New kids on the CPET: age-appropriate outdoor cardiopulmonary exercise testing in preschoolers

PURPOSE: Cardiopulmonary exercise testing (CPET) in preschoolers (4–6 years) represents a challenge. Most studies investigating CPET have been limited to older children (> 8 year). However, knowledge of the performance of small children is essential for evaluating their cardiorespiratory fitness. This study strives to compare a modified Bruce protocol with a new age-appropriate incremental CPET during natural movement running outdoors, using a mobile device. METHODS: A group of 22 4–6-year-old healthy children was tested indoor on a treadmill (TM) using the modified Bruce protocol. The results were compared with a self-paced incremental running test, using a mobile CPET device in an outdoor park. The speeds were described as (1) slow walking, (2) slow running, (3) regular running, and (4) running with full speed as long as possible. RESULTS: Mean exercise time outdoors (6,57 min) was significantly shorter than on the treadmill (11,20 min), [Formula: see text] (51.1 ml/min/kg vs. 40.1 ml/min/kg), RER (1.1 vs. 0.98) and important CPET parameters such as [Formula: see text] (max), O(2)pulse, heart rate and breath rate were significantly higher outdoors. The submaximal parameter OUES was comparable between both the tests. CONCLUSIONS: Testing very young children with a mobile device is a new alternative to treadmill testing. With a significantly shorter test duration, significantly higher values for almost all cardiopulmonary variables can be achieved without losing the ability to determine VT1 and VT2. It avoids common treadmill problems and allows for individualized exercise testing. The aim is to standardize exercise times with individual protocols instead of standardizing protocols with individual exercise times, allowing for better comparability.