The Influence of Acute Sprint Interval Training on Cognitive Performance of Healthy Younger Adults

There is considerable evidence showing that an acute bout of physical exercises can improve cognitive performance, but the optimal exercise characteristics (e.g., exercise type and exercise intensity) remain elusive. In this regard, there is a gap in the literature to which extent sprint interval training (SIT) can enhance cognitive performance. Thus, this study aimed to investigate the effect of a time-efficient SIT, termed as “shortened-sprint reduced-exertion high-intensity interval training” (SSREHIT), on cognitive performance. Nineteen healthy adults aged 20–28 years were enrolled and assessed for attentional performance (via the d2 test), working memory performance (via Digit Span Forward/Backward), and peripheral blood lactate concentration immediately before and 10 minutes after an SSREHIT and a cognitive engagement control condition (i.e., reading). We observed that SSREHIT can enhance specific aspects of attentional performance, as it improved the percent error rate (F%) in the d-2 test (t (18) = −2.249, p = 0.037, d = −0.516), which constitutes a qualitative measure of precision and thoroughness. However, SSREHIT did not change other measures of attentional or working memory performance. In addition, we observed that the exercise-induced increase in the peripheral blood lactate levels correlated with changes in attentional performance, i.e., the total number of responses (GZ) (rm = 0.70, p < 0.001), objective measures of concentration (SKL) (rm = 0.73, p < 0.001), and F% (rm = −0.54, p = 0.015). The present study provides initial evidence that a single bout of SSREHIT can improve specific aspects of attentional performance and conforming evidence for a positive link between cognitive improvements and changes in peripheral blood lactate levels.

Changes in carbon dioxide production and oxygen uptake evaluated using indirect calorimetry in mechanically ventilated patients with sepsis

Background Several clinical guidelines recommend monitoring blood lactate levels and central venous oxygen saturation for hemodynamic management of patients with sepsis. We hypothesized that carbon dioxide production (VCO2) and oxygen extraction (VO2) evaluated using indirect calorimetry (IC) might provide additional information to understand the dynamic metabolic changes in sepsis. Methods Adult patients with sepsis who required mechanical ventilation in the intensive care unit (ICU) of our hospital between September 2019 and March 2020 were prospectively enrolled. Sepsis was diagnosed according to Sepsis-3. Continuous measurement of VCO2 and VO2 using IC for 2 h was conducted within 24 h after tracheal intubation, and the changes in VCO2 and VO2 over 2 h were calculated as the slopes by linear regression analysis. Furthermore, temporal lactate changes were evaluated. The primary outcome was 28-day survival. Results Thirty-four patients with sepsis were enrolled, 26 of whom survived 76%. Significant differences in the slope of VCO2 (− 1.412 vs. − 0.446) (p = 0.012) and VO2 (− 2.098 vs. − 0.851) (p = 0.023) changes were observed between non-survivors and survivors. Of note, all eight non-survivors and 17 of the 26 survivors showed negative slopes of VCO2 and VO2 changes. For these patients, 17 survivors had a median lactate of − 2.4% changes per hour (%/h), whereas non-survivors had a median lactate of 2.6%/hr (p = 0.023). Conclusions The non-survivors in this study showed temporal decreases in both VCO2 and VO2 along with lactate elevation. Monitoring the temporal changes in VCO2 and VO2 along with blood lactate levels may be useful in predicting the prognosis of sepsis.

Target blood pressure management during cardiopulmonary bypass improves lactate levels after cardiac surgery: a randomized controlled trial

Background Hyperlactatemia is associated with a poor prognosis in cardiac surgery patients. This study explored the impact of target blood pressure management during cardiopulmonary bypass (CPB) on blood lactate levels after cardiac surgery. Methods Adult patients undergoing cardiac valve surgery between 20/1/2020 and 30/6/2020 at Shanghai Chest Hospital were enrolled. The patients were randomized into a low mean arterial pressure (L-MAP) group (target MAP between 50 and 60 mmHg) or a high mean arterial pressure (H-MAP) group (target MAP between 70 and 80 mmHg), n = 20 for each. Norepinephrine was titrated only during CPB to maintain MAP at the target level. Blood lactate levels in the two groups were detected before the operation (T0), at the end of CPB (T1), at the end of the operation (T2), 1 h after the operation (T3), 6 h after the operation (T4) and 24 h after the operation (T5). The primary outcome was the blood lactate level at the end of the operation (T2). The secondary outcomes included the blood lactate level at T1, T3, T4, and T5 and the dose of epinephrine and dopamine within 24 h after the operation, time to extubation, length of stay in the ICU, incidence of readmission within 30 days, and mortality within 1 year. Results Forty patents were enrolled and analyzed in the study. The lactate level in the H-MAP group was significantly lower than that in the L-MAP group at the end of the operation (3.1 [IQR 2.1, 5.0] vs. 2.1 [IQR 1.7, 2.9], P = 0.008) and at the end of CPB and 1 hour after surgery. The dose of epinephrine within 24 h after the operation, time to extubation and length of stay in the ICU in the L-MAP group were significantly higher than those in the H-MAP group. Conclusions Maintaining a relatively higher MAP during CPB deceased the blood lactate level at the end of surgery, reduced epinephrine consumption, and shortened the time to extubation and length of stay in the ICU after surgery. Trial registration This single-center, prospective, RCT has completed the registration of the Chinese Clinical Trial Center at 8/1/2020 with the registration number ChiCTR2000028941. It was conducted from 20/1/2020 to 30/6/2020 as a single, blinded trial in Shanghai Chest Hospital.

Alteration of Blood Lactate Levels in Severe Falciparum Malaria: A Systematic Review and Meta-Analysis

Metabolic acidosis in severe malaria usually occurs in the form of lactic acidosis. The present study aimed to collate articles from the literature that have reported blood lactate levels in patients with severe malaria and tested the hypothesis that blood lactate levels are elevated in patients with malaria compared to those with uncomplicated malaria. Moreover, the difference in lactate levels between patients who died and those who survived was estimated using a meta-analytic approach. Potentially relevant studies were searched for in PubMed, Web of Science, and Scopus. The quality of the included studies was assessed using the Jadad scale and strengthening the reporting of observational studies in epidemiology (STROBE). The pooled mean blood lactate in patients with severe malaria, the pooled weighted mean difference (WMD) of blood lactate between patients with severe malaria and those with uncomplicated malaria, and the pooled WMD and 95% CI of blood lactate between patients who died from and those who survived severe malaria were estimated using the random-effects model. Heterogeneity among the outcomes of the included studies was assessed using Cochran’s Q and I2 statistics. A meta-regression analysis was performed to identify the source(s) of heterogeneity of outcomes among the included studies. A subgroup analysis was further performed to separately analyze the outcomes stratified by the probable source(s) of heterogeneity. Publication bias was assessed by the visual inspection of the funnel plot asymmetry. Of 793 studies retrieved from the searches, 30 studies were included in qualitative and quantitative syntheses. The pooled mean lactate in patients with severe malaria was 5.04 mM (95% CI: 4.44–5.64; I2: 99.9%; n = 30,202 cases from 30 studies). The mean lactate in patients with severe malaria (1568 cases) was higher than in those with uncomplicated malaria (1693 cases) (p = 0.003; MD: 2.46; 95% CI: 0.85–4.07; I2: 100%; nine studies). The mean lactate in patients with severe malaria who died (272 cases) was higher than in those with severe malaria who survived (1370 cases) (p < 0.001; MD: 2.74; 95% CI: 1.74–3.75; I2: 95.8%; six studies). In conclusion, the present study showed a high mean difference in blood lactate level between patients with severe malaria and patients with uncomplicated malaria. In addition, there was a high mean difference in blood lactate level between patients with severe malaria who died compared to those with severe malaria who survived. Further studies are needed to investigate the prognostic value of blood lactate levels to identify patients who are at high risk of developing severe malaria or dying.

Do Blood Lactate Levels Affect the Kinematic Patterns of Jump Shots in Handball?

The aim of this study was to determine whether the dynamic motor stereotype of movement (shooting technique) is violated under conditions of an increased lactate concentration in a player's blood after a 30–15 intermittent fitness test. The hypotheses was that there would be statistically significant differences in ball speed and shooting accuracy in jump shots on the goal before and after the occurrence of fatigue in the player. The sample of respondents consisted of 10 top-level handball players of the highest competition rank in Croatia. The results showed significant differences before and after the fatigue protocol in the run-up speed (F = 5.66; p = 0.02), in the maximum speed of the forearm (F = 5.85; p = 0.02) and the hand (F = 4.01; p = 0.04), in the speed in the shoulder joint (F = 5.39; p = 0.02) and wrist joint (F = 4.06; p = 0.04), and in the ball shooting speed (F = 5.42; p = 0.02). The accuracy of the shot was, on average, lower (36.20 vs. 33.17 cm) but not significantly so. High blood lactate levels affect changes in certain kinematic parameters during the performance of a jump shot in handball. Consequently, this reduces the speed of the shot, which can affect situational performance as one of the two significant parameters of scoring success.

A Novel Approach to Safe Special Fitness Testing in Judo Players

Background: Measurements of physical fitness indices obtained in laboratory tests using an ergometer or a treadmill are very accurate, but they involve selected groups of muscles and do not reproduce the structure of the sport-specific exercise in judo. For this reason, researchers seek for the tests that use movements similar to the characteristic offensive techniques used during competitions (i.e. throwing). The most commonly recommended is the seoi-nage throwing test, known as SJFT (special judo fitness test).The aim of the study was to develop a new test in which uke is replaced by a dummy, in order to reduce the injury rate and ensure the safety of the participants.Methods: During the 3-week period, competitors from different weight classes performed at the beginning and then after the 2-week period one 1-minute series of continual dummy throws using the o-goshi technique and the seoi-nage technique. Post-exercise physiological responses (heart rate [HR] and blood lactate levels [La]) were evaluated.Results: Significant improvements were reported in o-goshi performance level after the training period. Physiological responses to exercise did not change significantly after training sessions. On both measurement days, post-exercise La levels were similar for o-goshi and seoi-nage throws, whereas post-exercise HR was significantly greater after seoi-nage throws.Conclusions: The dummy throwing test can be a recommended alternative to uke throwing due to the elimination of the risk of injuries to practising athletes.

Effects of General Fatigue Induced by Exhaustive Exercise on Posture and Gait Stability of Healthy Young Men

Bipedal walking is a composite task requiring integration of many control circuitries in the brain and spinal cord. The present study was carried out to verify whether an increase in blood lactate, such as that associated with a high intensity exercise, is able to significantly modify the qualitative and/or quantitative aspects of human walking. Eighteen healthy physically male participants, aged between 20 and 24 years (M = 21.8, SD = 1.22), were recruited for the study. For this purpose, the experimental protocol included the measure of blood lactate levels with the aim of assessing possible relations between lactate blood values and different aspect of walking after an exhaustive exercise. An exhaustive exercise was associated with a strong increase of blood lactate levels and produced a significant worsening in the ability to maintain the bipodalic upright posture as well as the fluidity of walking. Our results suggest that exhausting bouts impose greater challenges on postural control.

The Influence of Acute Sprint Interval Training on Cognitive Performance of Healthy Younger Adults

Considerable evidence has been accumulated showing that an acute bout of physical exercise can improve cognitive performance but the optimal exercise characteristics (e.g., exercise type and intensity) remain elusive. In this regard, there is a gap in the literature to which extent Sprint Interval Training (SIT) can enhance cognitive performance. Thus, this study aimed to investigate the effect of SIT on cognitive performance. We assessed in healthy younger adults (n = 19; 20.0 to 28.0 years old), the attentional performance (via d2 test), the working memory performance (via Digit Span Forward/ Backward) and the peripheral blood lactate concentration immediately before and 10 minutes after an exercise condition (SIT) and a control condition (i.e., reading). We observed that SIT can enhance specific aspects of attentional performance as it improved F% (t (19) = -2.249, p = 0.037, d = − 0.516) which constitutes a qualitative measure of precision and thoroughness. However, SIT did not change other measures of attentional or working memory performance. In addition, we observed that the exercise-induced increase in peripheral blood lactate levels correlated with changes in attentional performance (e.g., F% (rm = -0.54, p = 0.015)). The present study provides initial evidence that a time-efficient SIT can improve specific aspects of attentional performance and conforming evidence for a positive link between cognitive improvements and changes in peripheral blood lactate levels. Further research is warranted to substantiate our findings by investigating (i) the optimal exercise characteristics (e.g., number of sprints), (ii) further neurobiological mechanisms driving the cognitive improvements (e.g., changes in functional brain activation patterns), and (iii) the generalizability of the effects (e.g., older adults).