The Effect of Pedal Pump Lymphatic Technique Versus Passive Recovery Following Maximal Exercise: A Randomized Cross-Over Trial

Context Muscle damage and delayed onset muscle soreness (DOMS) can occur following intense exercise. Various modalities have been studied to improve blood lactate accumulation, which is a primary reason for DOMS. It has been well established that active recovery facilitates blood lactate removal more rapidly that passive recovery due to the pumping action of the muscle. The pedal pump is a manual lymphatic technique used in osteopathic manipulative medicine to increase lymphatic drainage throughout the body. Pedal pump has been shown to increase lymphatic flow and improve immunity. This may improve circulation and improve clearance of metabolites post-exercise. Objective This study compared the use of pedal pump lymphatic technique to passive supine recovery following maximal exercise. Methods 17 subjects (male n = 10, age 23 ± 3.01; female n = 7, age 24 ± 1.8), performed a maximal volume O2 test (VO2 max) using a Bruce protocol, followed by a recovery protocol using either pedal pump technique or supine passive rest for 10 min, followed by sitting for 10 min. Outcome measures included blood lactate concentration (BL), heart rate (HR), systolic blood pressure (SBP) and VO2. Subjects returned on another day to repeat the VO2 max test to perform the other recovery protocol. All outcomes were measured at rest, within 1- minute post-peak exercise, and at minutes 4, 7, 10 and 20 of the recovery protocols. A 2 × 6 repeated measures ANOVA was used to compare outcome measures (p ≤ 0.05). Results No significant differences were found in VO2, HR, or SBP between any of the recovery protocols. There was no significant difference in BL concentrations for recovery at minutes 4, 7, or 10 (p > 0.05). However, the pedal pump recovery displayed significantly lower BL concentrations at minute 20 of recovery (p = 0.04). Conclusion The pedal pump significantly decreased blood lactate concentrations following intense exercise at recovery minute 20. The use of manual lymphatic techniques in exercise recovery should be investigated further.

Metabolic, Cardiac, and Hemorheological Responses to Submaximal Exercise under Light and Moderate Hypobaric Hypoxia in Healthy Men

We compared the effects of metabolic, cardiac, and hemorheological responses to submaximal exercise under light hypoxia (LH) and moderate hypoxia (MH) versus normoxia (N). Ten healthy men (aged 21.3 ± 1.0 years) completed 30 min submaximal exercise corresponding to 60% maximal oxygen uptake at normoxia on a cycle ergometer under normoxia (760 mmHg), light hypoxia (596 mmHg, simulated 2000 m altitude), and moderate hypoxia (526 mmHg, simulated 3000 m altitude) after a 30 min exposure in the respective environments on different days, in a random order. Metabolic parameters (oxygen saturation (SPO2), minute ventilation, oxygen uptake, carbon dioxide excretion, respiratory exchange ratio, and blood lactate), cardiac function (heart rate (HR), stroke volume, cardiac output, and ejection fraction), and hemorheological properties (erythrocyte deformability and aggregation) were measured at rest and 5, 10, 15, and 30 min after exercise. SPO2 significantly reduced as hypoxia became more severe (MH > LH > N), and blood lactate was significantly higher in the MH than in the LH and N groups. HR significantly increased in the MH and LH groups compared to the N group. There was no significant difference in hemorheological properties, including erythrocyte deformability and aggregation. Thus, submaximal exercise under light/moderate hypoxia induced greater metabolic and cardiac responses but did not affect hemorheological properties.

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.

Muscle Oxygenation, Heart Rate, and Blood Lactate Concentration During Submaximal and Maximal Interval Swimming

This study aimed to determine the relationship between three testing procedures during different intensity interval efforts in swimming. Twelve national-level swimmers of both genders executed, on different occasions and after a standardized warm-up, a swimming protocol consisting of either a submaximal (Submax: 8 efforts of 50 m) or a maximal interval (Max: 4 efforts of 15 m), followed by two series of four maximal 25 m efforts. Near-infrared spectroscopy in terms of muscle oxygen saturation (SmO2), heart rate (HR), and blood lactate concentration (BLa) were analyzed at three testing points: after the Submax or the Max protocol (TP1), after the 1st 4 × 25-m (TP2), and after the 2nd maximal 4 × 25-m set (TP3). BLa and HR showed significant changes during all testing points in both protocols (P ≤ 0.01; ES range: 0.45–1.40). SmO2 was different only between TP1 and TP3 in both protocols (P ≤ 0.05–0.01; ES range: 0.36–1.20). A large correlation during the Max protocol between SmO2 and HR (r: 0.931; P ≤ 0.01), and also between SmO2 and BLa was obtained at TP1 (r: 0.722; P ≤ 0.05). A range of moderate-to-large correlations was revealed for SmO2/HR, and BLa/HR for TP2 and TP3 after both protocols (r range: 0.595–0.728; P ≤ 0.05) were executed. SmO2 is a novel parameter that can be used when aiming for a comprehensive evaluation of competitive swimmers' acute responses to sprint interval swimming, in conjunction with HR and BLa.

Justification of the choice of indicators for assessing load hypoxia in humans and laboratory animals

In a study on healthy athletes of the track and field profile, it was shown that the hypoxia of physical activity is most fully reflected by the indicator of specific oxygen debt (maximum oxygen debt divided by 1000 J of work performed). When simulating load hypoxia in laboratory animals, direct registration of the arising oxygen debt is technically difficult to implement, and its indirect signs may be a decrease in peripheral blood saturation, excessive tachycardia, and hyperlactatemia of the post-load period. Key words: hypoxia of physical activity, oxygen debt, athletes, laboratory animals, blood lactate, physical activity.

Effects of Light Pedaling Added to Contrast Water Immersion for Recovery after Exhaustive Exercise

For years, athletes and coaches have been looking for new strategies to optimize post-exercise recovery; it has recently been suggested that combining several methods might be a great option. This study therefore aimed to investigate the efficacy of contrast water therapy (CWT) used alone or associated with pedaling to recover from exhaustive exercise. After high-intensity intermittent exercise, 33 participants underwent 30 min of either (i) passive rest (PASSIVE), (ii) CWT with pedaling while in water (COMB) or (iii) classic CWT (CWT). Blood lactate concentration, countermovement jump height and perceived exhaustion were recorded before exercise, immediately after, after recovery interventions and after an additional 30 min of passive rest. Blood lactate concentration returned to initial values after 30 min of COMB (5.9 mmol/L), whereas in the other conditions even 60 min was not enough (10.2 and 9.6 mmol/L for PASSIVE and CWT, respectively, p < 0.05). Jump height was close to initial values after 30 min of CWT (37.3 cm), whereas values were still depressed after 60 min in the PASSIVE (36.0 cm) and COMB (35.7 cm) conditions (p < 0.05). Perceived exertion was still high for all conditions after 60 min. The present results are in favor of the utilization of CWT after exhaustive exercise, but the modality has to be chosen depending on what comes next (subsequent exercise scheduled in the following hours or further away).

Blood lactate concentration in COVID-19: a systematic literature review

Coronavirus disease 2019 (COVID-19) is an infectious respiratory condition sustained by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which manifests prevalently as mild to moderate respiratory tract infection. Nevertheless, in a number of cases the clinical course may deteriorate, with onset of end organ injury, systemic dysfunction, thrombosis and ischemia. Given the clinical picture, baseline assessment and serial monitoring of blood lactate concentration may be conceivably useful in COVID-19. We hence performed a systematic literature review to explore the possible association between increased blood lactate levels, disease severity and mortality in COVID-19 patients, including comparison of lactate values between COVID-19 and non-COVID-19 patients. We carried out an electronic search in Medline and Scopus, using the keywords “COVID-19” OR “SARS-CoV-2” AND “lactate” OR “lactic acid” OR “hyperlactatemia”, between 2019 and present time (i.e. October 10, 2021), which allowed to identify 19 studies, totalling 6,459 patients. Overall, we found that COVID-19 patients with worse outcome tend to display higher lactate values than those with better outcome, although most COVID-19 patients in the studies included in our analysis did not have sustained baseline hyperlactatemia. Substantially elevated lactate values were neither consistently present in all COVID-19 patients who developed unfavourable clinical outcomes. These findings suggest that blood lactate monitoring upon admission and throughout hospitalization may be useful for early identification of higher risk of unfavourable COVID-19 illness progression, though therapeutic decisions based on using conventional hyperlactatemia cut-off values (i.e., 2.0 mmol/L) upon first evaluation may be inappropriate in patients with SARS-CoV-2 infection.