Department of Health Promotion and Human Development, University of Wisconsin, Stevens Point, Wisconsin, USA.
Nutrition. 2013 Jan;29(1):42-5. doi: 10.1016/j.nut.2012.01.021. Epub 2012 Jun 5.
Moderate energy restriction and exercise are recommended for effective weight loss. Obese individuals oxidize less fat and report a higher perceived exertion during exercise, characteristics that may negatively influence exercise behavior. Because vitamin C status has been linked to fatigability, we compared the effects of vitamin C supplementation on self-reported fatigue and on the respiratory exchange ratio and the Ratings of Perceived Exertion scale during moderate exercise in healthy obese adults adhering to a hypocaloric diet.
Twenty adults (4 men and 16 women) were stratified and randomly assigned to receive 500 mg of vitamin C (VC) or placebo (CON) daily for 4 wk while adhering to a vitamin C-controlled, calorie-restricted diet. Feelings of general fatigue as assessed by the Profile of Mood States questionnaire were recorded on a separate day from the exercise session at weeks 0 and 4. Participants walked on a treadmill at an intensity of 50% predicted maximal oxygen consumption for 60 min at weeks 0 and 4, and heart rate, respiratory exchange ratio, and Ratings of Perceived Exertion were recorded.
After 4 wk, the two groups lost similar amounts of weight (≈ 4 kg), and the respiratory exchange ratio was not altered by group. Heart rate and the Ratings of Perceived Exertion during exercise were significantly decreased in the VC versus the CON group (-11 versus -3 beats/min, P = 0.022, and -1.3 versus +0.1 U, P = 0.001, respectively), and the general fatigue score was decreased 5.9 U for the VC group versus a 1.9 U increase for the CON group (P = 0.001).
These data provide preliminary evidence that vitamin C status may influence fatigue, heart rate, and perceptions of exertion during moderate exercise in obese individuals.
适量的能量限制和运动被推荐用于有效的减肥。肥胖个体氧化脂肪较少，并报告在运动中更高的感知用力，这些特征可能会对运动行为产生负面影响。由于维生素 C 状态与疲劳有关，我们比较了维生素 C 补充对健康肥胖成年人在遵循低热量饮食时中度运动中的自我报告疲劳以及呼吸交换比和感知用力等级的影响。
20 名成年人（4 名男性和 16 名女性）分层并随机分配每天接受 500 毫克维生素 C（VC）或安慰剂（CON），同时遵循维生素 C 控制的热量限制饮食。使用心境状态问卷（Profile of Mood States questionnaire）在第 0 周和第 4 周的运动日之外的另一天记录总体疲劳感。参与者在第 0 周和第 4 周以 50%预测最大摄氧量的强度在跑步机上行走 60 分钟，并记录心率、呼吸交换比和感知用力等级。
4 周后，两组体重减轻量相似（约 4 公斤），且组间呼吸交换比无变化。与 CON 组相比，VC 组的运动中心率和感知用力等级显著降低（-11 与-3 次/分钟，P=0.022 和-1.3 与+0.1 U，P=0.001），且 VC 组的一般疲劳评分降低了 5.9 U，而 CON 组则增加了 1.9 U（P=0.001）。
这些数据初步提供了证据，表明维生素 C 状态可能影响肥胖个体在中度运动中的疲劳、心率和用力感知。
