Exercise helps astronauts protect heart in space

Toronto, March 23 (IANS) Astronauts who exercise regularly and intensively on extended space missions mitigated the effects of low-gravity environment on their cardiac health, a study reveals.

Researchers reported these findings after examining the cardio-health of astronauts who followed a rigorous exercise regimen on board the International Space Station (ISS) as little was known about their effects.

R.L. Hughson, D.K. Greaves, P.P. Pereira-Junior and D. Xu of the University of Waterloo; J.K. Shoemaker of the University of Western Ontario and others collected data from six male astronauts, aged between 41 and 55 years, who stayed on ISS missions from 52 to 199 days.

A month before they embarked, the research team collected a wealth of data on each subject's cardiovascular health, the Journal of Applied Physiology reported.

This data was collected during spontaneous and paced breathing, both sitting up and lying down, to reflect a variety of conditions and cardiovascular stresses, said the university statement.

The researchers measured various factors including finger arterial blood pressure (BP), heart rate, left ventricular ejection time, and cardiac output.

Results showed that heart rate, BP and arterial baroreflex response (the body's natural way to regulate heart rate and BP based on continuous sensing of both) were unchanged from pre-flight to in-flight.

On these particular missions, the astronauts were each allotted 2.5 hours per day to set up for exercise, complete a workout, and clean up after the session, with options to exercise on a cycle, treadmill, or doing resistance training.

These exercise sessions appear to keep astronauts relatively healthy and prepared for return to Earth, despite the potentially negative effects of a low-gravity environment.