Faculty Collaboration Database

Cardiovascular responses to military antishock trouser inflation during standing arm exercise. J Appl Physiol (1985) 1987 Sep;63(3):1224-9

Date

09/01/1987

Pubmed ID

3654467

DOI

10.1152/jappl.1987.63.3.1224

Scopus ID

2-s2.0-0023276483 (requires institutional sign-in at Scopus site)   14 Citations

Abstract

Military antishock trousers (MAST) inflated to 50 mmHg were used with 12 healthy males (mean age 28 +/- 1 yr) to determine the effects of lower-body positive pressure on cardiac output (Q), stroke volume (SV), heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial blood pressure (MABP), total peripheral resistance (TPR), and O2 uptake (VO2) during graded arm-cranking exercise. Subjects were studied while standing at rest and at 25, 50, and 75% of maximal arm-cranking VO2. At each level, rest or work was continued for 6 min with MAST inflated and for 6 min with MAST deflated. Order of inflation and deflation was alternated at each experimental rest or exercise level. Measurements were obtained during the last 2 min at each level. Repeated-measures analysis of variance revealed significant increases (P less than 0.001) in Q, SV, and MABP and a consistent decrease in HR with MAST inflation. There was no apparent change in Q/VO2 between inflated and control conditions. There was no effect of MAST inflation on VO2 or TPR. MAST inflation counteracts the gravitational effect of venous return in upright exercise, restoring central blood volume and thereby increasing Q and MABP from control. HR is decreased consequent to increased MABP through arterial baroreflexes. The associated decrease in TPR is not observed, being offset by the mechanical compression of leg vasculature with MAST inflation.

Author List

Ng AV, Hanson P, Aaron EA, Demment RB, Conviser JM, Nagle FJ

Author

Alexander V. Ng PhD Associate Professor in the Exercise Science department at Marquette University

MESH terms used to index this publication - Major topics in bold

Adult
Arm
Blood Pressure
Heart Rate
Humans
Leg
Male
Military Medicine
Physical Exertion
Pressure
Protective Clothing
United States