Physical activity monitoring devices, such as sports armbands and smart watches, have become a common tool among physically active people. They are used to monitor health and fitness parameters, but studies show that these popular gadgets do not always provide accurate information. Polish researchers have conducted a number of studies that shed new light on the real effectiveness of these devices in assessing the body’s fitness. 

Inaccuracy of measurements: Challenges of sports devices 

Today’s sports bands and watches use various algorithms to predict the body’s fitness, often relying on estimates that are not directly measured.  A NOODLE (predictioN mOdels fOr enDurance athLetEs) study conducted by researchers in Poland, revealed that these devices do not always accurately represent actual fitness parameters, especially for people with higher levels of training. The results indicate the possibility of both overestimating and underestimating exercise intensity, which can lead to erroneous workout planning and excessive strain on the body. 

As noted by Przemyslaw Kasiak, a doctoral student at Warsaw Medical University and co-author of the study, such devices can be wrong, especially in the case of endurance athletes. Physiological parameters are not measured directly, but only predicted based on benchmarks, which in many cases are mismatched with the actual capabilities of the body. 

Key performance parameters and their importance in sports 

The NOODLE project studied a number of physiological parameters that are crucial in both sports and medicine. Among the most important of these are the minute ventilation to carbon dioxide excretion ratio (VE/VCO2-slope), peak oxygen pulse (O2Ppeak), oxygen uptake efficiency slope (OUES) and oxygen uptake efficiency plateau (OUEP). They play an important role in the assessment of physical performance and can help in the precise planning of workouts. 

One of the interesting findings of the study is that the OUEP index is stable regardless of the level of training. This is a parameter that can be used as one of the more objective indicators of fitness. Unlike VO2max, which increases with the level of training, OUEP remains stable and decreases only during illness. 

How to improve prediction accuracy of sports devices? 

The findings also show the possibility to further improve the calibration methods of existing predictive models to better meet the individual needs of athletes. A good example is the calibration method of the FRIEND model, which allows more precise adjustment of predictions to different training groups. Such an improvement can enable better monitoring of the training of both professional and amateur athletes, which is crucial for optimal planning of physical activity. 

Importance of exercise testing in fitness assessment 

Despite the advantages of sports devices, researchers stress that they should not replace professional exercise tests, which offer more accurate data on the body’s performance. Przemysław Kasiak points out the need to conduct exercise tests at least once in a lifetime, and for those who train regularly – once a year or every two years. Only then can overtraining be avoided, reducing the risk of injury and health problems associated with overexertion. 

Sources: Nauka w Polsce, PAP, BMC Sports Science, Medicine and Rehabilitation, Journal of Clinical Medicine, Frontiers in Physiology, Scientific Reports