Astronauts well-being and possibly anti-aging improved during long-duration spaceflight

Figures

• 

  Figure 1. Estimation of sleep span (left) and assessment of sleep quality (right). Left: Sleep span is estimated by wrist activity data with postural change (row 1), RR-intervals (row 2), heart rate (row 3), and changes in the HF-component (row 4). This example shows day-to-day differences in the sleep-related increase in the HF-component of HRV. The spectral power of the HF-component is higher on the first day (row 4). In addition, the nocturnal HR dip is blunted on the second day as compared to the first day (row 3). Right: Representative example of a 48-h concomitant record of wrist activity, RR-intervals, and HF-component, LF-band and VLF-component of HRV. Right and left results are from different astronauts. Sleep quality is assessed by determining whether there is a sleep-related (1) decrease in activity (row 1); and increase during the sleep span in (2) RR-intervals (row 2); (3) power in the HF-component (row 3); (4) power of the LF-band (row 4); and (5) power of the VLF-component (row 5). A sleep quality score is obtained by summing the 5 items for each night, on a scale of 0 to 10 points (Yes/No is 1/0).

• 

  Figure 2. Change in the circadian amplitude of HR related to the space mission. The circadian amplitude of HR increased during spaceflight from 10.90 ± 1.79 bpm (Before) to 12.54 ± 2.78 (ISS01), 12.77 ± 2.69 (ISS02), returning to 10.55 ± 3.49 (After).

• 

  Figure 3. Changes in sleep duration (left) and quality of sleep score (right) in Group B astronauts. Sleep duration shortened from 454.0 ± 64.7 min (Before) to 408.9 ± 43.8 min (ISS01, P = 0.0201) and 381.6 ± 49.2 min (ISS02, P = 0.0011) during spaceflight, returning to 426.7 ± 67.5 min after the mission (left). Quality of sleep improved from 7.07 ± 1.10 to 8.36 ± 1.25 (ISS01, P = 0.1148) and 9.36 ± 0.95 (ISS02, P = 0.0001), returning to 6.42 ± 1.93 after return to Earth (right).

• 

  Figure 4. Representative example of correlation between the circadian amplitude of HR and the amplitude of the 12-, 24- and 48-h components of the geomagnetic declination (D) of the geomagnetic field. Effect of magnetic fluctuations on the circadian amplitude of human HR is suggested by its strong correlation with the 12-h (circasemidian; r = 0.6963, P = 0.0253, left panel), circadian (r = 0.8110, P = 0.0044, middle panel), and 48-h (circaduodian; r = 0.6921, P = 0.0266, right panel) amplitudes of D, the declination of the geomagnetic field.