4周限制饮食结合低氧训练对超重和肥胖青少年骨的影响
Influence of Diet plus Hypoxic Training on Bone Health in Overweight and Obese Adolescents
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摘要: 目的:探讨4周限制饮食结合低氧训练对骨健康相关指标及血清瘦素、内脂素的影响。方法:身体健康的世居平原超重或肥胖青少年,随机分为常氧运动组(简称“常氧组”)和低氧运动组(2 300 m高住高练低练,简称“低氧组”)。运动干预持续4周,每周运动6天,常氧组每天运动和生活均在平原环境;低氧组每天晚上7点至次日晨居住在模拟2 300 m海拔高度的低氧环境中,并且每天在相同海拔高度的低氧环境中运动2 h,其他安排与常氧组相同。以静息代谢率为基础适当控制饮食。运动强度控制在低强度有氧耐力范畴。以双能X射线吸收法测量骨矿含量和骨密度。结果:1)4周干预后,全身骨矿含量仅常氧组与干预前比较有统计学意义上的显著性升高(+1.85%,P=0.006),组间无显著交互效应;2)4周干预后,常氧组、低氧组全身骨密度均显著升高,组间存在显著交互效应,常氧组骨密度升高幅度显著高于低氧组(+3.09%vs+1.29%,P=0.011,η2=0.176);3)4周干预后,脊椎骨矿含量、骨密度仅常氧组与干预前比较有统计学意义上的显著升高(+3.64%,P=0.025);4)4周干预后,血清内脂素的变化两组间存在显著交互效应(常氧组vs低氧组:+31.87%vs-18.76%,P=0.033,η2=0.143);5)4周干预后,血清内脂素的变化与全身骨密度的变化呈中等显著负相关(P=0.04,r=-0.37)。躯干脂肪质量的变化与血清内脂素的变化呈中等显著正相关(P=0.02,r=0.38)。结论:4周限制饮食结合低氧训练在有效减重减脂的同时,总骨密度显著升高,未对骨健康相关指标造成负面影响。但低氧对骨表现出一定程度的不利影响,内脂素可能在其中发挥重要作用。Abstract: Objective: To explore the effects of diet plus hypoxic training on bone health in overweight and obese adolescents.Methods: Healthy overweight or obese adolescents who was born and living in the plain took part in the intervention camp and were divided into plain training group or hypoxic training group(living high-training low and high group, altitude≈2 300 m), the intervention last for four weeks. The normoxic group lived in plain and exercised six days per week under normoxia. The hypoxic group slept in simulated ≈2 300 m nomobaric hypoxia from 19:00 to next morning and trained 2 hours under the same hypoxia in the daytime, but other arrangements were the same as the plain group. Diet was controlled based on the resting metabolic rate. Target exercise intensity was set at low-intensity aerobic range. Body mineral content(BMC) and body mineral density(BMD) were measured by dual energy X-ray absorption. Results: 1) After 4 weeks intervention, only the total BMC of the normoxic group exhibited a significant increase(+1.85%,P=0.006). No interaction effect existed between two groups. 2) Total BMD was increased in these two groups, and a significant interaction effect was observed between groups. Compared with the plain group, the elevation of the BMD was lower in the hypoxic group(+3.09% vs +1.29%, P=0.011,η2=0.176). 3) After 4-weeks intervention, a significant increase in BMD of the spine was observed only in the normoxic group(P=0.025). 4) A significant interaction effect was existed between the two groups in the serum visfatin level(normoxic group vs. hypoxic group:+31.87% vs-18.76%, P=0.033, η2=0.143).5) The changes of serum visfatin level was negatively correlated with the changes of total BMD(P=0.04, r=-0.37), but positively correlated with the changes of trunk fat mass(P=0.02, r=0.38). Conclusions: A 4-week diet combined with hypoxic training intervention reduced body mass and body fat mass effectively; meanwhile, the total BMD increased. The intervention didn't exert negative effect on bone health. However, hypoxia induced some side effects on BMD and visfatin may play an important role in those response.