Research
Minute ventilation and heart rate relationship for estimation of the ventilatory compensation point at high altitude: a pilot study
1 Lung Function Unit, Department of Public Health and Infectious Diseases, University of Rome “La Sapienza”, viale Università 37, Rome, 00185, Italy
2 Biomedical Sport Studies Center, University of Ferrara, Via Gramicia 35, Ferrara, 44123, Italy
3 Eleonora Lorillard Spencer Cenci Foundation, Piazzale Aldo Moro n. 5, Rome, 00185, Italy
Extreme Physiology & Medicine 2013, 2:7 doi:10.1186/2046-7648-2-7
Published: 1 March 2013Abstract
Background
The ventilatory compensation point (VCP) is an exercise threshold which has been used
in the design of training programs in sports medicine and rehabilitation. We recently
demonstrated that changes in the slope of the minute ventilation to heart rate relationship
(
) can be utilized for estimation of the VCP during incremental exercise at sea level
(SL). We hypothesized that in hypoxic conditions, such as high altitude (HA), VCP
can be also reliably estimated by 
.
Methods
At SL and on immediate ascent to HA (5,050 m), six healthy subjects (42 ± 14 SD years)
performed a maximal incremental exercise test on a cycle ergometer; O2 uptake (
), CO2 output (
), 
, and HR were measured breath-by-breath. The 
method for VCP estimation was compared to the standard method using the ventilatory
equivalent for CO2 (
) and end-tidal PCO2 (PETCO2). The 
slope values below (S1) and above (S2) VCP were computed by linear regression analysis.
Results
A significant difference between S1 and S2 was observed, at SL and HA, for both the 
and 
methods for VCP estimation. A good agreement between the two methods (
vs. 
) was found for both environmental conditions; the mean difference ± 2 SD of 
at VCP (VCP-
) was −22 ± 112 ml/min at SL and 39 ± 81 ml/min at HA. The VCP-
was significantly lower at HA compared to SL; in addition, S1 and S2 mean values were significantly higher at HA compared to SL.
Conclusion
At HA, VCP may be reliably estimated by the 
method.
