Effects of L-arginine on impaired blood fluidity after high-intensity exercise: An in vitro evaluation

BACKGROUND

Exercise-induced impairment of blood fluidity is considered to be associated with thrombosis development. However, the effects of L-arginine on blood fluidity after exercise remain unclear.

OBJECTIVE

We investigated the mechanisms of impaired blood fluidity after high-intensity exercise, and examined whether L-arginine improves exercise-induced blood fluidity impairment in vitro.

METHODS

Ten healthy male participants performed 15 minutes of ergometer exercise at 70% of their peak oxygen uptake levels. Blood samples were obtained before and after exercise. L-arginine and NG-monomethyl-L-arginine acetate (L-NMMA)-a nitric oxide (NO) synthase inhibitor-were added to the post-exercise blood samples. Using Kikuchi's microchannel method, we measured the blood passage time, percentage of obstructed microchannels, and the number of adherent white blood cells (WBCs) on the microchannel terrace.

RESULTS

Exercise increased the hematocrit levels. The blood passage times, percentage of obstructed microchannels, and the number of adherent WBCs on the microchannel terrace increased after exercise; however, they decreased in a dose-dependent manner after the addition of L-arginine. L-NMMA inhibited the L-arginine-induced decrease in blood passage time.

CONCLUSIONS

High-intensity exercise impairs blood fluidity by inducing hemoconcentration along with increasing platelet aggregation and WBC adhesion. The L-arginine-NO pathway improves blood fluidity impairment after high-intensity exercise in vitro.

Effect of Vibrotherapy on Body Fatness, Blood Parameters and Fibrinogen Concentration in Elderly Men

Elderly people need activities that will positively contribute to a satisfactory process of getting older. Vibration training uses mechanical stimulus of a vibrational character that, similarly to other forms of physical activity, affects metabolic processes and conditions of health. The aim of this work was to assess the influence of thirty vibration treatments on body fatness, hematologic and rheologic indexes of blood, and proteinogram and fibrinogen concentration in elderly men’s blood. The study included twenty-one males, aged 60–70 years (mean age 65.3 ± 2.7), who were randomly assigned into a vibrotherapy group (VG) and took part in interventions on mattresses generating oscillatory-cycloid vibrations, and a control group (CG), without interventions. In all patients the following assessments were performed twice: an assessment of body fatness using the bioimpedance method, a complete blood count with a hematology analyzer, and erythrocyte aggregation by a laser-optical rotational cell analyzer; whereas, total plasma protein and fibrinogen values were established, respectively, by biuret and spectrophotometric methods. In order to compare the impact of vibrotherapy on changes in the analyzed variables, analysis of variance (ANOVA) or the Wilcoxon test were used. After applying thirty vibration treatments in the VG, a significant decrease in body fatness parameters was confirmed: BM (∆BM: −2.7 ± 2.0; p = 0.002), BMI (∆BMI: −0.9 ± 0.7; p = 0.002), BF (∆BF: −2.5 ± 2.5; p = 0.013), and %BF (∆%BF: −2.0 ± 2.7; p = 0.041), as well as in RBC (∆RBC: −0.1 ± 0.1; p = 0.035). However, changes in erythrocyte aggregation and proteinogram were not confirmed. It was found that after thirty treatments with VG, a significant decrease of fibrinogen level took place (∆ = −0.3 ± 0.3, p = 0.005). Application of thirty vibrotherapy treatments positively affected body fatness parameters and fibrinogen concentrations in the examined. However, further research should include a greater number of participants.

Effects of whole-body neuromuscular electrical stimulation device on hemodynamics, arrhythmia, and sublingual microcirculation

Neuromuscular electrical stimulation has been used to treat cardiovascular diseases and other types of muscular dysfunction. A novel whole-body neuromuscular electrical stimulation (WB-NMES) wearable device may be beneficial when combined with voluntary exercises. This study aimed to investigate the safety and effects of the WB-NMES on hemodynamics, arrhythmia, and sublingual microcirculation. The study included 19 healthy Japanese volunteers, aged 22-33 years, who were not using any medication. Electrocardiogram (ECG), echocardiography, and blood sampling were conducted before a 20-min WB-NMES session and at 0 and 10 min after termination of WB-NMES. Their tolerable maximum intensity was recorded using numeric rating scale. Arrhythmia was not detected during neuromuscular electrical stimulation or during 10 min of recovery. Blood pressure, heart rate, left ventricular ejection fraction, and diastolic function remained unchanged; however, mild mitral regurgitation was transiently observed during WB-NMES in a single male participant. A decrease in blood glucose and an increase in blood lactate levels were observed, but no changes in blood fluidity, sublingual microcirculation, blood levels of noradrenaline, or oxidative stress were shown. WB-NMES is safe and effective for decreasing blood glucose and increasing blood lactate levels without changing the blood fluidity or microcirculation in healthy people.

Wearable sensors enable personalized predictions of clinical laboratory measurements

Vital signs, including heart rate and body temperature, are useful in detecting or monitoring medical conditions, but are typically measured in the clinic and require follow-up laboratory testing for more definitive diagnoses. Here we examined whether vital signs as measured by consumer wearable devices (that is, continuously monitored heart rate, body temperature, electrodermal activity and movement) can predict clinical laboratory test results using machine learning models, including random forest and Lasso models. Our results demonstrate that vital sign data collected from wearables give a more consistent and precise depiction of resting heart rate than do measurements taken in the clinic. Vital sign data collected from wearables can also predict several clinical laboratory measurements with lower prediction error than predictions made using clinically obtained vital sign measurements. The length of time over which vital signs are monitored and the proximity of the monitoring period to the date of prediction play a critical role in the performance of the machine learning models. These results demonstrate the value of commercial wearable devices for continuous and longitudinal assessment of physiological measurements that today can be measured only with clinical laboratory tests.

The type of training program affects appetite-regulating hormones and body weight in overweight sedentary men

Exercise-induced weight loss can occur for several reasons, including changes in circulatory levels of appetite-regulating hormones. The purpose of this study was to compare the effect of various training programs on fasting serum levels of acylated ghrelin, peptide YY 3-36 (PYY3-36) and glucagon-like peptide-1 (GLP-1), as well as weight and body mass index (BMI) changes. Forty-four overweight men were randomly assigned into 4 groups of 11 individuals, which included (i) endurance group (3 sets of 10 min with 80%–90% of maximum heart rate), (ii) resistance group (4 sets of 8 repetitions with 80% of 1-repetition maximum), (iii) concurrent group (combination of programs of endurance and resistance groups in an alternate manner), and (iv) control group. Training protocols were conducted for 12 weeks for 3 sessions per week. Results showed that all 3 types of training programs resulted in weight loss (p = 0.000, p = 0.000, and p = 0.036 for resistance, concurrent, and endurance groups, respectively), BMI reduction (p = 0.000, p = 0.000, and p = 0.034), decreased serum acylated ghrelin (p = 0.000, p = 0.000, and p = 0.004), and increased PYY hormone levels (p = 0.028, p = 0.035, and p = 0.036). However, the effect of resistance training on these changes was more pronounced. Moreover, none of the exercise programs had any effect on serum levels of GLP-1. In addition, there was a significant positive correlation between weight (p = 0.003) and BMI (p = 0.009) changes with ghrelin while a negative correlation was observed between weight (p = 0.003) and BMI (p = 0.03) changes with PYY. The findings suggest that regular exercise training, in particular resistance training, is likely to reduce body weight and improve body composition of overweight inactive people by suppressing orexigenic hormones and stimulating the anorexigenic hormones.

Influences of two high intensity interval exercise protocols on the main determinants of blood fluidity in overweight men

BACKGROUND

Acute effects of continuous exercise on the markers of blood fluidity have been addressed in different populations and the changes are intensity related. However, the effect of different high intensity interval exercise (HIIE) on these variables is unclear.

OBJECTIVE

This study is designed to determine the effects of two different HIIE with different work/rest ratios but the same energy expenditure on the main determinants of blood fluidity.

METHODS

Ten overweight men (age, 26.3±1.7 yrs) completed two HIIE protocols on two separate occasions with one week intervening. The two HIIE encompassed performing: 1) 6 intervals of 2 min activity at 85% of VO2max interspersed by 2 min active recovery at 30% of VO2max (ratio 1 to 1, HIIE1/1), and 2) 6 intervals of 30 s activity at 110% of VO2max interspersed by 4 min active recovery at 40% of VO2max (ratio 1 to 8, HIIE1/8). Each exercise trial was followed by 30 min rest. Venous blood samples were obtained before exercise, immediately after exercise and after recovery and analyzed for blood and plasma viscosity, fibrinogen and red blood cell indices.

RESULTS

The HIIE1/1 protocol led to higher reduction (P < 0.01) in plasma volume changes compared to HIIE1/8 (9.9% vs 5.7%). Moreover, increases in blood viscosity, plasma viscosity, hematocrit, RBC count and mean arterial blood pressure observed following HIIE1/1 were significantly (P < 0.05) higher than HIIE1/8 ; whereas, the changes in fibrinogen concentration neither were significant in response to both trials nor were significantly different between two protocols (P > 0.05). However, the changes in all variables during exercise were transient and returned to the baseline levels after 30 min recovery.

CONCLUSIONS

It is concluded that the HIIE protocol with lower intensity and shorter rest intervals (higher work to rest ratio) clearly results in more physiological strain than HIIE with higher intensity but longer rest intervals (lower work to rest ratio) in overweight individuals, and that the work to rest ratio could be as important as exercise intensity when considering the hemorheological variables during HIIE.

The effect of exercise on blood fluidity: Use of the capillary model to assess the clogginess of blood

AIM

The goal was to evaluate the effects of exercise on the clogginess of blood as well as the effect of increased blood cell count and hematocrit levels after exercise. We also investigated the mechanisms underlying the clogginess of blood.

METHODS

The time required for blood to pass through microchannels was measured. We focused on assessing the consecutive passage times for serial 20 μL volumes. We used heparinized peripheral blood obtained from subjects after exercise conducted at three intensity levels. Blood samples were also adjusted to achieve specific hematocrit levels or supplemented by addition of adenosine diphosphate (ADP).

RESULTS

The sequential blood passage times of consecutive 20 μL volumes increased with platelet aggregation and adhesion of white blood cells (WBC). We also observed an increase with blood cell counts and hematocrit levels. These changes occurred after high intensity exercise but not after low or medium intensity exercise. Furthermore, the sequential blood passage times of 20 μL volumes increased with platelet aggregation and adhesion of WBC at an ADP concentration at the threshold of aggregation but not at higher levels of hematocrit.

CONCLUSIONS

These findings suggested that high intensity exercise might induce the clogginess of blood by enhanced platelet aggregation and adhesion of WBC.

Dihydropyridine calcium channel blockers inhibit non-esterified-fatty-acid-induced endothelial and rheological dysfunction

Circulating NEFAs (non-esterified fatty acids) from adipose tissue lipolysis lead to endothelial dysfunction and insulin resistance in patients with the metabolic syndrome or Type 2 diabetes mellitus. The aim of the present study was to test the hypothesis that DHP (dihydropyridine) CCBs (calcium channel blockers) prevent NEFA-induced endothelial and haemorheological dysfunction independently of their antihypertensive properties. Using a double-blind cross-over study design, nifedipine, amlodipine, diltiazem or placebo were administered to eight healthy subjects for 2 days before each study day. On the study days, the following were assessed before and after the infusion of lipid and heparin to raise serum NEFAs: endothelial function, by measuring FBF (forearm blood flow) responses to ACh (acetylcholine); leucocyte activation, by ex vivo measurement of plasma MPO (myeloperoxidase) levels, adherent leucocyte numbers and whole blood transit time through microchannels; and oxidative stress, by determining plasma levels of d-ROMs (derivatives of reactive oxygen metabolites). Effects of the CCBs on NF-κB (nuclear factor κB) p65 phospholylation stimulated by NEFAs were assessed in cultured monocytic cells in vitro. Elevated NEFAs reduced the responses to ACh and significantly increased whole blood transit time, adherent leucocyte numbers and d-ROMs. Nifedipine and amlodipine, but not diltiazem, prevented NEFA-induced endothelial dysfunction, leucocyte activation and enhancement of oxidative stress without affecting BP (blood pressure), whereas all these drugs prevented NEFA-induced p65 activation in vitro. These results suggest that DHP CCBs, independent of their antihypertensive properties in humans, prevent NEFA-induced endothelial and haemorheological dysfunction through inhibition of NEFA-induced leucocyte activation, although the sensitivity to drugs of leucocyte Ca2+ channels may differ among cells.

Persistent sympathoexcitation long after submaximal exercise in subjects with and without coronary artery disease

There is an increased risk of cardiac events after exercise, which may, in part, be mediated by the sympathoexcitation that accompanies exercise. The duration and extent of this sympathoexcitation following moderate exercise is unknown, particularly in those with coronary artery disease (CAD). Twenty control subjects (mean age, 51 years) and 89 subjects with CAD (mean age, 58 years) underwent two 16-min bicycle exercise sessions followed by 30-45 min of recovery. Session 1 was performed under physiological conditions to peak workloads of 50-100 W. In session 2, parasympathetic blockade with atropine (0.04 mg/kg) was achieved at end exercise at the same workload as session 1. RR interval was continually recorded, and plasma catecholamines were measured at rest and selected times during exercise and recovery. Parasympathetic effect, measured as the difference in RR interval with and without atropine, did not differ between controls and CAD subjects in recovery. At 30 and 45 min of recovery, RR intervals were 12% and 9%, respectively, shorter than at rest. At 30 and 45 min of recovery, plasma norepinephrine levels were 15% and 12%, respectively, higher than at rest. A brief period of moderate exercise is associated with a prolonged period of sympathoexcitation extending >45 min into recovery and is quantitatively similar among control subjects and subjects with CAD, with or without left ventricular dysfunction. Parasympathetic reactivation occurs early after exercise and is also surprisingly quantitatively similar in controls and subjects with CAD. The role of these autonomic changes in precipitating cardiac events requires further evaluation.