Sharma Priyanka, Agarwal Mayank
Department of Physiology, School of Medical Science and Research, Sharda University, Greater Noida, Uttar Pradesh, India.
Department of Physiology, Autonomous State Medical College, Pratapgarh, Uttar Pradesh, India.
J Family Med Prim Care. 2022 Jan;11(1):240-244. doi: 10.4103/jfmpc.jfmpc_1209_21. Epub 2022 Jan 31.
Few studies have reported that circadian rhythm affects fat oxidation (FOx) during exercise. Time-of-day causing greater FOx and energy expenditure (EE) during exercise would be beneficial in the prevention of physical inactivity-related health disorders such as metabolic syndrome. The study aims to compare EE and FOx rate after an endurance exercise session done in the morning and late-afternoon hours by apparently healthy young male participants.
The present crossover quasi-experimental study involved 10 moderately active but physically untrained male participants of age 18-25 years with normal body mass index. Participants did a steady-state exercise on a motorized treadmill for 30 minutes at a moderate-intensity (50 ± 2% of their heart rate reserve) on two separate occasions at 9:00-10:00 and 15:00-16:00. A similar meal followed by 2 hours of fasting was done before each trial session. During the last 2 minutes of the exercise session, the respiratory gas analysis estimated volume of oxygen (VO) and volume of carbon dioxide (VCO) consumed in L/min. Indirect calorimetry equations assessed FOx (mg/min), EE (Kcal/min) and respiratory exchange ratio (RER). Data of one participant were removed to adjust for extreme chronotype. Paired -test was applied, and ≤ 0.05 was considered significant.
Morning versus late-afternoon variations in FOx (269 ± 110 vs 290 ± 110, = 0.016), RER (0.86 ± 0.05 vs 0.85 ± 0.05, = 0.040), EE (5.454 ± 0.987 vs 5.494 ± 0.959, = 0.079) and VO2 (1.104 ± 0.201 vs 1.113 ± 0.196, = 0.035) were present after adjustment for chronotype.
In an acute bout of endurance, exercise done by young and healthy male individuals, FOx was significantly higher, while EE tends to be higher in late-afternoon than in the morning.
很少有研究报道昼夜节律会影响运动期间的脂肪氧化（FOx）。在运动期间能引起更高脂肪氧化和能量消耗（EE）的时间段，对于预防诸如代谢综合征等与身体活动不足相关的健康问题将是有益的。本研究旨在比较明显健康的年轻男性参与者在上午和下午晚些时候进行耐力运动后的能量消耗和脂肪氧化率。
本交叉准实验研究纳入了10名年龄在18 - 25岁、体重指数正常、中等活跃但未经体育训练的男性参与者。参与者在电动跑步机上以中等强度（心率储备的50±2%）进行30分钟的稳态运动，分别在9:00 - 10:00和15:00 - 16:00这两个不同时间段进行。每次试验前先摄入类似的餐食，然后禁食2小时。在运动的最后2分钟，通过呼吸气体分析估算每分钟消耗的氧气量（VO）和二氧化碳量（VCO），单位为升/分钟。间接测热法公式用于评估脂肪氧化（毫克/分钟）、能量消耗（千卡/分钟）和呼吸交换率（RER）。剔除了一名参与者的数据以调整极端的昼夜类型。应用配对t检验，P≤0.05被认为具有显著性。
在调整昼夜类型后，上午与下午晚些时候相比，脂肪氧化（269±110对290±110，P = 0.016）、呼吸交换率（0.86±0.05对0.85±0.05，P = 0.040）、能量消耗（5.454±0.987对5.494±0.959，P = 0.079）和耗氧量（1.104±0.201对1.113±0.196，P = 0.035）均存在差异。
在年轻健康男性进行的一次急性耐力运动中，下午晚些时候的脂肪氧化显著更高，而能量消耗也往往高于上午。
