Researchers reveal how human heart adapts to space

Scientists have analysed how the human heart adapts in space in a recent study.

In this study, scientists compared the cardiac effect of extreme duration swimming and space light to determine whether low density, long-duration exercise counteracts the effects of repeated weightlessness.

For research, scientists compared Benoit Lecomte who swam 2821 kilometres over 159 days and Scott Kelly who spent 340 days in space.

What do extreme-duration swimming and extreme duration spaceflight have in common and how are they different? Both are associated with the removal of gravitational loading of the musculoskeletal system and the absence of weight-bearing activities.

Water immersion and supine bed rest ground-based models for spaceflight, initially increase central blood volume as a result of reversed hydrostatic gradients but over time lead to diuresis partially through avail natriuretic peptide stimulation and antidiuretic hormone inhibition.

During spaceflight, the loss of a gravitational gradient results in a similar short-term rise in preload followed by a compensatory decrease in blood volume and a long-term reduction in the period. Without countermeasures, extended spaceflight results in cardiac atrophy and orthostatic intolerance.