Biomedical subjects

V Baldissera

Publications and source records attributed to V Baldissera.

5 recordsLinked to original sources

PubMed2006

L-carnitine as an ergogenic aid for patients with chronic obstructive pulmonary disease submitted to whole-body and respiratory muscle training programs.

The effects of adding L-carnitine to a whole-body and respiratory training program were determined in moderate-to-severe chronic obstructive pulmonary disease (COPD) patients. Sixteen COPD patients (66 +/- 7 years) were randomly assigned to L-carnitine (CG) or placebo group (PG) that received either L-carnitine or saline solution (2 g/day, orally) for 6 weeks (forced expiratory volume on first second was 38 +/- 16 and 36 +/- 12%, respectively). Both groups participated in three weekly 30-min treadmill and threshold inspiratory muscle training sessions, with 3 sets of 10 loaded inspirations (40%) at maximal inspiratory pressure. Nutritional status, exercise tolerance on a treadmill and six-minute walking test, blood lactate, heart rate, blood pressure, and respiratory muscle strength were determined as baseline and on day 42. Maximal capacity in the incremental exercise test was significantly improved in both groups (P < 0.05). Blood lactate, blood pressure, oxygen saturation, and heart rate at identical exercise levels were lower in CG after training (P < 0.05). Inspiratory muscle strength and walking test tolerance were significantly improved in both groups, but the gains of CG were significantly higher than those of PG (40 +/- 14 vs 14 +/- 5 cmH2O, and 87 +/- 30 vs 34 +/- 29 m, respectively; P < 0.05). Blood lactate concentration was significantly lower in CG than in PG (1.6 +/- 0.7 vs 2.3 +/- 0.7 mM, P < 0.05). The present data suggest that carnitine can improve exercise tolerance and inspiratory muscle strength in COPD patients, as well as reduce lactate production.

Aged↗

PubMed2005

Relationships and significance of lactate minimum, critical velocity, heart rate deflection and 3 000 m track-tests for running.

AIM: The running velocities associated to lactate minimum (V(lm)), heart rate deflection (V(HRd)), critical velocity (CV), 3.000 m (V(3000)) and 10 000 m performance (V10km) were compared. Additionally the ability of V(lm) and V(HRd) on identifying sustainable velocities was investigated. METHODS: Twenty runners (28.5+/-5.9 y) performed 1) 3,000 m running test for V3000; 2) an all-out 500 m sprint followed by 6x800 m incremental bouts with blood lactate ([lac]) measurements for V(lm); 3) a continuous velocity-incremented test with heart rate measurements at each 200 m for V(HRd); 4) participants attempted to 30 min of endurance test both at V(lm)(ETV(lm)) and V(HRd)(ETV(HRd)). Additionally, the distance-time and velocity-1/time relationships produced CV by 2 (500 m and 3 000 m) or 3 predictive trials (500 m, 3,000 m and distance reached before exhaustion during ETV(HRd)), and a 10 km race was recorded for V10km. RESULTS: The CV identified by different methods did not differ to each other. The results (m.min(-1)) revealed that V(lm) (281+/-14.8)<CV (292.1+/-17.5)=V10km (291.7+/-19.3)<V(HRd) (300.8+/-18.7)=V3000 (304+/-17.5) with high correlation among parameters (P<0.001). During ETVlm participants completed 30 min of running while on the ETV(HRd) they lasted only 12.5+/-8.2 min with increasing [lac]. CONCLUSIONS: We evidenced that CV and Vlm track-protocols are valid for running evaluation and performance prediction and the parameters studied have different significance. The V(lm) reflects the moderate-high intensity domain (below CV), can be sustained without [lac] accumulation and may be used for long-term exercise while the V(HRd)overestimates a running intensity that can be sustained for long-time. Additionally, V3000 and V(HRd) reflect the severe intensity domain (above CV).

Adult↗

PubMed2004

Lactate and glucose minimum speeds and running performance.

This study aimed to analyse the validity of glucose minimum speed (GMS) for lactate minimum speed (LMS) assessment during running and their relationship to endurance performance. Eight male trained runners (28.7 +/- 9.0 years) volunteered to take part in this study and underwent an official 10-km road race and a track lactate minimum test (LMT) (0.5-km sprint plus 6 x 800 m from 87 to 98% of maximal 3-km speed). Lactate and glucose minimum speeds were considered those related to the minimum blood lactate and glucose concentrations respectively attained during the graded phase of LMT. Significant correlations (p < 0.05) were found between LMS and GMS (r = 0.72) and LMS and 10-km performance (r = 0.83), but not between GMS and 10-km performance (r = 0.49). No significant differences (p > 0.05) were found between LMS (4.75 +/- 0.08 m/s), GMS (4.73 +/- 0.07 m/s) and 10-km mean speed (4.79 +/- 0.17 m/s). In conclusion, we found GMS to be a good predictor of LMS during track LMT, LMS being well related to endurance running performance.

Adult↗

PubMed2003

Stage length, spline function and lactate minimum swimming speed.

AIM: Lactate minimum test (LMT) has become popular in running evaluation. This study analysed the influence of different stage lengths and determination methods on lactate minimum swimming speed (LMS) and its validity for maximal lactate steady-state speed (MLSS-S) assessment. METHODS: Twelve male swimmers (19.7+/-1.6 years, 70.3+/-8.7 kg, 181.4+/-7.9 cm) randomly underwent 4-5 evaluations in a 2-week period. LMS was accessed by simple visualisation (SV) and spline function (SF) methods during 200 and 300 m stages LMT (LMT200 and LMT300, respectively), and MLSS-S was determined during constant speed 2000 m efforts. RESULTS: Respectively, SV and SF provided LMS during LMT200 (1.31+/-0.12 m x s-1 and 1.32+/-0.10 m x sec-1) and LMT300 (1.28+/-0.11 m x sec-1 and 1.28+/-0.10 m x sec-1) which were not significantly different (p>0.05) from each other. However, LMS accessed during LMT200 were significantly greater (p<0.05) than MLSS-S (1.25+/-0.06 m x sec-1). In addition, significant relationships (r=0.79 to 0.98; p<0.05) were found between all studied speeds and lactate minimum values during LMT300 were not significantly different (p>0.05) from those found during LMT200 (5.4+/-2.2 and 5.5+/-2.2 mM vs 6.8+/-2.5 and 7.0+/-2.6 mM, respectively for SV and SF). CONCLUSIONS: Our results suggest that LMS is not affected by different stage lengths and determination METHODS: However, LMT300 results seems to provide a more accurate MLSS-S prediction, being adequate for swimmers evaluation.

Adult↗

PubMed1999

Blood glucose responses in humans mirror lactate responses for individual anaerobic threshold and for lactate minimum in track tests.

The equilibrium point between blood lactate production and removal (La-(min)) and the individual anaerobic threshold (IAT) protocols have been used to evaluate exercise. During progressive exercise, blood lactate [La-]b, catecholamine and cortisol concentrations, show exponential increases at upper anaerobic threshold intensities. Since these hormones enhance blood glucose concentrations [Glc]b, this study investigated the [Glc] and [La-]b responses during incremental tests and the possibility of considering the individual glucose threshold (IGT) and glucose minimum (Glc(min)) in addition to IAT and La-(min) in evaluating exercise. A group of 15 male endurance runners ran in four tests on the track 3000 m run (v3km); IAT and IGT - 8 x 800 m runs at velocities between 84% and 102% of v3km; La-(min) and Glc(min) - after lactic acidosis induced by a 500-m sprint, the subjects ran 6 x 800 m at intensities between 87% and 97% of v3km; endurance test (ET) - 30 min at the velocity of IAT. Capillary blood (25 microl) was collected for [La-]b and [Glc]b measurements. The IAT and IGT were determined by [La-]b and [Glc]b kinetics during the second test. The La-(min) and Glc(min) were determined considering the lowest [La-] and [Glc]b during the third test. No differences were observed (P < 0.05) and high correlations were obtained between the velocities at IAT [283 (SD 19) and IGT 281 (SD 21) m. x min(-1); r = 0.096; P < 0.001] and between La-(min) [285 (SD 21)] and Glc(min) [287 (SD 20) m. x min(-1) r = 0.77; P < 0.05]. During ET, the [La-]b reached 5.0 (SD 1.1) and 5.3 (SD 1.0) mmol x l(-1) at 20 and 30 min, respectively (P > 0.05). We concluded that for these subjects it was possible to evaluate the aerobic capacity by IGT and Glc(min) as well as by IAT and La-(min).

Adult↗