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Inspiratory muscle strength training suppression of sympathetic nervous outflow in young adults: Time course and differential recovery.
Author(s) -
DeLucia Claire M.,
Debonis Dean R.,
Schwyhart Sarah M.,
Bailey E. Fiona
Publication year - 2020
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.2020.34.s1.06396
Subject(s) - medicine , blood pressure , heart rate , cardiology , sympathetic nervous system , resistance training , anesthesia
Background Our laboratory has shown that an abbreviated form of inspiratory muscle strength training (IMST) performed 5 minutes/day, 5 days/week for 6 weeks lowers casual systolic blood pressure and systemic vascular resistance in healthy young adults. While the effects of IMST have been characterized in the short term, the acute effects of the training protocol on cardiovascular function have not been documented. Purpose To characterize the acute cardiovascular response to a bout of IMST (comprising 5 sets of 6 breaths) in healthy young adults. Methods Fourteen healthy women and men (n=14, 7F/7M, age: 22±2 years) performed five sets of six inspiratory efforts against a target resistance set at 75% of maximum inspiratory pressure (PI max ). We recorded inspiratory pressure, postganglionic, multiunit muscle sympathetic nerve activity (MSNA), beat‐to‐beat changes in blood pressure (SBP and DBP), and heart rate (HR) at baseline, during IMST and in recovery. Results There were no differences between women and men in regard to PI max (F: −79.9±17.7 and M: −78.3±21.7 mmHg, p=0.8794), or baseline measures of MSNA (F: 7.3±1.8 bursts/15s bin and M:6.2±1.4 bursts/15s bin, p=0.6377), SBP (F:114.0±9.1 and M:114.0±4.7 mmHg, p=0.9855), and HR (F: 75±8 bpm and M:74±15 bpm, p=0.6994). During IMST, women and men attained the same target pressure (75% PI max ) (F: −58.6±13.0 mmHg and M: −58.7 ±16.3 mmHg, p=0.8794) and performed the same amount of inspiratory work per breath (F: 84.1±22.2 and M: 85.0±25.9 mmHg.s, p=9176). Relative to baseline, HR increased 25±10%, (p<0.0001) and MSNA decreased 43±20% (p<0.0001) in all subjects. In recovery, MSNA suppression persisted in women but not in men (p=0.015). There were no acute effects of IMST on systolic (p=0.895) or diastolic (p=0.761) blood pressures. Conclusion IMST exerts an acute inhibitory effect on MSNA in young men and women. Our data highlight a disparity in the time course of the recovery of MSNA post IMST for women vs. men. Support or Funding Information National Institutes of Health Interdisciplinary Training Grant in Cardiovascular Sciences T32 HL007249