Caffeine intake reduces sedentary time and increases physical activity predisposition in obese police officers

Sedentary time is associated with increased obesity in police officers. Caffeine intake may reduce sedentary time but it has not been extensively investigated. In the present study, the effect of caffeine ingestion on sedentary time was investigated in obese police officers. Fourteen obese police officers ingested either 5 mg/kg of caffeine or cellulose (placebo) for six days. Information on inactivity time, time spent with physical activities, self-reported perception of tiredness, and physical activity disposition was obtained daily during the intervention period. Sedentary and physical activity times were divided into two intraday periods (T1: 08:00 am-02:00 pm and T2: 02:00 pm-08:00 pm). Caffeine intake decreased the sedentary time in both T1 (79.2±2.2%) and T2 (79.1±2.5%), when compared with T2 of the placebo condition (81.1±3.6%, P<0.05). Caffeine intake also increased the time spent on light physical activities in T1 and T2 (17±2 and 18±2%), when compared with T2 of the placebo condition (16±3%, P<0.05). In addition, sedentary time increased and light physical activity time decreased from T1 to T2 in the placebo (P<0.001) but not in the caffeine condition (P=0.81). Caffeine intake had no effect on tiredness (P>0.05), but it increased the self-reported physical activity disposition compared to the placebo condition (4.5±2.7 vs 3.2±2.3 units, P<0.05). Caffeine intake reduced the sedentary time and increased the time spent on light physical activities of obese police officers, which seems to be related to a higher disposition for the practice of physical activity.

久坐时间（Sedentary Time）与警官群体的肥胖风险升高密切相关。咖啡因（Caffeine）摄入或可减少久坐时长，但目前相关研究尚不充分。本研究针对肥胖警官群体，探究了咖啡因摄入对其久坐时间的影响。14名肥胖警官参与本实验，在6天内分别摄入5mg/kg剂量的咖啡因或纤维素（Cellulose，安慰剂Placebo）。干预期间每日收集受试者的非活动时长、体育活动（Physical Activity）时长、自我报告的疲劳感知程度以及体育活动意愿相关信息。将久坐及体育活动时长划分为两个日内时段：T1（上午08:00至下午02:00）与T2（下午02:00至晚上08:00）。与安慰剂组的T2时段（81.1±3.6%，P<0.05）相比，咖啡因摄入组在T1（79.2±2.2%）与T2（79.1±2.5%）的久坐时间均显著降低。此外，相较于安慰剂组T2时段的轻度体育活动时长占比（16±3%，P<0.05），咖啡因摄入组在T1与T2时段的轻度体育活动时长占比均显著提升（分别为17±2%与18±2%）。安慰剂组中，久坐时间从T1到T2显著升高，轻度体育活动时长则显著降低（P<0.001），但该趋势在咖啡因摄入组中未出现（P=0.81）。咖啡因摄入对受试者的疲劳感知无显著影响（P>0.05），但相较于安慰剂组（3.2±2.3分），咖啡因组的自我报告体育活动意愿显著提升（4.5±2.7分，P<0.05）。综上，咖啡因摄入可缩短肥胖警官的久坐时间并提升其轻度体育活动时长，这一效应或与受试者更高的体育活动参与意愿相关。