Effects of walking with blood flow restriction on limb venous compliance in elderly subjects

Venous compliance declines with age and improves with chronic endurance exercise. KAATSU, an exercise combined with blood flow restriction (BFR), is a unique training method for promoting muscle hypertrophy and strength gains by using low‐intensity resistance exercises or walking. This method also induces pooling of venous blood in the legs. Therefore, we hypothesized that slow walking with BFR may affect limb venous compliance and examined the influence of 6 weeks of walking with BFR on venous compliance in older women. Sixteen women aged 59–78 years were partially randomized into either a slow walking with BFR group (n = 9, BFR walk group) or a non‐exercising control group (n = 7, control group). The BFR walk group performed 20‐min treadmill slow walking (67 m min^?1), 5 days per week for 6 weeks. Before (pre) and after (post) those 6 weeks, venous properties were assessed using strain gauge venous occlusion plethysmography. After 6 weeks, leg venous compliance increased significantly in the BFR walk group (pre: 0·0518 ± 0·0084, post: 0·0619 ± 0·0150 ml 100 ml^?1 mmHg^?1, P<0·05), and maximal venous outflow (MVO) at 80 mmHg also increased significantly after the BFR walk group trained for 6 weeks (pre: 55·3 ± 15·6, post: 67·1 ± 18·9 ml 100 ml^?1 min^?1, P<0·01), but no significant differences were observed in venous compliance and MVO in the control group. In addition, there was no significant change in arm compliance in the BFR walk group. In conclusion, this study provides the first evidence that 6 weeks of walking exercise with BFR may improve limb venous compliance in untrained elder female subjects.     

Determination of the oxygen cost of level walking

Summary. We have developed devices and methods for the determination of the oxygen cost of level walking. Oxygen uptake is determined with an argon dilution method. The validity of this technique is demonstrated. Walking speed is recorded and controlled by means of a speedometer cart. The reproducibility of a convenient, self-selected walking speed and of a predetermined speed was studied. Coefficients of variation were below two per cent. Corresponding values of the oxygen cost of walking at a predetermined speed were three per cent or less up to an interval between tests of six months. We conclude that the proposed methods are suited for longitudinal studies of the oxygen cost of level walking, for example in patients with walking disorders.     

Loaded treadmill walking and cycle ergometry to assess work capacity: a retrospective comparison in 424 firefighters

The fitness of firefighters is regularly evaluated using exercise tests. We aimed to compare, with respect to age and body composition, two test modalities for the assessment work capacity. A total of 424 Swedish firefighters with cycle ergometer (CE) and treadmill (TM) tests available from Jan 2004 to Dec 2010 were included. We compared results from CE (6 min at 200 W, 250 W or incremental ramp exercise) with TM (6 min at 8° inclination, 4·5 km h⁻¹ or faster, wearing 24-kg protective equipment). Oxygen requirements were estimated by prediction equations. It was more common to pass the TM test and fail the supposedly equivalent CE test (20%), than vice versa (0·5%), P<0·001. Low age and tall stature were significant predictors of passing both CE and TM tests (P<0·05), while low body mass predicted accomplishment of TM test only (P = 0·006). Firefighters who passed the TM but failed the supposedly equivalent CE test within 12 months had significantly lower body mass, lower BMI, lower BSA and shorter stature than did those who passed both tests. Calculated oxygen uptake was higher in TM tests compared with corresponding CE tests (P<0·001). Body constitution affected approval differently depending on the test modality. A higher approval rate in TM testing suggests lower cardiorespiratory requirements compared with CE testing, even though estimated oxygen uptake was higher during TM testing. The relevance of our findings in relation to the occupational demands needs reconsidering.     

Indirect calorimetry during treadmill walking — a study of two methods

Walking is a complex process and the physiotherapist must focus on physical signs as well as functional and practical tests to evaluate treatment. Measurement of energy expenditure during level walking is a useful objective parameter for assessing walking as being a valuable supplement to evaluate the outcome of physiotherapy. This study had two purposes. The first purpose was to investigate whether sampling and measurement of oxygen consumption were reproducible when using two different devices during walking on a treadmill. A second purpose was to find out whether the measurements were sensitive enough to reveal differences in energy expenditure and respiratory quotient (RQ) during different walking speeds. Ten healthy students (mean age 22 years; range 20–25 years) volunteered in the test-retest of a slightly adjusted Deltatrac metabolic monitor. Thirteen volunteers (mean age 45 years; range 31–57 years) participated in the test-retest of Sensormedics 2900. In the first test, the subjects walked for 10 min in order to get a steady state both at an individual comfortable speed and at a preset speed. The retest was done with the same design and within 2 weeks. Nobody experienced any discomfort during the tests. The repeatability of measuring energy expenditure and RQ was acceptable for both methods and the methods were sensitive in revealing differences in energy expenditure during different walking speeds. The RQ were, however, too low when using the Deltatrac monitor, probably as a result of low air flow. We therefore conclude that only the method using Sensormedics 2900 may be used for the evaluation of energy expenditure during walking on a treadmill.     

Regional blood flow during cardiopulmonary resuscitation with abdominal counterpulsation in dogs

The addition of abdominal counterpulsation to standard cardiopulmonary resuscitation (AC-CPR) during ventricular fibrillation has been shown to improve cardiac output, oxygen uptake, and central arterial blood pressure in dogs. The present study was performed to determine the effect of AC-CPR on regional blood flow. Regional blood flow was measured with radioactively labeled microspheres during sinus rhythm and during alternate periods of AC-CPR and standard CPR (STD-CPR) in nine dogs anesthetized with pentobarbital. Blood pressures and oxygen uptake were measured continuously. As in previous studies, diastolic arterial pressure was higher (30.8%) during AC-CPR than during STD-CPR, as were cardiac output (24.5%) and oxygen uptake (37.5%). Whole brain and myocardial blood flow increased 12.0% and 22.7%, respectively, during AC-CPR. Blood flow to abdominal organs was not changed appreciably in response to abdominal compression, and postmortem examination revealed no gross trauma to the abdominal viscera. The AC-CPR technique is simple and is easily added to present basic life support procedures. In light of the improvements observed in myocardial and cerebral blood flow, AC-CPR could significantly improve the outcome of CPR attempts.     

Arm and ankle blood pressure response to treadmill exercise in normal people

Summary. Ninteen healthy volunteers, 10 men and nine women (mean age 38 and 30 years), exercised on a treadmill. The systolic blood pressure (BP) was measured at the ankle and in the arm after submaximal (8 min with a final load of 2 W kg^-1 body weight) and maximal exercise. The BP was measured for 10 min after exercise, or until the elimination of a negative pressure difference between ankle and arm. The pre-study resting systolic arm and ankle pressures were 122 ± 11 and 144 ± 13 mmHg. One minute after submaximal exercise, arm and ankle BP were 147 ± 18 and 159 ± 19 mmHg (ankle-arm pressure difference 12 ± 13 mmHg); 1 min after maximal exercise the corresponding figures were 182 ± 26 and 153 ± 35 mmHg (ankle-arm pressure difference -29 ± 33 mmHg). We conclude that maximal exercise, but not an appropriately chosen submaximal exercise level, causes a negative BP difference between ankle and arm in normal people.     

反重力跑台系统在老年脑卒中患者平衡及步行训练中的疗效

目的:观察反重力跑台训练系统在老年脑卒中患者平衡及步行训练中的应用效果.方法:选取我院60例老年卒中住院患者,随机分为研究组和对照组各30例.2组均予常规康复训练及步行训练,研究组加用反重力跑台步行训练,连续治疗12周,并在治疗前后采用Berg平衡量表、Tinetti步态评估量表、10m最大步行速度测试评估患者平衡及步...     

Let's talk about sex: where are the young females in blood flow restriction research?

Low‐load resistance exercise with the blood flow restriction (BFR) has been shown to increase muscle size similar to that of traditional high‐load resistance training. Throughout the BFR literature, there is a vast difference between the quantity of young females included in the literature compared to young males, older males and older females. Therefore, the purpose of this minireview is to discuss the underrepresentation of young females in the BFR literature and review the potential physiologic reasons as to why they may have been excluded. In conclusion, the female menstrual cycle, a normal physiological occurrence, is presumably the reason as to why majority of young females are excluded from participation in BFR studies. Instead of excluding females, we recommend that BFR studies should include both sexes and plot the results separately to determine whether a sex difference exists.     

Association between blood pressure changes during self-paced outdoor walking and air temperature

Exaggerated elevation of systolic blood pressure (SBP) during exercise is a risk factor for future cardiovascular disease. Although there are differences between the outdoor exercise and exercise tests in the laboratory setting, there is little information regarding SBP changes during practical outdoor exercise. We investigated SBP changes during self-paced outdoor walking and the relationship to air temperature. Subjects (n = 109, 47–83 years) walked outdoors at their own pace wearing a blood pressure monitor on their wrist. SBP increased during walking compared to rest, but was higher at the 1 km mark than both the 2 and 3 km marks (rest, 124 ± 14 mmHg; 1 km, 140 ± 16 mmHg; 2 km, 136 ± 18 mmHg; 3 km, 135 ± 18 mmHg). SBP at rest, air temperature, body mass index (BMI) and walking intensity during the first 1 km were identified as predictors of SBP at the 1 km mark in the stepwise regression analysis, independent of other confounders (R² = 0·606). SBP at the 1 km mark was higher in the lower temperature group (11·6–14·3°C, 145 ± 14 mmHg) than in the intermediate (15·1–16·7°C, 140 ± 18 mmHg) and higher (17·0–19·6°C, 136 ± 16 mmHg) temperature groups, independent of SBP at rest, BMI and walking intensity. These results suggest that increases in SBP are higher on lower temperature days and are greater at 1 km than at 2 and 3 km. It is therefore recommended that measures are taken against the cold on lower temperature days to attenuate the SBP response during onset of walking.     

不同方式的单次步行训练对中老年男性收缩压的影响

摘要 目的：观察单次不同强度和时间的步行训练对中老年男性24h内收缩压的效应。 方法：实验选取40例血压正常或者轻中度高血压的中老年男性受试者,所有受试者均在研究开始时进行1d的血压监测,记录受试者日常生活状态下的血压以进行空白对照（空白对照组）。受试者在进行心肺运动试验检测其峰值摄氧量VO2peak之后,采用自身对照法,分别进行运动量为30min 45% VO2peak（3045组）、30min 65%VO2peak（3065组）、60min 45%VO2peak（6045组）的单次步行训练,每两次步行训练之间间隔3—5d。每次干预后,分别记录每组受试者在运动前、运动结束时、运动结束后1h、4h、12h和24h的收缩压。 结果：与运动前相比,3045组患者收缩压在运动后、运动结束后1h均明显下降（P＜0.05）,在运动结束后4h降低程度最显著（P＜0.01）,在运动结束后12h时仍有降低,但差异已无显著性（P＞0.05）;3065组和6045组患者收缩压在运动后1h时显著下降（P＜0.05）,在运动后4h时仍有降低,但差异无显著性意义（P＞0.05）。空白对照组患者24h内血压波动无明显变化,所有干预组在运动后24h时收缩压均回到原有水平。 结论：相对于30min 65%VO2peak、60min 45%VO2peak的运动量来说,30min 45%VO2peak的单次步行训练降压时效更长,接近12h。因此,对于血压正常或轻中度高血压的中老年男性来说,一天两次30min 45%VO2peak的步行训练能够有效维持急性运动的降压效应。     

Portal blood flow in man during graded positive end-expiratory pressure ventilation

The cardiovascular response to graded PEEP ventilation (5–10 cm H₂O) was studied peroperatively in patients undergoing chllecystectomy (n=8) or hepatic tumour surgery (n=3). Portal blood flow was measured by the continuous thermodilution technique and cardiac output, in a sub-group of the patients, by impedance cardiography. A parallel reduction in cardiac output and portal blood flow was demonstrated in patients undergoing cholecystectomy as the result of the application of PEEP. Thus, ventilation with 5 cm H₂O of PEEP elicited a 17% decrease in cardiac output and a 26% decrease in portal blood flow. During 10 cm H₂O of PEEP cardiac output decreased by 22% and portal blood flow by 32%. However, there were no significant changes in preportal tissue perfusion pressure by the application of PEEP and preportal vascular resistance increased by 22% and 30%, respectively. This indicates that a vasoconstrictor response, elicited by PEEP, in the preportal tissue is the predominating mechanism for the observed decrease in portal blood flow. Systemic oxygen transport decreased by 214 ml/min during PEEP ventilation, but preportal tissue oxygen utilization was not significantly changed due to a concurrent increase (2.9%; p<0.05) in oxygen extraction.     

血流量限制结合低强度抗阻训练对下肢骨科术后肌肉功能的影响

目的:探索血流量限制结合低强度抗阻训练对下肢骨科术后肌肉功能的影响.方法:选取下肢骨科术后4～12周患者39例,随机将患者分为观察组19例和对照组20例.2组患者均接受为期4周的康复训练,对照组根据渐进抗阻原则进行肌力训练,观察组使用血流量限制结合低强度抗阻肌力训练.等速伸膝峰力矩、超声下股四头肌肌肉形态、肢体围度、静...     

A bibliometric analysis study of blood flow restriction using CiteSpace

[Purpose] To assess the current state-of-the-art and the prevailing trends regarding the global use of blood flow restriction (BFR) in the past 20 years. [Participants and Methods] We retrieved literature relating to BFR from 1999 to 2020 using Web of Science. We conducted a bibliometric analysis of countries/institutions, cited journals, authors/cited authors, cited references, and keywords using CiteSpace. An analysis of counts and centrality was used to examine publication output, countries/institutions, core journals, active authors, foundation references, hot topics, and frontiers. [Results] Seven hundred seventy five references were included and the total number of publications has been continually increasing over the investigated period. Representatives of important academic groups are the Japanese scholars from the University of Tokyo as represented by Takashi Abe. Jeremy Paul Loenneke’s article (centrality: 0.15) was the most representative and symbolic reference with the highest centrality. The three topics identified were intervention (intensity resistance exercise, IRE), physiology (ischemia and muscular function) and behavior (adaptation and increase). The four frontier topics were phosphorylation, reduction, low intensity and arterial occlusion. [Conclusion] This study provides an insight into BFR and offers valuable information for BFR researchers to identify new perspectives for potential cooperation with collaborators and their related cooperative institutions.     

活动平板运动试验中血压异常增高的意义

目的探讨活动平板运动试验所激发的血压异常增高的现象及临床意义。方法从561例受检者中选择运动中SBP≥200mmHg45例作为血压异常增高组,高血压血压反应正常组40例,对照组54例,比较3组间运动与血压反应关系。结果血压异常增高组:运动前静息时的血压(SBP/DBP)均高于其他两组(P<0.001);运动中SBP、血压上升幅度(ΔSBP)显著增高,有统计学意义(P<0.001);而运动时间(time)、代谢当量(Mets)均小于其他两组(P<0.05),说明该组病人运动耐量有不同程度的减退。结论运动所激发的血压异常增高可预示发生高血压的可能性,而对高血压患者应注意运动时血压高峰的控制及运动处方的制定。