José L. Chicharro

Saliva Composition and Exercise

Little attention has been directed toward identifying the changes which occur in salivary composition in response to exercise. To address this, our article first refers to the main aspects of salivary gland physiology. A knowledge of the neural control of salivary secretion is especially important for the understanding of the effects of exertion on salivary secretion. Both salivary output and composition depend on the activity of the autonomic nervous system and any modification of this activity can be observed indirectly by alterations in the salivary excretion.The effects of physical activity (with reference to factors such as exercise intensity and duration, or type of exercise protocol) on salivary composition are then considered. Exercise might indeed induce changes in several salivary components such as immunoglobulins, hormones, lactate, proteins and electrolytes. Saliva composition might therefore be used as an alternative noninvasive indicator of the response of the different body tissues and systems to physical exertion.In this respect, the response of salivary amylase and salivary electrolytes to incremental levels of exercise is of particular interest. Beyond a certain intensity of exercise, and coinciding with the accumulation of blood lactate (anaerobic threshold or AT), a ’saliva threshold’ (Tsa) does indeed exist. Tsa is the point during exercise at which the levels of salivary α-amylase and electrolytes (especially Na+) also begin to rise above baseline levels. The occurrence of the 2 thresholds (AT and Tsa) might, in turn, be attributable to the same underlying mechanism, that of increased adrenal sympathetic activity at high exercise intensities.

Analysis of the aerobic-anaerobic transition in elite cyclists during incremental exercise with the use of electromyography.

OBJECTIVES: To investigate the validity and reliability of surface electromyography (EMG) as a new non-invasive determinant of the metabolic response to incremental exercise in elite cyclists. The relation between EMG activity and other more conventional methods for analysing the aerobic-anaerobic transition such as blood lactate measurements (lactate threshold (LT) and onset of blood lactate accumulation (OBLA)) and ventilatory parameters (ventilatory thresholds 1 and 2 (VT1 and VT2)) was studied. METHODS: Twenty eight elite road cyclists (age 24 (4) years; VO2MAX 69.9 (6.4) ml/kg/min; values mean (SD)) were selected as subjects. Each of them performed a ramp protocol (starting at 0 W, with increases of 5 W every 12 seconds) on a cycle ergometer (validity study). In addition, 15 of them performed the same test twice (reliability study). During the tests, data on gas exchange and blood lactate levels were collected to determine VT1, VT2, LT, and OBLA. The root mean squares of EMG signals (rms-EMG) were recorded from both the vastus lateralis and the rectus femoris at each intensity using surface electrodes. RESULTS: A two threshold response was detected in the rms-EMG recordings from both muscles in 90% of subjects, with two breakpoints, EMGT1 and EMGT2, at around 60-70% and 80-90% of VO2MAX respectively. The results of the reliability study showed no significant differences (p > 0.05) between mean values of EMGT1 and EMGT2 obtained in both tests. Furthermore, no significant differences (p > 0.05) existed between mean values of EMGT1, in the vastus lateralis and rectus femoris, and VT1 and LT (62.8 (14.5) and 69.0 (6.2) and 64.6 (6.4) and 68.7 (8.2)% of VO2MAX respectively), or between mean values of EMGT2, in the vastus lateralis and rectus femoris, and VT2 and OBLA (86.9 (9.0) and 88.0 (6.2) and 84.6 (6.5) and 87.7 (6.4)% of VO2MAX respectively). CONCLUSION: rms-EMG may be a useful complementary non-invasive method for analysing the aerobic-anaerobic transition (ventilatory and lactate thresholds) in elite cyclists.

Hormone levels of world class cyclists during the Tour of Spain stage race

Objectives—To evaluate the hormonal response to strenuous endurance exercise performed by elite athletes. Methods—Nine professional cyclists (mean (SD) age 28 (1) years; mean (SD) Vo2max 75.3 (2.3) ml/kg/min) who participated in a three week tour race (Vuelta a España 1999) were selected as subjects. Morning urinary levels of 6-sulphatoxymelatonin (aMT6s) and morning serum levels of testosterone, follicle stimulating (FSH), luteinising hormone (LH), and cortisol were measured in each subject at t0 (before the competition), t1 (end of first week), t2 (end of second week), and t3 (end of third week). Urine samples of aMT6s were also evaluated in the evening at t0, t1, t2, and t3. Results—Mean urinary aMT6s levels had increased significantly (p<0.01) during the day after each stage (1091 (33) v 683 (68) ng/ml at t1; 955 (19) v 473 (53) ng/ml at t2; 647 (61) v 337 (47) ng/ml at t3). Both morning and evening aMT6s levels decreased significantly during the study. A similar pattern was observed for morning serum levels of cortisol and testosterone. Conclusions—The results suggest that the basal activity of the pineal gland, adrenal glands, and testis may be decreased after consecutive days of intense, long term exercise.

Short-term effects of marathon running: no evidence of cardiac dysfunction

PURPOSE The purpose of this study was to analyze the short-term effects of a marathon race (Madrid Marathon) on both markers of cardiac damage and echocardiographic parameters in a group of 22 runners (17 male and 5 female; 34 +/- 5 yr; VO2max: 55.7 +/- 9.1 mL x kg(-1) x min(-1) with a wide range of fitness levels. METHODS Venous blood samples were collected from each subject 48 h before the race, at race finish, and 6, 24, and 48 h postexercise for the determination of myoglobin, total creatine kinase catalytic activity (total CK), mass concentration of creatine kinase isoenzyme MB (CK-MB mass), and cardiac isoforms of troponin T and I (TnT-c and TnI-c, respectively). In addition, echocardiographic parameters (M-mode two-dimensional and Doppler analysis) indicative of both left ventricular (LV) systolic and diastolic function were obtained three times from each runner: 2-5 d before the race, at race finish, and 24-36 h after exercise. RESULTS Except in one subject, levels of TnT-c and TnI-c were within normal limits (<0.1 ng x mL(-1)) in all the samples collected before or after the race. Overall LV systolic function was not altered by marathon running. Finally, LV diastolic function was transiently altered after the race since the ratio between peak early and late transmitral filling velocities (E/A) was significantly reduced at race finish (P < 0.01) and returned to resting levels after 24-36 h. CONCLUSIONS Our findings suggest that marathon running does not adversely affect the hearts of healthy individuals independently from their training status.

Trace elements and electrolytes in human resting mixed saliva after exercise.

OBJECTIVES: Exercise is known to cause changes in the concentration of salivary components such as amylase, Na, and Cl. The aim of this investigation was to evaluate the effect of physical exercise on the levels of trace elements and electrolytes in whole (mixed) saliva. METHODS: Forty subjects performed a maximal exercise test on a cycle ergometer. Samples of saliva were obtained before and immediately after the exercise test. Sample concentrations of Fe, Mg, Sc, Cr, Mn, Co, Cu, Zn, Se, Sr, Ag, Sb, Cs, and Hg were determined by inductively coupled plasma mass spectrometry and concentrations of Ca and Na by atomic absorption spectrometry. RESULTS: After exercise, Mg and Na levels showed a significant increase (p < 0.05) while Mn levels fell (p < 0.05). Zn/Cu molar ratios were unaffected by exercise. CONCLUSIONS: Intense physical exercise induced changes in the concentrations of only three (Na, Mg, and Mn) of the 16 elements analysed in the saliva samples. Further research is needed to assess the clinical implications of these findings.

The slow component of VO2 in professional cyclists.

Objectives—To analyse the slow component of oxygen uptake (V̇o2) in professional cyclists and to determine whether this phenomenon is due to altered neuromuscular activity, as assessed by surface electromyography (EMG). Methods—The following variables were measured during 20 minute cycle ergometer tests performed at about 80% of V̇o2max in nine professional road cyclists (mean (SD) age 26 (2) years; V̇o2max 72.6 (2.2) ml/kg/min): heart rate (HR), gas exchange variables (V̇o2, ventilation (V̇e), tidal volume (VT), breathing frequency (fb), ventilatory equivalents for oxygen and carbon dioxide (V̇e/V̇o2 and V̇e/V̇co2 respectively), respiratory exchange ratio (RER), and end tidal Po2 and Pco2 (Peto2 and Petco2 respectively)), blood variables (lactate, pH, and [HCO3−]) and EMG data (root mean from square voltage (rms-EMG) and mean power frequency (MPF)) from the vastus lateralis muscle. Results—The mean magnitude of the slow component (from the end of the third minute to the end of exercise) was 130 (0.04) ml in 17 minutes or 7.6 ml/min. Significant increases from three minute to end of exercise values were found for the following variables: V̇o2 (p<0.01), HR (p<0.01), V̇e (p<0.05), fb (p<0.01), V̇e/V̇o2 (p<0.05), V̇e/V̇co2 (p<0.01), Peto2 (p<0.05), and blood lactate (p<0.05). In contrast, rms-EMG and MPF showed no change (p>0.05) throughout the exercise tests. Conclusions—A significant but small V̇o2 slow component was shown in professional cyclists during constant load heavy exercise. The results suggest that the primary origin of the slow component is not neuromuscular factors in these subjects, at least for exercise intensities up to 80% of V̇o2max.

Breathing pattern in highly competitive cyclists during incremental exercise

Abstract The purpose of our investigation was to analyse the breathing patterns of professional cyclists during incremental exercise from submaximal to maximal intensities. A group of 11 elite amateur male road cyclists [E, mean age 23 (SD 2) years, peak oxygen uptake (V˙O2peak) 73.8 (SD 5.0) ml · kg−1 · min−1] and 14 professional male road cyclists [P, mean age 26 (SD 2) years, (V˙O2peak) 73.2 (SD 6.6) ml · kg−1 · min−1] participated in this study. Each of the subjects performed an exercise test on a cycle ergometer following a ramp protocol (exercise intensity increases of 25 W · min−1) until the subject was exhausted. For each subject, the following parameters were recorded during the tests: oxygen consumption (V˙O2), carbon dioxide output (V˙CO2), pulmonary ventilation (V˙E), tidal volume (VT), breathing frequency (fb), ventilatory equivalents for oxygen (V˙E·V˙O2−1) and carbon dioxide (V˙E·V˙CO2−1), end-tidal partial pressure of oxygen and partial pressure of carbon dioxide, inspiratory (tI) and expiratory (tE) times, inspiratory duty cycle (tI/tTOT, where tTOT is the time for one respiratory cycle), and mean inspiratory flow rate (VT/tI). Mean values of V˙E were significantly higher in E at 300, 350 and 400 W (P < 0.05, P < 0.05 and P < 0.01, respectively); fb was also higher in E in most moderate-to-maximal intensities. On the other hand, VT showed a different pattern in both groups at near-to maximal intensities, since no plateau was observed in P. The response of tI and tE was also different. Finally, VT/tI and tI/tTOT showed a similar response in both P and E. It was concluded that the breathing pattern of the two groups differed mainly in two aspects: in the professional cyclists, V˙E increased at any exercise intensity as a result of increases in both VT and fb, with no evidence of tachypnoeic shift, and tE was prolonged in this group at high exercise intensities. In contrast, neither the central drive nor the timing component of respiration seem to have been significantly altered by the training demands of professional cycling.

Relation between physical exertion and heart rate variability characteristics in professional cyclists during the Tour of Spain

Background: Continued exposure to prolonged periods of intense exercise may unfavourably alter neuroendocrine, neuromuscular, and cardiovascular function. Objective: To examine the relation between quantifiable levels of exertion (TRIMPS) and resting heart rate (HR) and resting supine heart rate variability (HRV) in professional cyclists during a three week stage race. Method: Eight professional male cyclists (mean (SEM) age 27 (1) years, body mass 65.5 (2.3) kg, and maximum rate of oxygen consumption (V˙o2max) 75.6 (2.2) ml/kg/min) riding in the 2001 Vuelta a España were examined for resting HR and HRV on the mornings of day 0 (baseline), day 10 (first rest day), and day 17 (second rest day). The rest days followed stages 1–9 and 10–15 respectively. HR was recorded during each race stage, and total HR time was categorised into a modified, three phase TRIMPS schema. These phases were based on standardised physiological laboratory values obtained during previous V˙o2max testing, where HR time in each phase (phase I  =  light intensity and less than ventilatory threshold (VT; ∼70% V˙o2max); phase II  =  moderate intensity between VT and respiratory compensation point (RCP; ∼90% V˙o2max); phase III  =  high intensity (>RCP)) was multiplied by exertional factors of 1, 2, and 3 respectively. Results: Multivariate analysis of variance showed that total TRIMPS for race stages 1–9 (2466 (90)) were greater than for stages 10–15 (2055 (65)) (p<0.0002). However, TRIMPS/day were less for stages 1–9 (274 (10)) than for stages 10–15 (343 (11)) (p<0.01). Despite a trend to decline, no difference in supine resting HR was found between day 0 (53.2 (1.8) beats/min), day 10 (49.0 (2.8) beats/min), and day 17 (48.0 (2.6) beats/min) (p  =  0.21). Whereas no significant group mean changes in HR or HRV indices were noted during the course of the race, significant inverse Pearson product-moment correlations were observed between all HRV indices relative to total TRIMPS and TRIMPS/day accumulated in race stages 10–15. Total TRIMPS correlated with square root of mean squared differences of successive RR intervals (r  =  −0.93; p<0.001), standard deviation of the RR intervals (r  =  −0.94; p<0.001), log normalised total power (r  =  −0.97; p<0.001), log normalised low frequency power (r  =  −0.79; p<0.02), and log normalised high frequency power (r  =  −0.94; p<0.001). Conclusion: HRV may be strongly affected by chronic exposure to heavy exertion. Training volume and intensity are necessary to delineate the degree of these alterations.

Kinetics of VO(2) in professional cyclists.

PURPOSE To analyze the kinetics of oxygen uptake (VO(2)) in professional road cyclists during a ramp cycle ergometer test and to compare the results with those derived from well-trained amateur cyclists. METHODS Twelve professional cyclists (P group; 25 +/- 1 yr; maximal power output (W(max)), 508.3 +/- 9.3 watts) and 10 amateur cyclists (A group; 22 +/- 1 y; W(max), 429.9 +/- 8.6 watts) performed a ramp test until exhaustion (power output increases of 25 watts x min(-1)). The regression lines of the VO(2):power output (W) relationship were calculated for the following three phases: phase I (below the lactate threshold (LT)), phase II (between LT and the respiratory compensation point (RCP)), and phase III (above RCP). RESULTS In group P, the mean slope (Delta VO(2):Delta W) of the VO(2):W relationship decreased significantly (P < 0.01) across the three phases (9.9 +/- 0.1, 8.9 +/- 0.2, and 3.8 +/- 0.6 mL O(2) x watts(-1) x min(-1) for phases I, II, and III, respectively). No significant differences (P > 0.05) were found between phases I and II (P > 0.05) in group A, whereas Delta VO(2):Delta W significantly increased in phase III (P < 0.01), compared with phase II (10.2 +/- 0.3, 9.2 +/- 0.4, and 10.1 +/- 1.1 mL O(2) x watts(-1) x min(-1) in phases I, II, and III, respectively). The mean value of Delta VO(2):Delta W for phase III was significantly lower in group P than in group A (P < 0.01). CONCLUSION Contrary to the case in amateur riders, the rise in VO(2) in professional cyclists is attenuated at moderate to high workloads. This is possibly an adaptation to the higher demands of their training/competition schedule.

Immunolabelling, histochemistry and in situ hybridisation in human skeletal muscle fibres to detect myosin heavy chain expression at the protein and mRNA level

The distribution of muscle fibres classified on the basis of their content of different myosin heavy chain (MHC) isoforms was analysed in vastus lateralis muscle biopsies of 15 young men (with an average age of 22 y) by correlating immunohistochemistry with specific anti‐MHC monoclonal antibodies, myofibrillar ATPase (mATPase) histochemistry and in situ hybridisation with probes specific for MHC β‐slow, MHC‐IIA and MHC‐IIX. The characterisation of a large number of individual fibres was compared and correlated on a fibre‐to‐fibre basis. The panel of monoclonal antibodies used in the study allowed classification of human skeletal muscle fibres into 5 categories according to the MHC isoform they express at the protein level, types I, I+IIA, IIA, IIAX and IIX. Hybrid fibres coexpressing two isoforms represented a considerable proportion of the fibre composition (about 14%) and were clearly underestimated by mATPase histochemistry. For a very high percentage of fibres there was a precise correspondence between the MHC protein isoforms and mRNA transcripts. The integrated methods used demonstrate a high degree of precision of the immunohistochemical procedure used for the identification and quantification of human skeletal muscle fibre types. The monoclonal antibody S5‐8H2 is particularly useful for identifying hybrid IIAX fibres. This protocol offers new prospects for muscle fibre classification in human experimental studies.