Effects of heated water-based versus land-based exercise training on vascular function in individuals with peripheral artery disease

Oxidative stress and vascular dysfunction: Potential therapeutic targets and therapies in peripheral artery disease

Peripheral artery disease (PAD) is the manifestation of atherosclerosis characterized by the accumulation of plaques in the arteries of the lower limbs. Interestingly, growing evidence suggests that the pathology of PAD is multifaceted and encompasses both vascular and skeletal muscle dysfunctions, which contributes to blunted physical capabilities and diminished quality of life. Importantly, it has been suggested that many of these pathological impairments may stem from blunted reduction-oxidation (redox) handling. Of note, in those with PAD, excessive production of reactive oxygen species (ROS) outweighs antioxidant capabilities resulting in oxidative damage, which may have systemic consequences. It has been suggested that antioxidant supplementation may be able to assist in handling ROS. However, the activation of various ROS production sites makes it difficult to determine the efficacy of these antioxidant supplements. Therefore, this review focuses on the common cellular mechanisms that facilitate ROS production and discusses how excessive ROS may impair vascular and skeletal muscle function in PAD. Furthermore, we provide insight for current and potential antioxidant therapies, specifically highlighting activation of the Kelch-like ECH-associated protein 1 (Keap1) - Nuclear Factor Erythroid 2-related factor 2 (Nrf2) pathway as a potential pharmacological therapy to combat ROS accumulation and aid in vascular function, and physical performance in patients with PAD. Altogether, this review provides a better understanding of excessive ROS in the pathophysiology of PAD and enhances our perception of potential therapeutic targets that may improve vascular function, skeletal muscle function, walking capacity, and quality of life in patients with PAD.

The effects of water-based circuit exercise training on vascular function in people with coronary heart disease

Impaired endothelial function in people with coronary heart disease (CHD) is associated with increased mortality. Water immersion can increase peripheral artery shear stress which may provide an additional stimulus to the endothelium during exercise. This study compared the effects of water-based circuit exercise training (WEX) and gym-based circuit exercise training (GEX) on vascular function in people with stable CHD. Participants were randomized to 12 wk of WEX (n = 20), GEX (n = 20), or a control group (usual activities; n = 12). Endothelium-dependent flow-mediated dilation (FMD) and glyceryl trinitrate-mediated dilation (GTN) of the brachial artery were assessed pre- and postintervention. FMD increased following WEX [4.0% (3.0%-5.1%) to 5.3% (4.1%-6.5%); P = 0.016], but was unchanged following GEX [4.9% (3.8%-5.9%) to 5.0% (3.8%-6.1%); P = 0.822]. There were no between-group differences in the change in FMD and no significant changes in GTN-mediated dilation percentage. Triglycerides decreased following GEX [1.2 mmol·L-1 (1.0-1.4 mmol·L-1) to 1.0 mmol·L-1 (0.8-1.3 mmol·L-1); P = 0.022], but there were no further differences in lipid profiles. WEX improved endothelial function of the brachial artery in people with stable CHD, suggesting that WEX is an effective alternative to gym-based exercise in people living with CHD, which may specifically address vascular health.NEW & NOTEWORTHY This study found that 12 wk of water-based circuit exercise training was well tolerated and improved vascular endothelial function in people with stable coronary heart disease. However, there was no effect on endothelium-independent function. Water-based exercise appears to be an effective alternative to gym-based exercise for people with coronary heart disease, which has specific benefits to vascular health and function.

The Effect of Exercise Modalities on Walking Capacity in Patients With Intermittent Claudication: A NETWORK META-ANALYSIS

INTRODUCTION

Despite extensive research on the effect of supervised exercise therapy on walking performance in patients with symptomatic peripheral arterial disease (PAD), it remains unclear which training modality provides the greatest improvement in walking capacity. The objective of this study was to compare the effect of different types of supervised exercise therapy on walking capacity in individuals with symptomatic PAD.

METHODS

A random-effect network meta-analysis was performed. The following databases were searched from January 1966 to April 2021: SPORTDiscus, CINAHL, MEDLINE, AMED, Academic Search Complete and, Scopus. Trials had to include at least one type of supervised exercise therapy for patients with symptomatic PAD, with an intervention lasting ≥2 wk with ≥5 training sessions, and an objective measure of walking capacity.

RESULTS

Eighteen studies were included for a total sample of 1135 participants. Interventions duration ranged from 6-24 wk and included aerobic exercise (treadmill walking, ergometer, and Nordic walking), resistance training (lower and/or upper body), a combination of both, and underwater exercise. Results showed that combined training improved treadmill walking capacity to a comparable extent to aerobic walking (+122.0 [24.2-219.8] m vs +106.8 [34.2-179.4] m), but with a larger effect size (1.20 [0.50-1.90] vs 0.67 [0.22-1.11]). Similar results were observed for the 6-min walk distance, with combined training being the most promising modality (+57.3 [16.2-98.5] m), followed by underwater training (+56.5 [22.4-90.5] m) and aerobic walking (+39.0 [12.8-65.1] m).

CONCLUSION

While not statistically superior to aerobic walking, combined exercise seems to be the most promising training modality. Aerobic walking and underwater training also improved walking capacity for patients with symptomatic PAD.

Impact of Exercise on Vascular Function in Middle-Aged and Older Adults: A Scoping Review

There is a substantial literature gap related to the vascular response to different types of exercise training in middle-aged and older populations. Thus, this scoping review aimed to examine the outcomes of controlled trials testing the long-term effects of exercise interventions on vascular function-related outcomes in middle-aged and older populations. The literature search was conducted following PRISMA guidelines. Data sources: five databases were used (EBSCO, MEDLINE, Web of Science, Science Direct, and Google Scholar). Eligibility criteria: controlled trials, published in the last 10 years, in English, containing well-described exercise interventions, reporting vascular quantitative effects of exercise in middle-aged and older people. A total of 62 publications were included. The studies included distinct types and intensities of exercise and were heterogeneous in volume and frequency. The assessed vascular outcomes also presented considerable variability. Overall, most studies reported positive effects of exercise on vascular function outcomes, regardless of exercise characteristics. Different exercise interventions can be applied to improve vascular function in middle-aged and older adults. Studies on combined and stretching exercises reported encouraging results in improving vascular function. Stretching exercises rise as an effective alternative in promoting vascular function among older adults, while combined exercise delivered promising vascular benefits in both populations.

The Impact of Controlled Physical Training with Hydrotherapy on Changes in Swelling and Claudication Distance in Patients with Atherosclerotic Ischemia of the Lower Limbs

BACKGROUND

Patients with peripheral artery disease (PAD) often experience intermittent claudication. It is manifested by pain typically seen in the distal part of the legs during walking, which impairs the ability to walk, limits physical activity and results in lower health-related quality of life. It often leads to chronic ischemic pain, ulceration and even amputation. The aim of the study was to evaluate the effect of controlled physical training and whirlpool massage on changes in circuits, range of motion and distance of claudication in people with atherosclerotic ischemia of the lower limbs.

MATERIAL AND METHODS

The study included 100 patients, males and females aged 39 to 79 years, with peripheral circulation disorders of the lower limbs. The subjects were randomly divided into two groups. Group I (G) was treated with a series of 10 lower-limb whirling massages and took part in individually planned training, including breathing, relaxation and active free lower-limb exercises. Group II-control group (GC) took part only in individually planned training. Prior to the treatment procedures and after their completion, the ranges of movement of the ankle joint and the circumference of the lower limbs were measured and the corridor test (6MWT, six-minute walk test) was performed.

RESULTS

Statistically significant reduction in the circumference of the foot, ankle, calf and thigh in the G group was noticed. Both, in G and in GC group, a statistically significant increase in the range of dorsiflexion of the foot was found in comparison to the period before the procedures (p = 0.010; p = 0.006, respectively). There was also a statistically significant increase in the range of motion of the plantar flexion of the foot after the procedures in G (p = 0.007) and in GC (p = 0.048). Differences in the circumference of the lower limbs and the range of ankle joint movements between the study group and the control group before and after the therapy were not statistically significant. However, there was a statistically significant difference between these groups after the procedures in the 6-min walk test-significantly higher values of 6MWT were recorded in group G (p = 0.003).

CONCLUSIONS

Individually planned training, supplemented with hydrotherapy as thermal therapy, has a beneficial effect on reducing swelling of the lower limbs, increasing the range of foot movements and extending the distance in the 6-min walk test.

Effect of Exercise on Vascular Function and Blood Lipids in Postmenopausal Women: A Systematic Review and Network Meta-Analysis

This study aimed to compare and rank the effectiveness of aerobic exercise (AE), resistance training (RT), combined training (CT), and water exercise (WE) on vascular function and blood lipids in postmenopausal women using a network meta-analysis (NMA).

METHODS

We searched the PubMed, Cochrane, Embase, Web of Science, and EBSCO (SPORTDiscus) databases to identify randomized controlled trials investigating the effects of exercise on vascular function and blood lipids in postmenopausal women. The retrieval period was from inception to March 2022. Two reviewers independently screened the retrieved articles, extracted pertinent data, and assessed the risk of bias of the included studies.

RESULTS

A total of 38 studies involving 1407 patients were included in this study. The results of the NMA indicated that WE had the greatest effect on systolic blood pressure (SBP) (surface under the cumulative ranking [SUCRA] = 84.9) and total cholesterol (TC) (SUCRA = 93.1); CT had the greatest effect on triglycerides (TG) (SUCRA = 96.2), high-density lipoprotein cholesterol (HDL-C) (SUCRA = 94.8), and diastolic blood pressure (DBP) (SUCRA = 91.1); RT had the greatest effect on low-density lipoprotein cholesterol (LDL-C) (SUCRA = 79.4).

CONCLUSION

The results suggest that exercise can effectively improve the PWV, SBP, and DBP and the levels of TC, TG, and LDL-C in postmenopausal women. WE had the best effect on improving TC and SBP. CT had the best effect on improving TG, HDL-C, and DBP. To improve LDL-C, RT can achieve a good effect. Considering the limitations of NMA, more RCTS need to be performed in the future to provide more direct evidence of the effectiveness of various exercise interventions on vascular health in postmenopausal women.

Effects of passive and active leg movements to interrupt sitting in mild hypercapnia on cardiovascular function in healthy adults

Prolonged sitting in a mild hypercapnic environment impairs peripheral vascular function. The effects of sitting interruptions using passive or active skeletal muscle contractions are still unclear. Therefore, we sought to examine the vascular effects of brief periods (2 min every half hour) of passive and active lower limb movement to interrupt prolonged sitting with mild hypercapnia in adults. Fourteen healthy adults (24 ± 2 yr) participated in three experimental visits sitting for 2.5 h in a mild hypercapnic environment (CO₂ = 1,500 ppm): control (CON, no limb movement), passive lower limb movement (PASS), and active lower limb movement (ACT) during sitting. At all visits, brachial and popliteal artery flow-mediated dilation (FMD), microvascular function, plasmatic levels of nitrate/nitrite and endothelin-1, and heart rate variability were assessed before and after sitting. Brachial and popliteal artery FMDs were reduced in CON and PASS (P < 0.05) but were preserved (P > 0.05) in ACT. Microvascular function was blunted in CON (P < 0.05) but was preserved in PASS and ACT (P > 0.05). In addition, total plasma nitrate/nitrite was preserved in ACT (P > 0.05) but was reduced in CON and PASS (P < 0.05), and endothelin-1 levels were decreased in ACT (P < 0.05). Both passive and active movement induced a greater ratio between the low-frequency and high-frequency bands for heart rate variability (P < 0.05). For the first time, to our knowledge, we found that brief periods of passive leg movement can preserve microvascular function, but that an intervention that elicits larger increases in shear rate, such as low-intensity exercise, is required to fully protect both macrovascular and microvascular function and circulating vasoactive substance balance.NEW & NOTEWORTHY Passive leg movement could not preserve macrovascular endothelial function, whereas active leg movement could protect endothelial function. Attenuated microvascular function can be salvaged by passive movement and active movement. Preservation of macrovascular hemodynamics and plasma total nitrate/nitrite and endothelin-1 during prolonged sitting requires active movement. These findings dissociate the impacts induced by mechanical stress (passive movement) from the change in metabolism (active movement) on the vasculature during prolonged sitting in a mild hypercapnic environment.

Effects of Aquatic Exercise in Post-exercise Hypotension: A Systematic Review and Meta-Analysis

Background

Post-exercise hypotension (PEH) can be an important non-pharmacological strategy in the treatment of arterial hypertension. Both aerobic and resistance exercises produce PEH, but it is not clear if the exercise environment can lead to a higher PEH.

Objective

This meta-analysis investigated whether a session of aquatic exercise (AE) induces PEH in comparison with control conditions such as land exercise (LE) or rest in hypertensive subjects.

Methods

The present systematic review and meta-analysis was conducted using the following electronic databases: PubMed, Google Scholar, and EMBASE. Ambulatory blood pressure measurements made in randomized clinical trials were pooled to compare PEH induced by AE with LE and rest conditions in hypertensive subjects.

Results

Data from four trials were included, which comprised 127 participants (94 women and 33 men). A 24-h analysis did not detect significant differences between AE and LE or rest for either systolic blood pressure (SBP) or diastolic blood pressure (DBP). Monitoring during the night showed that AE induced significant PEH in comparison with LE for SBP [−8.6 (−15.0 to −1.5) mmHg (p = 0.01)]. For DBP, the AE had pronounced PEH during the night in comparison with LE [−3.7 (−4.7 to −2.8) mmHg, p = 0.000] and rest [−1.7 (−1.9 to −0.8) mmHg, p = 0.000]. There were no differences in daytime values.

Conclusion

AE showed a higher PEH effect than LE sessions and rest conditions. PEH was observed in both SBP and DBP during the night. The number of studies was low, but all studies included in this meta-analysis used 24-h monitoring. The understanding of clinical relevance of AE, inducing a higher PEH, depends on a standardization of exercise protocols plus a rigorous monitoring of blood pressure.

Systematic Review Registration

PROSPERO registration: CRD42021271928.

Effects of Water Immersion on the Internal Power of Cycling

PURPOSE

Water immersion adds additional drag and metabolic demand for limb movement with respect to air, but its effect on the internal metabolic power (Ėint) of cycling is unknown. We aimed at quantifying the increase in Ėint during underwater cycling with respect to dry conditions at different pedaling rates.

METHODS

12 healthy subjects (4 females) pedaled on a waterproof cycle ergometer in an experimental pool that was either empty (DRY) or filled with tap water at 30.8 ± 0.6 °C (WET). Four different pedal cadences (fp) were studied (40, 50, 60 and 70 rpm) at 25, 50, 75 and 100 W. The metabolic power at steady state was measured via open circuit respirometry and Ėint was calculated as the metabolic power extrapolated for 0 W.

RESULTS

Ėint was significantly higher in WET than in DRY at 50, 60 and 70 rpm (81 ± 31 vs 32 ± 30 W, 167 ± 35 vs 50 ± 29 W, 311 ± 51 vs 81 ± 30 W, respectively, all p < 0.0001), but not at 40 rpm (16 ± 5 vs 11 ± 17 W, p > 0.99). Ėint increased with the third power of fp both in WET and DRY (R2 = 0.49 and 0.91, respectively).

CONCLUSION

Water drag increased Ėint, although limbs unloading via the Archimedes' principle and limbs shape could be potential confounding factors. A simple formula was developed to predict the increase in mechanical power in dry conditions needed to match the rate of energy expenditure during underwater cycling: 44 fp3 - 7 W, where fp is expressed in hertz.

Body mass-normalized moderate dose of dietary nitrate intake improves endothelial function and walking capacity in patients with peripheral artery disease

Peripheral artery disease (PAD) is characterized by the accumulation of atherosclerotic plaques in the lower extremity conduit arteries, which impairs blood flow and walking capacity. Dietary nitrate has been used to reduce blood pressure (BP) and improve walking capacity in PAD. However, a standardized dose for PAD has not been determined. Therefore, we sought to determine the effects of a body mass-normalized moderate dose of nitrate (0.11 mmol nitrate/kg) as beetroot juice on serum nitrate/nitrite, vascular function, walking capacity, and tissue oxygen utilization capacity in patients with PAD. A total of 11 patients with PAD received either nitrate supplement or placebo in a randomized crossover design. Total serum nitrate/nitrite, resting BP, brachial and popliteal artery endothelial function (flow-mediated dilation, FMD), arterial stiffness (pulse-wave velocity, PWV), augmentation index (AIx), maximal walking distance and time, claudication onset time, and skeletal muscle oxygen utilization were measured pre- and postnitrate and placebo intake. There were significant group × time interactions (P < 0.05) for serum nitrate/nitrite, FMD, BP, walking distance and time, and skeletal muscle oxygen utilization. The nitrate group showed significantly increased serum nitrate/nitrite (Δ1.32 μM), increased brachial and popliteal FMD (Δ1.3% and Δ1.7%, respectively), reduced peripheral and central systolic BP (Δ-4.7 mmHg and Δ-8.2 mmHg, respectively), increased maximal walking distance (Δ92.7 m) and time (Δ56.3 s), and reduced deoxygenated hemoglobin during walking. There were no changes in PWV, AIx, or claudication (P > 0.05). These results indicate that a body-mass normalized moderate dose of nitrate may be effective and safe for reducing BP, improving endothelial function, and improving walking capacity in patients with PAD.

Microvascular Dysfunction in Peripheral Artery Disease: Is Heat Therapy a Viable Treatment?

Peripheral artery disease (PAD) is characterized by the development of atherosclerotic plaques in the lower-body conduit arteries. PAD is commonly accompanied by microvascular disease, which may result in poor wound healing, plantar ulcer development, and subsequent limb amputation. Understanding the mechanisms underlying the development of plantar ulcers is a critical step in the development of adequate treatment options for patients with PAD. Skin is classified into two major components: glabrous and non-glabrous. These skin types have unique microcirculation characteristics, making it important to differentiate between the two when investigating mechanisms for plantar ulcer development in PAD. There is evidence for a microcirculation compensatory mechanism in PAD. This is evident by the maintenance of basal microcirculation perfusion and capillary filling pressure despite a reduced pressure differential beyond an occlusion in non-critical limb ischemia PAD. The major mechanism for this compensatory system seems to be progressive vasodilation of the arterial network below an occlusion. Recently, heat therapies have emerged as novel treatment options for attenuating the progression of PAD. Heat therapies are capable of stimulating the cardiovascular system, which may lead to beneficial adaptations that may ultimately reduce fatigue during walking in PAD. Early work in this area has shown that full-body heating is capable of generating an acute cardiovascular response, similar to exercise, which has been suggested as the most efficient treatment modality and may generate adaptations with chronic exposure. Heat therapies may emerge as a conservative treatment option capable of attenuating the progression of PAD and ultimately impeding the development of plantar ulcers.

Acute mitochondrial antioxidant intake improves endothelial function, antioxidant enzyme activity, and exercise tolerance in patients with peripheral artery disease

The results of this study reveal for the first time that acute oral intake of mitochondrial-targeted antioxidant (MitoQ, 80 mg) is effective for improving vascular endothelial function and superoxide dismutase in patients with peripheral artery disease (PAD). Acute MitoQ intake is also effective for improving maximal walking capacity and delaying the onset of claudication in patients with PAD. These findings suggest that the acute oral intake of MitoQ-mediated improvements in vascular mitochondria play a pivotal role for improving endothelial function, the redox environment, and skeletal muscle performance in PAD.