journal article
LitStream Collection
Acute Upper and Lower Limb Hemodynamic Responses During Single Sessions of Low- Versus High-Intensity Inspiratory Muscle Strength Training
Plouffe, Audrey A.; Fischer, Kylah P.; Vranish, Jennifer R.
2023 Journal of Applied Physiology
doi: 10.1152/japplphysiol.00558.2023
Inspiratory muscle strength training (IMST) has shown potential to improve both respiratory and cardiovascular function in health and disease. Less is known about acute hemodynamic responses to a single IMST session, therefore we assessed upper and lower limb blood flow via Doppler ultrasound in the brachial and popliteal arteries, respectively. Mean, anterograde, and retrograde blood flow (BF) and shear rate (SR) were assessed relative to baseline during low-intensity (15% maximal inspiratory pressure - PImax) and high-intensity (75% PImax) IMST. During low-intensity IMST, popliteal BF and SR were reduced by ~10% and brachial BF and SR were reduced by ~40%. During high-intensity IMST, popliteal BF and SR were reduced by ~20% and brachial BF and SR were reduced by ~35%. BF and SR responses were not statistically different between low-intensity and high-intensity training for either blood vessel (P > 0.05). In addition, anterograde BF and SR were significantly decreased in the brachial artery for both low-intensity and high-intensity training (P < 0.05), but not the popliteal artery (P > 0.05). Finally, during IMST retrograde BF and SR were significantly increased in both the upper and lower limbs during low-intensity and high-intensity training (P < 0.05). These data provide novel insight into the acute BF and SR responses to a single bout of IMST, and may enhance our understanding of the mechanism(s) by which IMST imparts its beneficial chronic effects on cardiovascular function.