Isometric exercise promotes arteriogenesis in rats after myocardial infarction

Isometric exercise(IE)is a promising intervention of noninvasive revascularization in patients with acute myocardial infarction(AMI).This study aimed to investigate the impact and mechanisms of IE training on arteriogenesis in AMI.Male Sprague-Dawley rats were randomly assigned into the sham-operation group(SO),myocardial infarction(MI)group,and 13 IE subgroups treated according to training intensity,frequency,duration,or monocyte chemoattractant protein-1(MCP-1),or/and fibroblast growth factor-2(FGF-2)inhibitors for eight weeks.Our results demonstrated that the IE group achieved superior improvement compared with the MI group in terms of left ventricular ejection fraction(LVEF),myocardial infarction size(MIS),arterial density(AD),monocytes(MNCs),smooth muscle cells(SMCs),endothelial cells(ECs),relative collateral blood flow(RCBF),MCP-1,and FGF-2 at the endpoint.Positive correlations between MCP-1 and MNCs,MNCs and FGF-2,FGF-2 and SMCs,SMCs and AD,as well as AD and RCBF were observed.This study demonstrated that with MI of 100%load 20 times daily for eight weeks,the arteriogenesis was improved,which may be attributed to the recruitment of MNCs and SMCs in remote ischemic myocardium caused by increases in MCP-1 and FGF-2 expression.

Effects of Facial Isometric Exercise on Antioxidant Capacity

Background: Facial isometric exercise is a static contraction of facial muscles without any visible movement in the angle of the joints. To examine the effects of facial isometric exercise on subjective stress and oxidative stress/antioxidant capacity. Methods: In this study, we included 13 participants (6 males, 7 females;average age, 44.8 ± 19.6 years;age range: 20 - 74 years) who were exposed to constant temperature and humidity in a room. Fifteen minutes after entering the room, the force was measured before and after facial isometric exercise of the target muscles: upper lip levator, small zygomatic, large zygomatic, levator animus, laughing, buccal, muzzle, mental, temporal, masseter, and cervical muscles), and further evaluated by comparing the facial isometric exercise group and control (non-facial isometric exercise) group (crossover test). Results: Subjective stress significantly improved by 8.7 ± 16.3 in the facial isometric exercise group, and no significant difference in oxidative stress level was observed in both the groups. However, the antioxidant capacity significantly increased by 126.8 ± 168.1 μmol/l in the facial isometric exercise group. Conclusion: The results of this study suggest that facial isometric exercise is an exercise therapy that can provide mental stability and antiaging effects due to improvement in subjective stress and biological antioxidant potential.

A Case of Muscle Contraction-Induced Ischemic Limb Hyperemia in a Patient with Peripheral Arterial Disease during Incremental Repeat Isometric Knee Extensor Workloads

Background: To determine whether muscle contraction-induced leg blood flow (LBF) during exercise may be altered in a patient with an ischemic limb due to peripheral arterial disease (PAD) compared with the non-PAD limb. Case Presentation: A 66-year-old male patient with intermittent claudication due to PAD in the right leg (ankle brachial pressure index, 0.69) showed complete obstruction in both common iliac arteries including internal/external segments with collaterals above the femoral artery and popliteal artery with collaterals, and in the healthy left non-PAD-leg (1.06). He attempted unilateral repeat isometric knee extensions at a target contraction rhythm with each leg at incremental contraction intensities (5%, 10%, and 30% of maximum voluntary contraction [MVC] for 3 min at each intensity). Blood velocity/flow (Doppler ultrasound) in the femoral artery, blood pressure, and leg vascular conductance (LVC) were measured. Isometric thigh MVC strength pre-exercise was similar between the PAD-leg (48.0 kg) and non-PAD-leg (48.7 kg). Pre-exercise LBF (ml/min) was also similar between the PAD-leg (316) and non-PAD-leg (327). Blood pressure increases were similar during exercise. Average exercising LBF in ml/min in the last 1 min at each intensity was higher in the PAD-leg than the non-PAD-leg: 1087 vs. 471 at 5%, 2097 vs. 712 at 10%, and 2656 vs. 1517 at 30% MVC with a close positive linear relationship between LBF and %MVC in the non-PAD-leg (r = 0.999, P < 0.01), in agreement with previous findings, but less significant in the PAD-leg (r = 0.879, P = NS), indicating intense vasodilation (increasing LVC) in the PAD-leg compared with the non-PAD-leg. Conclusion: Knee extensor exercising LBF in the femoral artery was dissimilar between the PAD-leg and non-PAD-leg at the same exercise intensity, even though pre-exercising LBF was the same. Further research on the time-course in hemodynamics during leg exercise in PAD might potentially provide insight for the cardiovascular adjustment in severity of arteriosclerosis, stenosis and/or collaterals reserve.

Relationship between isometric exercise and myocardial ischemia in patients with coronary artery disease: an Echo- Doppler study

Objective To study the relationship between isometric exercise and myocardial ischemia in patients with coronary artery disease (CAD) Methods Twenty CAD patients and 10 normal subjects were included in our study All subjects performed maximal brief isometric exercise (BIE), maximal sustained isometric exercise (SIE) and dynamic exercise (DE) Hemodynamic parameters and cardiac function were measured by Echo Doppler technique To avoid influence of different baseline values, increment (Δ%) of exercise response was used as parameter for significant analysis: Δ%=(exercise values-baseline values)/baseline values×100% Results Positive exercise testing (PET) showed no evidence of myocardial ischemia during BIE and SIE even though their rates of perceived exertion (RPE) were similar to DE Δ% heart rate (HR) and Δ% rate pressure product (RPP) were higher during DE than during SIE and BIE in negative exercise testing (NET) and normal controls (NOR) ( P <0 01), except PET during DE and SIE; Δ% systolic blood pressure (SBP) was higher during DE than during BIE in NOR ( P <0 01) Δ% SBP in NOR and NET during SIE was higher than during BIE ( P <0 05) Δ% diastolic blood pressure (DBP) was the highest during SIE among exercises in all groups ( P <0 05) There were no significant inter group differences of Δ% HR, Δ% SBP, Δ% DBP and Δ% RPP during SIE, BIE and DE, except that Δ% SBP during SIE was higher in NET than in NOR and PET ( P <0 05) In NOR, Δ% ejection fraction (EF), Δ% fractional shortening of the minor semi axis (SF), Δ% cardiac output (CO), Δ% E/A was higher during DE than during SIE and BIE ( P <0 01) Δ% stroke volume (SV) was similar during DE, SIE and BIE There were no significant differences in Δ% EF, Δ% SF, Δ% CO, Δ% SV and Δ% E/A during DE, SIE and BIE in both NET and PET, except lower Δ% CO in NET during SIE and BIE than DE ( P <0 01) There were no inter group differences in Δ% EF, Δ% SF, Δ% CO and Δ% E/A, except that Δ% E/A was higher during SIE in NET than PET ( P <0 01) During DE, NOR and NET had higher Δ% SV, Δ% SF, Δ% CO and Δ% E/A than PET ( P <0 05) Conclusions The incidence of myocardial ischemia in CAD patients was lower during isometric exercise than dynamic exercise at similar perceived exertion levels Isometric exercise might protect the myocardium from ischemia through high coronary artery perfusion pressure and long perfusion duration We suggest that application of isometric exercise in a cardiac rehabilitation program may have reasonable physiological background