproducibility [67] | – Exercise cannot be performed to maximum exertion |
Isometric Handgrip Exercise and the Effects on Heart Rate Variability and Blood Pressure in Pediatric Populations
Name, year | Population | Used handgrip exercise protocol | Main cardiovascular outcomes |
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Dipla (2010) [68] | 27 healthy boys: age: 11 years | 3 min at 30% MVC | In rest obese boys had higher stroke volume and lower total peripheral resistance than lean boys. During exercise, ΔMAP was not significantly different between lean and obese boys (22.7 ± 2.6 vs. 19.6 ± 1.5 mmHg in lean vs. obese boys) ΔHR was higher in lean boys than in obese boys: 14.5 ± 1.6 vs. 8.2 ± 1.3BPM |
Ferrara (1991) [78] | 162 healthy children: age: 11 years | 2 min at 60%MVC | Significant increase in BP and HR |
Goulopoulou (2010) [69] | 23 healthy children: age: 7–9 years | 3 min at 30% MVC | SBP: 107.9 ± 2.0 mmHg to 122.1 ± 2.7 mmHG DBP: 64.6 ± 2.0 mmHg to 78.1 ± 2.5 nmmHG MAP: 82.8 ± 2.4mmHG to 96.4 ± 2.4 mmHg HR: 84.0 ± 2.0BPM to93.5 ± 2.2 BPM Cardiac index (L/min/m2): 1.5 ± 0.06 to 1.7 ± 0.07 Stroke index (mL/beat/m2: 17.6 ± 0.6 to 17.9 ± 0.7 Al rises were significant |
Gumbiner (1983) [70] | 18 healthy children 28 children with aortic insufficiency Age: 13 years | 3 min at 33% MVC | Control: HR: 78 to 91 BPM (P < 0.05) Blood pressure 115/64 to 128/76 mmHg Patients: HR: 75.4 to 89.5 BPM (P < 0.05) Blood pressure: 117/53 to 150/72 mmHg |
Laird (1979) [71] | 32 healthy children: age: 15 years | 4 min at 25%MVC | Heart rate (beats/min) 70 ± 9 to 88 ± 11 Systolic pressure (mm Hg): 110 ± 7 to 124 = 10 Diastolic pressure(mm Hg) 61 ± 8 to 76 ± 8 Mean pressure (mm Hg) 78 ± 7 to 92 ± 7 Al rises were significant |
Legantis (2012) [72] | 48 healthy children: age: 11.6 ± 0.3 years | 3 min at 30% MVC | At rest and during exercise, unfit obese/overweight children had higher systolic, mean arterial pressure, and rate pressure product than fit obese/overweight children whose responses were similar to normal weight children, fit or unfit. Changes from rest, in cardiac output, cardiac index, and stroke volume were higher in unfit than in fit obese/overweight children |
Matthews (1988) [80] | 217 children: age: 13 years | 2,5 min at 30% MVC | Significant increase in BP and HR which was larger in boys than in girls |
Mehta (1996) [74] | 18 children with presence of parental hypertension 29 healthy children Age: 10 to 18 years | 4 min at 25% MVC | The between-group difference in heart rate was not statistically significant at rest (70 _ + 9 BPM vs 75 _ + 9 BPM) With exercise, the heart rates were significantly higher in subjects from the patients group (87 _ + 10 BPM vs 79—+ 13 PBM) |
Nageswari (2007) [75] | 20 obese/overweight children 20 non-obese children Age: 12–16 years | 30%MVC until the point of fatigue | Change in diastolic BP: Control:15.9 ± 4.61mmHG Obese: 11.4 ± 4.02mmHG |
Schieken (1983) [76] | 264 students: age: 9–18 years | 3 min at 30% MVC | Significant increase in BP and HR |
Woehrle (2018) [77] | 19 concussed adolescents 16 healthy controls Age: 15 ± 2 years) | 30 s at 30% MVC | Greater ΔHR among control participants (13 ± 10 BPM) compared with concussed patients (6.4 ± 6.3 BPM) |
Garg (2013) [79] | 100 participants aged 17–24 years with or without a family history of primary hypertension | 2 min at 30% MVC | Greater ΔSBP, ΔDBP and ΔMAP in offspring of hypertensive parents |
Isometric Handgrip Exercise and the Effects on Cardiac Adaptations Measured by Advanced Imaging Techniques
Name, year | Population | Used handgrip exercise protocol | MRI protocol | Cardiac outcomes |
---|---|---|---|---|
Al-Otaibi (2010) [84] | One epileptic 24 year old patient 10 healthy subjects: age: 27.3 ± 4.0 years | 2 exercise conditions: 30% MVC and 70% MVC. Each session consisted of repeated handgrip contractions each lasting 2 s. 27 trials were completed per condition | FMRI of the brain | The HR response to the IHE was lower in the patient during both 30% and 70% MVC (0.2 and 3.4BPM, respectively) relative to the control group (2.9 ± 1.8 and 7.3 ± 4.1 bpm, respectively) |
Betim Paes (2013) [85] | 28 patients with Chagas Heart Disease: age: 48 ± 11 years 8 healthy subjects: age: 29 ± 4 years | 8 min | Magnetic Resonance Spectroscopy of the heart | Both groups had a significant HR and RPP increase after exercise. The control group had a higher mean HR both at rest and during exercise |
Bonanno (2018) [86] | 10 healthy subjects: age: 24 ± 5.5 years | 5–8 min at 30% MVC | Coronary MRI | RPP increase: 37% |
Globits (1997) [87] | 9 healthy subjects: age: 31 ± 4 years | 3 min at 50% MVC | Coronary MRI | HR increase: 24% Mean BP increase: 25% RPP increase: 54.4% |
Haddock (2018) [88] | 10 healthy subjects: age: 20–48 years | 5-min at 70% MVC | Renal arterial flow (RAF) | HR: increase: 17 ± 9% Systolic BP increase: 25 ± 11% |
Hays (2010) [59] | 20 healthy subjects: age: 40 years 17 patients with CAD: age: 55 years | 4,5 min at 30% MVC | Coronary MRI | Healthy: HR increase: 15.9% MAP increase: 12.5% RPP increase: 27% CAD: HR increase: 12.6% Mean BP increase: 12.5% RPP increase: 26% The RPP during IHE and the percent increase in RPP from baseline did not significantly differ between CAD patients and healthy subjects |
Hays (2010) [59] | 20 healthy subjects: age: 40.2 ± 13.7 years 17 patients with CAD: age: 55.5 ± 6.8 years | 4.5 min 30% MVC | Coronary MRI | Healthy: HR increase: 15.9% Systolic BP increase: 12.5% RPP increase: 27% CAD: HR increase: 12.6% Systolic BP increase: 12.5% RPP increase: 26% |
Hays (2012) [89] | 14 healthy subjects: age: 39 ± 19 years 14 patients with non-obstructive CAD: age: 59 ± 7 years | 4½ minutes at 30% MVC | Coronary MRI | Healthy: HR increase: 15.7% Systolic BP increase: 9.6% RPP increase: 28% CAD: HR increase: 17.0%, Systolic BP increase: 9.2% RPP increase: 28% |
Hays (2015) [67] | 10 healthy subjects: age: 31 years 8 patients with CAD: age: 60 years | 30% MVC | Coronary MRI | Coronary arteries in healthy subjects significantly dilated in response to IHE. RPP increase: 8000 to 12,000 |
Hays (2017) [61] | 29 subjects with CAD: Age: 58 years 16 healthy subjects: Age: 57 years | 4,5 min at 30% MVC | Coronary MRI | Healthy: RPP increase: 30.1 ± 17.6% CAD: RPP increase: 32.8 ± 17.2% Difference between healthy and CAD was not significant |
Iantorno (2016) [90] | 26 healthy subjects, age: 45 ± 3.5 years 15 patients with CAD, age: 61 ± 1.5 years | 4 to 7 min at 30% MVC | Coronary MRI | IHE induced significant and similar hemodynamic changes in healthy subjects and patients with CAD Healthy: RPP increase: 35.4 ± 4.6% CAD: RPP increase: 28.7 ± 3.9% |
Iantorno (2017) [91] | 18 patients HIV + CAD-, age: 52 years 36 patients HIV- CAD-, age: 52 years 41 patients HIV- CAD + , age: 59 years 17 patients HIV + CAD + , age: 59 years | 4–7 min at 30% MVC | Coronary MRI | HIV + patients with no significant CAD have severely impaired CEF that is similar to that of HIV- patients with established CAD.No significant differences in mean RPP change or peak RPP during IHE among the four groups |
Iantorno (2018) [92] | 36 patients HIV + CAD-: age: 53 ± 8 years 15 patients HIV + CAD + : age: 57 ± 4 years 14 patients HIV-CAD-: age: 50 ± 7 years | 6–7 min at 30% MVC | Coronary MRI | HIV + CAD-: RPP increase: 17% HIV + CAD + : RPP increase: 21% HIV-CAD-: RPP increase: 25% |
Knobelsdorff-Brenkenhoff (2016) [60] | 7 patients with hypertensive heart disease [HYP]:age: 56 ± 12 years 12 patients with aortic stenosis [AS]: age: 60 ± 15 years 24 healthy subjects: age: 47 ± 17 years | 6–8 min at 30% MVC | Heart protocol | HYP subjects showed a higher systolic blood pressure during exercise than controls HYP HR increase: 20.6612.1% Systolic BP increase: 19.469.0% AS HR increase: 12.566.6% Systolic BP increase: 16.4618.9% Healthy HR increase: 15.368.5% Systolic BP increase: 13.169.2% |
Knobelsdorff-Brenkenhoff (2013) [52] | 53 healthy subjects: age: 45 ± 17 years | 6–8 min at 30% MVC | Heart protocol | HR increase: 20 ± 13%, Systolic BP increase: 15 ± 11%: Diastolic BP increase: 20 ± 18% Mean BP increase: 17 ± 13%, RPP increase: 37 ± 21%, CO increase: 27 ± 16% Stroke volume did not significantly increase. Higher age was associated with reduced increase of stroke volume and cardiac output Overweight subjects showed less increases in heart rate and cardiac output |
Leucker (2018) [93] | 48 HIV + patients: age: 49 ± 8 years 15 healthy subjects: age: 52 ± 12 years | 4 to 7 min at 30% MVC | Coronary MRI | CEF was significantly reduced in the HIV + versus HIV- subjects |
Macey (2017) [94] | 63 healthy subjects: age: 47.0 ± 9.1 years | 4 × 16 s challenges at 80% MVC | FMRI of the brain | Females showed higher resting HR than males, but smaller percent HR change increases during exercise |
Mathews (2017) [95] | 30 healthy women: age: 49.8 ± 16.7 years 20 healthy men: age: 44.1 ± 16.4 years | 5–6 min at 30% MVC | Coronary MRI | In men baseline CSA was 13.4 ± 4.6 mm2 and increased 8.8 ± 5.2% with IHE. In women baseline CSA was 10.7 ± 2.6mm2, and increased 1.4 ± 9.6% with IHE Men: HR increase: 20,0% Systolic BP increase: 10,7% Diastolic BP increase: 15,9%: RPP increase: 33,9% Women: HR increase: 17,2% Systolic BP increase: 8,0% Diastolic BP increase: 17,9% RPP increase: 28,1% |
Norton (2013) [96] | 29 subjects: age: 21–80 years | 40% MVC | FMRI of the brain | The average change in HR from baseline was 6BPM |
Norton (2015) [97] | 23 healthy subjects: age: 63 years 17 patients with CAD: age: 59 years | 7 repeated bouts at 40% MVC with each contraction lasting 20 s and separated by 40 s of rest | FMRI of the brain | HR during exercise in control participants was greater than CAD patients Specifically, young individuals (25 ± 4 year) have a larger HR response (6–15 beats/min) to a similar relative IHE tension |
Rokamp (2014) [98] | 11 healthy subjects: age: 24 ± 3 years | Squeeze 30–60 times per minute with as much effort as possible | FMRI of the brain | Diastolic BP increase: 4 mmHg Mean BP increase: 5 mmHg No significant changes were observed for SBP and HR |
Verbree (2017) [99] | 20 healthy subjects: age: 30 years | The first minute at 80% MVC to be directly followed by 4 min at 60% MVC | Middle cerebral artery | HR increase: 11.2 ± 1.7% |
Williamson (2003) [100] | 8 healthy subjects: age: 26 ± 3 years | IHE beginning at 40% MVC until 15 mmHg BP increase | FMRI of the brain | Mean BP increase: 14,9% HR increase: 7 ± 3 BPM |
Wong (2007) [101] | 17 healthy subjects: age: 25 ± 4 years | 3 × 30 s blocks separated by 1 min of rest at 5% or 35% MVC | FMRI of the brain | HR and MAP were increased in the 35% MVC trials but not the 5%MVC trials. Both the left and right hand trials elicited similar cardiovascular responses |
Wood (2017) [102] | 52 healthy subjects Age: 59 years | 7 repeated bouts at 40% MVC. Each contraction bout lasted 20 s and was separated by 4 s of rest | FMRI of the brain | HR responses to IHE showed high variability across individuals. Linear regression revealed that cardiorespiratory fitness was not a strong predictor of the HR response |
Zhang (2012) [103] | 4 healthy subjects Age: 25–36 years | 3 × 1 min at 100%MVC | Retina/choroid blood flow | HR increase: 19% ± 8%, Mean BP increase: 22% ± 5% |