Effect of Exercise on Arterial Stiffness: Is There a Ceiling Effect?

Effects of aerobic exercise training on cerebral pulsatile hemodynamics in middle-aged adults with elevated blood pressure/stage 1 hypertension

Mechanisms behind the protective effects of aerobic exercise on brain health remain elusive but may be vascular in origin and relate to cerebral pulsatility. This pilot study investigated the effects of 12-wk aerobic exercise training on cerebral pulsatility and its vascular contributors (large artery stiffness, characteristic impedance) in at-risk middle-aged adults. Twenty-eight inactive middle-aged adults with elevated blood pressure or stage 1 hypertension were assigned to either moderate/vigorous aerobic exercise training (AET) for 3 days/wk or no-exercise control (CON) group. Middle cerebral artery (MCA) pulsatility index (PI), large artery (i.e., aorta, carotid) stiffness, and characteristic impedance were assessed via Doppler and tonometry at baseline, 6, and 12 wk, whereas cardiorespiratory fitness (V̇o2peak) was assessed via incremental exercise test and cognitive function via computerized battery at baseline and 12 wk. V̇o2peak increased 6% in AET and decreased 4% in CON (P < 0.05). Proximal aortic compliance increased (P = 0.04, partial η2 = 0.14) and aortic characteristic impedance decreased (P = 0.02, partial η2 = 0.17) with AET but not CON. Cerebral pulsatility showed a medium-to-large effect size increase with AET, although not statistically significant (P = 0.07, partial η2 = 0.11) compared with CON. Working memory reaction time improved with AET but not CON (P = 0.02, partial η2 = 0.20). Our data suggest 12-wk AET elicited improvements in central vascular hemodynamics (e.g., proximal aortic compliance and characteristic impedance) along with apparent, paradoxical increases in cerebral pulsatile hemodynamics.NEW & NOTEWORTHY We identify differential central versus cerebrovascular responses to 12 wk of aerobic exercise training in middle-aged adults. Although proximal aortic compliance and characteristic impedance improved after 12 wk of exercise, cerebral pulsatility tended to unexpectedly increase. These data suggest short-term aerobic exercise training may lead to more immediate benefits in the central vasculature, whereas longer duration exercise training may be required for beneficial changes in pulsatility within the cerebrovasculature.

Should mild obstructive sleep apnoea be treated? A systematic review from the standpoint of disease progression

OBJECTIVE

This study was a systematic review to investigate the progression of untreated obstructive sleep apnoea in order to evaluate whether mild obstructive sleep apnoea should be treated from the standpoint of disease progression.

METHOD

The database search study outcomes that were collected included Apnea Hypopnea Index and Respiratory Disturbance Index. A meta-analysis of obstructive sleep apnoea severity over time intervals was performed.

RESULTS

A total of 17 longitudinal studies and 1 randomised, controlled trial were included for review. For patients with mild obstructive sleep apnoea, mean pre-study and post-study Apnea Hypopnea Index was 5.21 and 8.03, respectively, over a median interval of 53.1 months. In patients with moderate to severe obstructive sleep apnoea, mean pre-study and post-study Apnea Hypopnea Index was 28.9 and 30.3, respectively, over a median interval of 57.8 months. Predictors for disease progression in mild obstructive sleep apnoea are patients aged less than 60 years and those with a baseline body mass index less than 25.

CONCLUSION

Mild obstructive sleep apnoea progression is observed, but it does not appear to reach any clinically significant progression to moderate or severe obstructive sleep apnoea.

Feasibility of implementing a supervised telehealth exercise intervention in frail survivors of hematopoietic cell transplantation: a pilot randomized trial

BACKGROUND

Patients undergoing hematopoietic cell transplantation (HCT) are at high risk of chronic health complications, including frailty and physical dysfunction. Conventional exercise programs have been shown to improve frailty in other cancer populations, but these have largely been based out of rehabilitation facilities that may act as geographic and logistical barriers. There is a paucity of information on the feasibility of implementing telehealth exercise interventions in long-term HCT survivors.

METHODS

We conducted a pilot randomized trial to assess the feasibility of an 8-week telehealth exercise intervention in 20 pre-frail or frail HCT survivors. Participants were randomized to either a telehealth exercise (N = 10) or delayed control (N = 10). We administered a remote physical function assessment at baseline, followed by an 8-week telehealth exercise intervention (30-60 min/session, 3 sessions/week), and post-intervention. The primary endpoint was feasibility as determined by 1) > 70% of participants completing all remote physical functional assessments, and 2) > 70% of participants in the exercise group completing > 70% (17/24) of the prescribed exercise sessions. Exploratory outcomes included changes in gait speed, handgrip strength, and short physical performance battery.

RESULTS

The mean [standard deviation] age at study enrollment was 64.7 [9.1] years old. Twelve had undergone allogenic and 8 had undergone autologous HCT at an average of 17 years from study enrollment. Both feasibility criteria were achieved. Nineteen patients (95%) completed all remote study outcome assessments at baseline and post-intervention, and nine participants in the exercise group completed > 70% of prescribed exercise sessions. Overall, no significant group x time interaction was observed on handgrip strength, fatigue, body mass index, and short physical performance battery test (P < 0.05). However, there were significant within-group improvements in four-meter gait speed (+ 13.9%; P = 0.004) and 5-minute gait speed (+ 25.4%; P = 0.04) in the exercise group whereas non-significant changes in four-meter gait speed (-3.8%) and 5-minute gait speed (-5.8%) were observed after 8 weeks.

CONCLUSION

Implementing an 8-week telehealth exercise intervention for long-term HCT survivors was feasible. Our findings set the stage for innovative delivery of supervised exercise intervention that reduces the burden of frailty in HCT survivors as well as other at-risk cancer survivors.

TRIAL REGISTRATION

The protocol and informed consent were approved by the institutional IRB (IRB#20731) and registered (ClinicalTrials.gov NCT04968119; date of registration: 20/07/2021).

The 18-month efficacy of an Intensive LifeStyle Modification Program (ILSM) to reduce type 2 diabetes risk among rural women: a cluster randomized controlled trial

BACKGROUND

Many lifestyle interventions have demonstrated efficacy up to one-year follow-up, yet maintaining improvements at longer-term follow-up is a well-recognized worldwide challenge, especially in underserved areas. The purpose of this study is to compare the 18-month efficacy of an Intensive LifeStyle Modification Program to usual care in reducing the risk for type 2 diabetes (T2D) among women with a history of gestational diabetes mellitus (GDM).

METHODS

We conducted a two-arm, cluster randomized controlled trial among women with a history of GDM in China. A total of 16 towns (clusters) in two distinct rural areas in south-central China were randomly selected (8 towns per area) and assigned (1:1) to the intervention (Intensive LifeStyle Modification Program) or control (usual care) group with stratification in the two rural areas. The strategies for maintaining intervention effects were used (including setting recursive goals and providing a supportive environment, etc.) under the guidance of social cognitive theory. The primary outcome was a change in T2D risk; secondary outcomes included glycemic, weight-related, behavioral, and psychological variables. All outcomes were collected at baseline, 6, and 18 months. All participants entered the intention-to-treat analysis. Data were analyzed via generalized estimation equation models (accounting for clusters) at the individual level, with subgroup analysis included in the model.

RESULTS

The sample included 320 women from 16 clusters (20 women per cluster). At 18 months, the intervention group demonstrated a significant improvement in T2D risk score, fasting blood glucose, body mass index (BMI), waist circumference, intention to eat low glycemic index food, perceived stress, quality of life in psychological and environmental domains, and social support over time (p < 0.05) based on the intention-to-treat analysis set. Subgroup analysis showed a significant interaction effect on T2D risk score in subgroups of different BMI, waist circumference, and blood glucose (p < 0.05).

CONCLUSIONS

Over 18 months, the Intensive LifeStyle Modification Program reduced T2D risk among rural women with a history of GDM in China. Women who were overweight, had high abdominal adiposity, or had blood glucose intolerance benefited more from this intervention. This program serves as a potential diabetes prevention model for women with a history of GDM in low-resource settings worldwide.

TRIAL REGISTRATION

Registered on Chinese Clinical Trial Registry (ChiCTR1800015023) on 1st March 2018, http://www.chictr.org.cn/showproj.aspx?proj=25569.

Effects of High-Intensity Interval Training on the Vascular and Autonomic Components of the Baroreflex at Rest in Adolescents

PURPOSE

In a sample of healthy adolescents, the authors aimed to investigate the effects of high-intensity interval exercise (HIIE) training and detraining on baroreflex sensitivity (BRS) and it's vascular and autonomic components at rest.

METHODS

Nineteen volunteers were randomly allocated to (1) 4 weeks HIIE training performed 3 times per week or (2) a control condition with no intervention for the same duration as HIIE training. PRE, POST, and following 2 weeks of detraining resting supine heart rate and blood pressure were measured, and a cross-spectral method (integrated gain [gain in low frequency]) was used to determine BRS gain. Arterial compliance (AC) was assessed as the BRS vascular component. LFgain divided by AC (LFgain/AC) was used as the autonomic determinant of BRS.

RESULTS

The HIIE training was completed with 100% compliance. HIIE did not change resting gain in low frequency (LFgain) (P = .66; effect size = 0.21), AC (P = .44; effect size = 0.36), or LFgain/AC (P = .68; effect size = 0.19) compared to control.

CONCLUSION

Four weeks of HIIE training does not change BRS and its autonomic and vascular determinant in a sample of healthy adolescents at rest.

Standalone sauna vs exercise followed by sauna on cardiovascular function in non-naïve sauna users: A comparison of acute effects

BACKGROUND AND AIMS

Sauna bathing and aerobic exercise have each been shown to affect cardiovascular function. However, direct comparisons between standalone sauna bathing and a combination of exercise and sauna on vascular indices remain limited. Therefore, we conducted a cross-over study using matched durations to explore the hemodynamic changes of sauna exposure when compared to a combination of aerobic exercise and sauna exposure.

METHODS

Participants (N = 72) with at least one cardiovascular risk factor underwent, on two separate occasions: (a) a 30-minute sauna at 75°C (SAUNA) and (b) the combination of a 15-minute cycling exercise at 75% maximum heart rate followed by 15-minute sauna exposure (EX+SAUNA). Relative changes to arterial stiffness (PWV), augmentation index (Alx), brachial systolic and diastolic blood pressure (SBP and DBP), central SBP (cSBP), mean arterial pressure (MAP), and heart rate (HR) were compared PRE-POST and pre- to 30-minutes post-intervention (PRE-POST30).

RESULTS

Baseline SBP and DBP were 143 (SD 18) mmHg and 86 (SD 10) mmHg, respectively. From PRE-POST, SAUNA had lower DBP (mean difference [95% CI] 2.5 [1.0, 4.1], P = .002) and MAP (2.5 [0.6, 4.3], P = .01). However, EX+SAUNA had lower SBP (-2.7 [-4.8, -0.5], P = .02), DBP (-1.8 [-3.3, -0.4], P = .01), and MAP (-2.0 [-3.5, -0.5], P = .009) PRE-POST30. There were no statistically significant differences between SAUNA and EX+SAUNA for other measured parameters.

CONCLUSION

This study demonstrated that when matched for duration, EX+SAUNA and SAUNA elicit comparable acute hemodynamic alterations in middle-aged participants with cardiovascular risk factors. The sauna is a suitable option for acute blood pressure reductions in those who are unable to perform aerobic exercise, and may be a viable lifestyle treatment option to improve blood pressure control.

The influence of habitual endurance exercise on carotid artery strain and strain rate in young and middle-aged men

NEW FINDINGS

What is the central question of this study? Carotid artery peak circumferential strain (PCS) and strain rate attenuate with age, but appear to be modulated by cardiorespiratory fitness status in young males. However, the relationship between habitual endurance exercise (running) and these parameters has not been studied in young and middle-aged men. What is the main finding and its importance? Young and middle-aged runners exhibited elevated PCS and systolic strain rate (S-SR) compared with non-runners, but habitual running did not influence diastolic strain rate (D-SR). Habitual exercise is associated with comparable improvements in carotid strain parameters in young and middle-aged men, but the age-related decline in PCS and S-SR might be more amenable to habitual endurance exercise than D-SR.

ABSTRACT

Central arterial stiffness is an independent predictor of cardiovascular risk that can be modified by exercise training. However, conventional local measures of carotid artery stiffness display conflicting responses to habitual endurance exercise in young and older adults. Two-dimensional (2D)-Strain imaging of the common carotid artery (CCA) quantifies circumferential deformation (strain) of the arterial wall across the cardiac cycle, which is more sensitive at detecting age-related alterations in CCA stiffness than conventional methods. Therefore, the study was designed to examine the relationship between habitual endurance exercise (running) and CCA 2D-Strain parameters in young and middle-aged men. Short-axis ultrasound images of the CCA were obtained from 13 young non-runners [23 years of age (95% confidence interval: 21, 26 years of age)], 19 young runners [24 (22, 26) years of age], 13 middle-aged non-runners [54 (52, 56) years of age] and 19 middle-aged runners [56 (54, 58) years of age]. Images were analysed for peak circumferential strain (PCS; magnitude of deformation) and systolic and diastolic strain rates (S-SR and D-SR; deformation velocity), and group differences were examined via two-way ANOVA. PCS, S-SR and D-SR were attenuated in middle-aged men compared with young men (all P ≤ 0.001). PCS and S-SR were elevated in young and middle-aged runners when compared with non-runners (P = 0.002 and P = 0.009, respectively), but no age × training status interaction was observed. In contrast, there was no influence of habitual running on D-SR. Habitual exercise is associated with comparable improvements in CCA 2D-Strain parameters in young and middle-aged men, but the age-related decline in PCS and S-SR might be more amenable to habitual endurance exercise than D-SR.

Carotid Artery Longitudinal Wall Motion Is Unaffected by 12 Weeks of Endurance, Sprint Interval or Resistance Exercise Training

Carotid artery longitudinal wall motion (CALM) exhibits reduced magnitude in older adults and in individuals with chronic diseases, although longitudinal data are lacking to indicate how changes in CALM might develop over time. Therefore, the aim of this study was to investigate the effect of exercise training in healthy men on CALM using a retrospective design. Carotid ultrasound data were analysed from two previous studies in which men performed 12 wk of moderate-intensity continuous exercise training (n = 9), sprint-interval training (n = 7), higher-repetition resistance exercise training (n = 15) or lower-repetition resistance exercise training (n = 15). The CALM pattern was unaltered after 12 wk of exercise training, regardless of exercise mode, with no differences in systolic or diastolic CALM magnitudes (p > 0.05), similar to carotid intima-media thickness (p > 0.05). Our findings suggest that CALM is resistant to transient changes in lifestyle factors, similar to wall thickness in otherwise healthy populations.

The effects of medication adherence on study outcomes in randomized clinical trials: A role for cognitive dysfunction?

Medication nonadherence is common and has been associated with poor health outcomes. Older adults are especially likely to be non-adherent to their medications, as they often have more medications to manage and are at greater risk for cognitive dysfunction. Though less frequently examined, the association between cognitive dysfunction and nonadherence also likely extends to clinical trials research. The current study used archival data to examine the potential impact of cognitive dysfunction on adherence to a nutritional supplement as part of a 90-day randomized clinical trial in neurologically healthy middle-aged and older adults. Results showed overall cognitive performance was predictive of adherence to capsule intake when controlling for polypharmacy [F(1,157) = 6.53, p < .01]. These results suggest that cognitive dysfunction may impact findings from RCTs through its adverse impact on adherence to study protocol, possibly leading to greater treatment variance, artificially reduced treatment effects, lower study power, and distorted study outcomes and conclusions. A better understanding of methodological and statistical approaches to account for these unwanted effects are needed.