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.
