Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Histamine tied to changes in blood pressure during exercise-recovery period

Finding may explain biggest cause of post-exercise fainting

Overactivation of two receptors for histamine, normally associated with common allergies and acid reflux, may explain why some people, including highly trained athletes, pass out soon after heightened physical activities, according to researchers at the University of Oregon.

A series of studies led researchers in incremental steps to the discovery that the use of two commonly used antihistamines (fexofenadine and ranitidine) prior to exercise dramatically lower or completely eliminate low blood pressure following exertion. The drugs worked by preventing post-exercise hyperemia, an increased flow of blood, in the skeletal muscle during the critical 90-minute recovery period after exercise. In all, the pre-exercise consumption of the two antihistamines reduced the blood flow that occurs during recovery by 80 percent.

The study, funded by the American Heart Association, was posted online ahead of regular publication in the Journal of Applied Physiology. While fainting after exercise, a condition called syncope, can indicate a serious heart disorder, most cases are linked to low blood pressure and low blood flow to the brain.

"There is reason to believe that histamine is the primary vasodilator contributing to post-exercise hypotension, but we cannot say for certain," cautioned principal investigator John R. Halliwill, a professor of human physiology. "Some people have problems regulating blood pressure during and after exercise. Trained athletes have had fainting bouts at the end of exercise. It may be that these result from a natural overactivation of these two receptors for histamine."

The histamine receptors involved are known as H1 and H2. Fexofenadine, which is the generic name for Allegra, works against H1, reducing the occurrence of such allergy symptoms as sneezing and runny nose. Ranitidine, or Zantac, acts against H2 in the treatment of acid reflux.

For the study, 28 sedentary and endurance-trained men and women were monitored closely throughout a session that covered a pre-exercise period, a 60-minute ride on a cycling machine and a 90-minute recovery period. The participants were all non-smokers without blood pressure problems and between the ages of 19 and 34. The group given the histamine blockers consumed them with water 60 minutes before beginning the exercise regimen.

The studies in Halliwill's Exercise and Environmental Physiology Laboratories were designed to pursue the mechanisms involved in the exercise recovery period. The findings that the two antihistamine products worked as they did do not mean that athletes or sedentary-turned-active people should head to their medicine cabinets before exercising.

The amount of fexofenadine used in the study was almost three times the strongest dose used for respiratory allergies, while the dosage for ranitidine matched the common starting dose for battling heartburn. Also, there may be a benefit to the normal activation of these receptors during physical activity, because routine exercise helps to reduce or prevent the development of hypertension, or high blood pressure. "Activating these receptors might be an important part of the health benefits of daily exercise," Halliwill said.

The two drugs, however, did not appear to affect the central nervous system or cause sedation during the exercise experiments, Halliwill and co-author Jennifer L. McCord, a doctoral student, noted in the study.

The big question now, Halliwill said, is what triggers the histamine responses during exercise.

"The body tends to be very good at recycling mechanisms," he said. "The body may be using these same receptors for other things. A bout of exercise appears to turn on a program for remodeling blood vessels in the body, and these receptors may be an important part of that program."

Jim Barlow | EurekAlert!
Further information:

More articles from Health and Medicine:

nachricht Resolving the mystery of preeclampsia
21.10.2016 | Universitätsklinikum Magdeburg

nachricht New potential cancer treatment using microwaves to target deep tumors
12.10.2016 | University of Texas at Arlington

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>