Acute Hemodynamic Responses to Three Types of Hamstrings Stretching in Senior Athletes

Although stretching is recommended for fitness and health, there is little research on the effects of different stretching routines on hemodynamic responses of senior adults. It is not clear whether stretching can be considered an aerobic exercise stimulus or may be contraindicated for the elderly. The purpose of this study was to compare the effect of three stretching techniques; contract/relax proprioceptive neuromuscular facilitation (PNF), passive straight-leg raise (SLR), and static sit-and-reach (SR) on heart rate (HR) and blood pressure (BP) in senior athletes (119 participants: 65.6 ± 7.6 yrs.). Systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and HR measurements were taken at baseline (after 5-minutes in a supine position), 45 and 90-seconds, during the stretch, and 2-minutes after stretching. Within each stretching group, (SLR, PNF, and SR) DBP, MAP and HR at pre-test and 2-min post-stretch were lower than at 45-s and 90-s during the stretch. SLR induced smaller increases in DBP and MAP than PNF and SR, whereas PNF elicited lower HR responses than SR. In conclusion, trained senior adult athletes experienced small to moderate magnitude increases of hemodynamic responses with SLR, SR and PNF stretching, which recovered to baseline values within 2-min after stretching. Furthermore, the passive SLR induced smaller increases in BP than PNF and SR, while PNF elicited lower HR responses than SR. These increases in hemodynamic responses (HR and BP) were not of a magnitude to be clinically significant, provide an aerobic exercise stimulus or warrant concerns for most senior athletes.

No Impact of Stochastic Galvanic Vestibular Stimulation on Arterial Pressure and Heart Rate Variability in the Elderly Population

Objective

Noisy galvanic vestibular stimulation (nGVS) is often used to improve postural stability in disorders, such as neurorehabilitation montage. For the safe use of nGVS, we investigated whether arterial pressure (AP) and heart rate vary during static supine and slow whole-body tilt with random nGVS (0.4 mA, 0.1–640 Hz, gaussian distribution) in a healthy elderly population.

Methods

This study was conducted with a double-blind, sham-controlled, cross-over design. Seventeen healthy older adults were recruited. They were asked to maintain a static supine position on a bed for 10 min, and the bed was tilted up (TU) to 70 degrees within 30 s. After maintaining this position for 3 min, the bed was passively tilted down (TD) within 30 s. Real-nGVS or sham-nGVS was applied from 4 to 15 min. The time course of mean arterial pressure (MAP) and RR interval variability (RRIV) were analyzed to estimate the autonomic nervous activity.

Result

nGVS and/or time, including pre-/post-event (nGVS-start, TU, and TD), had no impact on MAP and RRIV-related parameters. Further, there was no evidence supporting the argument that nGVS induces pain, vertigo/dizziness, and uncomfortable feeling.

Conclusion

nGVS may not affect the AP and RRIV during static position and whole-body tilting or cause pain, vertigo/dizziness, and discomfort in the elderly.

Under-appreciated and Overlooked Modes of Exercises on Key Vascular Functions

The arterial system has two primary functions. The conduit function is to transport adequate supply of oxygen and nutrients to the tissues, and the cushioning function is to buffer and cushion the pulsatile pressure exerted by intermittent ventricular contractions. The impairments in these two functions often result from physiological changes characterized by endothelial dysfunction and arterial stiffening. Habitual physical exercise has been advocated to combat these physiological dysfunctions. However, exercise is remarkably diverse, as it can be performed in different media (water, land or snow), seasons (winter or summer), and settings (individual, pair or team). In contrast to mainstream modes of exercise including walking and running, many of the alternative or "minor" forms of exercise have been under-researched by investigators in research fields and overlooked by clinicians and practitioners in clinical settings. It remains largely unknown whether these alternative forms of exercise are associated with favorable changes in arterial stiffness and endothelium-dependent vasodilation. The current review introduces and summarizes research investigations that evaluated the impacts of these under-appreciated and overlooked exercises and their impacts on key markers of vascular functions in humans.

High cardiovascular reactivity and muscle strength attenuate hypotensive effects of isometric handgrip training in young women: A randomized controlled trial

OBJECTIVE

Isometric resistance training may reduce resting blood pressure (BP); however, the magnitude of this effect varies among individual subjects and few studies attempted to predict it. This study aimed to investigate the potential hypotensive effects of isometric training and their association with cardiovascular reactivity to acute isometric exercise and muscle strength in young women.

METHODS

In this randomized trial, twenty young women were randomly assigned to either the training (n = 10) or control (n = 10) group. Women from the training group performed unilateral isometric handgrip sessions for 8 weeks (4 × 2 min at 25% of maximal voluntary contraction [MVC]; 3 days/week). Cardiovascular reactivity to acute isometric exercise and MVC were measured at baseline. Resting BP was assessed during and after the intervention.

RESULTS

Resting systolic BP significantly lowered only in the training group. The change in resting systolic BP following an 8-week intervention was significantly associated with the systolic BP and diastolic BP reactivity to the acute exercise at baseline during set 3 and 4 (P <.05). The handgrip MVC was associated with changes in systolic BP (r = 0.79, P =.007), diastolic BP (r = 0.68, P =.032), and mean arterial pressure (r = 0.79, P =.006). These results indicated that high cardiovascular reactivity and strength attenuate the hypotensive effects following isometric training in young women.

CONCLUSIONS

The hypotensive effects following isometric training may be identified by BP reactivity to acute isometric exercise or handgrip strength in young women.

Effect of Isometric Resistance Training on Blood Pressure Values in a Group of Normotensive Participants: A Systematic Review and Meta-analysis

CONTEXT

Cardiovascular diseases cause 17 million deaths annually worldwide, of which hypertension is responsible for 9.4 million and a 7% burden of disease. High blood pressure is responsible for 45% of deaths from heart disease and 51% of deaths from stroke.

OBJECTIVE

The aim of this systematic review and meta-analysis was to quantify the effect of isometric resistance training on systolic, diastolic, and mean arterial blood pressure (SBP, DBP, and MAP, respectively) values in normotensive adult participants.

DATA SOURCES

This study was registered with the PROSPERO database. Eligible studies were identified after performing a systematic search within the following databases: PubMed, Scielo, BioMed Central, Clinical Trials, EMBASE, Cochrane Central Register of Controlled Trials, and EBSCO.

STUDY SELECTION

Randomized controlled trials that categorized participants as normotensive according to the guidelines of the American Heart Association and the American College of Cardiology were included.

STUDY DESIGN

Systematic review with meta-analysis.

LEVEL OF EVIDENCE

Level 1.

DATA EXTRACTION

Data related to participant characteristics, exercise programs, level of evidence, risk of bias, Consensus on Exercise Reporting Template, and outcomes of interest were systematically reviewed independently by 2 authors.

RESULTS

A total of 6 randomized controlled trials were included. The following reductions in blood pressure (compared with the control group) were generated by isometric resistance training: SBP (mean difference [MD], -2.83 mm Hg; 95% CI, -3.95 to -1.72; P < 0.00001), DBP (MD, -2.73; 95% CI, -4.23 to -1.24; P = 0.0003), and MAP (MD, -3.07; 95% CI, -5.24 to -0.90; P = 0.005).

CONCLUSION

It appears that isometric resistance training reduces SBP, DBP, and MAP in normotensive young adults in a statistically significant and clinically relevant manner. This type of exercise could be considered effective in preventing arterial hypertension.

Correction of estimation bias of predictive equations of energy expenditure based on wrist/waist-mounted accelerometers

Background

Using wearable inertial sensors to accurately estimate energy expenditure (EE) during an athletic training process is important. Due to the characteristics of inertial sensors, however, the positions in which they are worn can produce signals of different natures. To understand and solve this issue, this study used the heart rate reserve (HRR) as a compensation factor to modify the traditional empirical equation of the accelerometer EE sensor and examine the possibility of improving the estimation of energy expenditure for sensors worn in different positions.

Methods

Indirect calorimetry was used as the criterion measure (CM) to measure the EE of 90 healthy adults on a treadmill (five speeds: 4.8, 6.4, 8.0, 9.7, and 11.3 km/h). The measurement was simultaneously performed with the ActiGraph GT9X-Link (placed on the wrist and waist) with the Polar H10 Heart Rate Monitor.

Results

At the same exercise intensity, the EE measurements of the GT9X on the wrist and waist had significant differences from those of the CM (p < 0.05). By using multiple regression analysis—utilizing values from vector magnitudes (VM), body weight (BW) and HRR parameters—accuracy of EE estimation was greatly improved compared to traditional equation. Modified models explained a greater proportion of variance (R²) (wrist: 0.802; waist: 0.805) and demonstrated a good ICC (wrist: 0.863, waist: 0.889) compared to Freedson’s VM3 Combination equation (R²: wrist: 0.384, waist: 0.783; ICC: wrist: 0.073, waist: 0.868).

Conclusions

The EE estimation equation combining the VM of accelerometer measurements, BW and HRR greatly enhanced the accuracy of EE estimation based on data from accelerometers worn in different positions, particularly from those on the wrist.

Home-based isometric handgrip training on RBP in hypertensive adults-Partial preliminary findings from RCT

OBJECTIVE

The aim of this study is to confirm whether 8 weeks of home-based isometric handgrip (IHG) training would reduce resting blood pressure (RBP) in an adult Indian population.

METHODOLOGY

Hypertensive patients (Stage 1 [previously prehypertension] and Stage 2 [previously Stage 1 hypertension]) aged 30-45 years, male and female, were included.

INTERVENTION

Two groups were included (active control group and IHG training group at 30% of maximal voluntary isometric contraction). Outcomes of this study were resting pulse rate (PR) and RBP, which were taken at baseline and after 8 weeks. Stratified randomization was done by sex and hypertension grade. The study was a double-blind intervention (both participants and the assessor were blinded to intervention allotment).

RESULTS

Forty hypertensive individuals were randomly assigned to a control (N = 20) and an 8-week home-based IHG training (N = 20) using a stratified random sampling technique. Each training session consisted of 4 × 2 min bouts with a 4-min rest between bouts for 8 weeks. Resting PR and RBP were taken at baseline and after 8 weeks. After 8 weeks, there was a significant reduction in blood pressure and PR values in the IHG group as compared with those in the control group: systolic blood pressure (mean difference, MD -8.75 mmHg; 95% CI [-6.51, -10.39]); diastolic blood pressure (MD -8.35 mmHg; 95% CI [-6.25, -10.45]); mean arterial pressure (MD -8.13 mmHg; 95% CI [-6.21, -10.05]); and PR (MD -8.90 mmHg; 95% CI [-5.08, -12.72].

CONCLUSION

On the basis of study findings, home-based IHG training can be used as an adjunct to control BP in the initial stage of hypertension in an Indian population.

Resistance Exercise Training Is More Effective than Interval Aerobic Training in Reducing Blood Pressure During Sleep in Hypertensive Elderly Patients

Bertani, RF, Campos, GO, Perseguin, DM, Bonardi, JMT, Ferriolli, E, Moriguti, JC, and Lima, NKC. Resistance exercise training is more effective than interval aerobic training in reducing blood pressure during sleep in hypertensive elderly patients. J Strength Cond Res 32(7): 2085-2090, 2018-An appropriate fall in blood pressure (BP) during sleep is known to be related to a lower cardiovascular risk. The objective of this study was to compare the effect of different types of training on hypertensive elderly patients under treatment in terms of pressure variability assessed by the nocturnal decline in BP. Hypertensive elderly subjects under pharmacological treatment were randomly assigned to the following groups: 12 weeks of continuous aerobic training, interval aerobic training (IA), resistance training (R), or control (C). All subjects underwent ambulatory BP monitoring before and 24 hours after the last exercise session. The results were assessed using the mixed effects model. A greater nocturnal decline in diastolic BP compared with the wakefulness period was observed in R in comparison with C (11.0 ± 4.1 vs. 6.0 ± 5.7 mm Hg and p = 0.01) and with IA (11.0 ± 4. vs. 6.5 ± 5.1 mm Hg and p = 0.02). No fall in BP during a 24-hour period was observed in training groups compared with C, perhaps because the subjects were mostly nondippers, for whom the effect of training on BP is found to be lower. In conclusion, resistance training promoted a greater nocturnal fall in BP among hypertensive elderly subjects under treatment compared with IA subjects.

Characterizing and Comparing Acute Responses of Blood Pressure, Heart Rate, and Forearm Blood Flow to 2 Handgrip Protocols

PURPOSE

Growing evidence supports handgrip exercise training for reducing resting blood pressure (BP), with inconsistent exercise protocols reported throughout the literature. To verify safety of such protocols, real-time cardiovascular responses must be assessed. Consequently, this research sought to evaluate the acute impact of dissimilar handgrip protocols on the cardiovascular responses of BP, heart rate (HR), and forearm blood flow.

METHODS

Using a randomized intraindividual crossover design, 20 post-menopausal women completed 2 distinct handgrip protocols compared with a nonexercise control: 4 × 2-min sustained grips at 30% moderate intensity with 1-min rest between sets (ZONA), and 32 × 5-sec intermittent grips at maximal intensity with 5-sec rest between sets (MINT). Cardiovascular responses were measured throughout exercise and post-exercise recovery.

RESULTS

Compared to ZONA, the MINT protocol required less time and less exercise effort, yet caused greater average BP perturbations (systolic, MINT: 16.9 ± 12.9 mm Hg, ZONA: 7.9 ± 11.6 mm Hg; diastolic, MINT: 8.7 ± 7.2 mm Hg, ZONA: 4.5 ± 4.9 mm Hg) (P < .05), with peak BP changes far below published safety guidelines. Average HR responses were similarly elevated between protocols (MINT: 5.4 ± 4.9 beats/min, ZONA: 3.4 ± 3.6 beats/min). Post-exercise recovery of BP and HR occurred swiftly following MINT while remaining elevated following ZONA.

CONCLUSIONS

Handgrip exercise protocols with distinct design features (ie, grip intensity, grip strategy, and exercise duration) cause dissimilar acute cardiovascular responses. Careful and controlled attention should be directed toward determining how such acute dissimilarities influence corresponding training outcomes. Given the confirmed safety of acute BP perturbations, future researchers can have confidence in prescribing even the high-intensity MINT protocol for at-home, unsupervised activity.

Twenty weeks of isometric handgrip home training to lower blood pressure in hypertensive older adults: a study protocol for a randomized controlled trial

BACKGROUND

Hypertension markedly increases the risk of cardiovascular diseases and overall mortality. Lifestyle modifications, such as increased levels of physical activity, are recommended as the first line of anti-hypertensive treatment. A recent systematic review showed that isometric handgrip (IHG) training was superior to traditional endurance and strength training in lowering resting systolic blood pressure (SBP). The average length of previous IHG training studies is approximately 7.5 weeks with the longest being 10 weeks. Therefore, presently it is unknown if it is possible to further lower blood pressure levels beyond the 10-week mark. Recently, we developed a novel method for monitoring handgrip intensity using a standard Nintendo Wii Board (Wii). The primary aim of this study is to explore the effects of a 20-week IHG home training facilitated by a Wii in hypertensive older adults (50 + years of age) on lowering SBP compared to usual care. Secondary aims are to explore if/when a leveling-off effect on SBP will occur during the 20-week intervention period in the training group and to explore adherence and potential harms related to the IHG home training.

METHODS/DESIGN

Based on previous evidence, we calculated that 50 hypertensive (SBP between 140 and 179 mmHg), older adults (50 + years of age) are needed to achieve a power of 80% or more. Participants will be randomly assigned to either an intervention >group (IHG home training + hypertension guidelines on lifestyle changes) or to a control group (hypertension guidelines on lifestyle changes). Participants in the intervention group will perform IHG home training (30% of maximum grip strength for a total of 8 min per day per hand) three times a week for 20 weeks. Resting blood pressure and maximal handgrip strength will be obtained by a blinded outcome assessor in both groups at specific time points (baseline, follow-up at 5, 10, 15, and 20 weeks) throughout the study.

DISCUSSION

This assessor-blinded, randomized controlled trial will explore the effect of a 20-week IHG home training intervention on resting blood pressure in hypertensive older adults. In addition, the trial will report adherence and potential harms related to the IHG home training.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT03069443 . Registered on 3 March 2017.

High-intensity handgrip training lowers blood pressure and increases heart rate complexity among postmenopausal women: a pilot study

OBJECTIVE

Handgrip exercise is an emerging strategy for resting blood pressure (BP) reduction requiring minimal time and exercise effort. However, the research literature is currently limited to handgrip protocol designs predominantly prescribing sustained grip contractions, with little assessment of alternative options. Furthermore, our understanding of the utility of handgrip exercise would be strengthened by an evaluation of the physiological mechanisms driving BP reductions and an assessment of the interindividual response variability. As such, this research was designed to perform an initial evaluation of the pragmatic effectiveness of a novel at-home, high-intensity, unilateral (nondominant) handgrip exercise training program in reducing resting BP, while simultaneously exploring mediators of BP change including a neurocardiac index of autonomic nervous control [heart rate (HR) variability], measures of arterial stiffness (radial augmentation index and carotid-radial pulse wave velocity), and cardiovascular reactivity to psychophysiological stressors.

METHODS

Postmenopausal women were recruited to complete 8 weeks of handgrip exercise training. Aforementioned measures of resting BP and mediators of BP change were acquired at the midway point and end of training.

RESULTS

All participants (n=17) completed training with high self-reported adherence (96.9%) and improvement in grip strength (2.7±2.4kg, P<0.05). Handgrip training reduced resting systolic BP (-5.1±7.7 mmHg, P<0.05) and improved HR complexity (sample entropy: 0.24±0.31, P<0.05), without significant changes to resting diastolic BP, HR, or arterial stiffness (all P>0.05).

CONCLUSION

This pilot study successfully shows the potential utility of high-intensity intermittent handgrip exercise for improvements in cardiovascular health among postmenopausal women, with additional research required to further explore the underlying physiological mechanisms driving such improvements.

Maximal intermittent handgrip strategy: design and evaluation of an exercise protocol and a grip tool

Handgrip (HG) exercise has been prescribed as a lifestyle intervention to successfully reduce resting blood pressure (BP) among heterogeneous groups of participants. Current HG protocols have limited accessibility due to complicated exercise prescriptions and sophisticated required equipment. Therefore, this research describes the design and evaluation of the maximal intermittent (MINT) HG exercise strategy, consisting of both a novel exercise protocol (32×5 seconds maximal grip squeezes separated by 5 seconds of rest between sets) and an original grip tool. This research was a multistep progressive design that included 51 postmenopausal women as participants in three separate research studies. Part 1 of this research focuses on the MINT exercise protocol. A literature-informed rationale for the design of the protocol is described. This includes exercise intensity, work-to-rest ratio, and total exercise duration with reference to the unique physiology (mechanoreflex and metaboreflex) of postmenopausal women. Subsequent experimental analyses of acute responses to the MINT protocol revealed that women produced 50% of their maximum grip force with moderate cardiovascular responses (increases of systolic BP: 41.6 mmHg, diastolic BP: 20.1 mmHg, heart rate: 35.1 bpm) that remained far below the thresholds of concern identified by the American College of Sports Medicine. Part 2 of this research describes the creation of a novel grip tool, beginning with a mixed-methods assessment of participant opinions regarding two distinct in-laboratory grip tools, leading to the creation of four prototype MINT tools. Structured focus groups revealed a strong preference for MINT prototype 1 for all tool design features, including color, shape, size, and foam grip. Collectively, the result of this multistep research is a novel HG exercise strategy with enhanced accessibility by being easy to understand and simple to execute. The long-term training effectiveness of MINT as an exercise intervention for the reduction of resting BP has yet to be determined.

Intensity-dependent reductions in resting blood pressure following short-term isometric exercise training

To reduce resting blood pressure, a minimum isometric exercise training (IET) intensity has been suggested, but this is not known for short-term IET programmes. We therefore compared the effects of moderate- and low-intensity IET programmes on resting blood pressure. Forty normotensive participants (22.3 ± 3.4 years; 69.5 ± 15.5 kg; 170.2 ± 8.7 cm) were randomly assigned to groups of differing training intensities [20%EMGpeak (~23%MVC, maximum voluntary contraction, or 30%EMGpeak (~34%MVC)] or control group; 3 weeks of IET at 30%EMGpeak resulted in significant reductions in resting mean arterial pressure (e.g. -3.9 ± 1.0 mmHg, P < 0.001), whereas 20%EMGpeak did not (-2.3 ± 2.9 mmHg; P > 0.05). Moreover, after pooling all female versus male participants, IET induced a 6.9-mmHg reduction in systolic blood pressure in female participants, but only a 1.5-mmHg reduction in systolic blood pressure in male participants, although the difference was not significant. An IET intensity between 20%EMGpeak and 30%EMGpeak is sufficient to elicit significant resting blood pressure reductions in a short-term training period (3 weeks). In addition, sexual dimorphism may exist in the magnitude of reductions, but further work is required to confirm this possibility, which could be important in understanding the mechanisms responsible.