Running vs. resistance exercise to counteract deconditioning induced by 90-day head-down bedrest

Adrien Robin; Linjie Wang; Marc-Antoine Custaud; Jiexin Liu; Min Yuan; Zhili Li; Jean-Christophe Lloret; Shujuan Liu; Xiaoqian Dai; Jianfeng Zhang; Ke Lv; Wenjiong Li; Guillemette Gauquelin-Koch; Huijuan Wang; Kai Li; Xiaotao Li; Lina Qu; Nastassia Navasiolava; Yinghui Li

doi:10.3389/fphys.2022.902983

Running vs. resistance exercise to counteract deconditioning induced by 90-day head-down bedrest

Front Physiol. 2022 Aug 31:13:902983. doi: 10.3389/fphys.2022.902983. eCollection 2022.

Authors

Adrien Robin¹, Linjie Wang², Marc-Antoine Custaud¹, Jiexin Liu³, Min Yuan², Zhili Li², Jean-Christophe Lloret⁴, Shujuan Liu², Xiaoqian Dai², Jianfeng Zhang², Ke Lv², Wenjiong Li², Guillemette Gauquelin-Koch⁵, Huijuan Wang², Kai Li², Xiaotao Li², Lina Qu², Nastassia Navasiolava¹, Yinghui Li²

Affiliations

¹ Univ Angers, CHU Angers, CRC, INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, Angers, France.
² State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China.
³ Beijing Tiantan Hospital, Medical Capital University, Beijing, China.
⁴ CNES, Toulouse, France.
⁵ CNES, Paris, France.

Abstract

Spaceflight is associated with enhanced inactivity, resulting in muscular and cardiovascular deconditioning. Although physical exercise is commonly used as a countermeasure, separate applications of running and resistive exercise modalities have never been directly compared during long-term bedrest. This study aimed to compare the effectiveness of two exercise countermeasure programs, running and resistance training, applied separately, for counteracting cardiovascular deconditioning induced by 90-day head-down bedrest (HDBR). Maximal oxygen uptake ( $\dot{V}$ O₂max), orthostatic tolerance, continuous ECG and blood pressure (BP), body composition, and leg circumferences were measured in the control group (CON: n = 8), running exercise group (RUN: n = 7), and resistive exercise group (RES: n = 7). After HDBR, the decrease in $\dot{V}$ O₂max was prevented by RUN countermeasure and limited by RES countermeasure (-26% in CON p < 0.05, -15% in RES p < 0.05, and -4% in RUN ns). Subjects demonstrated surprisingly modest orthostatic tolerance decrease for different groups, including controls. Lean mass loss was limited by RES and RUN protocols (-10% in CON vs. -5% to 6% in RES and RUN). Both countermeasures prevented the loss in thigh circumference (-7% in CON p < 0.05, -2% in RES ns, and -0.6% in RUN ns) and limited loss in calf circumference (-10% in CON vs. -7% in RES vs. -5% in RUN). Day-night variations in systolic BP were preserved during HDBR. Decrease in $\dot{V}$ O₂max positively correlated with decrease in thigh (r = 0.54 and p = 0.009) and calf (r = 0.52 and p = 0.012) circumferences. During this 90-day strict HDBR, running exercise successfully preserved $\dot{V}$ O₂max, and resistance exercise limited its decline. Both countermeasures limited loss in global lean mass and leg circumferences. The $\dot{V}$ O₂max reduction seems to be conditioned more by muscular than by cardiovascular parameters.

Keywords: HDBR; V̇O2max; cardiovascular deconditioning; countermeasure; maximal working capacity; microgravity; orthostatic tolerance; oxygen uptake.