Isometric Handgrip Research Articles

Muscle Performance during the Menstrual Cycle Correlates with Psychological Well-Being, but Not Fluctuations in Sex Hormones.

ABSTRACTPurposeWe aimed to study variations in strength and power performance during the menstrual cycle (MC) in eumenorrheic young women and during the pill cycle in oral contraceptives (OC) users.MethodsForty healthy, normal-weight women between 18 and 35 yr (n = 30 eumenorrheic women; n = 10 OC users) completed this prospective cohort study. Seven to nine times during the MC/pill-cycle, the participants completed a physical performance test series, a questionnaire about psychological well-being, blood sampling, and determination of body mass. The physical tests included isometric handgrip strength, elbow flexor strength, countermovement jump (CMJ) height, and a 10-s Wingate bike test.ResultsNo direct correlation was observed between the variations in sex hormones and physical performance parameters. However, positive correlations were observed between physical performance outcomes and self-reported motivation, perception of own physical performance level, pleasure level, and arousal level. CMJ was 6% lower in the late luteal phase (LL) compared with the midluteal phase (ML) (P = 0.04). Wingate peak power was 3% lower in early follicular (EF) compared with the ML (P = 0.04). Furthermore, Wingate average power was 2%–5% lower in LL compared with all other MC phases. In line with these observations, physical pain was higher in EF and LL, and the pleasure level was lower in EF compared with the other MC phases. In OC users, we observed no variation in performance and self-reported parameters between the placebo-pill phase and the OC-pill phase.ConclusionsImpairments in CMJ and Wingate performance were observed at the end and start of MC compared with other MC phases, which were associated with lower psychological well-being, but not the sex hormone fluctuations.

Isometric handgrip exercise impacts only on very short-term blood pressure variability, but not on short-term blood pressure variability in hypertensive individuals: A randomized controlled trial.

Background: The effect of a single isometric handgrip exercise (IHG) on blood pressure (BP) variability (BPV) has not been addressed. This randomized controlled trial evaluated the effect of IHG vs. sham on BPV and BP. Methods: Hypertensive patients using up to two BP-lowering medications were randomly assigned to IHG (4 × 2 min; 30% of maximal voluntary contraction, MVC, with 1 min rest between sets, unilateral) or sham (protocol; 0.3% of MVC). Systolic and diastolic BP were assessed beat-to-beat in the laboratory before, during, and post-intervention and also using 24-h ambulatory BP monitoring (ABPM). BPV was expressed as average real variability (ARV) and standard deviation (SD). Results: Laboratory BPV, ARV and SD variability, had marked increase during the intervention, but not in the sham group, decreasing in the post-intervention recovery period. The overall change in ARV from pre- to 15 min post-intervention were 0.27 ± 0.07 (IHG) vs. 0.05 ± 0.15 (sham group), with a statistically significant p-value for interaction. Similarly, mean systolic BP increased during the intervention (IHG 165.4 ± 4.5 vs. sham 152.4 ± 3.5 mmHg; p = 0.02) as did diastolic BP (104.0 ± 2.5 vs. 90.5 ± 1.7 mmHg, respectively; p < 0.001) and decreased afterward. However, neither the short-term BPV nor BP assessed by ABPM reached statistically significant differences between groups. Conclusion: A single session of IHG reduces very short-term variability but does not affect short-term variability. IHG promotes PEH in the laboratory, but does not sustain 24-h systolic and diastolic PEH beyond the recovery period.

Impact Of Age On Aortic Pressure And Pressure Waves Responses To Metaboreflex Activation In Women

INTRODUCTION: Aging and hypertension are related to exaggerated peripheral blood pressure (BP) responses to exercise and metaboreflex activation (post-exercise muscle ischemia, PEMI). Postmenopausal (POST) women have greater risk of heart failure with preserved ejection fraction due to increased aortic pulsatile load on the left ventricle induced by increased systolic BP (SBP) and decreased diastolic BP (DBP) at rest. Age-related aortic stiffening augments pressures of the forward (Pf) and the reflected wave (Pb) traveling from peripheral arteries to the aorta. Increases in Pf and Pb contribute to elevated aortic SBP and pulse pressure (PP) responses to exercise, increasing the risk for cardiovascular events. However, the influence of Pf and Pb on aortic pulsatile load during isometric handgrip (IHG) and PEMI in normotensive premenopausal (PRE) and POST women have not been examined. PURPOSE: To investigate the effect of age on aortic BP, Pf, and Pb during IHG and PEMI in normotensive PRE and POST women. METHODS: Fifteen PRE (age: 24 ± 1 years) and 16 POST women (age: 59 ± 1 years) participated in this study. Brachial BP was obtained using an automated device and radial arterial tonometry was used to capture aortic waveforms to estimate aortic BP and pressure waves at rest, during a 2-min IHG at 30% of maximal force, and during a 3-min PEMI. RESULTS: BP responses to IHG were similar in both groups. Brachial PP (POST: Δ9 ± 1 mmHg vs PRE: Δ0 ± 2 mmHg, P < 0.01), aortic PP (POST: Δ8 ± 1 mmHg vs PRE: Δ3 ± 2 mmHg, P = 0.03), Pf (POST: Δ6 ± 1 mmHg vs PRE: Δ0 ± 1 mmHg, P < 0.01), and Pb (POST: Δ5 ± 1 mmHg vs PRE: Δ2 ± 1 mmHg, P = 0.02) responses to PEMI were significantly increased in POST compared to PRE women. Aortic DBP (POST: Δ6 ± 1 mmHg vs PRE: Δ11 ± 2 mmHg, P = 0.04) responses to PEMI was significantly lower in POST than PRE women. Brachial and aortic SBP significantly (P < 0.001) increased during PEMI in both PRE and POST women, but there was no difference (P > 0.05) between groups. CONCLUSION: Normotensive POST women have augmented aortic PP response to PEMI compared to PRE women due to increases in pressure of the forward and backward waves and a decrease in DBP. Our findings suggest that the age-related increase in muscle metaboreflex activation does not induce a systolic overload and the increase in aortic PP is attributed to reduced DBP in normotensive POST women.

The Effect Of Isometric Hand-grip Exercise With Blood Flow Restriction On Hemodynamic Responses

Several studies have examined the effect of isometric handgrip exercise at submaximal intensities on cardiovascular system. However, few studies have focused on hemodynamic responses and muscle fatigue while exercising with blood flow restriction (BFR). PURPOSE: This crossover study examined the hemodynamic responses and muscle fatigue of an isometric, low intensity hand grip exercise protocol performed under blood flow restriction. METHODS: Twenty-four healthy adult volunteers (12 women and 12 men, age: 23.3 ± 1.9, BMI: 24.9 ± 6.2 kg/m2) performed 4 sessions of isometric hand grip exercise at 30% of maximal isometric strength using a grip dynamometer. Each session lasted 2 min and was performed in two conditions, without (control-C) and with blood flow restriction- BFR on different days. Blood flow restriction was achieved by applying a blood flow restriction cuff at a pressure of 140 mmHg. Hemodynamic responses (systolic and diastolic arterial blood pressure-SBP and DBP, heart rate-HR, and oxygen saturation- OS SpO2) and muscle fatigue (maximal isometric grip strength- IMVC and Borg scale) were assessed before, at the end of each exercise session, and 15 minutes after exercise performed under the two different conditions. Two-way ANOVA with repeated measures was used for statistics and data are given as mean(SD). RESULTS: Outcomes measures mean score (SD) for each time point of measurement in the two exercise conditions.* Between groups significant comparisons in the post hoc testing. BFRT: Blood Flow Restriction Training, Control: Conduction of exercise with no blood restriction, HR: Heart Rate, SBP: Systolic Blood Pressure, DBP: Diastolic Blood Pressure, OS: Oxygen Saturation, IMVC: Isometric Maximal Voluntary Contraction CONCLUSIONS: A submaximal isometric hand grip exercise does not induce significant hemodynamic changes, though it causes a more intense feeling of fatigue.

Adjusting For Exercise Intensity Attenuates Sex Differences In Blood Pressure During Exercise In Healthy Adults

PURPOSE: The exercise pressor reflex, composed of the muscle mechano- and metaboreflex, increases blood pressure (BP). Compared to males, healthy female adults typically exhibit blunted BP responses to exercise. However, recent work suggests that sex differences in BP during isometric handgrip (HG) exercise and post-exercise ischemia (PEI; metaboreflex isolation) are attenuated after adjusting for differences in maximal voluntary contraction (MVC). Therefore, the purpose of this study was to determine whether sex differences in BP responses during HG and PEI would be attenuated after adjustment for submaximal HG squeezing force. METHODS: We analyzed data from 95 participants including 34 females (age: 24±4 years, BMI: 24±4 kg/m2, screening BP: 106±13/64±9 mmHg, Mean ± SD) and 61 males (age: 25±5 years, BMI: 2±3 kg/m2, screening BP: 113±11/66±9 mmHg). All females were tested during days 1-5 of their menstrual cycle. Maximal HG force for each participant was defined as the average of three MVCs. Following a 10-minute baseline period, participants performed static static HG exercise at 40% of their average MVC for two minutes followed by three minutes of PEI via brachial occlusion. We obtained beat-to-beat BP readings via finger photoplethysmography (Finometer). Statistical analyses included t-tests, 2-way ANOVAs (sex x time), and ANCOVAs (average HG force as a covariate). RESULTS: Females exhibited a lower absolute 40% HG force than males (105±30 N v. 169±45 N, p<0.001). There was a significant sex x time interaction for ∆ systolic BP during HG (e.g., minute 2, females: 20±12 mmHg v. 28±18 mmHg in males, p=0.014), but not ∆ diastolic (p=0.106) or ∆ mean BP (p=0.058). After adjusting for absolute HG force, the sex difference for peak ∆ systolic BP during HG was attenuated (p=0.072). During PEI there were sex x time interactions for ∆ systolic, ∆ diastolic, and ∆ mean BP (p<0.05 for all) and adjustment for HG force did not attenuate these differences. Additionally, in a small strength-matched cohort (N=48, 29 females, female HG force mean = 107±23 N, male HG force mean = 118 ± 24 N, p=0.092) there was not a significant sex difference for peak ∆ systolic BP during HG (p=0.667) or PEI (p=0.828). CONCLUSIONS: Our data indicate that the sex difference in BP reactivity is attenuated after adjusting for absolute HG force during exercise.

Blunted Cerebrovascular Resistance In Response To Isometric Handgrip Exercise Is Associated With Greater White Matter Hyperintensities In Middle-aged And Older Adults

Blunted Cerebrovascular Resistance In Response To Isometric Handgrip Exercise Is Associated With Greater White Matter Hyperintensities In Middle-aged And Older Adults

Dietary Nitrate Does Not Improve Neuromuscular Performance And Match-play Demands In Elite Female Hockey Players.

PURPOSE: Beetroot juice is a commonly used ergogenic aid that contains high levels of inorganic nitrate (NO3-) and that its intake has proven effectivity at increasing blood nitric oxide (NO) concentrations. The ingestion of beetroot juice has shown good evidence of benefits in endurance sports while team sports has been barely studied. In our knowledge, only a few studies have been developed in team sports athletes. The present study was designed to compare the acute effects of beetroot juice supplementation on physical performance and match-play demands in elite female field hockey players METHODS: Eleven well-trained female hockey players (22.78 ± 5.12 years) participated during the preparatory period of their hockey season in this study. Participants were randomly divided into two groups undergoing a neuromuscular test battery with ingestion of 70 mL beetroot juice (6.4 mmol NO3-) or 70 mL placebo (0.04 mmol NO3-) in two separated days with one week between protocols. A neuromuscular test battery consisted in different test such as; countermovement jump (CMJ), isometric handgrip strength (IHS), and repeated sprint ability test (RSA) were realized. Afterwards a simulated hockey match play (2 x 20 minutes) was realized and the data was recorded by Global Positioning System (GPS). RESULTS: No significant improvements were observed in any physical parameters analysed comparing beetroot juice versus placebo ingestion, CMJ (p = 0.776), IHS (p = 0.829), RSA (p = 0.466). Therefore, no differences were reported in any physical match demands measured by GPS (i.e., total distance covered, number of accelerations/decelerations, etc) (p = 0.063-0.941) CONCLUSIONS: Beetroot juice acute supplementation did not produce any statistically significant improvement in physical performance or match-play demands in elite female field hockey players

Effect of Lower- versus Higher-Intensity Isometric Handgrip Training in Adults with Hypertension: A Randomized Controlled Trial.

This study compared the effects of lower- versus higher-intensity isometric handgrip exercise on resting blood pressure (BP) and associated clinical markers in adults with hypertension. Thirty-nine males were randomly assigned to one of three groups, including isometric handgrip at 60% maximal voluntary contraction (IHG-60), isometric handgrip at 30% IHG-30, or a control group (CON) that had been instructed to continue with their current activities of daily living. The volume was equated between the exercise groups, with IHG-60 performing 8 × 30-s contractions and IHG-30 performing 4 × 2-min contractions. Training was performed three times per week for 8 weeks. Resting BP (median [IQR]), flow-mediated dilation, heart rate variability, and serum markers of inflammation and oxidative stress were measured pre- and post-intervention. Systolic BP was significantly reduced for IHG-60 (−15.5 mmHg [−18.75, −7.25]) and IHG-30 (−5.0 mmHg [−7.5, −3.5]) compared to CON (p < 0.01), but no differences were observed between both the exercise groups. A greater reduction in diastolic BP was observed for IHG-60 (−5.0 mmHg [−6.0, −4.25] compared to IHG-30 (−2.0 mmHg [−2.5, −2.0], p = 0.042), and for both exercise groups compared to CON (p < 0.05). Flow-mediated dilation increased for both exercise groups versus CON (p < 0.001). IHG-30 had greater reductions in interleukin-6 and tumor necrosis factor-α compared to the other groups (p < 0.05) and CON (p = 0.018), respectively. There was a reduction in Endothelin-1 for IHG-60 compared to CON (p = 0.018). Both the lower- and higher-intensity IHG training appear to be associated with reductions in resting BP and improvements in clinical markers of inflammation and oxidative stress.

Decreases in Arterial Stiffness and Wave Reflection after Isometric Handgrip Training Are Associated with Improvements in Cognitive Function in Older Adults.

This study aimed to investigate whether decreases in arterial stiffness and wave reflection after isometric handgrip (IHG) training improve cognitive function in older adults. Twenty-two older adults (mean age ± standard error: 75 ± 2 years) were randomly assigned to either a group that performed IHG training (IHG group, n = 11) or a sedentary control group (CON group, n = 11). The IHG exercise comprised four unilateral 2-minute isometric contractions at 30% of maximal voluntary contraction using a programmed handgrip dynamometer with 1-minute rest periods, performed 5 days per week for 8 weeks. Carotid pulse wave velocity (cPWV) and carotid augmentation index (cAIx) were measured, and the trail-making test (TMT) parts A (TMT-A) and B (TMT-B) were performed before (baseline) and after 8 weeks of training in both groups. After 8 weeks of training, cPWV, cAIx, TMT-A, and TMT-B were significantly reduced in the IHG group (p < 0.05). Significant positive correlations were found between the amount of change in cPWV and cAIx and that in TMT-A (p < 0.05 each). In addition, positive correlation trends were observed between the amount of change in cPWV and cAIx and that in TMT-B (p = 0.06, p = 0.05, respectively). The results of the present study suggest that IHG training-induced decreases in arterial stiffness and wave reflection are associated with improvements in cognitive function in older adults.

Association between obesity and the functions of the autonomic nervous system in young adults

Obesity is one of the most prevalent public health issues. Excess weight has been associated with autonomic dysfunction, but the evidence in young adults is scarce. Therefore, this study aims to assess the relationship between the body mass index (BMI) and the autonomic nervous system (ANS) function in young adults. Males are known to have higher sympathetic nervous system activity as compared to females, who are known to have a greater parasympathetic function. Hence, it is critical to assess the differences in ANS activity based on gender. This study was done on 120 university students aged 18 - 25 years, categorized based on BMI as normal (18kg/m2-24kg/m2) and obese (&gt;25kg/m2). The ANS function was assessed by performing the Isometric Handgrip Test (IHGT), Deep Breathing Test (DBT), and Cold Pressor Test (CPT). Our study revealed that obese individuals exhibited an increase in the blood pressure and heart rate as compared to normal individuals, indicating that the former might be at greater risk for the development of ANS dysfunction. Our study also revealed that obese males exhibited a greater change in their blood pressure as compared to their obese counterparts.

Proinflammatory and Anti-inflammatory Cytokine Response to Isometric Handgrip Exercise and the Effects of Duration and Intensity of the Isometric Efforts in Prehypertensive Participants

ObjectiveThe purpose of this study was to investigate the responses of selected inflammatory cytokines to isometric handgrip exercise and identify possible effects of intensity and duration of the isometric effort on these variables. MethodsA total of 192 sedentary prehypertensive Nigerian participants aged between 30 and 50 years were recruited into the study and randomly distributed into 3 groups of 64 participants each. The participants performed 24 consecutive days of isometric handgrip exercise at 30% maximum voluntary contraction. At the end of the 24 days, group 1 discontinued the exercise protocol, while group 2 continued the exercise protocol for another 24 consecutive days, and group 3 continued with the exercise protocol for another 24 consecutive days but at 50% maximum voluntary contraction. The parameters used to assess the inflammatory cytokine variables included interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor-alpha (TNF-α). ResultsThere was an increase in the resting values of IL-10 across the 3 groups, while the resting values of IL-6 and TNF-α were reduced significantly across groups. Generally, the exercise-induced changes in the levels of these cytokines (TNF-α, IL-6, and IL-10) should improve inflammatory and metabolic abnormalities. ConclusionThe isometric handgrip exercise protocols in this study resulted in elevation of anti-inflammatory cytokine (IL-10) and reductions in the values of proinflammatory cytokines TNF- α and IL-6.

Sympathoexcitatory Responses to Isometric Handgrip Exercise Are Associated With White Matter Hyperintensities in Middle-Aged and Older Adults.

Vascular dysfunction may occur prior to declines in cognitive function and accumulation of neuropathology. White matter hyperintensities (WMH) develop due to cerebral ischemia and elevated blood pressure in midlife. The purpose of this study was to evaluate associations between cardiovascular and cerebrovascular responses to sympathoexcitatory stimuli and WMH burden in cognitively unimpaired middle-aged and older adults. Sixty-eight adults (age = 63 ± 4y, men = 20, women = 48) participated in this study. Participants completed isometric handgrip exercise (IHG) exercise at 40% of maximal voluntary contraction until fatigue followed by a 90s period of post-exercise ischemia. Heart rate (HR), mean arterial pressure (MAP), middle cerebral artery blood velocity (MCAv), and end-tidal CO2 were continuously measured throughout the protocol. Cerebrovascular resistance index (CVRi) was calculated as MAP/MCAv. WMH lesion volume and intracranial volume (ICV) were measured using a FLAIR and T1 scan on a 3T MRI scanner, respectively. WMH fraction was calculated as (WMH lesion volume/ICV)*100 and cubic root transformed. Multiple linear regressions were used to determine the association between cardiovascular and cerebrovascular responses to IHG exercise and post-exercise ischemia and WMH fraction. Multiple linear regression models were adjusted for age, sex, apolipoprotein ε4 status, and total work performed during IHG exercise. During IHG exercise, there were significant increases from baseline in HR (25 ± 12%), MAP (27 ± 11%), MCAv (5 ± 10%), and CVRi (22 ± 17%; P < 0.001 for all). During post-exercise ischemia, HR (8 ± 7%), MAP (22 ± 9%), and CVRi (23 ± 16%) remained elevated (P < 0.001) while MCAv (0 ± 10%) was not different compared to baseline. There was an inverse association between the percent change in HR (r = −0.42, P = 0.002), MAP (r = −0.41, P = 0.002), and CVRi (r = −0.31, P = 0.045), but not MCAv (r = 0.19, P = 0.971) in response to IHG exercise and WMH fraction. There were no associations between responses to post-exercise ischemia and WMH fraction. Lower sympathoexcitatory responses to IHG exercise are associated with greater WMH burden in middle-aged to older adults. These findings suggest that individuals who demonstrate smaller increases in HR, MAP, and CVRi in response to sympathoexcitatory stress have greater WMH burden.

Effect of obesity on autonomic functions of Heart among healthy volunteers at a teaching Institute.

Obesity usually results from an imbalance between energy intake and energy expenditure, that is, energy homeostasis, which is controlled by the autonomic nervous system. This imbalance results from multifaceted interactions of genetic, physiological, behavioral, environmental, endocrine, nervous, metabolic factors, which lead to hemodynamic and metabolic alteration. To study the effect of obesity on the autonomic functions of the heart. An observational analytical study was carried out among 100 subjects. All healthy volunteers of 30-50 years were included. The subjects were grouped into two categories of body mass index (BMI): 30-39.99 kg/m2 as Obese group and BMI: 18.50-24.99 kg/m2 as Non -Obese group. Out of 100 subjects, 50 were obese and 50 were non-obese. The interview was taken. General physical examination and anthropometric measurements were recorded. The assessment of various cardiac autonomic function tests was carried out. Both groups were comparable for age and sex (P = 0.754). The resting heart rate, SBP, and DBP in the obese group were significantly higher compared to the non-obese group (P < 0.05). All values of autonomic function tests in the non-obese group were significantly higher compared to the obese group (P < 0.05) except for the Standing to lying ratio (P > 0.05). The values of SBP and DBP increased significantly in the non-obese people after the isometric handgrip test and cold press test compared to the obese people (P < 0.05). We conclude that the resting HR, SBP, and DBP were higher in obese people. However, after applying autonomic function tests, non-obese people respond better to these tests compared to obese people in the form of an increase in these parameters. Obesity is, thus, found to affect the autonomic function tests.

Effects of immersive virtual reality on upper limb function in subjects with multiple sclerosis: A cross-over study

BackgroundUpper limb dysfunctions are common in people with multiple sclerosis (PwMS) and lead to limitations in activities of daily living. In this study, we investigated the feasibility and effects of an immersive commercial virtual reality system for upper limb bilateral rehabilitation. MethodsA total of 20 participants were included in a cross over study with two arm sequences: Treatment-Waiting List (T-WL; N = 9) and Waiting List-Treatment (WT-T; N = 11). T-WL sequence performed 12 sessions of bilateral UL rehabilitation over a 4-week period, based on the use of a commercially VR immersive platform (Oculus Rift), followed by a 4-week wash-out period and a 4-week waiting list period. WL-T sequence followed the protocol in the reverse order.Participants were tested at baseline (T0), after the end of the first 4-week period (T1), at the end of the wash-out period and finally at the end of the third 4-week period (T2). The primary outcome was the Box and Blocks test (BBT). Secondary outcome measures were: Nine Hole Peg Test (NHPT), Maximal isometric handgrip strength, Manual Ability Measure-36 (MAM-36), Modified Fatigue Impact Scale (MFIS), and the System Usability Scale (SUS).In absence of carryover effects, we analyzed primary and secondary outcome measures with mixed linear effect models. Treatment efficacy was assessed on the within-subject differences. Specifically, we used the intra-individual differences at the end of treatment and waiting-list periods (T1 and T2) as dependent variables and sequences (T-WL or WL-T) as independent variable. In presence of carryover effects (p-value <0.05), we assessed between sequence differences by an unpaired t-test considering T0 and T1 as time points, and sequence as group factor. ResultsWe observed clinical and statistical improvements for BBT, with an overall between-sequence difference of 8.6 ± 2.6 blocks (p < 0.01) favoring treatment period in the less affected side, and a not significant change of 3.0 ± 2.6 blocks (p = 0.28) in the most affected side. Small and not significant between-sequence differences were found for 9HPT, and handgrip strength in both sides. Similarly, no differences were found for patient reported outcomes, MFIS and MAM-36. Finally, mean SUS score was 45.9 ± 11.1 points, representing a moderate usability of the system. ConclusionAn immersive VR-based approach resulted useful to improve gross manual dexterity in the less affected limb in PwMS. However, such improvement did not translate into modifications in terms of self-reported ability to carry out activities of daily living nor went along with improvement in fine hand dexterity, strength or fatigue. Finally, usability of this technology was overall judged moderate, with lower scores assigned to items representing user-friendliness.

Cardiovascular reactivity to stress shows proneness to future blood pressure status in students of a teaching hospital in Nepal

Stress is a condition that disrupts or threatens to disrupt homeostasis. Stress may be physical or mental. Physical stress includes exercise (isometric or isotonic), pain, temperature (too hot or cold) etc. The development of hypertension is usually preceded by a prehypertensive state that may be manifested by abnormal cardiovascular reactivity to different types of stress viz., mental stress, cold water immersion, isotonic exercise, isometric handgrip, and valsalva maneuver. In present study, we have used isometric handgrip (IHG) exercise, as a stressor, aiming to identify individuals at increased risk for developing hypertension at early life. Normotensive, non-smoker sedentary two hundred male subjects, one hundred each from normotensive and hypertensive families, of age group 18-25 years participated in the study as volunteers. The causal blood pressure and heart rate of the participants were recorded in the sitting position by using mercury sphygmomanometer and stethoscope. Then, the isometric handgrip (IHG) exercise demonstrated to each of them using handgrip dynamometer. Maximum voluntary contraction (MVC) was noted as maximum pressure (in Kg) sustained during three seconds of handgrip using a handgrip dynamometer. The participants were asked to sustain isometric handgrip at one third of MVC for one minute with the same instrument (handgrip dynamometer). Both blood pressure and heart rate were recorded immediately after 1 and 3 minutes following isometric handgrip (IHG) exercise. The data analyzed using t-test showed that diastolic blood pressure didn’t return and stabilized to pre-exercise level even after 3 minutes following exercise in volunteers who were mostly from hypertensive family. More number of volunteers with family history of hypertensive (24%) showed elevated diastolic blood pressure even after 3 minutes whereas a few of the volunteers (8%) with no family history of hypertension showed rise in DBP even after 3 minutes following isometric handgrip (IHG) exercise. This present study indicated that the individuals having family history of hypertension are prone to develop hypertension in their early life, therefore, must adopt the healthier life style like avoidance of alcohol, smoking, and practice yogic exercise.

Feasibility and Safety of Whole-Body Electromyostimulation in Frail Older People-A Pilot Trial.

Whole-body electromyostimulation (WB-EMS) induces high-intense stimuli to skeletal muscles with low strain on joints and the autonomic nervous system and may thus be suitable for frail, older people. However, if trained at very high intensities, WB-EMS may damage muscles and kidneys (rhabdomyolysis). This study aimed at investigating the feasibility, safety and preliminary efficacy of WB-EMS in frail, older people. Seven frail (81.3 ± 3.5 years), 11 robust (79.5 ± 3.6 years), 10 young (29.1 ± 6.4 years) participants completed an eight-week WB-EMS training (week 1–4: 1x/week; week 5–8: 1.5x/week) consisting of functional exercises addressing lower extremity strength and balance. Feasibility was assessed using recruitment, adherence, retention, and dropout rates. The satisfaction with WB-EMS was measured using the Physical Activity Enjoyment Scale for older adults (PACES-8). In week 1, 3, and 8 creatine kinase (CK) was assessed immediately before, 48 and 72 h after WB-EMS. Symptoms of rhabdomyolysis (muscle pain, muscle weakness, myoglobinuria) and adverse events were recorded. Functional capacity was assessed at baseline and after 8 weeks using the Short Physical Performance Battery (SPPB), Timed Up-and-Go Test (TUG), Choice Stepping Reaction Time Test (CSRT), 30-second Chair-Stand Test (30-STS), maximum isometric leg strength and handgrip strength. The recruitment rate of frail individuals was 46.2%, adherence 88.3% and the dropout rate 16.7%. All groups indicated a high satisfaction with WB-EMS. CK activity was more pronounced in young individuals with significant changes over time. Within older people CK increased borderline-significantly in the frail group from baseline to week 1 but not afterwards. In robust individuals CK increased significantly from baseline to week 1 and 3. No participant reached CK elevations close to the threshold of ≥5,000 U/l and no symptoms of rhabdomyolysis were observed. With the exception of the TUG (p = 0.173), frail individuals improved in all tests of functional capacity. Compared to the young and robust groups, frail individuals showed the greater improvements in the SPPB, handgrip strength, maximum isokinetic hip-/knee extension and flexion strength. WB-EMS is feasible for frail older people. There were no clinical signs of exertional rhabdomyolysis. WB-EMS proved to be sufficiently intense to induce meaningful changes in functional capacity with frail individuals showing greater improvements for several measures.

Differential control of blood flow in masseter and biceps brachii muscles during stress

ObjectiveThe present study aimed to compare sympathetic hemodynamic effects in masticatory and limb muscles in response to different stressors. DesignTwelve healthy participants were subjected to a randomized series of stressors, including cold pressor test (CPT), mental arithmetic test, apnea, isometric handgrip (IHG) and post-handgrip muscle ischemia (PHGMI), while in the supine position. Spatially-resolved near-infrared spectroscopy was used to measure relative changes in blood volume and oxygenation (TOI) of the resting masseter and biceps muscles. Cardiac output, heart rate, and arterial blood pressure (ABP) were also monitored. ResultsExcept apnea, all tests increased ABP. Different response patterns were observed in the 2 muscles: TOI significantly increased during contralateral IHG (1.24 ± 1.17%) but markedly decreased during CPT (−4.84 ± 4.09%) and PHGMI (−6.65 ± 5.31%) in the biceps muscle, while exhibiting consistent increases in the masseter (1.88 ± 1.85%; 1.60 ± 1.75%; 1.06 ± 3.29%, respectively) (p < 0.05). ConclusionsThe results allow us to infer differential control of blood flow in head and limb muscles. In general, the masseter appears more prone to dilatation than the biceps, exhibiting opposite changes in response to painful stimuli (CPT and PHGMI). Several mechanisms may mediate this effect, including reduced sympathetic outflow to the extracranial vasculature of the head, generally exposed to lower hydrostatic loads than the rest of the body.

Reliability and Validity of Shoulder and Handgrip Strength Testing.

Purpose: This study aimed to estimate the intra- and inter-rater reliability of the JTECH computerized, wireless apparatus and its validity (compared to established devices) for measurements of maximal shoulder isometric strength and handgrip strength among healthy adults with no shoulder pathology. Methods: Twenty healthy young adults had shoulder strength tested with JTECH and Micro-FET2 hand-held dynamometers, and the handgrip strength was tested using JTECH and Jamar handgrip dynamometers. Assessments were performed by the same rater to determine intra-rater reliability and convergent validity, at least two days apart, while on a third visit, the other rater performed measures to determine inter-rater reliability. Results: The JTECH computerized, wireless devices demonstrated good to excellent intra-rater reliability (ICCs (2,1)=0.78-0.97) and inter-rater reliability for strength measures (ICCs (2,1)=0.76-0.95). The JTECH computerized device compared to the Micro-FET2 hand-held dynamometer showed substantial concurrent validity for shoulder flexion (R2=0.87), extension (R2=0.87), abduction (R2=0.88), and adduction (R2=0.85). Substantial concurrent validity was shown for the JTECH computerized device and Jamar handgrip dynamometers (R2=0.92). Conclusions: The JTECH computerized, wireless devices demonstrated high intra- and inter-rater reliability and substantial concurrent validity for shoulder isometric strength and handgrip strength in healthy adults.

ACUTE POST-DYNAMIC, ISOMETRIC AND COMBINED RESISTANCE EXERCISE HYPOTENSION IN PATIENTS WITH HYPERTENSION: A RANDOMIZED STUDY

Objective: American guidelines included dynamic resistance exercise (DRE) and isometric handgrip (IH) in hypertension treatment. A single session of DRE decreases blood pressure (BP) during the recovery period, which has been described as post-exercise hypotension (PEH). However, the occurrence of PEH after a session of IH is controversial and the post-exercise effects of the association of DRE and IH, in a combined resistance exercise (CRE), has not been evaluated. Thus, this study investigated the effects of DRE, IH and CRE on post-exercise BP and its hemodynamic, autonomic and vascular mechanisms. Design and method: Seventy medicated hypertensive men (52 ± 8 years) were randomly allocated to perform 1 of 4 interventions: DRE (8 exercises, 3 sets, 50%1RM, repetitions until moderate fatigue), IH (4 sets, 2 min-unilateral contraction, 30% MVC), CRE (DRE + IH) and control (CO - seated resting). Office BP, systemic hemodynamics (CO2 rebreathing technique), cardiovascular autonomic modulation [spectral analysis of heart rate (HR) and BP variabilities] and brachial vascular parameters (ultrasound) were evaluated before and after the interventions. Thus, the responses to interventions (post – pre-intervention values) were calculated and compared among the groups by ANOVAs with significance level set at P &lt; 0.05. Results: Responses to IH were similar to CO, showing that a single session of IH did not promote PEH, and did not affect any of the BP mechanisms. On the other hand, DRE and CRE induced responses significantly different from IH and CO. DRE and CRE significantly decreased systolic BP, diastolic BP, mean BP, stroke volume and cardiac baroreflex sensitivity, while they significantly increased HR, brachial artery diameter, blood flow and vascular conductance during the post-exercise period. Additionally, DRE significantly decreased post-exercise cardiac vagal modulation (HFR-R, nu) and increased cardiac sympathovagal balance (LF/HF). Conclusions: DRE, but not IH, elicits PEH, which is accompanied by vasodilation and increased HR, via a higher sympathovagal balance and lower baroreflex sensitivity. The addition of IH to DRE, in a CRE, does not potentiate PEH and did not change its mechanisms.

989-P: Impaired Coronary Arterial Dilation in Youth-Onset Type 2 Diabetes

Young adults with type 2 diabetes (T2D-Y) have increased risk of subclinical atherosclerotic cardiovascular disease (ASCVD) . Cardiac magnetic resonance imaging (MRI) may guide risk stratification by noninvasively quantifying coronary wall thickness (CWT, an indicator of ASCVD) and endothelial function (arterial dilation during isometric hand grip exercise, IHE) . The utility of these novel MRI biomarkers in T2D-Y is unknown. We hypothesized that T2D-Y would be associated with increased CWT and impaired endothelial function. In T2D-Y (6 male, age 19.8±1.6y, BMI 37±7kg/m2) and 12 healthy controls (5 male, age 22.7±2.9 y, BMI 24±5 kg/m2) we measured CWT and coronary and brachial dilation during IHE with a 3.0 Tesla MRI. T2D-Y had higher HbA1c (6.5 ± 0.8 vs. 5.1 ± 0.6%, P&amp;lt;0.01) , C reactive protein (5.16 ± 5.35 vs. 1.25 ± 2.25 mg/L) , systolic blood pressure (129±13 vs. 116±14 mmHg) , heart rate (84±13 vs. 72±9 beats/min (all P&amp;lt;0.05) . T2D-Y had lower HDL cholesterol (40±vs. 66±15 mg/dL, P=0.002) but similar LDL-cholesterol and triglycerides. CWT was not different (1.26±0.12 vs. 1.34±0.14 mm, P=0.18) but coronary and brachial arterial dilation was impaired in T2D-Y (Figure) . Overall, compared to health peers, T2D-Y had comparable CWT but impaired coronary and brachial arterial dilation occurred in the absence of traditional risk factors such as severe hyperglycemia, frank hypertension or dyslipidemia. Disclosure A. Villalobos-Perez: None. J. Feeley: None. K.Z. Abd-Elmoniem: None. K.B. Dietsche: None. J.R. Matta: None. M.S. Stagliano: None. L. Mabundo: None. E.L. Shouppe: None. M. Walter: None. S.T. Chung: None. Funding NIDDK/NIH Intramural Research Program