Abbreviations
ANOVA analysis of variance
BMI body mass index
BMR basal metabolic rate
BP blood pressure
CP cold pressor
DBP diastolic blood pressure
HDL high density lipoprotein
HG handgrip
HR heart rate
LDL low density lipoprotein
MSNA muscle sympathetic nerve activity
MVC maximal voluntary contraction
SBP systolic blood pressure
STBR-IP short-term bedrest-integrative physiology

Authors’ contributions
MH and FB conceived of the bedrest and caloric restriction design. Together with FB and MH, JP participated in the design, coordination, and execution of autonomic testing including experimental stressors and measurements. JF helped with data collection and analyzed the data. MH, FB, and JP contributed to the interpretation of data. JF and JP drafted the manuscript, and FB and MH helped to revise the manuscript. All authors have read and approved the final manuscript.

Acknowledgements
We are indebted to the research subjects who participated in this ambitious and challenging study. Also, we are grateful to the DLR staff for their superb technical assistance and expertise.

Grants
This research was supported by National Space Biomedical Research Institute Contract TD00206.

Competing interests
The authors declare that they have no competing interests.