5 research outputs found
Effects of a very low-carbohydrate high-fat diet and high-intensity interval training on visceral fat deposition and cardiorespiratory fitness in overfat individuals: A randomized controlled clinical trial
Get PDFPurpose: This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12 weeks on visceral adipose tissue (VAT) and cardiorespiratory fitness (CRF) level in overfat individuals.Methods: Ninety-one participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Body composition and CRF were analyzed before the experimental period and after 4, 8, and 12 weeks. Dual-energy X-ray absorptiometry (DXA) and graded exercise test (GXT) to volitional exhaustion were used for the body composition and CRF assessments, respectively.Results: There were significant between-group differences in the VAT mass and body composition outcome changes. VAT mass decreased after 12 weeks only in the VLCHF and VLCHF+HIIT groups (p < 0.001, median [95% CI]: VLCHF: -142.0 [-187.0; -109.5] g; VLCHF+HIIT: -104.0 [-135.0; -71.0] g). Similarly, changes in body mass, total body fat, trunk fat mass, waist and hip circumferences were distinctly decreased in the VLCHF and VLCHF+HIIT groups, when compared to HIIT and Control groups. Total lean mass significantly decreased in the VLCHF and VLCHF+HIIT groups (-2.1 [-3.0; -1.6] kg and -2.5 [-3.6; -1.8] kg, respectively) after 12 weeks. While the HIIT program significantly increased total time to exhaustion in the GXT, peak oxygen uptake was unchanged.Conclusions: A VLCHF diet, either in isolation or in combination with HIIT, was shown to induce a significant reduction in VAT mass and body composition variables. HIIT alone did not cause such effects on body composition, but improved exercise capacity. Our findings indicate that the VLCHF diet and exercise training provoked different and isolated effects on body composition and CRF.Web of Science8art. no. 78569
Very low-carbohydrate high-fat diet improves risk markers for cardiometabolic health more than exercise in men and women with overfat constitution: Secondary analysis of a randomized controlled clinical trial
Get PDFPurpose: This randomized controlled parallel-group study examined the effects of a very low-carbohydrate high-fat (VLCHF) diet and high-intensity interval training (HIIT) program over 12-weeks on cardiometabolic risk factors in individuals with overfat constitution.
Methods: Ninety-one participants out of 109 completed the study. The participants were randomly allocated to the HIIT (N = 22), VLCHF (N = 25), VLCHF+HIIT (N = 25), or control (N = 19) groups for 12 weeks. Fasting plasma samples were collected before the intervention and after 4 and 12 weeks. The analyzed outcomes included complete blood count, glucose, insulin, glycated hemoglobin, triglycerides (TG), cholesterol, high- and low-density lipoprotein (HDL-C and LDL-C), lipoprotein(a), adiponectin (Adpn), leptin (Lep), tumor necrosis factor alpha (TNF-alpha), other interleukins (hs-IL-6, IL-1 beta, and IL-10), and IL-1RA. The homeostasis model assessment of insulin resistance (HOMA-IR), Adpn/Lep ratio, TG/HDL-C ratio, and TyG index were calculated and analyzed. Blood pressure was measured before the intervention, after 4, 8, and 12 weeks (: NCT03934476).
Results: Absolute changes in HOMA-IR, Adpn/Lep ratio, LDL-C, and diastolic blood pressure after 12 weeks differed by study groups (p < 0.05). The most pronounced changes were revealed in the VLCHF (& UDelta;M [95% CI]; HOMA-IR: -0.75 [-1.13; -0.55]; Adpn/Lep: 9.34 [6.33; 37.39]; LDL-C: 0.06 [-0.12; 0.50] mmol/l) and VLCHF+HIIT (HOMA-IR: -0.44 [-1.14; 0.12]; Adpn/Lep: 4.26 [2.24; 13.16]; LDL-C: 0.25 [-0.04; 0.50] mmol/l) groups.
Conclusions: A 12-week VLCHF diet intervention in individuals with overfat constitution is effective for favorable changes in HOMA-IR (compared to HIIT), Adpn/Lep ratio, and diastolic blood pressure. HIIT, or HIIT combined with the VLCHF diet, had no additional benefits for the analyzed variables. No adverse side effects were observed.Web of Science9art. no. 86769
Intra-day and inter-day reliability of heart rate variability measurement
No full textAt present, analysis of heart rate variability (HRV) is becoming widely used as a clinical or research tool. Supported reliability studies for HRV measurement are, however, still limited. The main purpose was to perform an assessment of the absolute and relative reliability of HRV parameters from short-term recordings by means of orthoclinostatic stimulation and to investigate, whether there is a difference in repeating the retest immediately or after several days. The study group consisted of 99 participants (mean age 22 ± 1.24 years). Standard HRV indexes were computed: PT (total spectral power), PHF (high frequency spectral power), PLF (low frequency spectral power) and LF/HF. Absolute reliability was assessed by the standard error of measurement and 95% limits of agreement; relative reliability was assessed by the intraclass correlation coefficient. There was also an estimate of the sample size needed to detect the mean difference ≥ 30% of the between-subject standard deviation. In conclusion, a large random variation (within individuals) of HRV parameters was revealed, regardless of whether the retest was repeated immediately or with an interruption. For most HRV parameters (particularly in the immediately repeated test-retest), however, random variation represents a limited portion of the between-subject variability.Web of Science31215815
Vliv intervenčních programů na změny klidového energetického výdeje Effects of intervention programs on changes in resting energy expenditure
No full textCílem naší studie bylo posoudit vliv dvou typů redukčních programů na změny klidového energetického výdeje (REE) u skupiny žen středního věku s nadměrnou hmotností. Intervenčních programů se zúčastnilo 28 asymptomatických žen ve věku 40–50 let s nadváhou či obezitou, 6 žen studii nedokončilo. Soubor byl rozdělen na 2 skupiny – D a DE. Ženy zařazené do skupiny D (n = 10) měly předepsanou pouze dietní intervenci a ve skupině DE (n = 12) kombinovaný program dietní a pohybové intervence. Dietní program byl v obou skupinách stejný a denní energetická restrikce činila pro každého jedince přibližně 2000 kJ. Ve skupině s pohybovou intervencí byla zvolená kombinace silového a aerobního tréninku. Oba programy trvaly 6 týdnů. Na počátku a konci intervence jsme sledovali hodnoty REE (nepřímou kalorimetrií), REE/kg a vybrané antropometrické parametry: tělesnou hmotnost, výšku, BMI, obvod pasu, boků a stehna a procento tělesného tuku. Ve skupině s kombinovaným intervenčním programem byl pokles REE menší než ve skupině s pouhou dietní restrikcí. Změny REE a REE/kg na konci sledovaného období však nebyly statisticky významné a nebyl zjištěn statisticky významný rozdíl ani mezi použitými intervenčními programy. Rozdílné intervenční programy rovněž neměly, kromě obvodu stehna, statisticky významně rozdílný vliv na změnu sledovaných antropometrických ukazatelů. Ve všech sledovaných parametrech (REE i antropometrických) můžeme však pozorovat tendenci efektivnějšího působení kombinace redukční diety a cvičení než samotné diety. Pro výraznější ovlivnění REE by bylo patrně zapotřebí použití předpisu pohybové aktivity s delším trváním, vyšší intenzitou a frekvencí cvičení. The aim of the study was to assess the effects of two types of weight reducing programs on changes in resting energy expenditure (REE) in overweight middle aged women. We recruited 28 overweight or obese premenopausal women at the age of 40–50 years via poster advertisements, of which 6 of the women were withdrawn early. Participants were divided into 2 groups – D and DC. Women assigned to group D (n = 10) had only a diet regime prescribed, whereas group DC (n = 12) followed a combined diet and exercise intervention. The diet was identical for both groups and the daily energy restriction for each participant was approximately 2000 kJ. Group DC combined resistance training and aerobic exercise. Both programs ran for 6 weeks. At the beginning and end of the intervention REE values (measured by indirect calorimetry), REE/kg and selected anthropometric parameters: body weight, stature, BMI, waist, hips and thigh girth, and body fat percentage were monitored. In the combined intervention program the REE decrease was smaller than in the group with only an energy restricted diet. However, the REE and REE/kg changes detected at the end of the monitored period were not statistically signifi cant, and there was no significant statistical difference between the applied intervention programs. Apart from the thigh circumference, the two intervention programs did not show different effects of any statistical significance on the change of monitored anthropometric indices. However, for all the parameters monitored (REE as well as the anthropometric ones) we can see that energy restricted diet combined with exercise is more effective than diet alone. To affect the REE more markedly, prescription of physical exercise of longer duration, and of greater intensity and frequency would be necessary
Pozorování aktivity autonomního nervového systému prostřednictvím spektrální analýzy variability srdeční frekvence u hráčů ledního hokeje Autonomic nervous system observation through to use of spectral analysis of heart rate variability in ice hockey players
No full textCílem studie bylo poodhalit vliv pravidelného sportovního tréninku na aktivitu autonomního nervového systému (ANS), která byla hodnocena pomocí spektrální analýzy variability srdeční frekvence (SA HRV). K vyhodnocení výsledků SA HRV byly použity komplexní indexy (celkové skóre – TS, aktivita vagu – VA, sympatovagová balance – SVB) a věkově standardizovaná hodnota celkového spektrálního výkonu (PT) (Stejskal et al., 2002). Výzkumný soubor tvořili čtyři hráči ledního hokeje. Na základě získaných výsledků jsme došli k závěru, že kvalita sportovního tréninku ovlivňuje aktivitu ANS. Změny aktivity ANS, a tím velikosti adaptability sportovce, mohou významně ovlivnit sportovní výkon. Optimalizace adaptačních procesů prostřednictvím kontroly tréninkového zatížení na základě měření SA HRV může přinést nové aspekty řízení sportovního tréninku. The aim of our study was to investigate the infl uence of regular sport training on the activity of the autonomic nervous system (ANS) and to disclose patterns of interrelations between them. The activity of the ANS was evaluated by means of the spectral analysis of heart rate variability (SA HRV). We used complex indices (total score – TS, vagal activity – VA, sympathovagal balance – SVB) and age standardized values of total spectral power (PT) for SA HRV results evaluation (Stejskal et al., 2002). The study group consisted of four ice hockey players, of whom all were 17 years old. The SA HRV was monitored by using VarCor PF7 hardware and VarCorMulti computer software, which enables four individuals to be measured at the same time. The examination of heart rate variability took place once a week in the morning. Information about the previous day’s training load, the duration and quality of sleep, and their self-reported health status (SRH) was also obtained by completing a questionnaire before the SA HRV examination. Overall sports performance was evaluated by the team’s coach on a scale of 1 (very poor) to 10 (excellent). The results demonstrated that the player with the highest average TS (0.8) and the highest average PT (3.22) also showed the most consistent results (SD of TS = 0.74; SD of PT = 1.02) and objectively the best performance in sport. On the other hand, the player with the lowest average TS (–2.15; SD = 1.42) and the lowest average PT (–2.52; SD = 1.4) also obtained the lowest average mark in the coach’s evaluation of his sports performance. The tendency to progression of the ANS activity was diff erent for each subject. The SRH, which was given before measurements were taken, did not correspond with the results of the SA HRV measurement. We came to the following conclusion: training quality infl uences the ANS activity and according to changes in the ANS activity we can deduce the athlete’s changes in adaptability
