Rhee Joohyun, Mehta Ranjana K
Department of Occupational and Environmental Health, School of Public Health, Texas A&M University, College Station, TX, United States.
Department of Industrial and Systems Engineering, Texas A&M University, College Station, TX, United States.
Front Hum Neurosci. 2018 Nov 13;12:455. doi: 10.3389/fnhum.2018.00455. eCollection 2018.
The prevalence of obesity in older adults, particularly in females, is increasing rapidly and is associated with declines in both the brain and physical health. Both the obese and the female populations have shown greater motor fatigue than their counterparts, however, the central neural mechanisms for fatigue are unclear. The present study measured fatigue-related functional connectivity across frontal and sensorimotor areas using functional near-infrared spectroscopy (fNIRS). Fifty-nine older adults (30 non-obese and 29 obese) performed submaximal handgrip motor fatigue until voluntary exhaustion. Functional connectivity and cerebral hemodynamics were compared across eight cortical areas during motor fatigue and across obesity and sex groups along with neuromuscular fatigue outcomes (i.e., endurance time, strength loss, and force steadiness). Both obesity- and sex-specific functional architecture and mean activation differences during motor fatigue in older adults were observed, which were accompanied by fatigue-related changes in variability of force steadiness that differed between groups. While primary indicators of fatigue, i.e., endurance and strength loss, did not differ between groups, the motor steadiness changes indicated different neural adaptation strategies between the groups. These findings indicate that obesity and sex differences exist in brain function in older adults, which may affect performance during motor fatigue.
老年人，尤其是女性的肥胖患病率正在迅速上升，且与大脑和身体健康的下降有关。肥胖人群和女性群体均表现出比其对应人群更大的运动疲劳，然而，疲劳的中枢神经机制尚不清楚。本研究使用功能近红外光谱技术（fNIRS）测量了额叶和感觉运动区之间与疲劳相关的功能连接。59名老年人（30名非肥胖者和29名肥胖者）进行次最大握力运动疲劳测试，直至自愿疲惫。在运动疲劳期间，比较了八个皮质区域的功能连接和脑血流动力学，并比较了肥胖和性别组之间以及神经肌肉疲劳结果（即耐力时间、力量损失和力量稳定性）。在老年人运动疲劳期间，观察到了肥胖和性别特异性的功能结构以及平均激活差异，同时伴随着力量稳定性变异性中与疲劳相关的变化，不同组之间存在差异。虽然疲劳的主要指标，即耐力和力量损失，在组间没有差异，但运动稳定性变化表明不同组之间存在不同的神经适应策略。这些发现表明，老年人的大脑功能存在肥胖和性别差异，这可能会影响运动疲劳期间的表现。
