Qiao Yujia Susanna, Blackwell Terri L, Cawthon Peggy M, Coen Paul M, Cummings Steven R, Distefano Giovanna, Farsijani Samaneh, Forman Daniel E, Goodpaster Bret H, Kritchevsky Stephen B, Mau Theresa, Toledo Frederico G S, Newman Anne B, Glynn Nancy W
medRxiv. 2023 Nov 6:2023.11.05.23298134. doi: 10.1101/2023.11.05.23298134.
Skeletal muscle energetics decline with age, and physical activity (PA) has been shown to counteract these declines in older adults. Yet, many studies were based on self-reported PA or structured exercise interventions. We examined the associations of objective daily PA and sedentary behavior (SB) with skeletal muscle energetics and also compared with self-reported PA and SB. We also explored the extent to which PA would attenuate the associations of age with muscle energetics.
Among the Study of Muscle, Mobility and Aging (SOMMA) enrolled older adults, 810 (mean age=76±5, 58% women) had maximal muscle oxidative capacity measured via high-resolution respirometry of permeabilized myofibers (maxOXPHOS) and by Phosphorus magnetic resonance spectroscopy (ATP ). Objective PA was measured using the wrist-worn ActiGraph GT9X over 7-days to capture sedentary behavior (SB), light, and moderate-to-vigorous PA (MVPA). Self-reported SB, MVPA, and all exercise-related PA were assessed with The Community Healthy Activities Model Program for Seniors questionnaire. Linear regression models with progressive covariate adjustments evaluated the associations between SB, PA and muscle energetics, and the attenuation of the age / muscle energetic association by PA.
Every 30 minutes more objective MVPA was associated with 0.65 pmol/smg higher maxOXPHOS and 0.012 mM/sec higher ATP , after adjustment for age, site/technician and sex. More time spent in objective light+MVPA was significantly associated with higher ATP , but not maxOXPHOS. In contrast, every 30 minutes spent in objective SB was associated with 0.43 pmol/smg lower maxOXPHOS and 0.004 mM/sec lower ATP . Only associations with ATP held after further adjusting for socioeconomic status, body mass index, lifestyle factors and multimorbidities. Self-reported MVPA and all exercise-related activities, but not SB, yielded similar associations with maxOXPHOS and ATP . Lastly, age was only significantly associated with muscle energetics in men. Adjusting for objective time spent in MVPA attenuated the age association with ATP by nearly 60% in men.
More time spent in daily PA, especially MVPA, were associated with higher muscle energetics. Interventions that increase higher intensity activity might offer potential therapeutic interventions to slow the age-related decline in muscle energetics. Our work also emphasizes the importance of taking PA into consideration when evaluating associations related to skeletal muscle energetics.
骨骼肌能量代谢随年龄增长而下降，而体育活动（PA）已被证明可抵消老年人的这些下降。然而，许多研究基于自我报告的PA或结构化运动干预。我们研究了客观的日常PA和久坐行为（SB）与骨骼肌能量代谢的关联，并与自我报告的PA和SB进行比较。我们还探讨了PA减弱年龄与肌肉能量代谢关联的程度。
在肌肉、 Mobility和衰老研究（SOMMA）纳入的老年人中，810人（平均年龄=76±5岁，58%为女性）通过对通透肌纤维进行高分辨率呼吸测定法（最大氧化磷酸化，maxOXPHOS）和磷磁共振波谱法（ATP）测量了最大肌肉氧化能力。使用腕戴式ActiGraph GT9X测量7天的客观PA，以获取久坐行为（SB）、轻度和中度至剧烈PA（MVPA）。通过老年人社区健康活动模型计划问卷评估自我报告的SB、MVPA和所有与运动相关的PA。采用逐步协变量调整的线性回归模型评估SB、PA与肌肉能量代谢之间的关联，以及PA对年龄/肌肉能量代谢关联的减弱作用。
在调整年龄、部位/技术人员和性别后，每多30分钟的客观MVPA与maxOXPHOS高0.65 pmol/smg和ATP高0.012 mM/sec相关。在客观的轻度+MVPA中花费更多时间与较高的ATP显著相关，但与maxOXPHOS无关。相比之下，每在客观SB中花费30分钟与maxOXPHOS低0.43 pmol/smg和ATP低0.004 mM/sec相关。在进一步调整社会经济地位、体重指数、生活方式因素和多种疾病后，仅与ATP的关联仍然存在。自我报告的MVPA和所有与运动相关的活动，但不包括SB，与maxOXPHOS和ATP产生类似的关联。最后，年龄仅与男性的肌肉能量代谢显著相关。在男性中，调整在MVPA中花费的客观时间可使年龄与ATP的关联减弱近60%。
在日常PA中花费更多时间，尤其是MVPA，与更高的肌肉能量代谢相关。增加高强度活动的干预措施可能提供潜在的治疗干预，以减缓与年龄相关的肌肉能量代谢下降。我们的工作还强调了在评估与骨骼肌能量代谢相关的关联时考虑PA的重要性。
