The use of net heart rate to estimate energetic expenditure in hiking: the trails4health project. Academic Article Conference Paper uri icon


  • The net heart rate (HRnet) is known as the HR value above rest as a result of physical activity. Associations between HRnet and energetic expenditure (EE) were already reported for treadmill and stationary bike (Bragada, Bartolomeu & São Pedro, 2017, Motricidade, 13(1), 121–122). The purpose of this study was to extend this approach to hiking and provide an easy way for practitioners to calculate EE and compare it with the healthrelated guidelines. With institutional approval, 29 subjects underwent a 11 km hike in a previously homologated circular route, divided into 9 sections according to the terrain characteristics. The velocity was monitored continuously with a GPS device (Fenix 5, Garmin, USA) to ensure a consistent 5.5 km· h−1 pace. No stops longer than 1 min were allowed. Every subject used a HR monitor (Fenix 5, Garmin, USA). In a different day, all subjects underwent an intermittent and progressive test protocol of 5 × 5 min in a treadmill at progressive velocities (4.5, 6.5, 8.5, 10.5 and 12.5 km· h−1). Both HR and VO2 were measured (MetaMax 3B, Cortex, Germany) allowing the EE calculation. Linear regressions between HRnet vs VO2 and HRnet vs RER (Respiratory Exchange Ratio) were used to make the link between field and lab tests, and predictive equations where retrieved. The measured HRnet values during the hike ranged from 10 to 101 bpm and the correspondent VO2 and EE ranged from 8.2 to 41 ml· kg- −1· min−1 & 2.4 and 15.6 kcal· min−1, respectively. No significant differences were found between genders. For both linear regressions, the mean coefficients of determination were very high (R2 = 0.97 and R2 = 0.95, respectively). The overall value for EE during the 9 stages of the hike were: i) 1.9411; ii) 2.4218; iii) 0.8535; iv) 0.7567; v) 1.6744; vi) 2.5470; vii) 1.4638; viii) 1.7223; and ix) 0.3112 kcal· kg−1. The overall hike EE was 13.76 kcal· kg−1. This allows to previously predict the individual EE and compare it to the standard guidelines. The only individual variable needed to be known is the weight. This approach can be extended to other hiking routes, as long as they are circular. According to this finding, it is possible to estimate the EE by simply applying the formula EE = 0.0013*kg*m, expressed in kcal· kg−1· m−1.

publication date

  • November 2018