Does heart rate response confirm the attainment of maximal oxygen uptake in adults 45 years and older?

Complexity and pitfalls in maximal exercise testing for persons with multiple sclerosis

BACKGROUND AND PURPOSE

Valid measurements of cardiorespiratory fitness in persons with multiple sclerosis (pwMS) are essential during inpatient rehabilitation for a precise evaluation of the current health status, for defining appropriate exercise intensities, and for evaluation of exercise intervention studies. We aim (i) to examine the proportion of pwMS who attain the American College of Sports Medicine (ACSM) criteria for maximal effort during graded cardiopulmonary exercise testing (CPET) and (ii) to provide insight into participant characteristics that limit maximal exercise performance.

METHODS

This cross-sectional study comprises a retrospective examination of ACSM criteria for maximal effort during graded CPET of n = 380 inpatient pwMS (mean age = 48 ± 11 years, 66% female). Chi-squared or Fisher's exact tests were conducted to compare differences in the distribution of criteria achieved. Participants' characteristics were examined as potential predictors using binary logistic regression.

RESULTS

Only 60% of the overall sample attained a respiratory exchange ratio ≥ 1.10. With regard to the definition applied, only 24% or 40% of the participants achieved an oxygen consumption plateau, and 17% or 50% attained the heart rate criterion. Forty-six percent met at least two of three criteria. Disability status, gender, disease course, and body mass index were associated with the attainment of maximal effort.

CONCLUSIONS

Our findings suggest that a relevant proportion of inpatient pwMS do not attain common criteria utilized to verify maximal oxygen consumption. Identified predictors for criteria attainment can be used to create models to predict cardiorespiratory fitness and to optimize CPET protocols in restrictive groups of pwMS.

Effect of Cardiorespiratory Fitness on Verifying VO2max in Middle-aged and Older Adults

We investigated the effect of cardiorespiratory fitness (CRF) on the probability of achieving the verification criterion to confirm that VO₂max was obtained in a sample of middle-aged to older adults. Data from twelve men and nine women (60.7±8.5 years, VO₂max: 34.8±9.4 mL/kg/min) were used for analysis. Participants had their VO₂max measured via a maximal graded exercise test and confirmed using a verification bout on a cycle ergometer. Logistic regression was used to evaluate the effect of CRF (VO₂max) on the probability a participant would successfully achieve the verification criterion. Odds ratios are reported to quantify the effect size. No statistically significant relationship was observed between CRF and achieving the verification criterion (β=.081, SE=.0619, Wald=1.420, p=.156). Estimated odds ratio for the effect of CRF on the verification criterion indicated an increase of 8% [Exp(β)=1.08, 95% CI (0.96, 1.22)] in the probability of achieving the verification criterion given a one unit increase in VO₂max. Each 1 mL/kg/min increase in VO₂max results in an 8% increase in the chance that an individual achieves the verification criterion confirming that VO₂max was obtained. Therefore, CRF is likely of practical significance and should be considered when deciding to use a verification trial.

Can linear regression confirm VO2max was attained in middle-aged and older adults?

PURPOSE

Evaluate the efficacy of a regression method for identifying a VO₂ plateau to confirm the attainment of VO₂max compared to a verification trial in middle-aged and older adults.

METHODS

Eleven men and ten women (age 61.0 ± 8.1, VO₂max 21.8-50.3 ml/kg/min, n = 21) completed an individualized ramp graded exercise test (GXT) on the cycle ergometer, and one hour later, a verification trial at 105% of their maximal work rate (WR) achieved during the GXT. A plateau in VO₂ was used to confirm VO₂max was attained. VO₂ plateau was identified using the difference between the highest VO₂ between the two trials and a linear regression analysis of the VO₂-WR relationship during the GXT. McNemar's test of marginal homogeneity was used to detect differences in the proportion of paired data of individuals' attainment of VO₂max criteria.

RESULTS

Of the 21 participants, 15 (71.4%) met the verification criterion while 6 (28.6%) did not, compared to the regression method where 16 (76.2%) achieved the regression criterion while 5 (23.8%) did not. McNemar's test revealed no significant difference between participants' ability to achieve the regression and verification criteria (p = 0.999).

CONCLUSION

The regression method is an effective strategy for confirming VO₂max was attained with middle-aged and older adults on a cycle ergometer. This time-efficient regression method is comparable with the verification criterion but does not require a second maximal test, which may be advantageous for those where the verification trial may not be practical.

Efficacy of estimating VO2max with the Heart Rate Ratio Method in middle-aged and older adults

PURPOSE

Investigate difference, agreement, and bias between maximal oxygen consumption (VO₂max) measured by indirect calorimetry and the Heart Rate Ratio Method (HRRM) for estimating VO₂max using measured and age-predicted maximum heart rate (HRmax) in a sample of middle-aged and older adults.

METHODS

Eleven men and nine women (age: 61.8 ± 8.5 years, VO₂max: 36.6 ± 9.5 mL/kg/min, N = 20) had their VO₂max measured via a maximal graded exercise test and confirmed using a verification bout on a treadmill ergometer. Participants' VO₂max was estimated via the HRRM using measured and age-predicted HRmax. Difference, agreement, and bias between methods were assessed using a one-way repeated measures Analysis of Variance (ANOVA), Lin's concordance correlation coefficient, and Bland-Altman plots, respectively.

RESULTS

There were no statistical differences between methods of assessing VO₂max, F(1.13, 21.47) = 0.583, p = 0.473, generalized eta-squared = 0.012. The standard error of the estimate (SEE) for the HRRM using measured or predicted HRmax was 5.2% and 5.6% of the mean VO₂max, respectively. Both HRRM predictions had poor agreement with VO₂max (r_c ≤ 0.40). There was a systematic bias to underestimate as VO₂max increased for HRRM using measured HRmax, F(1, 18) = 17.40, p < 0.001, and when using an age-predicted HRmax, F(1, 18) = 13.39, p = 0.002.

CONCLUSION

Both versions of the HRRM have poor agreement, relatively large SEEs, and a bias to misrepresent VO₂max. When possible, VO₂max should be measured via a maximal graded exercise test with indirect calorimetry for middle-aged and older adults.

MEDICAL EFFECT OF SPORTS ON IMPROVING THE MAXIMUM OXYGEN

ABSTRACT Introduction: Maximum oxygen uptake is an effective indicator of the level of human cardiopulmonary function and aerobic work capacity. Observing the effects of aerobic training and formulating scientific training plans are of considerable value. Objective: To observe the effect of physical exercise on the human body's maximum oxygen uptake and arterial blood ketone body ratio. Methods: Before and after 4 weeks of physical exercise, the maximum oxygen uptake, blood lactic acid and heart rate changes, and ketone body content in the incremental load exercise experiment was measured in the human body. Results: The subjects’ maximum oxygen uptake, maximum exercise load, heart rate, and blood lactic acid levels increased significantly after physical exercise. Conclusion: The human body's maximum oxygen uptake is enhanced under sports. Level of evidence II; Therapeutic studies - investigation of treatment results.