NASA - National Aeronautics and Space Administration

ISS Science Highlight: Integrated Cardiovascular (Cardiac Atrophy and Diastolic Dysfunction During and After Long Duration Spaceflight: Functional Consequences for Orthostatic Intolerance, Exercise Capability and Risk for Cardiac Arrhythmias)

Staying "“heart healthy" is important for everyone, but it is especially important to International Space Station (ISS) crewmembers who don’t have the advantage of an emergency room 15 minutes away in the event of a cardiac event. A new study aboard the ISS seeks to find out exactly how much the heart muscle decreases in size (atrophy) over a standard six-month station tour and how quickly this cardiac atrophy occurs. This study will also help us determine if there is a risk of abnormal heart rhythms and how significant the risk is in order to develop appropriate countermeasures. Changes in heart size may contribute to postflight orthostatic intolerance (lightheadedness or fainting when standing still) that is experienced by most crewmembers following long duration space flight.

This study utilizes all 6 crewmembers on Expedition 20, which began in May and will continue through October. Having a 6 member crew onboard the ISS provides enough crew time to conduct an experiment of this magnitude. Prior to Expeditions 19/20, an experiment this complex would not have been able to be completed. This study is the first of many that demonstrates the full potential of conducting science onboard the ISS.

The data for this study is collected before, during and after flight, by measuring crewmembers' heart rates, heart rhythms and blood pressure for 24- to 48-hours before and after exercise sessions. This will help determine how effective the current exercise program is at protecting the heart from getting smaller. They’re also performing cardiac ultrasound scans on each other on-orbit before and after exercise to look at how effectively the heart fills with blood and pumps it to the rest of the body. As we plan for exploration missions it is important to fully understand changes in how the cardiovascular system is affected by microgravity in order to develop countermeasures that will prevent any negative effects of microgravity on cardiovascular function.

More Information

> Weekly Research Summaries
> Expedition 20 Experiments