Graduate School of Medicine, Nagoya University, 65 Tsurumai, Showa-ku, Nagoya, Aichi, 466-8550, Japan.
Department of Health and Nutrition, Tokaigakuen University, 2-901 Nakahira, Tenpaku, Nagoya, Aichi, 468-8514, Japan.
Eur J Appl Physiol. 2019 Jan;119(1):113-122. doi: 10.1007/s00421-018-4005-x. Epub 2018 Oct 10.
Intramyocellular lipid (IMCL) is influenced by physical exercise; however, whether the habitual level of physical activity affects resting IMCL content remains unclear. The purpose of this study was to determine the relationship between physical activity levels and resting IMCL content in young and older adults.
In total, 15 nonobese young adults (21.0 ± 0.0 years) and 15 older adults (70.7 ± 3.8 years) were recruited. Time spent performing physical activities for 10 days was assessed using a three-dimensional ambulatory accelerometer, and intensity was categorized as light [< 3.0 metabolic equivalents (METs)], moderate (3.0-6.0 METs), or vigorous (> 6.0 METs). Physical activity level was calculated as the product of METs and time spent performing physical activities (MET h) at each intensity level. The IMCL content in the vastus lateralis was determined using H-magnetic resonance spectroscopy after overnight fasting.
No significant differences in IMCL content were observed between young and older adults. Vigorous intensity physical activity (time and MET h) was significantly lower in older than young adults (p < 0.01); this difference was not observed for light and moderate intensity physical activity. Light intensity physical activity (time and MET h) was significantly and inversely correlated with IMCL content in young adults (r = - 0.59 and r = - 0.58; both p < 0.05), but not in older adults.
These results suggest that daily light intensity physical activity reduces resting IMCL content in young adults, whereas no significant relationship was seen between daily physical activity and resting IMCL content in older adults.
肌内脂质（IMCL）受体育锻炼的影响；然而，习惯性的体力活动水平是否会影响静息 IMCL 含量尚不清楚。本研究旨在确定年轻和老年成年人的体力活动水平与静息 IMCL 含量之间的关系。
共招募了 15 名非肥胖的年轻成年人（21.0±0.0 岁）和 15 名老年人（70.7±3.8 岁）。使用三维可移动加速计评估 10 天内进行体力活动的时间，强度分为轻（<3.0 代谢当量（METs））、中（3.0-6.0 METs）或剧烈（>6.0 METs）。体力活动水平计算为每个强度水平下 MET 和体力活动时间的乘积（MET h）。在禁食过夜后，使用 H 磁共振光谱法测定股外侧肌的 IMCL 含量。
年轻和老年人的 IMCL 含量无显著差异。与年轻成年人相比，老年人剧烈强度体力活动（时间和 MET h）明显较低（p<0.01）；而轻、中强度体力活动则无差异。轻强度体力活动（时间和 MET h）与年轻成年人的 IMCL 含量呈显著负相关（r=-0.59 和 r=-0.58；均 p<0.05），但在老年人中则无相关性。
这些结果表明，日常轻强度体力活动可降低年轻成年人的静息 IMCL 含量，而日常体力活动与老年成年人的静息 IMCL 含量之间无显著关系。
