Relationship of ventilatory inefficiency and low cardiorespiratory fitness in the elderly: a retrospective observational study

Cardiorespiratory optimal point during exercise testing is related to cardiovascular and all-cause mortality

Cardiorespiratory optimal point (COP) during exercise may be a potentially clinically useful cardiopulmonary exercise testing (CPET) variable, but its prognostic relevance for adverse cardiovascular disease (CVD) outcomes is unknown. We aimed to assess the association of COP during exercise with fatal mortality outcomes and the extent to which COP could improve the prediction of CVD mortality. Cardiorespiratory optimal point, the minimum value of the ventilatory equivalent for oxygen (VE/VO2) in a given minute of a CPET, was defined in 2,205 men who underwent CPET. Hazard ratios (HRs) (95% confidence intervals [CIs]) for outcomes and measures of risk discrimination for CVD mortality were calculated. During a median follow-up of 28.8 years, 402 fatal CHDs, 607 fatal CVDs, and 1,348 all-cause mortality events occurred. COP was continually associated with each outcome in a dose-response manner. On adjustment for established and emerging risk factors, the HRs (95% CIs) for fatal CHD, fatal CVD, and all-cause mortality were 3.05 (1.94-4.81), 2.82 (1.91-4.18) and 2.46 (1.85-3.27), respectively, per standard deviation increase in COP. After further adjustment for high sensitivity C-reactive protein, the HRs were 2.82 (1.78-4.46), 2.57 (1.73-3.81), and 2.27 (1.70-3.02), respectively. Addition of COP to a CVD mortality risk prediction model containing established risk factors was associated with a C-index change of 0.0139 (0.0040 to 0.0238; p = 0.006) at 25 years. COP during exercise is directly associated with fatal cardiovascular and all-cause mortality events in dose-response fashions. COP during exercise may improve the prediction of the long-term risk for CVD mortality.

Outdoor circuit test: construction and validation of an instrument for the prediction of cardiorespiratory capacity for older adults

Abstract Objective: the present study aimed to construct, validate and verify the reliability of a protocol for assessing the cardiorespiratory capacity of older adults attending the Rio ao Ar Livre (Open Air Rio, or RAL) project entitled the “Outdoor Circuit Test” (OCT). Method: validity and reliability tests were carried out to assess the accuracy of the OCT, with 50 older adults (70.6 ± 6.3 years) of both sexes who regularly attended the RAL. Validity was tested by collecting VO2max data under maximal cardiopulmonary exercise test conditions, and the OCT variables: a) Circuit Execution Time; b) Heart Rate; c) Subjective Perception of Exertion; d) Average Heart Rate (HRméd). Reliability was tested through the reproducibility of the measurements of the OCT variables, expressed by the Intraclass Correlation Coefficient (ICC). The predictive capacity of VO2max was given by multiple linear regression and the final stability of the model by the analysis of the residues and the calculation of Cook’s distances, with a value of P≤ 0.05 adopted for statistical significance. Results: the predictive model based on age, sex, waist circumference, BMI and circuit execution time explained 41% of VO2max variance, with a standard error of estimate of 18.5%. Conclusion: the OCT exhibited satisfactory reproducibility (0.62 to 0.93), and proved to be valid, reliable, and specific for predicting the cardiorespiratory fitness of older adults attending RAL, demonstrating adequate reproducibility and a positive association with the physical fitness of older adults.