Monitoring exercise intensity in diabetes: applicability of "heart rate-index" to estimate oxygen consumption during aerobic and resistance training.

PURPOSE: Accurate quantification and monitoring of exercise "dose", described by oxygen consumption (VO2), is necessary for exercise prescription and individualization. However, due to the complexity and elevated cost of direct, gold-standard methods, this is rarely done outside research laboratories. Heart rate-index (HRindex) is a new simple method to estimate VO2 in healthy and clinical populations. We tested the performance of HRindex to estimate VO2 in diabetic patients during aerobic (AT) and isotonic training (IT). METHODS: Data from 12 males (age: 64 ± 5 years; BMI: 26 ± 12) with type 2 diabetes were analysed. VO2 and heart rate were measured during one AT and one IT session. Furthermore, VO2 was indirectly estimated based on HRindex. Then, the correspondence between measured and estimated VO2 was evaluated by two-way RM-ANOVA, correlation and Bland-Altman analysis. RESULTS: Estimated average VO2 values during AT (1292 ± 366 ml/min) were not different from (p = 0.243) and highly correlated with (r = 0.87, p < 0.001) the measured values (1369 ± 417 ml/min), with a small bias and imprecision. Conversely during IT, HRindex overestimated VO2 compared to the actual measures (1048 ± 404 vs 667 ± 230 ml/min, p ≤ 0.001) and only a moderate correlation was found between values (r = 0.43, p ≤ 0.001), with a large bias and imprecision. CONCLUSION: VO2 of aerobic exercises can be accurately estimated in diabetes patients using HRindex. During isotonic exercise, this method is not recommended for monitoring metabolic intensity due to large overestimation and imprecision. In aerobic exercise, HRindex offers a simple and valid alternative to the direct VO2 determination and may favour the applicability of time-resolved measures of exercise "dose".

Association of free-living physical activity measures with metabolic phenotypes in type 2 diabetes at the time of diagnosis. The Verona Newly Diagnosed Type 2 Diabetes Study (VNDS).

BACKGROUND AND AIM: Lifestyle is considered a major determinant of risk of type 2 diabetes (T2D). We investigated whether daily physical activity (DPA) is associated with beta-cell function (BF) and/or insulin sensitivity (IS) in patients with T2D at the time of diagnosis. METHODS AND RESULTS: In 41 subjects enrolled in the Verona Newly-Diagnosed Type 2 Diabetes Study we assessed: (1) IS, by euglycaemic insulin clamp; (2) BF, estimated by prolonged-OGTT minimal modeling and expressed as derivative and proportional control; (3) DPA and energy expenditure (EE), assessed over 48-h monitoring by a validated wearable armband system. Study participants (median [IQR]; age: 62 [53-67] years, BMI: 30.8 [26.5-34.3] Kg m-2, HbA1c: 6.7 [6.3-7.3]%; 49.7 [45.4-56.3] mmol/mol) were moderately active (footsteps/day: 7773 [5748-10,927]; DPA≥3MET: 70 [38-125] min/day), but none of them exercised above 6 metabolic equivalents (MET). EE, expressed as EETOT (total daily-EE) and EE≥3MET (EE due to DPA≥3MET) were 2398 [2226-2801] and 364 [238-617] Kcal/day, respectively. IS (M-clamp 630 [371-878] µmol/min/m2) was positively associated with DPA and EE, independent of age, sex and BMI (p < 0.05). Among the DPA and EE parameters assessed, DPA≥3MET and EETOT were independent predictors of IS in multivariable regression analyses, adjusted for age, sex, BMI (R2 = 16%, R2 = 19%, respectively; p < 0.01). None of model-derived components of BF was significantly associated with DPA or accompanying EE. CONCLUSIONS: Our study highlighted moderate levels of DPA and total EE as potential determinants of IS, but not BF, in T2D at the time of diagnosis. Intervention studies are needed to conclusively elucidate the effect of DPA on these features. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. UNIQUE IDENTIFIER: NCT01526720.

Effects of aerobic or resistance exercise training on cardiovascular autonomic function of subjects with type 2 diabetes: A pilot study.

BACKGROUND AND AIMS: Both aerobic (AER) and resistance (RES) training improve metabolic control in patients with type 2 diabetes (T2DM). However, information on the effects of these training modalities on cardiovascular autonomic control is limited. Our aim was to compare the effects of AER and RES training on cardiovascular autonomic function in these subjects. METHODS AND RESULTS: Cardiovascular autonomic control was assessed by Power Spectral Analysis (PSA) of Heart Rate Variability (HRV) and baroreceptors function indexes in 30 subjects with T2DM, randomly assigned to aerobic or resistance training for 4 months. In particular, PSA of HRV measured the Low Frequency (LF) and High Frequency (HF) bands of RR variations, expression of prevalent sympathetic and parasympathetic drive, respectively. Furthermore, we measured the correlation occurring between systolic blood pressure and heart rate during a standardized Valsalva maneuver using two indexes, b2 and b4, considered an expression of baroreceptor sensitivity and peripheral vasoactive adaptations during predominant sympathetic and parasympathetic drive, respectively. After training, the LF/HF ratio, which summarizes the sympatho-vagal balance in HRV control, was similarly decreased in the AER and RES groups. After AER, b2 and b4 significantly improved. After RES, changes of b2 were of borderline significance, whereas changes of b4 did not reach statistical significance. However, comparison of changes in baroreceptor sensitivity indexes between groups did not show statistically significant differences. CONCLUSION: Both aerobic and resistance training improve several indices of the autonomic control of the cardiovascular system in patients with T2DM. Although these improvements seem to occur to a similar extent in both training modalities, some differences cannot be ruled out. CLINICAL TRIAL REGISTRATION NUMBER: NCT01182948, clinicaltrials.gov.

Is cardiorespiratory fitness impaired in PCOS women? A review of the literature.

PURPOSE: Polycystic ovary syndrome (PCOS) is a common and heterogeneous endocrine disorder, affecting 8-12% of reproductive-aged women. Insulin resistance and body fat excess are common features in these subjects. Increased physical activity and diet modifications are the first recommended approach in the management of these women, at least in overweight/obese subjects. Evaluation of cardiorespiratory fitness (CRF) is important in assessing exercise performance and in monitoring the effects of physical exercise interventions. Several studies have shown that CRF may be impaired in metabolic and endocrine disorders. However, there are little data on this issue in PCOS women. The aim of this narrative review is to critically evaluate whether aerobic capacity is altered in PCOS women, focusing on maximal oxygen uptake. METHODS: An updated search of the literature was performed, identifying papers with maximal oxygen consumption measurements in women with PCOS compared to healthy controls. RESULTS: We have identified six studies on this specific topic: four of them showed an alteration of maximal oxygen consumption in PCOS women, whereas two did not. However, taken together these studies suggest that CRF may be strikingly impaired in both normal-weight and overweight/obese subjects with this condition. CONCLUSIONS: Women with PCOS appear to be characterized by a reduced cardiopulmonary fitness. However, further research on this topic is needed. This information may hopefully help clinicians and exercise specialist in planning individualized exercise programs aimed at improving the metabolic and endocrine outcomes in these women.

Low body weight and menstrual dysfunction are common findings in both elite and amateur ballet dancers.

BACKGROUND: Several studies have reported that low body weight and menstrual alterations are very frequent findings in elite dancers, suggesting they could be at risk for associated medical problems. However, it is still largely unknown whether these alterations are also common in the very large number of young amateur dancers. AIM: The aim of this study was to assess whether there is an increased prevalence of menstrual dysfunction also in amateur dancers. MATERIAL/SUBJECTS AND METHODS: Ninety-two professional ballet dancers, 93 non-professional ballet dancers, and 293 (160 sedentary, 133 physically active) control women, ranging in age 14-23 yr, were included in the study. In these subjects, a detailed questionnaire that included questions on weight, height, age at menarche, training profile and menstrual alterations was administered. RESULTS: BMI was lower in both professional and non-professional dancers than in controls. Frequency of menstrual dysfunction was 51%, 34% and 21% in professional dancers, non-professional dancers and controls, respectively (p<0.0001). Amenorrhea was reported by 23% of professional dancers, vs 1-7% in the other groups (p<0.0001). Age at menarche occurred later in professional dancers than in the other groups. Logistic regression analyses showed that menstrual dysfunction was associated with the training profile in professional dancers, and with BMI in non-professional dancers. Age at menarche was associated with menstrual dysfunction in both groups. CONCLUSIONS: This study shows that low body weight and menstrual dysfunction are frequent findings also in amateur ballet dancers.

Antiulcer action of the hydroalcoholic extract and fractions of Davilla rugosa Poiret in the rat.

Davilla rugosa Poiret ("Cipó- Caboclo") is commonly used in Brazilian folk medicine. The hydroalcoholic extract of the stems (HE) was fractionated with chloroform (CF), chloroform/ethyl acetate (CAF), ethyl acetate (AF), ethyl acetate/ethanol (AEF), ethanol (EF), and ethanol/water (EWF). The hydroalcoholic extract (HE) and fractions of the stems of D. rugosa Poiret were investigated for possible anti gastric ulcer properties. These extracts were shown to protect rats from developing gastric ulcers induced by two acute models: HCl/ethanol (400 mg/kg i.p.) and immersion-restraint stress (15 and 30 mg/kg of the HE and 15 mg/kg either of the ethanol or the ethanol/water fractions, p.o.). The daily oral dose of 800 mg/kg of HE for 30 consecutive days was tested for possible toxic effects. There were no modifications in body weight, water or food intake or in the external aspect of kidneys, spleen, lungs and liver. The only difference observed was a decrease of liver weight. These results suggest that the D. rugosa Poiret HE has an antiulcer activity in rats and the active components are in the two more polar fractions.

Antiulcer action of Microgramma squamulosa (Kaulf.) Sota.

Microgramma squamulosa (Kaulf.) Sota (Polypodiaceae) is commonly used as an antiulcer agent in the state of São Paulo, mainly in the upper land. The present work aims to study the antiulcer action of the crude extract of the plant rhizome and its toxicity. The effective dose was determined through acute ulcer induction test by stress. Using a determined dose, we performed a test against ulcer through acute induction by ethanol and hydrochloric acid, using cimetidine and misoprostol as reference drugs in both tests. The same extract, its ethanol and ethanol + water (1:1) fractions and the reference drug cimetidine were tested through subchronic induction test with acetic acid. The subchronic toxicity test was performed using a dose of 800 mg/kg of the crude extract, orally administered for 30 days. Finally the extracts and fractions were analysed in order to determine the main chemical groups of substances.

Antiulcer action of Styrax camporum and Caesalpinia ferrea in rats. '.

Stem extracts of Styrax camporum Pohl and Caesalpinia ferrea Martius were administered orally and intraperitoneally to rats and effected a decrease in the acute ulceration number. The volume, pH, and hydrochloric acid concentration of gastric secretions were measured after administration of both extracts, atropine, and cimetidine. After oral administration there was a decrease in the gastric secretion volume without modification of the other gastric secretion parameters studied. There were modifications, however, when the extracts were administered intraperitoneally. Analgesy, influence on sleeping time, and spontaneous motor activity test results indicate a probable absence of central action components in the extracts.

Antiulcer action and toxicity of Styrax camporum and Caesalpinia ferrea.

Oral administration of Styrax camporum Pohl and Caesalpinia ferrea Martius stem extracts, atropine, and cimetidine, during 15 days, decreased the ulceration size, gastric secretion volume, and increased collagen fibre number of chronic ulcer induced by acetic acid in rats. The pH increased and the concentration of hydrochloric acid decreased after administration of atropine and cimetidine. The ethyl acetate fraction, obtained by chromatography from Styrax camporum Pohl extracts, showed antiulcer activity. The subchronic toxicity was studied during 30 days, through weight variation, water and food consumption and spleen, lung, kidney and liver relative weights. No difference to the control-lot was observed.