Relationship of potassium ions and blood lactate to ventilation during exercise

2010 ◽  
Vol 35 (5) ◽  
pp. 691-698
Author(s):  
Robert G. McMurray ◽  
Matthew S. Tenan
Keyword(s):  
Blood Lactate ◽  
Exercise Intensity ◽  
Minute Ventilation ◽  
Potassium Ions ◽  
Ventilatory Control ◽  
Volitional Fatigue ◽  
Relationship Of ◽  
Glycogen Stores ◽  
The Relationship ◽  
Recent Attention

Ventilatory control during exercise is a complex network of neural and humoral signals. One humoral input that has received little recent attention in the exercise literature is potassium ions [K+]. The purpose of this study was to examine the relationship between [K+] and ventilation during an incremental cycle test and to determine if the relationship between [K+] and ventilation differs when blood lactate [lac–] is manipulated. Eight experienced triathletes (4 of each sex) completed 2 incremental, progressive (5-min stages) cycle tests to volitional fatigue: 1 with normal glycogen stores and 1 with reduced glycogen. Minute ventilation was measured during the final minute of each stage, and blood [lac–] and [K+] were measured at the end of each exercise stage. Minute ventilation and [K+] increased with exercise intensity and were similar between trials (p > 0.5), despite lower [lac–] during the reduced-glycogen trial. The concordance correlations (Rc) between [lac–] and minute ventilation were stronger for both trials (Rc = ~0.88–0.96), but the slopes of the relationships were different than the relationships between [K+] and minute ventilation (Rc = ~0.76–0.89). The slope of the relationship between [lac–] and minute ventilation was not as steep during the reduced-glycogen trial, compared with the normal trial (p = 0.002). Conversely, the slope of the relationships between [K+] and minute ventilation did not change between trials (p = 0.454). The consistent relationship of minute ventilation and blood [K+] during exercise suggests a role for this ion in the control of ventilation during exercise. Conversely, the inconsistent relationship between blood lactate and ventilation brings into question the importance of the relationship between lactate and ventilation during exercise.

scholarly journals THE RELATIONSHIP OF SHORT-TERM MEASURES OF HRV TO HEART RATE AND EXERCISE INTENSITY 795

1997 ◽  
Vol 29 (Supplement) ◽  
pp. 138
Author(s):  
R. W. Thompson ◽  
J. W. Wilkinson ◽  
R. M.T. Laukkanan ◽  
T. Sepp??nen
Keyword(s):  
Heart Rate ◽  
Exercise Intensity ◽  
Short Term ◽  
Relationship Of ◽  
The Relationship

CO2 homeostasis during periodic breathing in obstructive sleep apnea

2000 ◽  
Vol 88 (1) ◽  
pp. 257-264 ◽  
Author(s):  
Kenneth I. Berger ◽  
Indu Ayappa ◽  
I. Barry Sorkin ◽  
Robert G. Norman ◽  
David M. Rapoport ◽  
...  
Keyword(s):  
Obstructive Sleep Apnea ◽  
Sleep Apnea ◽  
Minute Ventilation ◽  
Periodic Breathing ◽  
Obstructive Sleep ◽  
Interevent Interval ◽  
Relationship Of ◽  
The Relationship ◽  
Kinetics Of ◽  
Ventilation And Perfusion

The contribution of apnea to chronic hypercapnia in obstructive sleep apnea (OSA) has not been clarified. Using a model (D. M. Rapoport, R. G. Norman, and R. M. Goldring. J. Appl. Physiol. 75: 2302–2309, 1993), we previously illustrated failure of CO2 homeostasis during periodic breathing resulting from temporal dissociation between ventilation and perfusion (“temporal V˙/Q˙mismatch”). This study measures acute kinetics of CO2 during periodic breathing and addresses interapnea ventilatory compensation for maintenance of CO2 homeostasis in 11 patients with OSA during daytime sleep (37–171 min). Ventilation and expiratory CO2 and O2 fractions were measured on a breath-by-breath basis by means of a tight-fitting full facemask. Calculations included CO2excretion, metabolic CO2production, and CO2 balance (metabolic CO2 production − exhaled CO2). CO2 balance was tabulated for each apnea/hypopnea event-interevent cycle and as a cumulative value during sleep. Cumulative CO2 balance varied (−3,570 to +1,388 ml). Positive cumulative CO2 balance occurred in the absence of overall hypoventilation during sleep. For each cycle, positive CO2 balance occurred despite increased interevent ventilation to rates as high as 45 l/min. This failure of CO2 homeostasis was dependent on the event-to-interevent duration ratio. The results demonstrate that 1) periodic breathing provides a mechanism for acute hypercapnia in OSA, 2) acute hypercapnia during periodic breathing may occur without a decrease in average minute ventilation, supporting the presence of temporalV˙/Q˙ mismatch, as predicted from our model, and 3) compensation for CO2 accumulation during apnea/hypopnea may be limited by the duration of the interevent interval. The relationship of this acute hypercapnia to sustained chronic hypercapnia in OSA remains to be further explored.

Human ventilatory responsiveness to hypoxia is unrelated to maximal aerobic capacity

2006 ◽  
Vol 100 (4) ◽  
pp. 1204-1209 ◽  
Author(s):  
A. William Sheel ◽  
Michael S. Koehle ◽  
Jordan A. Guenette ◽  
Glen E. Foster ◽  
Benjamin C. Sporer ◽  
...  
Keyword(s):  
Aerobic Capacity ◽  
Minute Ventilation ◽  
Maximal Oxygen Consumption ◽  
Endurance Athletes ◽  
Physical Conditioning ◽  
Maximal Aerobic Capacity ◽  
Ventilatory Control ◽  
Wide Range ◽  
Per Se ◽  
The Relationship

Ventilatory responsiveness to hypoxia (HVR) has been reported to be different between highly trained endurance athletes and healthy sedentary controls. However, a linkage between aerobic capacity and HVR has not been a universal finding. The purpose of this study was to examine the relationship between HVR and maximal oxygen consumption (V̇o2 max) in healthy men with a wide range of aerobic capacities. Subjects performed a HVR test followed by an incremental cycle test to exhaustion. Participants were classified according to their maximal aerobic capacity. Those with a V̇o2 max of ≥60 ml·kg−1·min−1 were considered highly trained ( n = 13); those with a V̇o2 max of 50–60 ml·kg−1·min−1 were considered moderately-trained ( n = 18); and those with a V̇o2 max of <50 ml·kg−1·min−1 were considered untrained ( n = 24). No statistical differences were detected between the three groups for HVR ( P > 0.05), and the HVR values were variable within each group (range: untrained = 0.28–1.61, moderately trained = 0.23–2.39, and highly trained = 0.08–1.73 l·min·%arterial O2 saturation−1). The relationship between HVR and V̇o2 max was not statistically significant ( r = −0.1723; P > 0.05). HVR was also unrelated to maximal minute ventilation and ventilatory equivalents for O2 and CO2. We found that a spectrum of hypoxic ventilatory control is present in well-trained endurance athletes and moderately and untrained men. We interpret these observations to mean that other factors are more important in determining hypoxic ventilatory control than physical conditioning per se.

Relationship between ventilatory response and body temperature during prolonged submaximal exercise

2006 ◽  
Vol 100 (2) ◽  
pp. 414-420 ◽  
Author(s):  
Keiji Hayashi ◽  
Yasushi Honda ◽  
Takeshi Ogawa ◽  
Narihiko Kondo ◽  
Takeshi Nishiyasu
Keyword(s):  
Body Temperature ◽  
Oxygen Uptake ◽  
Skin Temperature ◽  
Blood Lactate ◽  
Core Temperature ◽  
Core Body Temperature ◽  
Minute Ventilation ◽  
Submaximal Exercise ◽  
Rate Of Increase ◽  
The Relationship

We examined whether an increase in skin temperature or the rate of increase in core body temperature influences the relationship between minute ventilation (V̇e) and core temperature during prolonged exercise in the heat. Thirteen subjects exercised for 60 min on a cycle ergometer at 50% of peak oxygen uptake while wearing a suit perfused with water at 10°C (T10), 35°C (T35), or 45°C (T45). During the exercise, esophageal temperature (Tes), skin temperature, heart rate (HR), V̇e, tidal volume, respiratory frequency (f), respiratory gases, blood pressure (BP), and blood lactate were all measured. We found that oxygen uptake, carbon dioxide output, BP, and blood lactate did not differ among the sessions. Tes, HR, V̇e, and f remained nearly constant from minute 10 onward in the T10 session, but all of these parameters progressively increased in the T35 and T45 sessions, and significantly higher levels were seen in the T45 than the T35 session. For all but two subjects in the T35 and T45 sessions, plotting V̇e as a function of Tes revealed no threshold for hyperventilation; instead, increases in V̇e were linearly related to Tes, and there were no significant differences in the slopes or intercepts between the T35 and T45 sessions. Thus, during prolonged submaximal exercise in the heat, V̇e increases with core temperature, and the influences of skin temperature and the rate of increase in Tes on the relationship between V̇e and Tes are apparently small.

Work and Love: Their Relationship in Adulthood

1993 ◽  
Vol 16 (4) ◽  
pp. 609-627 ◽  
Author(s):  
Sharan B. Merriam ◽  
M. Carolyn Clark
Keyword(s):  
Life Events ◽  
Qualitative Data ◽  
Healthy Adult ◽  
Adult Life ◽  
Ability To Work ◽  
Relational Patterns ◽  
Relationship Of ◽  
The Relationship ◽  
Depth Interviews ◽  
Recent Attention

The ability to work and to love, according to Freud, is what defines a healthy adult. Work and love have been studied extensively, but usually separately, although recent attention has been given to how to balance the two. There has been little research, however, that focuses on the relationship of one domain to the other. The purpose of this study was to uncover the ways in which work and love relate in adult life. Qualitative data were collected from 405 adults who charted their assessment, by year, of their work and loverelated life events. These data were augmented with data from 19 in-depth interviews. Three distinct relational patterns (parallel, steady/fluctuating, and divergent) of work and love were uncovered.

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