Rayner Jennifer J, Chamley Rebecca R, Davies Robert Barker, O'Sullivan Oliver, Ladlow Peter, Bennett Alex N, Nicol Edward D, Rider Oliver J, Holdsworth David A
Division of Cardiovascular Medicine, Radcliffe Department of Medicine, Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, Oxford, UK.
Department of Cardiology, Oxford University Hospitals NHS Trust, John Radcliffe Hospital, Headley Way, Oxford, OX3 9DU, UK.
Eur J Appl Physiol. 2025 Sep 6. doi: 10.1007/s00421-025-05929-5.
Both obesity and cardiorespiratory fitness are crucial determinants of symptoms and prognosis. However, interpreting the gold-standard cardiopulmonary exercise test (CPET) is complicated by increasing body size and varying body composition. We hypothesised that the 'metabolic cost of external work' (or oxygen uptake (ml/min)/workload (Watts); V̇O/W), a body weight-independent determinant of endurance capacity, would reflect metabolic health more accurately than V̇O alone.
A test cohort of 160 fit individuals underwent anthropomorphic and metabolic assessment, maximal bicycle ergometer CPET, and six-minute walk test (6MWT). V̇O/W was calculated at VT1 and peak. The performance of V̇O/W was validated in 62 older, less fit individuals, undergoing the same protocol. 24 obese volunteers were assigned a weight loss intervention, and the impact on V̇O/W examined.
In both test and validation cohort, V̇O/W at VT1 and peak correlated with 6MWT distance, more strongly than standard CPET parameters. Including V̇O/W improved the accuracy of predicting 6MWT distance. V̇O/W correlated with BMI, insulin sensitivity and waist-to-hip ratio. Metabolic cost falls with weight loss, in parallel to metabolic and functional improvements, in contrast to other CPET parameters.
Metabolic cost is strongly associated with functional capacity and metabolic health across a range of body weight and fitness, outperforming standard CPET metrics. It is a simple measure which may improve our assessment of the extent to which exertional symptoms are determined by metabolic factors in an individual, and thereby target the most appropriate intervention to those who will benefit most.
肥胖和心肺适能都是症状和预后的关键决定因素。然而，随着体型增大和身体成分变化，解读金标准心肺运动试验（CPET）变得复杂。我们假设，“外部工作的代谢成本”（即摄氧量（毫升/分钟）/工作量（瓦特）；V̇O₂/W），一种与体重无关的耐力能力决定因素，比单独的V̇O₂更能准确反映代谢健康状况。
160名健康个体组成的测试队列接受了人体测量和代谢评估、最大运动功率自行车CPET以及六分钟步行试验（6MWT）。在VT1和峰值时计算V̇O₂/W。在62名年龄较大、身体不太健康的个体中，按照相同方案验证了V̇O₂/W的性能。24名肥胖志愿者接受了减肥干预，并检查了对V̇O₂/W的影响。
在测试队列和验证队列中，VT1和峰值时的V̇O₂/W与6MWT距离相关，比标准CPET参数的相关性更强。纳入V̇O₂/W提高了预测6MWT距离的准确性。V̇O₂/W与BMI、胰岛素敏感性和腰臀比相关。与其他CPET参数不同，随着体重减轻，代谢成本下降，同时代谢和功能得到改善。
在一系列体重和健康状况下，代谢成本与功能能力和代谢健康密切相关，优于标准CPET指标。它是一种简单的测量方法，可能会改善我们对个体运动症状受代谢因素影响程度的评估，从而针对那些将受益最大的人采取最合适的干预措施。
