Pennington Biomedical Research Center, Baton Rouge, Louisiana, USA.
Obesity (Silver Spring). 2009 Dec;17 Suppl 3:S39-42. doi: 10.1038/oby.2009.387.
Higher levels of fitness are associated with reduced risk of a wide variety of illnesses and chronic conditions. For cardiovascular disease (CVD) and many metabolic conditions, the fitness-morbidity/mortality curve is not linear but curvilinear, with lower levels of fitness being associated with significantly higher levels of risk compared to moderate and high levels of fitness. We have a very poor understanding of what the low fit phenotype represents as it is clearly more than just low physical activity levels. For example, there are likely some metabolic disadvantaged individuals with intrinsically low fitness and low oxidative capacity that are also prone to being sedentary due to easy fatigability. For these individuals, there exists a worse case scenario of a sedentary lifestyle superimposed on metabolically disadvantaged muscle resulting in the exaggerated CVD and metabolic risk. There is clearly a need for more work exploring the risk associated with low fitness and developing strategies to address the risk of low fitness. For example, we need to (i) define the mechanisms responsible for the exceptional risk associated with being low fit, (ii) identify best physical activity programs for reversing low fitness, (iii) examine whether exercise training nonresponders receive health benefits from exercise training despite the failure to improve fitness, and (iv) explore methods to identify individuals with the "low fit" phenotype without conducting a maximal exercise test. Individuals in the low fit category typically account for the majority of accumulated metabolic/CVD events, thus reducing this risk in this category would have substantial public health and clinical payoff.
更高的健康水平与降低各种疾病和慢性病的风险有关。对于心血管疾病（CVD）和许多代谢疾病，健康-发病/死亡率曲线不是线性的，而是曲线性的，与中度和高度健康水平相比，较低的健康水平与显著更高的风险水平相关。我们对低健康表型代表什么知之甚少，因为它显然不仅仅是低身体活动水平。例如，可能有一些代谢不利的个体，其内在的健康水平和氧化能力较低，由于容易疲劳，也容易久坐不动。对于这些个体，存在一种更糟糕的情况，即久坐不动的生活方式叠加在代谢不利的肌肉上，导致 CVD 和代谢风险的夸大。显然需要更多的工作来探索与低健康水平相关的风险，并制定策略来解决低健康水平的风险。例如，我们需要（i）确定与低健康水平相关的异常风险的机制，（ii）确定逆转低健康水平的最佳身体活动方案，（iii）检查尽管未能改善健康水平，但运动训练无反应者是否从运动训练中获得健康益处，以及（iv）探索在不进行最大运动测试的情况下识别具有“低健康”表型的个体的方法。低健康水平类别的个体通常占累积代谢/CVD 事件的大多数，因此降低该类别的风险将对公共卫生和临床产生重大影响。
