Natural Killer cells responsiveness to physical esercise: a brief review

Natural killer cells (NK) are a group of peripheral blood lymphocytes which display cytotoxic ac- tivity against a wide range of tumour cells. They are a consistent part of the inflammatory re- sponse that is activated when either internal or external injuries occur as they are able to syn- thesize perforins. An important role is played by NK cells in the host defence against tumours without expressing any antigen-binding recap- tor in their membrane which, however, distin- guish T and B lymphocytes. NK activity appears early in the immune response, thus providing immediate protection during the time required for the activation and proliferation of cytotoxic T lymphocytes and for their differentiation into functional cells. Even though much research regarding the effects of aerobic training exercise on NK cell numbers and function, there appears to be much controversy regarding its effect. NK cells are rapidly mobilized into circulation in response to acute exercise, most likely by in- creased shear stress and catecholamine-in- duced down-regulation of adhesion molecule expression. However, tissue injury and inflam- mation which often accompanies strenuous ex- ercise have been associated to post-exercise NK cell suppression. Scientific evidence indicates exercise-induced changes in NK cell redistribu- tion and function should be strongly influenced by stress hormones including catecholamines, cortisol and prolactin as well as by soluble me- diators such as cytokines and prostaglandins. The role of exercise therapy in cancer patients and survivors rehabilitation is becoming increasingly important as it is thought to modulate immunity and inflammation. However, more knowledge about the effects of exercise on im-mune function in these patients is needed

Aggiustamenti metabolici durante il recupero nell'Interval Training: studio in laboratorio e sul campo in atleti di mezzofondo e velocità prolungata

Lo scopo di questo studio è stato quello di quantificare l'affidabilità della frequenza cardiaca (HR), come parametro utile per valutare le condizioni di recupero di mezzofondisti e velocisti, durante un Interval Training (IT). Sono stati studiati ventidue atleti sottoposti a due diverse sessioni di IT: al 80% e 120% della soglia anaerobica (SA). Durante entrambe le sessioni abbiamo misurato HR, consumo di ossigeno (VO₂), produzione di anidride carbonica (VCO₂), ventilazione polmonare (Ve), mediante un analizzatore portatile di gas. Inoltre, è stato calcolato l'eccesso di produzione di anidride carbonica (CO₂excess) per verificare l'ipotesi che la deriva cardiaca, che si è verificata durante il recupero tra le ripetizioni di IT, fosse collegata ad uno stato di acidosi lattica. La deriva cardiaca è avvenuta in entrambi i gruppi ad entrambe le intensità lavorative, mentre CO₂excess, VO₂ e Ve non si sono modificati. Sulla base della nostra ricerca, l'utilizzo della HR come parametro di valutazione del recupero metabolico appare impreciso e fuorviante ed in definitiva non idoneo per la gestione del recupero nell’allenamento. ----------------------------------------------------------------------------------------------------------------------------The aim of this study was to quantify the reliability of heart rate (HR) monitoring to assess recovery status, after moderate and high-intensity exercise, in prolonged sprint and middle distance running specialties of athletics. Twenty-two runners underwent two different sessions of interval training: at 80% and 120% of anaerobic threshold (AT). Throughout both sessions we measured HR, oxygen uptake (VO₂), carbon dioxide production (VCO₂), pulmonary ventilation (Ve), by means a portable gas analyzer. The excess in carbon dioxide production (CO₂excess) was also measured to test the hypothesis that a cardiac drift, that occurred during recovery between repetitions of interval training, was related to lactic acidosis. The heart rate charts in both groups of athletes and with respect to the two workloads showed a progressive increase of the same during recovery periods, while CO2excess as well as VO₂ and Ve were not modified. On the basis of our research, the use of HR as a parameter of evaluation of the established recovery is inaccurate and unfit for training

The Influence of the Differentiation of Genes Encoding Peroxisome Proliferator-Activated Receptors and Their Coactivators on Nutrient and Energy Metabolism

Genetic components may play an important role in the regulation of nutrient and energy metabolism. In the presence of specific genetic variants, metabolic dysregulation may occur, especially in relation to the processes of digestion, assimilation, and the physiological utilization of nutrients supplied to the body, as well as the regulation of various metabolic pathways and the balance of metabolic changes, which may consequently affect the effectiveness of applied reduction diets and weight loss after training. There are many well-documented studies showing that the presence of certain polymorphic variants in some genes can be associated with specific changes in nutrient and energy metabolism, and consequently, with more or less desirable effects of applied caloric reduction and/or exercise intervention. This systematic review focused on the role of genes encoding peroxisome proliferator-activated receptors (PPARs) and their coactivators in nutrient and energy metabolism. The literature review prepared showed that there is a link between the presence of specific alleles described at different polymorphic points in PPAR genes and various human body characteristics that are crucial for the efficacy of nutritional and/or exercise interventions. Genetic analysis can be a valuable element that complements the work of a dietitian or trainer, allowing for the planning of a personalized diet or training that makes the best use of the innate metabolic characteristics of the person who is the subject of their interventions

Cardiovascular Responses to Simultaneous Diving and Muscle Metaboreflex Activation

Background: The aim of study was to assess hemodynamic changes during the simultaneous activation of muscle metaboreflex (MM) and diving reflex (DR) in a laboratory setting. We hypothesized that as long as the exercise intensity is mild DR can overwhelm the MM. Methods: Ten trained divers underwent all four phases (randomly assigned) of the following protocol. (A) Postexercise muscle ischemia session (PEMI): 3 min of resting followed by 3 min of handgrip at 30% of maximum force, followed immediately by 3 min of PEMI on the same arm induced by inflating a sphygmomanometer. Three minutes of recovery was further allowed after the cuff was deflated for a total of 6 min of recovery. (B) Control exercise recovery session: the same rest-exercise protocol used for A followed by 6 min of recovery without inflation. (C) DR session: the same rest-exercise protocol used for A followed by 1 min of breath-hold (BH) with face immersion in cold water. (D) PEMI-DR session: the same protocol used for A with 60 s of BH with face immersion in cold water during the first minute of PEMI. Stroke volume (SV), heart rate (HR), and cardiac output (CO) were collected by means of an impedance method. Results: At the end of apnea, HR was decreased in condition C and D with respect to A (−40.8 and −40.3%, respectively vs. −9.1%; p < 0.05). Since SV increase was less pronounced at the same time point (C = +32.4 and D = +21.7% vs. A = +6.0; p < 0.05), CO significantly decreased during C and D with respect to A (−23 and −29.0 vs. −1.4%, respectively; p < 0.05). Conclusion: Results addressed the hypothesis that DR overcame the MM in our setting

Improvement in Hemodynamic Responses to Metaboreflex Activation after One Year of Training in Spinal Cord Injured Humans

Spinal cord injured (SCI) individuals show an altered hemodynamic response to metaboreflex activation due to a reduced capacity to vasoconstrict the venous and arterial vessels below the level of the lesion. Exercise training was found to enhance circulating catecholamines and to improve cardiac preload and venous tone in response to exercise in SCI subjects. Therefore, training would result in enhanced diastolic function and capacity to vasoconstrict circulation. The aim of this study was to test the hypothesis that one year of training improves hemodynamic response to metaboreflex activation in these subjects. Nine SCI individuals were enrolled and underwent a metaboreflex activation test at the beginning of the study (T0) and after one year of training (T1). Hemodynamics were assessed by impedance cardiography and echocardiography at both T0 and T1. Results show that there was an increment in cardiac output response due to metaboreflex activity at T1 as compared to T0 (545.4 ± 683.9 mL · min(-1) versus 220.5 ± 745.4 mL · min(-1), P < 0.05). Moreover, ventricular filling rate response was higher at T1 than at T0. Similarly, end-diastolic volume response was increased after training. We concluded that a period of training can successfully improve hemodynamic response to muscle metaboreflex activation in SCI subjects

Collagen Gene Variants and Anterior Cruciate Ligament Rupture in Italian Athletes: A Preliminary Report

Several studies have investigated the role of genetics in anterior cruciate ligament (ACL) rupture, often returning conflicting results. The present pilot study aimed to analyze the association between six Single Nucleotide Polymorphisms (SNPs) (rs1800012; rs12722; rs13946; rs240736; rs970547; and rs4870723, located on the COL1A1, COL5A1, COL12A1, and COL14A1 genes), and ACL rupture, among Italian athletes. A hypothesis-driven association study was conducted. In total, 181 male and female athletes (n = 86 injured; n = 96 non-injured) were genotyped for the prioritized variants. All polymorphisms were genotyped using PCR RFLP, with the only exception being the rs1800012 on the COL1A1 gene, which was detected using MTPA PCR. The allele frequency distribution fell within the worldwide range. Despite the evident population variability, no selective pressure signals were recorded using PBS analysis. No significant difference was detected between the cases and controls for any of the SNPs (rs1800012; rs13946; rs240736; rs970547, and rs4870723) included in the analyses (p &gt; 0.008, Bonferroni-adjusted for multiple comparisons). Moreover, no significant differences were found when males and females were assessed separately. Further investigations based on a larger sample size are needed, in order to draw solid conclusions for the influence between collagen genes and ACL rupture. © 2023 by the authors

A 12-week vigorous exercise protocol in a healthy group of persons over 65: study of physical function by means of the senior fitness test

The aim of this study was to assess the effects of vigorous exercise on functional abilities bymeans of a Senior Fitness Test (SFT) in a group of elderly adults. Twenty healthy and inactive people performed vigorous exercise (VE: 12 men and 8 women, aged 69.6 ± 3.9 years). At the beginning of the study (T0) and after 3months (T1), each subject’s functional ability was tested formuscular strength, agility, cardiovascular fitness, flexibility, and balance.The VE was designed with continuous and interval exercise involving large muscle activities. Functional exercises were performed between 60% and 84% of heart rate reserve (HRR) for a duration of 65 minutes. Five out of the 6 SFTs performed were found significantly improved: Chair Stand (T0 12.4 ± 2.4, T1 13.5 ± 2.6, < 0.01), Arm Curl (T0 14.2 ± 3.6, T1 16.6 ± 3.6, < 0.01), 2 min step (T0 98.2 ± 15.7, T1 108.9 ± 16.2, < 0.01), Chair Sit-and-Reach (T0 −9.9 ± 7.7 cm, T1 1.7 ± 6.3 cm, < 0.01), and Back Scratch (T0 −15.8 ± 10.9 cm, T1 −8.4 ± 13.1 cm, < 0.01). Our results suggest that a high intensity protocol and functional exercises can improve functional mobility and muscle endurance in those over 65 years of age. SFTs are an effective method for assessing improvements in the functional capacity of elderly adults

Role of heart rate and stroke volume during muscle metaboreflex-induced cardiac output increase: differences between activation during and after exercise

We hypothesized that the role of stroke volume (SV) in the metaboreflex-induced cardiac output (CO) increase was blunted when the metaboreflex was stimulated by exercise muscle ischemia (EMI) compared with post-exercise muscle ischemia (PEMI), because during EMI heart rate (HR) increases and limits diastolic filling. Twelve healthy volunteers were recruited and their hemodynamic responses to the metaboreflex evoked by EMI, PEMI, and by a control dynamic exercise were assessed. The main finding was that the blood pressure increment was very similar in the EMI and PEMI settings. In both conditions the main mechanism used to raise blood pressure was a CO elevation. However, during the EMI test CO was increased as a result of HR elevation whereas during the PEMI test CO was increased as a result of an increase in SV. These results were explainable on the basis of the different HR behavior between the two settings, which in turn led to different diastolic time and myocardial performance

Diving response after a one-week diet and overnight fasting

Background: We hypothesized that overnight fasting after a short dietary period, especially with carbohydrates, could allow performing breath-hold diving with no restraint for diaphragm excursion and blood shift and without any increase of metabolism, and in turn improve the diving response. Methods: During two separate sessions, 8 divers carried out two trials: (A) a 30-m depth dive, three hours after a normal breakfast and (B) a dive to the same depth, but after following a diet and fasting overnight. Each test consisted of 3 apnea phases: descent, static and ascent whose durations were measured by a standard chronometer. An impedance cardiograph, housed in an underwater torch, provided data on trans-thoracic fluid index (TFI), stroke volume (SV), heart rate (HR) and cardiac output (CO). Mean blood pressure (MBP), arterial O-2 saturation (SaO(2)), blood glucose (Glu) and blood lactate (BLa) were also collected. Results: In condition B, duration of the static phase of the dive was longer than A (37.8 +/- 7.4 vs. 27.3 +/- 8.4 s respectively, P < 0.05). In static phases, mean Delta SV value (difference between basal and nadir values) during fasting was lower than breakfast one (-2.6 +/- 5.1 vs. 5.7 +/- 7.6 ml, P < 0.05). As a consequence, since mean. HR values were equally decreased in both metabolic conditions, mean. CO value during static after fasting was lower than the same phase after breakfast (-0.4 +/- 0.5 vs. 0.4 +/- 0.5 L . min(-1) respectively, P < 0.05). At emersion, despite the greater duration of dives during fasting, SaO(2) was higher than A (92.0 +/- 2.7 vs. 89.4 +/- 2.9 % respectively, P < 0.05) and BLa was lower in the same comparison (4.2 +/- 0.7 vs. 5.3 +/- 1.1 mmol L-1, P < 0.05). Conclusions: An adequate balance between metabolic and splancnic status may improve the diving response during a dive at a depth of 30 m, in safe conditions for the athlete's healt

Mean blood pressure assessment during post-exercise: Result from two different methods of calculation

At rest the proportion between systolic and diastolic periods of the cardiac cycle is about 1/3 and 2/3 respectively. Therefore, mean blood pressure (MBP) is usually calculated with a standard formula (SF) as follows: MBP = diastolic blood pressure (DBP) + 1/3 [systolic blood pressure (SBP) – DBP]. However, during exercise this proportion is lost because of tachycardia, which shortens diastole more than systole. We analysed the difference in MBP calculation between the SF and a corrected formula (CF) which takes into account changes in the diastolic and systolic periods caused by exercise-induced tachycardia. Our hypothesis was that the SF potentially induce a systematic error in MBP assessment during recovery after exercise. Ten healthy males underwent two exercise-recovery tests on a cycle-ergometer at mild-moderate and moderate-heavy workloads. Hemodynamics and MBP were monitored for 30 minutes after exercise bouts. The main result was that the SF on average underestimated MBP by –4.1 mmHg with respect to the CF. Moreover, in the period immediately after exercise, when sustained tachycardia occurred, the difference between SF and CF was large (in the order of -20-30 mmHg). Likewise, a systematic error in systemic vascular resistance assessment was present. It was concluded that the SF introduces a substantial error in MBP estimation in the period immediately following effort. This equation should not be used in this situation