It is likely that the use of stroke volume index and cardiac index in lieu of stroke volume (SV) and cardiac output (CO) could have resulted in larger changes due to training-related weight loss. Normalizing SV and CO with lean body mass might also have been an interesting avenue (as the authors have shown with VO2max and VO2 at the ventilatory threshold (VT)).
Accepted Oct 31, 2014; Epub ahead of print Dec 1, 2014
Frank Bour, CEO,
PhysioFlow Inc. USA/Manatec Biomedical France, Poissy, France. E-mail: f.bour@physioflow.com
Response to the “Letter to the Editor: RE: Effect of interval training on cognitive functioning and cerebral oxygenation in obese patients: A pilot study”
We thank Mr Frank Bour for his comment. Table I presents the cardiac index (CImax), stroke volume index (SVImax), cardiac output (COmax LBM) and stroke volume (SVmax LBM) normalized by lean body mass (LBM) at maximal effort. There were no significant changes (Wilcoxon’s signed-rank test) in these 4 parameters, and larger effect sizes were generally observed compared with non-normalized values (1).
In conclusion, future studies on high-intensity interval training in obese subjects with larger sample size will be required to document their effects on haemodynamic variables.
|
Table I. Normalized maximal haemodynamic variables before and after 4 months of high-intensity interval training in obese subjects (n = 6) |
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|
Parameters |
Pre Mean (SD) |
Post Mean (SD) |
p-value |
Effect size Hedge’s, g |
|
CImax (l/min/m2) |
8.45 (1.59) |
8.87 (1.09) |
0.50 |
0.28 |
|
SVImax (ml/m2) |
47 (7) |
53 (6) |
0.13 |
0.85 |
|
COmax LBM (l/min/kg) |
0.30 (0.06) |
0.31 (0.08) |
0.50 |
0.17 |
|
SVmax LBM (ml/kg) |
1.68 (0.33) |
1.90 (0.49) |
0.22 |
0.48 |
|
LBM: lean body mass; CImax: cardiac index; SVImax: stroke volume index; COmax LBM: cardiac output; SVmax LBM: stroke volume; SD: standard deviation. |
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Reference
Mathieu Gayda,
Cardiovascular Prevention and Rehabilitation Centre (Centre ÉPIC), Montreal Heart Institute and University of Montreal, 5055 St-Zotique Street East, Montreal, Quebec H1T 1N6, Canada. E-mail: mathieu.gayda@icm-mhi.org
