Exercise as potential countermeasure for the effects of 70 days of bed rest on cognitive and sensorimotor performance

Vincent Koppelmans; Ajitkumar P Mulavara; Peng Yuan; Kaitlin E Cassady; Katherine A Cooke; Scott J Wood; Patricia A Reuter-Lorenz; Yiri E De Dios; Vahagn Stepanyan; Darcy L Szecsy; Nichole E Gadd; Igor Kofman; Jessica M Scott; Meghan E Downs; Jacob J Bloomberg; Lori Ploutz-Snyder; Rachael D Seidler

doi:10.3389/fnsys.2015.00121

Exercise as potential countermeasure for the effects of 70 days of bed rest on cognitive and sensorimotor performance

Front Syst Neurosci. 2015 Sep 3:9:121. doi: 10.3389/fnsys.2015.00121. eCollection 2015.

Authors

Vincent Koppelmans¹, Ajitkumar P Mulavara², Peng Yuan¹, Kaitlin E Cassady³, Katherine A Cooke³, Scott J Wood⁴, Patricia A Reuter-Lorenz⁵, Yiri E De Dios⁶, Vahagn Stepanyan⁶, Darcy L Szecsy⁷, Nichole E Gadd⁶, Igor Kofman⁶, Jessica M Scott⁸, Meghan E Downs⁹, Jacob J Bloomberg¹⁰, Lori Ploutz-Snyder², Rachael D Seidler¹¹

Affiliations

¹ School of Kinesiology, University of Michigan Ann Arbor, MI, USA.
² NASA Johnson Space Center Houston, TX, USA ; Universities Space Research Association Houston, TX, USA.
³ School of Kinesiology, University of Michigan Ann Arbor, MI, USA ; Department of Psychology, University of Michigan Ann Arbor, MI, USA.
⁴ NASA Johnson Space Center Houston, TX, USA ; Department of Psychology, Azusa Pacific University Azusa, CA, USA.
⁵ Department of Psychology, University of Michigan Ann Arbor, MI, USA ; Neuroscience Program, University of Michigan Ann Arbor, MI, USA.
⁶ Wyle Science, Technology and Engineering Group Houston, TX, USA.
⁷ Bastion Technologies Houston, TX, USA.
⁸ Universities Space Research Association Houston, TX, USA.
⁹ Department of Health and Human Performance, University of Houston Houston, TX, USA.
¹⁰ NASA Johnson Space Center Houston, TX, USA.
¹¹ School of Kinesiology, University of Michigan Ann Arbor, MI, USA ; Department of Psychology, University of Michigan Ann Arbor, MI, USA ; Neuroscience Program, University of Michigan Ann Arbor, MI, USA ; Institute of Gerontology, University of Michigan Ann Arbor, MI, USA.

Abstract

Background: Spaceflight has been associated with changes in gait and balance; it is unclear whether it affects cognition. Head down tilt bed rest (HDBR) is a microgravity analog that mimics cephalad fluid shifts and body unloading. In consideration of astronaut's health and mission success, we investigated the effects of HDBR on cognition and sensorimotor function. Furthermore, we investigated if exercise mitigates any cognitive and sensorimotor sequelae of spaceflight.

Method: We conducted a 70-day six-degree HDBR study in 10 male subjects who were randomly assigned to a HDBR supine exercise or a HDBR control group. Cognitive measures (i.e., processing speed, manual dexterity, psychomotor speed, visual dependency, and 2D and 3D mental rotation) and sensorimotor performance (functional mobility (FMT) and balance performance) were collected at 12 and 8 days pre-HDBR, at 7, 50, and 70 days in HDBR, and at 8 and 12 days post-HDBR. Exercise comprised resistance training, and continuous and high-intensity interval aerobic exercise. We also repeatedly assessed an outside-of-bed rest control group to examine metric stability.

Results: Small practice effects were observed in the control group for some tasks; these were taken into account when analyzing effects of HDBR. No significant effects of HDBR on cognition were observed, although visual dependency during HDBR remained stable in HDBR controls whereas it decreased in HDBR exercise subjects. Furthermore, HDBR was associated with loss of FMT and standing balance performance, which were almost fully recovered 12 days post-HDBR. Aerobic and resistance exercise partially mitigated the effects of HDBR on FMT and accelerated the recovery time course post-HDBR.

Discussion: HDBR did not significantly affect cognitive performance but did adversely affect FMT and standing balance performance. Exercise had some protective effects on the deterioration and recovery of FMT.

Keywords: bed rest; cognition; exercise; longitudinal; microgravity; sensorimotor functioning; spaceflight analog.