TY - JOUR
T1 - Vascular and central hemodynamic changes following exercise-induced heat stress
AU - Lefferts, Wesley K.
AU - Heffernan, Kevin S.
AU - Hultquist, Eric M.
AU - Fehling, Patricia C.
AU - Smith, Denise L.
N1 - Funding Information:
This study was supported by a research grant from the Department of Homeland Security through a Federal Emergency Management Agency Assistance to Firefighters Grant (EMW-2010-FP-01992, Smith, PI).
Publisher Copyright:
© The Author(s) 2015.
PY - 2015/6/5
Y1 - 2015/6/5
N2 - This study examined the effects of moderate exercise-induced heat stress (EIHS) on vascular function, central hemodynamic load and indices of coronary perfusion. Vascular-hemodynamic measures were collected in 12 healthy men (aged 22±3 years) pre and post 100 minutes of moderate, intermittent exercise in two randomized conditions: heat stress (HS; wearing firefighter personal protective equipment (PPE)), and no heat stress (NHS; wearing a cooling shirt and equivalent PPE weight). Aortic blood pressure, reflected wave pressure (Pb), systolic (SPTI) and diastolic pressure time-integral (DPTI), and aortic stiffness were assessed before and after each condition. SPTI was significantly greater, and DPTI and Pb were significantly lower for HS-post compared to NHS-post (p<0.05). Pulse wave velocity was not different between conditions. In conclusion, EIHS does not affect aortic stiffness, but increases indices of myocardial work and reduces indices of coronary perfusion which may be related to chronotropic responses to EIHS. The mismatch between oxygen demand and oxygen supply may increase cardiac vulnerability to ischemia during strenuous work in the heat.
AB - This study examined the effects of moderate exercise-induced heat stress (EIHS) on vascular function, central hemodynamic load and indices of coronary perfusion. Vascular-hemodynamic measures were collected in 12 healthy men (aged 22±3 years) pre and post 100 minutes of moderate, intermittent exercise in two randomized conditions: heat stress (HS; wearing firefighter personal protective equipment (PPE)), and no heat stress (NHS; wearing a cooling shirt and equivalent PPE weight). Aortic blood pressure, reflected wave pressure (Pb), systolic (SPTI) and diastolic pressure time-integral (DPTI), and aortic stiffness were assessed before and after each condition. SPTI was significantly greater, and DPTI and Pb were significantly lower for HS-post compared to NHS-post (p<0.05). Pulse wave velocity was not different between conditions. In conclusion, EIHS does not affect aortic stiffness, but increases indices of myocardial work and reduces indices of coronary perfusion which may be related to chronotropic responses to EIHS. The mismatch between oxygen demand and oxygen supply may increase cardiac vulnerability to ischemia during strenuous work in the heat.
KW - arterial stiffness
KW - heat stress
KW - personal protective equipment
KW - pulse wave reflections
KW - wave separation analysis
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U2 - 10.1177/1358863X14566430
DO - 10.1177/1358863X14566430
M3 - Article
C2 - 25939655
AN - SCOPUS:84930385734
SN - 1358-863X
VL - 20
SP - 222
EP - 229
JO - Vascular Medicine (United Kingdom)
JF - Vascular Medicine (United Kingdom)
IS - 3
ER -