Vascular and central hemodynamic changes following exercise-induced heat stress.
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.
Skidmore College, Saratoga Springs, NY, USA Syracuse University, Syracuse, NY, USA.
Wesley K
WK
Lefferts
Syracuse University, Syracuse, NY, USA.
Kevin S
KS
Heffernan
Skidmore College, Saratoga Springs, NY, USA.
Eric M
EM
Hultquist
Skidmore College, Saratoga Springs, NY, USA.
Patricia C
PC
Fehling
Skidmore College, Saratoga Springs, NY, USA dsmith@skidmore.edu.
Denise L
DL
Smith
D001794:Blood Pressure; D001808:Blood Vessels / Q000502:physiology*; D003326:Coronary Circulation / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D006321:Heart / Q000502:physiology*; D018869:Heat-Shock Response / Q000502:physiology*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D059289:Vascular Stiffness; D055815:Young Adult
arterial stiffness; heat stress; personal protective equipment; pulse wave reflections; wave separation analysis