The Inverse Relationship between Cardiorespiratory Fitness and Intima-Media Thickness with Prehypertensive Middle-Aged Women

Effect of lifestyle interventions on carotid arterial structure - The DR's EXTRA study

No lifestyle-based interventions with medium-term duration on carotid atherosclerotic have been performed so far. We aimed to investigate whether guideline-based dietary and physical activity interventions slow the progression of atherosclerotic changes in the general elderly population. 1410 Finnish men and women from a representative population sample were randomly assigned to one of six groups in the four-year intervention study: 1) reference, 2) aerobic training, 3) resistance training, 4) Nordic Diet, 5) aerobic training + Nordic Diet, 6) resistance training + Nordic Diet. The primary outcome was mean common carotid artery intima-media thickness (cIMT). The lumen diameter of the common carotid artery (cLD) was also analyzed. 567 men and 565 women aged 57 to 78 years were included. None of the intervention groups significantly slowed cIMT progression compared to the reference group. A subgroup analysis showed that men in the diet group had significantly smaller cIMT progression than in the reference group (-0.078 mm, 95% CI: -0.146 to -0.009, p = 0.02) and no significant increase in cIMT (p = 0.23). No other group showed a slowed cIMT progression. Among guideline-based lifestyle interventions, only diet leads to a significantly smaller progression of cIMT in older men of a representative population sample. No other lifestyle intervention contributed to a slowing of the progression of structural carotid markers. It must be questioned whether the guideline-based recommendations for a lifestyle change that were in place until recently are adequate to decelerate the atherosclerotic process.

A Systematic Review and Meta-Analysis of Tai Chi Training in Cardiorespiratory Fitness of Elderly People

Objectives

The purpose of this study was to investigate the influence of Tai Chi on cardiorespiratory fitness (CRF) in elderly people using meta-analysis.

Methods

This study used seven electronic databases and data retrieved from randomized controlled trials (RCTs) investigating the role of Tai Chi on CRF in the elderly. All these 24 RCTs were screened and selected from 7 literature databases. The Stata 11.2 software (StataCorp, USA) was used for the meta-analysis, subgroup analysis, and bias test, while the Cochrane Collaboration's tool was used for the assessment of the risk of bias (RoB). 4 researchers independently participated in sample selection, data extraction, and RoB assessment.

Results

Following the inclusion criteria, 24 eligible studies were included in our analysis. The meta-analysis indicated that Tai Chi practice significantly increased the maximum rate of oxygen consumption (VO_{2 max}) (weighted mean difference (WMD)  = 3.76, 95% CI: 1.25 to 6.26, P < 0.1), leading to an overall reduction in the heart rate (HR) (WMD  = −1.84, 95% CI: −2.04 to −1.63, P  ≤ 0.001) and an increase in the O_{2 pulse} (WMD = 0.94, 95% CI: 0.60 to 1.28, P ≤ 0.001) in individuals who practiced Tai Chi regularly compared with those who did not. The subgroup analysis suggested that overall in those who practiced Tai Chi, males (WMD = 1.48, 95% CI: 0.85 to 2.12, P ≤ 0.001) had higher O_{2 pulse} than females (WMD = 0.73, 95% CI: 0.33 to 1.12, P ≤ 0.001). The subgroup analysis also showed an increase in the vital capacity (VC) (WMD = 316.05, 95% CI: 239.74 to 392.35, P ≤ 0.001) in individuals practicing Tai Chi. When the samples were further stratified by Tai Chi practicing time, the subgroup analysis suggested that individuals practicing Tai Chi over a period of 24 weeks showed no significant difference in VC (WMD = 82.95, 95% CI: -98.34 to 264.23, P=0.370), while those practicing Tai Chi over a period of 48 weeks showed a significant increase (WMD = 416.62, 95% CI: 280.68 to 552.56, P ≤ 0.001). Furthermore, the subgroup analysis demonstrated that the increase in VC is significantly correlated with the Tai Chi practicing time (WMD = 344.97, 95% CI: 227.88 to 442.06, P ≤ 0.001).

Conclusion

Regular Tai Chi practice could improve the CRF in the elderly, as indicated by significant improvement in indicators including VO_2max, O_2pulse, VC, and HR. However, gender and practice time might influence the overall beneficial outcomes.

Quantification and Verification of Cardiorespiratory Fitness in Adults with Prehypertension

Background: Low cardiorespiratory fitness is associated with increased risk of hypertension and atherosclerosis in adults with prehypertension. The purpose of this study was to quantify cardiorespiratory fitness and to examine the utility of supramaximal constant-load verification testing for validating maximal oxygen uptake (VO_2max) attainment in adults with prehypertension. Methods: Eleven adults (four women) with prehypertension (22.5 ± 2.9 y; body mass index (BMI): 24.6 ± 3.2 kg·m²) underwent an incremental exercise test followed 15 min later by a verification test at 105% of maximal work rate on a cycle ergometer. Results: There was no statistical difference in VO₂ between the incremental (2.23 ± 0.54 L·min⁻¹) and verification tests (2.28 ± 0.54 L·min⁻¹; p = 0.180). Only three out of eleven participants had a higher VO₂ during the verification when compared with the incremental test. If the verification test had not been conducted, one participant would have been incorrectly classified as having low cardiorespiratory fitness based on incremental test results alone. Conclusions: Verification testing validates the attainment of VO_2max and can potentially reduce the over-diagnosis of functional impairment (i.e., deconditioning) in adults with prehypertension.